Patent Grant
7567843
Not applicable.
A beneficial response elicited by a heating of neoplastic tissue was reported by investigators in 1971. See the following publication in this regard:
Notwithstanding a straightforward need for more effective techniques in the confinement of thermotherapy to localized internally located target tissue regions, investigators have established that tumor cells may be physiologically inhibited by elevating their temperatures above normal body temperature, for example, 37° C. for one major population, to a range exceeding about 40° C. The compromising but beneficial results further are predicated upon that quantum of thermal exposure achieved, based upon the time interval of controlled heat application. Thus, effective thermotherapies are characterized by an applied quantum of thermal energy established within a restrictive tissue periphery or volume of application with an accurately controlled temperature over an effective component of time.
One modality of thermotherapy is termed “hyperthermia” therapy, an approach to thermal treatment at temperatures elevated within somewhat narrow confines above normal body temperature. For instance, the elevation above a normal body temperature of 37° C. typically will fall within a range of 42° C. to 45° C. While higher temperature links have been described, hyperthermia therapy conventionally looks to affecting tissue to the beneficial effect of, for instance, negating neoplastic development, while avoiding denaturization, i.e., cell death or necrosis. It follows that an embracing of this therapeutic modality calls for the application of thermal control over specific tissue volumes.
Confinement of thermotherapy to a neoplasm-suspect target tissue volume internally disposed within the body without a generation of damage to healthy surrounding tissue has been considered problematic and thus the subject of diverse investigation. A variety of approaches toward intra-body localized heat applications has evolved. Such efforts generally have been based upon the application of microwave energy (U.S. Pat. No. 4,138,998); the application of acoustic wave-based systems (ultrasound); and the application of electric fields at RF frequencies from transmitting antenna arrays including an application subset utilizing inductive systems driven at relatively lower frequencies below the RF realm. With the former approach, thermal localization has been evolved by developing constructive wave interference with annular phased-array antennas. (See U.S. Pat. No. 5,251,645).
Inductively-based approaches to thermotherapy systems have received important attention by investigators. The coil transmitted outputs of these systems generally are focused for field convergence toward the target tissue volume and the resultant, internally thermally affected tissue region has been monitored in situ by thermo-responsive sensors such as rod-mounted thermocouples and thermistors. Typically, those tethered heat sensors are inserted percutaneously into the target tissue region, being coupled by extra-body electrical leads extending to connections with temperature monitoring readouts. The invasiveness of the monitoring electrical leads extending into the patients' body for this procedure has been considered undesirable. This particularly holds where repetitive but time-spaced procedures are called for, or the therapeutic modality is employed in thermally treating tumor within the brain.
Efforts to regionalize or confine therapeutic tissue heating to predefined borders or volumetric peripheries have included procedures wherein small wire or iron-containing crystals (U.S. Pat. No. 4,323,056) are implanted strategically within the tissue region of interest. Implantation is achieved with an adapted syringe instrumentality. Electromagnetic fields then are introduced to the region to inductively heat the implanted radiative-responsive heater components and thus evoke a more regionally controlled form of thermotherapy. In one such approach, ferromagnetic thermoseeds have been employed which exhibit Curie temperature values somewhat falling within the desired temperature range for an elected thermotherapy. This achieves a form of self regulation by operation of the system about those Curie transitions. For instance, as radiative excitation drives the thermoseeds to temperatures to within the permeability based state change levels associated with attainment of a Curie temperature range, the thermoseeds become immune to further application of external excitation energy. (See generally U.S. Pat. No. 5,429,583). Unfortunately, the Curie transition temperature range of the thermoseeds is relatively broad with respect to the desired or target temperature. See generally:
Thermotherapeutic approaches designed to avoid the subcutaneous insertion of one or more temperature sensors have looked to the control of heating using modeling methodology. These approximating modeling methods are subject to substantial error due to differences or vagaries exhibited by the tissue of any given patient. Such differences may be due to variations in vascularity, as well as the gradual metamorphosis of a tumor mass. The latter aspect may involve somewhat pronounced variations in tissue physiologic characteristics such as density. See generally the following publication:
Some aspects of thermotherapy have been employed as an adjunct to the use of chemotherapeutic agents in the treatment of tumor. Because of the precarious blood supply or vascularity and of the high interstitial fluid presence, such agents may not be effectively delivered to achieve a 100% cell necrosis. Further the tumor vessel wall may pose a barrier to such agents, and resultant non-specific delivery may lead to significant systemic toxicities. Studies have addressed these aspects of chemotherapy, for instance, by the utilization of liposomes to encapsulate the chemotherapeutic agents to achieve preferential delivery to the tumor. However the efficiencies of such delivery approaches have been somewhat modest. Clinically, hyperthermia therapy has been employed as a form of adjunct therapy to improve the efficiency of more conventional modalities such as radiation therapy and chemotherapy. For the latter applications the thermal aspect has been used to augment bloodstream borne release agents or liposome introduction to the tumor site. Hyperthermia approaches have been shown to trigger agent release from certain liposomes, making it possible to release liposome contents at a heated site (U.S. Pat. Nos. 5,490,840; 5,810,888). For any such thermotherapeutic application, an accurate temperature control at the situs of the release is mandated. See the following publications:
Hyperthermia when used in conjunction with radiation treatment of malignant disease has been demonstrated as beneficial for destroying a specific tumor site. Clinical data has evolved demonstrating an improved efficacy associated with combined radiation and hyperthermia treatments as compared to radiation therapy alone. Such multimodal therapy concepts also have been extended to a combination of hyperthermia treatment with both radiation treatment and chemotherapy (radiochemotherapy). See generally:
Biological mechanisms at the levels of single cells activated by heat became the subject of scientific interest in the early 1960s as consequence of the apparently inadvertent temperature elevation of an incubator containing Drosophila melanogaster (fruit flies). These creatures, upon being heat shocked, showed the characteristic puffs indicative of transcriptional activity and discrete loci. See the following publication:
Beneficial thermal compromization of target tissue volumes is not entirely associated with HSP based treatments for neoplastic tissue and other applications, for instance, having been studied in connection with certain aspects of angioplasty. Catheter-based angioplasty was first intentionally employed in 1964 for providing a transluminal dilation of a stenosis of an adductor hiatus with vascular disease. Balloon angioplasty of peripheral arteries followed with cautious approaches to its implementation to the dilation of stenotic segments of coronary arteries. By 1977 the first successful percutaneous transluminal coronary angioplasty (PTCA) was carried out. While, at the time, representing a highly promising approach to the treatment of angina pectoris, subsequent experience uncovered post-procedural complications. While PTCA had been observed to be effective in 90% or more of the subject procedures, acute reclosure, was observed to occur in approximately 5% of the patients. Stenosis was observed to occur in some patients within a period of a few weeks of the dilational procedure and restenosis was observed to occur in 15% to 43% of cases within six months of angioplasty. See generally:
In general, the remedy for immediate luminal collapse has been a resort to urgent or emergency coronary bypass graft surgery. Thus, the original procedural benefits attributed to PTCA were offset by the need to provide contemporaneous standby operating room facilities and surgical personnel. A variety of modalities have been introduced to avoid post PTCA collapse, including heated balloon-based therapy, (Kaplan, et al., supra) the most predominate being the placement of a stent extending intra-luminally across the dilational situs. Such stents currently are used in approximately 80% to 90% of all interventional cardiology procedures. While effective to maintain or stabilize intra-luminal dilation against the need for emergency bypass procedures, the stents are subject to the subsequent development of in-stent stenosis or restenosis (ISR). See generally:
See additionally the following publications with respect to atherectomy for therapeutically confronting restenosis:
In each such approach, additional percutaneous intervention is called for See generally the following publication:
Davis Company (Mayo Foundation) (1987).
Other approaches have been proposed including the application of electrical lead introduced electrical or RF applied energy to metallic stents, (U.S. Pat. No. 5,078,736); the incorporation of radioisotopes with the stents (U.S. Pat. Nos. 6,187,037; 6,192,095); and resort to drug releasing stents (U.S. Pat. No.6,206,916 B1). While non-invasive control of ISR has been the subject of continued study, the development of a necessarily precise non-invasively derived control over it has remained an elusive goal.
Another application of hyperthermia is in orthopedics, as a means to stimulate bone growth and fracture healing. There are several FDA approved devices for stimulation of bone growth or healing, each with limitations and side effects. Therapies include invasive electrical stimulation, electromagnetic fields, and ultrasound stimulation. Decades old research has claimed a stimulation of bone growth by a mild increase in temperature of the boney tissue. Previous researchers have used such methods as inductive heating of implanted metal plates, or heating coils wrapped around the bone. The utility of these methods is limited by the invasive nature of the surgery needed to implant the heating elements and the inability to closely control tissue temperature. Moreover, therapeutic benefits have been inconsistent between different studies and experimental protocols. For a summary of past work, see generally:
A number of protocols have demonstrated a beneficial effect of hyperthermia on bone healing. Several studies indicate temperature affects bone growth and remodeling after injury. Hyperthermia may both improve blood supply and stimulate bone metabolism and have a direct effect on bone-forming cells by inducing heat shock proteins or other cellular proteins. In one experiment, rabbit femurs were injured by drilling and insertion of a catheter. Hyperthermia treatments were given at four-day intervals for 2-3 weeks using focused microwave radiation. Bones which had suffered an insult as a result of the experimental procedure showed a greater density of osteocytes and increased bone mass when treated with hyperthermia. Injured bones treated with hyperthermia showed completely ossified calluses after two weeks, while these processes normally take four weeks in untreated injuries. One problem with microwave heating of bone mass is the difficulty in predicting heat distribution patterns and maintaining the target tissue within the appropriate heat range.
When tissue is heated at too high of temperature, there can be irreversible cytotoxic effects which could damage bone and other tissues, including osteogenic cells, rather than induce healing. Certain studies have shown that induction of mild heat shock promotes bone growth, while more severe heat shock inhibits bone growth. Therefore, control and monitoring of the temperature of the targeted bone tissue is imperative to achieve therapeutic benefit and avoid tissue damage.
See additionally the following publications with respect to hyperthermia for therapeutically promoting osteogenesis:
Existing protocols for therapeutically promoting osteogenesis are limited by the invasive nature and concomitant potential for infection for instance with tethered electrical stimulators; poor temperature control, and potential for tissue injury or reduced therapeutic benefit, for instance with microwave heating or other induced electromagnetic fields; difficulty in effectively applying therapy to the injured bone because of targeting difficulties or low patient compliance with prescribed repetitive therapy.
The host immune system can be activated against infectious disease by heat shock protein chaperoned peptides in a manner similar to the effect seen against metastatic tumors. Heat shock proteins chaperoning peptides derived from both viral and bacterial pathogens have been shown to be effective at creating immunity against the infectious agent. For infectious agents for which efficacious vaccines are not currently available (especially for intracellular pathogens e.g. viruses, Mycobacerium tuberculosis or Plasmodium) HSP chaperoned peptides may be useful for the development of novel vaccines. It is expected that purified HSP chaperoned peptides (e.g. gp96 complexes) used as vaccines for diseases caused by highly polymorphic infectious agents would be less effective against genetically distinct pathogen populations. For a summary of past work on HSP vaccines against infectious agents, see generally:
The present invention is addressed to method, system and apparatus for accurately carrying out an in situ elevation of the temperature of a target tissue volume. Accuracy is achieved using an untethered temperature sensor implant positionable within or adjacent to the target tissue volume using minimally invasive procedures or using intraoperatively implanted sensors adjunctly to surgery. Such implants may be in the form of (1) a single macroscopic device (e.g., wire shaped implant), (2) multiple macroscopic devices (e.g., wire shaped implants) and/or (3) multiple microscopic devices (e.g., devices in particulate form that can be injected into a volume of the tissue or attach preferentially systemic injection using chemical binding targeting modalities such as possible with monoclonal antibody vehicles). Positioning of macroscopic implants may be carried out utilizing an implant instrument somewhat resembling a hypodermic needle. The implant essentially sharply transitions between externally discernable states as a setpoint or target temperature is reached at the target tissue volume, and is implemented having a soft ferrite component formulated with oxides of Fe, Mn and Zn. Such formulations are elected to derive a Curie point temperature corresponding with the setpoint or target temperature. Thus configured, the implants exhibit a discernable permeability attribute until the Curie point temperature is reached, whereupon the attribute essentially disappears. Interrogation of the implant is carried out by moving it with respect to the lines of flux of a relatively low intensity magnetic field such as the earth's magnetic field. With such field intensities, the soft ferrite components of the implants exhibit sharp Curie transitions which, in turn, permit accurate setpoint temperature measurements using magnetometer-based technologies. Curie transitions may be experienced within a range of from about 0.1° C. to several ° C.
The method has broad application to thermotherapy endeavors including an in vivo stimulation of heat shock proteins, a procedure having important utility in the treatment of cancer, infectious diseases and other therapies. As another modality, the implant is combined with an intra-luminal stent and when so combined and implanted, permits a non-invasive repeatable and accurate hyperthermia therapy for restenosis.
In situ heating is carried out using conventional alternating current field-based devices such as RF heating, inductive heating, microwave-based procedures and ultrasound, all of which are of a non-invasive nature.
The volumetrically defined heating of a target tissue may be facilitated through the utilization of implanted non-magnetic heater components. These heater components may be combined with the sensor components in intimate thermal exchange relationship. In this regard, a variety of such structures are described. In one approach, both the heater component and the temperature sensing component are each of generally semi-cylindrical form having the semi-cylindrically defined flat surfaces of such geometric structures coupled together in the noted heat exchange relationship. The entire structure may be coated with an electrically insulative biocompatible conformal coating. Additionally, the implant may carry a thermally activatable release agent layer which functions to release a therapy supporting agent at the situs of the target tissue when the heater component reaches an induced temperature at a setpoint temperature detected by the temperature sensing component. In another combined implant approach, the heater component is formed as a discontinuity containing covering of the sensor which, for instance, may assume a cylindrical geometric shape. The discontinuities permit interaction of the sensor component with the monitoring magnetic field. In another approach, the cylindrical sensor component may be surmounted by a heater component which is configured as a generally open, spiral sleeve positioned against the surface of the temperature sensor in thermal exchange relationship. This defines a helical-shaped open, outwardly exposed surface portion of the sensor component, again functioning in conjunction with a magnetic field to provide a discernable magnetic permeability state change at a desired setpoint temperature. Another geometry for the combinational implant provides a generally cylindrical temperature sensor component with combined heater components configured as metal caps which fit over the sensors adjacent the ends of their cylindrical structures. Several such sensors may be combined with such end caps and intermediately disposed heater component sleeves to, in effect, develop an implant formed of a chain of sensors which, for example, may be configured to exhibit a permeability state change at different setpoint temperatures.
The implants may perform in conjunction with a variety of system scenarios. In one approach a single channel magnetometer is employed in conjunction with a single channel pick-up. This pick-up is located externally of the patient's body at a location in somewhat close adjacency with the position of the implant. Additionally, the broadcasting component of an alternating current field heating assembly is positioned in adjacency with that targeted area. To carry out detection of the permeability state of the sensor component of the implant, the patient will be supported on an oscillative platform or chair in order to achieve single channel detection of a magnetic permeability Curie temperature state change. Either the earth's magnetic field or an applied magnetic field may be employed with this system. In another system approach a multi-channel magnetometer assembly is employed incorporating an arrayed pick-up. With this arrangement the patient support may remain stationary and the magnetometer-based detection assembly determines a differentiation of magnetic field disturbance and non-disturbance in association with the minor but inherent movement of a living animal body. In the presence of a non-disturbance condition, the target temperature or setpoint temperature at the targeted tissue will have been achieved.
A feature of the system and method of the invention is concerned with a typical patient management regimen wherein a relatively substantial repetition of hyperthermia therapeutic procedures are called for. The implants remain in position with respect to the target tissue volume and may, in this regard, be fashioned with implant barbs or the like for the purpose of migration avoidance. Where a succession of treatments is involved, not only is there no requirement to re-install sensors, but also, the aligning of the sensing system magnetometer remains quite simple, involving the observation of signal response amplitudes on the part of the attending technician. Another aspect of this feature resides in the utilization of the pre-implanted sensors or sensor-heaters as a conventional tumor situs marker for subsequent patient evaluation imaging procedures.
While any of the above approaches may be used in connection with stents and the treatment for restenosis, where the stent along with temperature sensor is implanted in a coronary artery, then the natural beating of the heart of the patient will provide sufficient movement of the sensor itself to permit single channel detection by a magnetometer.
Control over the alternating current field (ACF) heating system preferably is achieved by controlling the actuation of the heating assembly and the magnetometer in an intermittent manner. With this approach, the heater assembly is activated for a predetermined interval of time following which the magnetometer is activated for a much shorter interval. This sequencing continues until setpoint temperature is detected, whereupon the magnetometer remains enabled while the heater remains deactuated until the temperature sensing component reverts to a higher relative permeability to again disturb the monitored magnetic field.
The implant controlled heating approach of the invention also may be applied to the field of orthopedics. In this regard, the sensor component may be combined in intimate thermal exchange relationship with non-magnetic metal bone support devices implanted within boney tissue. The setpoint temperature elected for such modality is selected to enhance the repair of the mending boney tissue.
Implant based controlled in vivo heating according to the precepts of the invention also may be employed as a vehicle for inducing immunity against or for the treatment of diseases caused by infectious agents.
Other objects of the invention will, in part, be obvious and will, in part appear hereinafter;
The invention, accordingly, comprises the method, system and apparatus possessing the construction, combination of elements, arrangement of parts and steps which are exemplified in the following detailed description.
For a fuller understanding of the nature and objects of the invention, reference should be made to the following detailed description taken in connection with the accompanying drawings.
While a variety of techniques for evolving an effective interstitial thermotherapy of target tissue volumes have been approached by investigators, an earlier development deemed somewhat promising involved the implantation of ferromagnetic alloy heaters sometimes referred to as “ferromagnetic seeds” within that volume. The ferromagnetic alloy heaters were adapted so as to alter in exhibited magnetic permeability in consequence of temperature. For example, with this arrangement, when a Curie temperature transition range was thermally reached, permeability would, in turn, diminish over the transition range and correspondingly thermal responsiveness to an applied inductive field would diminish. Thus it was opined that a temperature auto-regulation could be achieved to optimize a thermally based implantation therapy. Such an arrangement is depicted in
Traditionally, the change in magnetic permeability of ferromagnetic alloys with increasing temperature has not been abrupt as would be preferred for precise temperature regulation of an implanted heating component as at 16. In this regard, characteristic curve 22 reveals that under the relatively intense, applied fields a permeability transition occurs gradually over a span typically of 10° C. to 15° C. or more. As a result, the implanted heater device 16 may not reach the intended Curie temperature and resultant relative permeability of unity. Often, that elevation in temperature above normal body temperature has not been achieved. Accordingly, accommodation has been made by electing Curie temperature transition ranges falling well above what would have otherwise been a target temperature for thermotherapy with a result that critical temperature limits of the tissue being treated have been exceeded. Thermotherapeutic procedures also are prone to inaccuracies by virtue of the unknown environmental conditions within which an implant as at 16 is situated. With respect to such unknown phenomena, temperatures achieved with ferromagnetic implants will vary depending upon cooling phenomena within the tissue surrounding the device. Such phenomena occur, for example, as a consequence of the degree of vascularity in the target region and proximity of the heating element as at 16 to blood vessels. These vessels will tend to perform as inherent cooling mechanisms. Accordingly, while attempting to achieve an effective heat therapy, the auto-regulating implants as at 16 generally have been unable to establish a necessary precise temperature output for requisite therapeutic time intervals.
Now turning to the subject of the physiological consequence of elevating tissue temperature, studies have been carried out to investigate both the component of temperature elevation as well as the time component within which such asserted higher temperatures are maintained, i.e., the temporal aspect thereof. Such investigations have established critical temperature and time relationships which identify the occurrence of irreversible tissue damage effects. In this regard, looking to
A more severe heat shock may irreversibly damage cellular components. Under certain conditions, when a cell is damaged, an ordered process, apoptosis, is induced that leads to the death of the damaged cell. Apoptosis is considered a form of “programmed cell death,” and cells undergoing apoptosis often exhibit distinctive morphologic changes. Apoptosis is also involved in many developmental processes, defensive responses to microbial infection, the homeostasis of cell populations (e.g. lymphocytes) and as means of eliminating genetically damaged cells, such as cancer cells.
It is generally accepted that apoptosis is an active, highly organized, form of cell death, requiring both RNA and protein synthesis. A classic example is the systematic death of a finite number of cells, 131, at a certain stage in the life cycle of the nematode Caenorhabditis elegans, a process controlled by the negative and positive regulation of specific genes. As demonstrated by development in C. elegans, certain genes are involved in the regulation of cell death by apoptosis. A specific example is the human gene bcl-2. In certain human follicular B-cell lymphomas, deregulation of the expression of bcl-2 has been identified as a cause of the prolonged survival of the lymphoma cells. Altered expression of bcl-2 interferes with the typical programmed cell death pattern, blocking apoptosis even when hematopoeitic growth factors are absent.
Apoptotic cells exhibit a pronounced decrease in cellular volume, modification of the cytoskeleton that results in convolution of the cell, and eventual blebbing of the cell's membrane, compaction of chromatin and its segregation within the nucleus that the cell. The DNA is degraded into small fragments, and the apoptotic cell sheds small membrane-bound apoptotic bodies which may contain intact organelles. The apoptotic bodies are phagocytosed (e.g. by macrophages) and the contents of apoptotic bodies are intracellularly degraded, with little release of the contents of the apoptotic cells. In this manner, apoptosis does not induce a localized inflammatory response.
Apoptosis is differentiated from necrosis by the general absence of inflammation. It is a physiological type of cell death, part of a homeostatic mechanism to maintain an optimal number and arrangement of cells. In certain physiological conditions, massive apoptosis is not followed by necrosis and inflammation, such as the removal of interdigital webs during early human development, the regression of liver hyperplasia following withdrawal of a primary mitogen [Columbano citing Bursch, Carcinogenesis 5: 453-458.], and cellular loss in the premenstrual endometrium.
If thermotherapy is sufficiently severe, cells and tissues may be so damaged that cellular integrity is destroyed, or the cellular machinery is so disabled that the induction of apoptosis does not occur. In contrast to apoptosis, necrosis is a type of cell death morphologically characterized by extensive cell loss, which results in the recruitment of inflammatory cells. In necrosis, injured cells may exhibit clumping of chromatin, swelling of the cell and organelles (demonstrating a loss of control of ion balance), flocculent mitochondria, and eventual bursting and disintegration of the necrotic cell. If necrosis is extensive enough, the architecture of a tissue is destroyed. Extensive necrosis is characteristic of tissue destruction induced following severe damage by toxic chemicals, invasive microorganisms or ischemia. The wholesale release of cellular components into a tissue itself can trigger a damaging inflammatory response.
When a tissue is damaged, cells may die by a combination of apoptosis and necrosis. Many agents capable of inducing necrosis also induce apoptosis. Apoptosis often precedes extensive necrosis, with apoptosis in these situations possibly acting in a self-protective manner. When the level of insult to a tissue is too great, necrotic cell death cannot be avoided. Murine mastocytoma cells have been reported to undergo apoptosis after a moderately severe heat shock, but the same cells die via necrosis when the heat shock exposure is more severe.
For a comparison of apoptosis and necrosis, see:
The cellular response to a heat-shock has been extensively studied. Certain heat shock inducible proteins such as Heat Shock Protein 70 (HSP70), HSP 90 and gp96 are expressed constitutively at low levels. During mild to moderate heat-shock, cellular proteins may undergo conformational changes. It is this alteration in the structure of proteins, or other reversible denaturation effects, which are believed to play a role in inducing the heat shock response. (Note that other stressors, such as nutrient deprivation, release of oxygen radicals, or viral infection may also induce conformational aberrations.) Following a heat shock, mRNA expression of the genes encoding HSP70, HSP 90 and gp96, for example (along with that of other heat-shock responsive genes) is induced by activating proteins called “Heat Shock Factors.” The response of two “Heat Shock Factors”, HSF-I and HSF-II is triggered by different levels of thermal stress. As an example, HSP70 is thought to be induced more rapidly than (by either less heat stress, or a shorter duration) HSP90. Therefore, different thermotherapy regimes will induce different panels of heat inducible genes.
For additional background on the heat shock response see:
Initiation of a heat-shock will induce conformational changes in cellular proteins, and lead to the induction of heat shock genes. HSP70 has the ability to bind to proteins, is thought to act as a molecular chaperone, and may use an ATP dependant activity to renature stress-damaged proteins. It is thought that HSP 70 is involved in a process that ‘repairs’ partially denatured proteins. If the native conformation of a protein is not restored, then the denatured protein is degraded. During the degradation process, HSP70 can retain a peptide fragment derived from the degraded protein. In essence HSP 70 may then chaperone an antigenic peptide fragment of the denatured protein. These HSP70 chaperoned fragments are then processed though the cell's endoplasmic reticulum and Golgi apparatus, and can then appear on the cell surface, presented by MHC-I molecules. Antigens presented on the surface of a cell can then lead to an immune response being generated to those antigens.
In order to have processing of peptide fragments, and presentment of potentially immunogenic fragments on the cell surface, it is necessary to have a living cell. An apoptotic cell, since the cellular contents are degraded (for instance, without presenting antigens on the phagocytitic cell's surface MHC-I molecules), may have lower immunogenicity than either a heat shocked, but recovering cell or a necrotic cell.
Accordingly, with accurate temperature and time controls therapy employing heat shock protein induction becomes available. Other adjunct therapies available with accurately controlled thermotherapy are, for example, release agent systems associated with a heating instigated release, radiation treatment, chemotherapy and radiochemotherapy.
Some approaches utilized by investigators, in the use of hyperthermia therapy, have achieved accurate temperature measurement and consequent control by inserting temperature sensors such as fiber optic temperature sensors, thermocouples or thermistors into the tissue adjacent to or integrally with implanted heaters. These fiberoptic, thermocouple or thermistor-based sensors necessarily are tethered having one or more electrical or optical leads extending externally or to a surface region of the body each time a hyperthermia therapy is administered. In the latter regard, the somewhat involved procedure often must also be repeated a number of times over many weeks or months to effect the desired therapeutic results. This becomes particularly problematic where the approach is employed in thermal therapy procedures associated with the human brain. See generally:
Referring to
Should those sensors as at 34a-34d not be utilized, the temperatures reached at the target tissue volume 26 during application of ACF radiofrequency or microwave heating can only be approximated by modeling methods which are subject to substantial error due to physical differences in the tissue of given patients. In this regard, tissues will exhibit differences in vascularity, as well as otherwise assumed average properties. As noted hereinbefore, vascularity functions as a conveyance for heat removal in the vicinity of the targeted tissue region. For further discussion of thermal modeling based methods of thermotherapy, reference is made to publication (7) supra.
The present invention generally is characterized by the partitioning of the function of heating the target tissue volume to requisite temperatures from the function of measurement of tissue temperature. For the latter function, the remotely interrogatable material property of magnetic permeability can achieve accurate temperature measurement over very narrow temperature ranges, for example, between about 0.1° C. to about 1° C. Untethered implanted soft ferromagnetic sensors are employed, which are of diminutive size and can be structured to provide such a very sharp Curie transition. For example, a transition of relative magnetic permeability, μr, from about 100 to 1000 to 1 obtains. Returning to
See generally the following publications;
The heater materials employed with these sensors are selected from materials which are non-magnetic so as to permit their performance with sensors having magnetic properties. With the combination of a heating component with a sensor structure formed with a narrow Curie transition-based material, precise setpoint temperatures can be detected non-invasively using magnetometer technology in conjunction with low intensity magnetic fields such as the earth's magnetic field as it is influenced or perturbed by confrontation with the sensing component. Such magnetometer monitoring can be carried out in one approach by evoking relative movement of the target tissue volume with respect to the position of influence of the magnetometer and in another approach through the use of detector arrays. Alternately the system may perform with a derived magnetic field, for example, one which is electromagnetically generated.
Referring to
The target tissue volume of interest for the instant embodiment is represented internally within the body of patient 50 by a symbolically represented dashed boundary 90. Within this boundary 90 there is shown at least one sensor implant configured according to the invention as represented schematically at 92. However, that sensor implant or combination of such implants may be intimately combined with an internally disposed nonmagnetic heating component. Where those two components are combined in a single implant arrangement, at least a portion of the surface of both the nonmagnetic heating component and sensor component are exposed. Note that the implant 92 is untethered, having no electrical leads extending exteriorly of the patient 50.
Heating of the region of interest 90 under thermotherapy conditions and, in particular, hyperthermia conditions for the instant system, is provided from an inductive form of alternating current field (ACF) heating assembly represented at block 94. Line power input is represented as being directed to the assembly 94 as indicated at arrow 96. Substantially focused radiative heating is provided from the heating assembly 94 by a typical coil-implemented heating component represented at 98 which is positioned in close proximity to the skin of patient 50 in the vicinity of a predetermined and earlier marked location of the target tissue volume 90. Association of the component 98 with the heating assembly 94 is represented schematically by line pair 100. Preferably, the component 98 may be associated with an induction heating assemblage operating at a lower frequency within the generally identified radiofrequency range. In the latter regard, such an induction heating arrangement may be provided, for example, as a type NK-24 induction heating system marketed by Pillar Industries, Inc., of Brookfield, Wis. Other radiative heating systems will include those employing higher frequency RF, microwave or ultrasound technologies. (See f1 in Table 1). As used herein, the terms “alternating current field” or “ACF” are meant to include radiofrequency (RF) systems, inductive systems, microwave systems, ultrasound systems and other non-invasive heating approaches which may perform in concert with untethered temperature sensors.
Now looking to the magnetometer-based detection of the magnetic field disturbances evoked by the state of permeability of the sensor component at implant 92, a magnetometer control assembly is represented at block 104. The assembly 104 performs in conjunction with a remotely disposed pick-up or probe 106 oriented for discerning and/or differentiating magnetic field flux lines as they may be affected by the implant or implants as at 92. The association of probe or pick-up 106 with the assembly 104 is represented at cable 108. Assembly 104 is seen receiving line power, as represented by arrow 110, and is controlled and provides outputs to a console mounted control assembly represented generally at 112 as indicated at arrow 114. It may be noted that the control assembly 112 also is in communication with the motor control 78 as represented at arrow 84 and with the ACF heating assembly 94 as represented at arrow 102. While the magnetometer assembly 104 with its probe 106 may perform with a generated and applied magnetic field, for the instant embodiment, the field utilized is the earth's magnetic field. Because of the on/off or binary nature of the temperature sensing function of implant 92, relative amplitudes or variations and declinations in contemplated areas of use of the instant system will have no particular effect with respect to the use of this earth involved magnetic field.
For the instant application, magnetometer assemblies as at 104 and associated probes or pick-ups 106 are configured in the manner of fluxgate sensors. The basic fluxgate sensor principal is schematically illustrated in connection with
Concerning the earth's magnetic field with which the instant embodiment performs, it may be recalled that earth has a crust, a metal and a metallic core. The inner part of that core is solid and complex processes are associated with the increase of the inner core together with the earth's rotational drive, the earth's so-called magnetic dynamo which is believed to cause the earth's magnetic field. That field has a dipole character with a north magnetic pole displaced from the geographical north pole by about 1000 km. That pole, paradoxically, is a south pole of an equivalent bar magnet, inasmuch as it attracts the north pole of a magnet needle. The earth's field is changing in time, for example, the amplitude is decreasing by 0.1% each year and the pole is drifting westward by 0.1° per year. The tilt of the dipole axis is decreasing by 0.2° per year.
A magnetometer which may be employed to carry out the functions of magnetometer assembly 104 and associated probe or pick-up 106 may be provided, for example, as a multipurpose precision magnetometer identified as a type (MPN) 4.0 marketed by Walker LDJ Scientific, Inc. of Troy, Mich. For a further discourse concerning magnetic sensors and magnetometers, reference is made to the following publication:
To carry out temperature sensing using the soft ferrite sensors having permeability/temperature characteristics as represented at curve 42 (
A graphic illustration of the performance of the ACF heating function 94 and magnetometer function 104 is provided in connection with
Now considering the intermittent activation or duty cycle-defined application of power and enablement of sensing features, it may be observed that power is represented as initially being applied as shown at power curve 148 between times to and t1, representing a power application increment of time δt1. Following this power application interval, ACF heating function 94 is turned off for a sensing or interrogation interval extending between times t1, t2, representing an increment of measurement time, δt2. Note that during the intervals, δt1 and δt2, the temperature value of the implanted sensor as indexed along ordinate 132 and shown at dashed curve 144 commences to rise and is seen to exhibit a modicum of thermal inertia during interrogation interval δt2. This power-on-power-off-interrogation sequence continues, for example, a power-on condition being applied between times t2 and t3 with an interrogation interval occurring between times t3 and t4. As these power-on and sensing or interrogation intermitting cycles continue, curve 144 is seen to rise, eventually approaching the setpoint temperature TSP. For illustrative convenience, note that the figure is broken following time, t5. Setpoint temperature at line 142 is shown being acquired during the heating interval tn to tn+1. At the termination of that power application time interval, tn+1, Curie temperature is achieved with a slight thermal overshoot as represented at point 150 of curve 144. Note, as this occurs, that a permeability curve 138 knee 152 change of state is experienced and the relative permeability of the implanted sensor component drops dramatically, essentially to a unity value as represented at curve 138 inflexion point 154 occurring at time tn+2. Under the ensuing time element, until the temperature of the sensing component drops, for example, as represented at temperature drop identification, ΔTS at point 156 of curve 144, relative permeability will remain at the unity level 158 of curve 138. This unity level 158 will continue until a sufficient temperature drop excursion at the implanted sensor component is experienced, whereupon, as represented by knee 160 in curve 138, relative permeability then abruptly rises, as represented at curve portion 162, to reassume a high relative permeability, μN at time tn+3 and as illustrated at the knee of 164 of curve 138. With a magnetic disturbance now being detectable by the magnetometer function 104 and probe or pick-up 106, at the next timed heating increment at time tn+4 power again is applied for a fixed interval of heat application and the result is illustrated by curve 144 at region 166 showing a positive temperature slope extending to a slight thermal over-shoot at time tn+5 a time condition wherein the sharp knee 168 of a Curie transition is witnessed at curve 138 to evoke a sharp drop in relative permeability as represented by curve portion 170. This fluctuating activity evokes the noted binary form of sensory response wherein magnetic field disturbance essentially is stopped and the disturbance termination is detected through pick-up 106 by magnetometer 104. As represented by sensor/tissue temperature curve 144 at region 172, the sensor/heater/tissue temperature then dwells in lower adjacency with the temperature setpoint TSP until the pre-model-based election of heat application interval is completed to define a thermal energy quantum of treatment to the given target tissue volume. It may be recalled that the Curie transition evoking this binary control of heat application is quite accurate, being within about 0.1° C. and 1° C. for a typical application.
If the power setting for the ACF heating assembly 94 is set only to a level which eventually will reach the setpoint, TSP, sometimes referred to as a saturation level, then as the temperature curve 144 approaches the setpoint level, power will be on, for example, about 90% of the time. However, for typical applications, the power will be more than twice that saturation level in view of differences in the effect of the quantum of thermal energy applied. In the latter regard, vascularity in the region of the target tissue and the nature of that tissue itself will influence the effectiveness of the thermal energy introduction. Of course, this power level can be backed off as the tissue or sensor detected temperature reaches or approaches the setpoint value to avoid an overshoot or excessive overshoot.
Recalling the commentary provided in connection with the critical temperature curve 24 of
Returning to
The control represented at console 112 is powered-on with a key switch 180, such a power-on condition being represented by the illumination of a green LED 182. While typically established by the manufacturer of the control 112, the duty cycles for the application of power or heat and the quiescent interval immediately following such heat application are shown as being electable by the user. Insertion of this operational criteria is provided at the switch combination shown generally at 184. The switches 184 include a heat interval input 186 and a corresponding sensor interrogation interval adjustment function 188. See the time interval ranges for δt1 and δt2 set forth in Table 1. With the duty cycles established, next, the timing aspects of the procedure are addressed in conjunction with a “Therapy Times” user input. Two times are set by the user, a therapy duration (TD) commencing with the attainment of setpoint temperature TSP, and a maximum time to reach setpoint temperature (TTTSP). Insertion of these times into the control 112 is carried out using up/down switches represented generally at 190 in conjunction with switch display 192 providing a visually perceptible visual time selection, for example, in minutes. Election between the setting of therapy duration (TD) and maximum time to setpoint temperature (TTTSP) is made by throwing toggle switch 191 between its two election orientations.
The platform 52 or corresponding chair assemblage for supporting the patient 50 is adjusted for its motion parameters, particularly that of travel distance. It may be recalled that, in general, this travel may extend to as much as about 10 cm. The frequency of that travel preferably is pre-established by the manufacturer of the system. However, if desired, adjustment can be provided in conjunction with the control console 112. However, the extent of movement of platform 52 along a linear locus is established by up/down switches represented generally at 194 which are actuated in conjunction with observation of a digital display readout provided in centimeters as illustrated at 196. Oscillatory drive is initiated for the platform 52 by actuating the motor control circuit 78 via momentary on switch 198. Actuation of switch 198 will, in turn, cause the illumination of a green LED 200. The operator can stop this oscillation of platform 52 by actuation of momentary off switch 202.
In the course of setting up a therapy, certain associated interconnections will be made by the operator. The control system represented by the console 112 will respond to errors in that set-up procedure and provide visual cues as to the error involved and additionally will provide a prompt as to corrective action to be taken. That information is provided at a visual display 204. Display 204 also will provide a display of pertinent data concerning a completed therapy by operator actuation of momentary on-switch 206. That data also will be recorded automatically in data log memory.
During the course of setup and subsequent therapeutic operation of the system, an array of visual indicators as to the progress of the procedure as represented generally at 208 will provide confirmational outputs. In this regard, a table/chair ready indication is provided by illumination of green LED 210. The motor control 78 is configured with a motor status comparator which provides an on or enabled condition where the voltage of the motor control system exceeds or equals, for example, 3 volts. Next, the illumination of a green LED 211 indicates that an ACF heating assembly 94 switch located at that unit has been thrown to apply power. Additionally, it's illumination indicates that the magnetometer control 104 monitoring features have indicated that peak-to-peak variations of its control voltages are greater than a reference value.
LED 212, when illuminated, provides for an indication that magnetometer 104 is in a ready condition. In this regard, its power-on switch will have been actuated to an on condition and its peak-to-peak drive voltage will have equaled or exceeded a reference voltage value. Next, green LED 213 is illuminated to provide an indication that therapy is in progress, and green LED 214, when illuminated, indicates that the therapy duration has now been reached and therapy is completed. Finally, green LED 215 is illuminated to indicate that the target temperature or setpoint temperature, TSP (
Therapy is commenced with the user actuation of the momentary on start therapy switch 220. During the interval of the therapy, the elapsed time of therapy is indicated at display 222. That display may be reset to zero by actuation of momentary on switch 224. If, during the progress of therapeutic performance by the system, the operator deems it advisable to stop the therapy, then the stop therapy switch 226 is momentarily actuated and the therapy stopped red LED 228 is illuminated.
Concerning the general operation of the control function 112, it may be noted that unless the checking logic of the control system will have functioned to carry out the illumination of the “ready” LEDs 210-212, then the start therapy switch 220 will not be enabled. In general, error and prompt messages will remain at the display 204 where these startup conditions are not satisfied.
Referring to
Magnetometer assembly 104 control is enabled from a comparator/discriminator circuit represented at block 250, the interactive relationship being represented in general by the arrow pair 252. Upon powering up of magnetometer assembly 104, the comparator carries out a determination as to whether its peak-to-peak drive voltage excursions VMO are equal to or exceed a reference voltage VFM. That reference voltage is provided by a reference network represented at block 254 and arrow 256. Where that test is met, then an enable signal is provided to controller 240 as represented by arrow 258. The controller 240 additionally transmits start and stop commands to the circuit 250 as represented at arrow 260. The locus of travel distance supplied by the operator from up/down switch 194 is submitted to controller 240 as represented at arrow 243 while the corresponding display of the elected travel extent represented at corresponding block 196 is applied from controller 240 as represented at arrow 245. That information is supplied to the motor control function at block 78 as represented at dual arrow 238.
Where multiple implants, for example, combining a heater component and a sensor component are positioned within the target tissue volume, they may be identified, inter alia, by orientation as well as position. In the former regard, where the implants have a predominate lengthwise dimension, i.e., wherein their aspect ratio is less than unity, then their orientational aspect with respect to an impinging magnetic field will result in an alteration of the resultant perturbance-related amplitude detected by the magnetometer assembly 104. By submitting such amplitude data to a discriminator or window function, the location of these implant sensors can be confirmed. Under circumstances where it is desirable to utilize sensor implants exhibiting different temperature setpoints, the acquisition of these differing setpoint temperatures may be detected in correspondence with magnetometer output signal amplitudes, i.e., as signals representing lower temperatures and their associated amplitudes disappear, signals exhibiting a different amplitude representing a higher setpoint temperature will persist. Accordingly, threshold data can be supplied to the controller 240 from the comparator/discriminator function 250 as represented by arrow 262. Where the peak output, VMO satisfies the requirement of reference voltage 254, then the comparator 250 also provides an enable signal voltage VC, as represented at arrow 264, to the comparator network 266 operationally associated with the ACF heating assembly 94.
Returning to controller 240, an enablement of the magnetometer control provides for the energization of the magnetometer ready LED 212 as represented at arrow 268. Binary signals representing the acquisition of Curie temperature are provided from the network 250 and magnetometer control 104 to the controller function 240 as represented at arrow 270. This, in turn, provides for the controller 240 energization of the target temperature reached LED 215 as represented at arrow 272 and corresponding block 215 as well as the commencement of time-out of therapy duration. Operator inputted or manufacturer established duty cycle data and, particularly, the interrogation interval input switch function 188 of switch grouping 184 is asserted to the controller as represented at arrow 274 extending from corresponding block 188.
ACF heating assembly 94 performs only upon the satisfaction of a triad of preliminary conditions. Initially, the enablement of the magnetometer control signal, VC as presented at line 264 must be present and verified as being greater than a reference voltage value, Z as derived from a reference network represented at block 280 and arrow 282. This comparison is provided at a comparator network represented at block 266. Next, the comparator network 266 determines a closure of ACF activation switch by determining that the corresponding signal, VRF is above a reference value, Y. Finally, the comparator determines the presence of a start therapy switch 220 activation by observing a resultant voltage output generation VT as being greater than reference voltage value, X. Upon the occurrence of these three enablement conditions, an enablement input is provided to controller 240 as represented at arrow 286. Inputs from the ACF heating apparatus 94 are provided to the comparator function 284 as represented at arrow 288 and a comparator verified on and off input to the ACF heating assembly 94 is provided from the controller 240 as represented at arrow 290.
Controller 240 responds with respect to the actuation of power on/off switch 180 as represented at arrow 292; responds to the start therapy switch 220 as represented at arrow 294; and responds to the stop therapy switch 226 actuation as represented at arrow 296. Heating interval, δt1 information as provided either by the manufacturer or from switch 186 is supplied to the controller 240 as represented at arrow 298. Controller 240 responds to the above-noted actuation of on/off switch 180 as represented at arrow 292 to energize the on LED 182 as represented at arrow 300.
A timing network as represented at block 304 performs in concert with the controller function 240 as represented by dual arrow 306. Network 304 responds to the time selections from duration up/down switch 190 as represented at arrow 308, as well as to a reset input from the reset switch 224 as represented at arrow 310. That reset signal additionally is submitted to the controller 240 as represented by arrows 310 and 312. The output of time election switch 191 is submitted to the controller 240 as represented at arrow 309. Elected time data is supplied from the controller 240 to the display 192 as represented at arrow 314 and the therapy time elapsed data as retrieved from timing network 304 is supplied by the controller 240 to the therapy time elapsed display 222 as represented at arrow 316. Therapy in progress LED 213 is controlled from controller 240 as represented by arrow 322. The completion of therapy as is derived from timing network 304 is responded to by controller 240 to energize the therapy completed green LED 214 as represented at arrow 318. Correspondingly, the stop therapy input from switch 226 is asserted to controller 240 as represented at arrow 296. This provides for a corresponding reaction to energize the therapy stopped red LED 228 as represented at arrow 320. For safety purposes, the output of the stop therapy switch 226 also is simultaneously submitted to the ACF heating assembly 94 as represented by arrow 297.
The error, prompt and data display 204 is reproduced in the instant figure in block form with the same identifying numeration in conjunction with a display driver represented at block 324. Operative association between driver 324 and display 204 is represented at arrow 326 and the corresponding operational association between controller 240 and driver 324 is represented at arrow 328. By operator actuation of the display data switch 206, as represented at communications arrow 330, controller 240 reacts to provide corresponding visual data at display 204. Controller 240 also maintains a memory based data log as represented at arrow 332 and block 334. The data log retained data, of course, can be downloaded to paper or magnetic records. Power supply for requisite components of the control circuitry is represented at block 336 in conjunction with line input arrow 338 and regulated d.c. circuit power input as represented by an arrow array shown generally at 340.
The discourse now turns to discussion of the implanted sensor components as they may be intimately combined with implanted heater components or perform separately with or without such heater components. In an initial embodiment, the implant assumes a cylindrical form of dimension effective for implantation within a target tissue volume. In this regard, its configuration and dimensions should be suitable, for example, for percutaneous placement by utilizing a modified version of a hypodermic syringe. Thus, a minimally invasive implantation scheme is available to the practitioner. Looking to
Looking to
Once implants as at 350 are accurately positioned within or in adjacency with targeted tissue, it is desirable that they remain in place. This follows, inasmuch as hyperthermia therapy typically will be repeated at given intervals for a multi-application treatment regimen. Advantageously re-implantation is not necessary. Of further benefit, typical surgical or biopsy procedures, for example, involving the breast call for the implantation of a radiographic marker. These markers are employed in subsequently occurring patient management procedures. The instant implants contribute the same radio-opaque marker function in subsequent patient management practice.
Referring to
Another exemplary release agent coating includes a temperature-responsive polymeric micelle prepared using block copolymers of poly (N-isopropylacrylamide-b-butylmethacrylate) as discussed in publication (9) supra.
In one arrangement of this release agent embodiment, the thermally activated release agent coating is formulated to provide a controlled rate of release of an anti-tumor when the heater/sensor implant 350 reaches its pre-selected therapy temperature, for example, the temperature setpoint, TSP, as discussed in connection with
The ferromagnetic sensing components of implants as at 350 generally are fabricated utilizing molded pressed powder technology. As such, they generally will exhibit adequate compressional strength but somewhat lower tensile strength. Thus, where they are incorporated in an embedded or clad heater/sensor combination it is preferred that the sensor component be internally disposed. However, it is essential that the surface of the sensor be exposed somewhat for appropriate reaction to the impinging magnetic field. Conversely, it is important that the surface of the heater component be readily exposed to, for example, E-field imposed activity to achieve requisite temperature development.
An embodiment for a heater/sensor implant structured having an outwardly disposed heater sleeve is shown in
As before, the alphanumerically identified dimensions and operational attributes are compiled in Table 1. Heater segment width, W1 will be within a range from about 0.005 inch (0.13 mm) to about 0.25 inch (6.3 mm) and preferably within a range from about 0.010 inch (0.25 mm) to about 0.10 inch (2.5 mm). The distance between heater segments, W2 will be within the same dimensioned ranges or dimension W1. Further, the tabulated ranges for ΔTheater and ΔT sensor continues to be applicable as well as the values for thermal resistance, TR1 and TR2.
As discussed in connection with
Referring to
Another embodiment for a combined sensor and heater implant is revealed in connection with
Referring to
Looking to
Referring to
Multiple numbers of the sensor components described at 402 may be combined as represented at
Each of the sensor components 402a-402d may be coated with an electrically insulative conformal coating of thickness, t2 such as the earlier-described “Parylene” as indicated at 448. This same conformal coating also may be employed to coat the entire implant 430. As noted earlier, such coatings provide an adhesive coupling contribution supporting the integrity of the multiple component arrangement. Table 1 sets forth ranges for ΔT heater or heater component temperature around the set point, ΔT sensor or sensor component temperature around the set point, Pheater or instantaneous heating power generated within the heater component, Theater or nominal hyperthermia temperature for the heater component, TR1 the nominal thermal resistance between the heater components and sensor components, and TR2, the preferred thermal resistance between the heater component and the sensor component.
As is the case of all of the implant embodiments, the implant 430 may be utilized to support a thermally activatable release agent coating as shown at 450 in
As discussed in connection with
Referring to
In some applications of the instant system, the heating components may be dispensed with target tissue being, in effect, directly heated from the ACF heating assembly 94 and coil or antenna 98 as described in conjunction with
In general, the implants described in conjunction with
However, with the instant system and method the surgeon is given an opportunity for deploying hyperthermia-based temperature control implants by direct access. Of special interest, colorectal cancers tend to metastasize through the lymph system. Accordingly, the implants can be intraoperatively positioned within lymph nodes to provide for the induction of HSPs at the node-retained cancer cells. Other sites of tumor similarly can be implanted. Following surgical closure, the hyperthermia therapy procedures described herein can be undertaken in mitigation of the metastasis. In general, practitioners employing the method herein described with respect to hyperthermia will elect to implant the most or more accessible target tissue volume.
A target tissue volume is represented in
Sensor components having the physical attributes discussed above in connection with
Particularly for the predominating hyperthermia based procedures described herein, the soft ferrites are formulated to derive relatively low Curie point values within, for instance, a range extending from about 39° C. to about 65° C. and more typically within a range extending from about 41° C. to about 50° C. Generically, ferromagnetic materials exhibit pronounced magnetic effects occurring in atoms and ions and stem from only a limited number of metallic elements, to wit: Fe, Co, Ni and certain rare earths. Alloys or oxides of these materials typically will contain neighboring ions such as Mn to substantially enhance the atomic spin effect. Zn substitution both increases the magnetic moment of Mn and Ni ferrites and lowers the Curie point of a resultant product. Such substitution will be seen to appear in the ferrite formulations disclosed herein. The metal ion present in largest concentration in ferrites is Fe3+. Because of its high ionic moment it has a high potential for controlling magnetic characteristics. Such effects are not chemical but crystallographic, being related to lattice site distribution.
The processes for preparing ferrites have an extensive but relatively short history (Snork, D. L., 1936, 1947). Such processes generally reflect the common goal of formation of a spinel structure. Starting materials typically are oxides or precursors of oxides of the cations and their processing involves an interdiffusion of metal ions of a select composition to form a mixed crystal. Ferrite powders have been produced by precipitation and digestion methods. These powders are blended, calcined and milled and, for the case of spinel ferrites, sintered for a variety of purposes including: (a) completing the interdiffusion of the component metal ions into a desired crystal lattice; (b) establishing appropriate valences for the multi-valent ions by proper oxygen control; and (c) developing a desired microstructure. During this procedure, the materials are consolidated into a body or component, for example, by die-pressing.
Referring to
For the instant system and method, product formulation and processing further is called upon to establish Curie points within the above designated range or ranges of values. Customizing ferrites to so establish a desired Curie point can be carried out, for example, by blending a ferrite exhibiting a Curie transition above the desired value, TSP, with one exhibiting a corresponding transition point below that target value.
Recalling curve 42 of
The resulting ferrite as represented by curve 484 exhibited the following chemistry:
Further this ferrite represents a formulation of the following oxides:
Another formulation achieving a 44.5° C. Curie point resulted from a combinational blending, for example, of a 40° C. Curie point batch with a 50° C. Curie point batch.
As a prelude to considering detailed features of the procedure at hand, the discourse now turns to its aspects particularly with respect to heat shock phenomena. Previous research demonstrates that in vitro hyperthermia of cultured tumor cells can act as a vaccine against metastatic cancers. Hyperthermia of cultured cancer cells can partially denature proteins, induce HSPs, and lead to the presentment of intracellular peptides on the cell surface. Earlier work has isolated the antigen presenting HSPs and used these cell preparations as an autologous vaccine against syngeneic tumors. See:
The autologous cell vaccine described in Tamura presumably functions using heat shock to cause the presentment of intracellular cancer cell antigens. A subset of these cancer cell antigens represent aberrant proteins, and these aberrant proteins can be immunogenic. Once antigens derived from aberrant proteins unique to the cancer cell are presented to the cells of the immune system, then an immune response can occur. An immune response raised against aberrant proteins apparently does not trigger an auto-immune response, since only those cells which are syngeneic with the cancer cell would be likely to produce the antigen from the aberrant protein. An immune response so induced can be effective against syngeneic cancer cells and can activate the immune system against metastatic tumors too small to be otherwise detected.
In the present invention, rather than using invasive surgical techniques to excise a tumor and then produce a vaccine for that tumor by growing and heat-shocking the tumor in vitro, the tumor is heat shocked in situ, and tumor antigens are presented on the tumor cell surface. Heat-shock can cause the presentment of novel antigens on the cell surface. Presentment of novel peptides on the cell surface can induce immunogenicity. A cell which was previously not immunogenic, after heat shock, can thus become immunogenic. For additional background on immunogenicity induced via a heat-shock mechanism, See:
The present invention offers the advantages of reduction in the invasive nature of the therapy, as a tumor need not be removed from the body if the tumor responds to thermotherapy. Moreover, tumors which are otherwise inoperable because present surgical techniques do not allow their excision (e.g. certain brain tumors), could not be excised for in vitro treatment. By appropriate placement of the instant implant near or within targeted tumor, hyperthermia in situ can offer the same benefits as an autologous vaccine derived from excised, cultured cells. Additional complications caused by surgery and infection potential caused by reintroduction of tumor derived products can likewise be avoided.
The present approach also offers the thermal control aspect of being able to take advantage of different thermotherapy regimes, so that tumor cells, at different occasions can be induced to undergo heat shock, apoptosis or necrosis. A tumor may receive an implant and then be subjected to an initial round of mild thermotherapy, sufficient to induce only heat shock, but not apoptosis or necrosis. The initial therapeutic regime may be for a short duration (or at lower temperature, or both) designed to induce to a panel of heat shock proteins induced by only mild heat shock (e.g. activating HSF1 and HSP70). Referring to
For a discussion of induction of the heat shock response following mild heat shock see:
It should be noted that different tissues respond at differing rates to heat-shock, for instance brain tissue responds more rapidly than liver or muscle tissue. Though the response curve in
A second round of therapy, timed 10 days to 14 days later (in order to allow time for autologous adaptive immunity to begin to develop) may be for longer duration (which would not necessarily require the use of additional or different implants) for a higher temperature level. The subsequent round of therapy can be designed to induce a panel of heat shock proteins that are induced by more severe heat shock (e.g. activating HSF1 and inducing HSP70, activating HSF2 and inducing HSP90 and gp96). One example of this regime would be a setpoint temperature representing a ΔT=+4° C. for a duration of 90 minutes. Additional rounds of mild and moderate heat shock could be used to maximize tumor antigen presentation to immunoresponsive cells, and lead to an immune response to tumor cells, wherever they might reside in the body.
Advantages of initial moderate thermotherapy include minimization of damage to surrounding non-cancerous tissues, minimization of debilitating or damaging inflammatory responses, and maximizing the induction of immune response. For additional background discussing antigenicity of heat shocked cells see:
After heat shock has been used to induce antigen presentation (e.g. by HSP70), a more severe thermotherapy regime could be implemented to induce apoptosis. Apoptotic cells may not allow presentation of antigens in the same manner as heat shocked cells, and therefore hold the possibility of inducing a different immune response that could offer protection against tumor cells that did not activate an immune response via mild heat shock. It is expected that thermotherapy sufficiently severe to induce apoptosis would be in the range depicted at or above the curve 24 in
A subsequent round of thermotherapy can be used to induce necrosis of cancerous tissues. Thermotherapy sufficiently severe to induce necrosis would be in the range depicted above curve 24 in
Necrotic cells are more immunogenic than typical apoptotic cells (note the inflammatory immune response activated by necrosis). See:
Looking to
Next, the methodology provides a confirmational procedure as represented at line 522 and block 524 wherein the imaging and other such instrumentation are used for purposes of ascertaining if the implants are in the proper location with respect to the target tissue. Should the implant positioning not be appropriate, then as represented at loop line 526, the method reverts to the procedure described in connection with block 520. Upon an affirmative determination with respect to the query posed at block 524, then as represented at line 528 and block 530 the patient is positioned on the treatment support such as a table or chair so that the earlier located marker or outline on the surface of the patient is visible for the next step in the procedure. That step provides for locating the ACF heating coil or microwave antenna as well as the magnetometer probe at the proper locations with respect to the skin of the patient.
The procedure then continues as represented at line 532 and block 534 wherein, guided by the marker at the skin surface of the patient, the heating coil 98 or microwave antenna is positioned as close as practical with respect to the skin of the patient to sensor/heater implants. The method then continues as represented at line 536 which reappears in
In the event of an affirmative determination with respect to the query posed at block 554, then as represented at line 566 and block 568 green LED 210 is illuminated (
Where the query posed at block 580 is responded to in the affirmative, then as represented at line 592 and block 594 green LED 212 at console 112 is illuminated and the program continues as represented at line 596 and block 598. At this juncture in the procedure, the operator will be positioning the magnetometer probe 106 as close as practical to the implants. This positioning will involve orientation of that probe to achieve a maximum magnetometer signal change with the oscillations of the platform 52. The program then continues as represented at line 600.
As an optional procedure, the instant system may utilize, the orientation of sensor components having a principal elongate dimension or, as noted above, an aspect ratio of less than unity such that when subjected to magnetic flux lines, for example, of the earth's magnetic field, the disturbance that evokes, if any, depending upon the state of permeability, will draw a response at magnetometer assembly 104, the amplitude of which will vary depending upon that orientation. Thus, by initially selectively orienting the sensor components, the magnetometer function may discern their location in a lateral, as it were, scanning aspect resulting from the oscillation of platform 52. In this regard, that aspect of interrogation is one generally normal to the longitudinal orientation of the probe component 106. Of course, probe orientation will be dependent upon the particular mechanism employed for that function. However, where sensor amplitude-based positional information is desired, then as represented by optional dashed line 602 and dashed block 604 the system will acquire sensor-based magnetic response amplitude values with respect to each implanted sensor. The program then reverts, as represented at dashed line 606 to line 600. Line 600 extends to block 607 (
The procedure continues as represented at line 608 and block 609 which provides for the operator switch-based selection of both therapy duration commencing with the attainment of setpoint temperature, TSP and the maximum allotted time to attain TSP. Insertion of this temporal data is made with switches 190 and 191 in conjunction with the visual readout at numerical display 192.
The ACF heating assembly actuation next is addressed as represented at line 610 and block 612 providing that the ACF heating assembly 94 is turned on and, as represented at line 614 and block 616 a query is posed as to whether the ACF heating unit is enabled both by the development of a requisite on voltage level, VRF as being greater than or equal to three volts and the presence of the earlier-described magnetometer signal Vc as being greater than or equal to three volts. If those ANDed conditions are not met, then as represented at line 616 and block 618 an error visual cue is displayed at display 204 indicating that the control leads 102 are not properly connected to the control console 112. The program then continues as represented at line 620 and block 622 to display a prompt advising the operator to turn off the ACF heating unit and check the cable attachment 102 extending to the console 112. The program then reverts to line 610 as represented at line 624.
Where the query posed at block 616 results in an affirmative determination, then as represented at line 626 and block 628 green LED 211 at console 112 is illuminated and the program continues as represented at line 630. Line 630 extends to the query posed at block 632 determining whether the duration for therapy and the maximum time allocated for reaching TSP have set to correct and intended intervals. These times are set by the operator employing the up/down switches 190 and election switch 191 in conjunction with display 192 on console 112. It may be recalled that for adjunct therapies to HSP induction such as the temperature controlled dispersion of chemotherapeutic release agents, proteins and/or combined radiation therapy, one or more levels of predetermined Curie transition temperatures may be utilized in conjunction with a corresponding sequence of sensor component containing implants. In the latter aspect, such therapy may involve maintenance of the quantum of thermal energy below critical curves as at 24 described in connection with
Where the query posed at block 632 is responded to in the affirmative, then as represented at line 640 and block 642 a determination is made as to whether the therapy time elapsed indicates zero minutes. This readout is provided at console 112 at display 222. In the event that that display does not register zero minutes, then as represented at line 644 and block 646 reset button switch 224 is actuated and the program continues as represented at lines 648 and 640. With the therapy time elapsed set at zero, the procedure continues as represented at line 650 and block 652
In the event the query posed at block 652 results in an affirmative determination, then as represented at line 660 and block 661 thermal therapy which may comprise hyperthermia therapy commences with the operator actuation of the start therapy button switch 220 at console 112. With this actuation, as represented at line 662 and block 664, the green LED 213 indicating that therapy is in progress at console 112 is illuminated and the procedure continues as represented at line 666 to the query at block 668. Therapy being underway, but setpoint temperature TSP not having been reached, the program determines whether or not the stop therapy button switch 226 at console 112 has been actuated. In the event that such an actuation occurred, then as represented at line 669 and block 670 the ACF heating assembly 94 is turned off as well as the motor control circuit 78 of the support assemblage 54. As a visual cue that the therapy is stopped, red LED 228 is illuminated and, correspondingly, green LEDs 200 and 213 are de-energized. The procedure then continues as represented at line 671 and block 672 wherein the operator determines whether or not the therapy mode is to be resumed. In the event that it is to be so resumed, then as represented at line 673 and block 679, to resume the therapy mode for the duration of the unlapsed therapy, the start therapy button switch 220 is actuated at control console 112 which, in turn, causes the turning off of red LED 228 and the turning on of green LEDs 200 and 213. This automatically restarts the platform 52 oscillation and the activation of the ACF heating assembly 94. As noted above, for HSP induction procedures, therapy duration is timed from the attainment of setpoint temperature, TSP. If that setpoint value has not been reached in the presence of a stop command, the system, upon re-start, will proceed to derive TSP and then commence therapy duration time-out. The program then continues as represented at line 675 which extends to line 666.
Where the query posed at block 672 results in a determination that therapy is not to be resumed, then as represented at line 676 and node 677 the therapy is ended.
Returning to block 668, where a determination has been made that the stop therapy switch 226 has not been actuated, then as represented at line 678 and block 679 (
Returning to block 682, where the maximum time for reaching setpoint temperature, TSP has been reached before the attainment of setpoint temperature, then an error is at hand and is represented at line 708 and block 710, an error signal is visually displayed which may be accompanied by an acoustical cue. The program then continues as represented at line 712 to line 706.
Line 706 extends to block 720 which provides for the deactivation of the active components of the system. In this regard, the ACF heating assembly 94 is deactivated as is the magnetometer assembly 104. Control circuit 78 for the platform support assemblage 54 is deactivated. Therapy complete green LED 214 is illuminated and green LED 213 representing therapy in progress is de-energized. The program then continues as represented at line 722 and block 724 wherein pertinent data for the procedure parameters is recorded. It may be recalled that this data can be displayed at display 204 by the actuation of button switch 206. The procedure then continues as illustrated at line 724 extending to node 726 representing a therapy ended stage.
Hyperthermia currently is employed for purpose of limiting restenosis at the location of implanted stents in blood vessels. In general, such stents, for example, may be utilized in percutaneous transluminal coronary angioplasty (PTCA) for purposes of avoiding a collapse of arteries subsequent to balloon implemented dilation. As in other thermotherapeutic procedures, necessary sensing of temperature heretofore has been carried out in an invasive manner. This prior approach is illustrated in connection with
The mesh-like generally cylindrically-shaped stent 748 is seen to be implanted such that its outwardly disposed contact surface will have been urged into abutting and fixed intimate connection with the intima of blood vessel 752. Fixed in intimate thermal exchange relationship to this contact surface 750 at the central region of the stent 748 is an untethered temperature responsive component assembly represented generally at 754, the outwardly disposed surface of which at 756 is seen to slightly additionally distend blood vessel 752 at region 758. Sensor component assembly 754 is seen to be formed of four discrete components 754a-754d which, as in the earlier embodiments may be fashioned of a soft ferromagnetic material, i.e., a soft ferrite having a Curie point temperature elected to provide a significant change in magnetic permeability, for example, a 20 to 1000 fold change over a relatively narrow range of temperature change, for example, between about 0.1° C. and about 1° C. The sensors 754a-754d are intimately bonded with the non-magnetic metallic stent 748 and their securement may be further assured by the positioning of a biocompatible flexible sheath or band 760 over the central portion of the stent 748 and over the outwardly disposed surfaces of the sensor component assembly 754. Band 760 may, for instance, be formed of a silicone elastomer, Dacron, Teflon, titanium, nitinol or a Type 316 stainless steel. Multiple temperature sensing components 754a-754d are used for the component assembly 754 in the interest of providing operational redundancy and for the purpose of providing a structural aspect wherein the sensor assembly 754 exhibits a flexibility called for to accommodate tortuous access through the vasculature of the body and placement, for example, of the stent 748 within a curved blood vessel as opposed to a vessel exhibiting more straight or uncurving characteristics. An intimate thermal exchange relationship is called for between the stent 748 and the untethered temperature responsive component 754. In this regard, the preferred thermal resistance, TR4 between the stent 748 and the sensors 754a-754d will be about 0.5° C./watt, while the nominal thermal resistance, TR3 will be about 5° C./watt. Providing a biocompatible electrically insulative conformal coating such as the earlier-described “Parylene” as shown at 762 in
The technique and instrumentation discussed in connection with
The combined stent and unthethered sensor component assemblies discussed in conjunction with
The nominal drug release temperature, TDRS will range from about 39° C. to about 65° C. and preferably from about 41° C. to about 50° C. Drug release coating 792 when non-invasively heated to a drug releasing temperature provides a controlled amount of a selected drug at the situs of the stent 778 to limit restenosis phenomena. Such a drug release process can be repeated at therapeutic intervals which may range from weeks to months to even years. Additionally, the coating may be activated in the event the patient's symptoms or diagnostic methods indicate that restenosis is occurring and progressing to the point that therapeutic intervention is warranted. Where hyperthermal therapy is combined with drug release activity, sensor segments or components 784a-784d may be assigned corresponding different setpoint or target temperatures (Curie transition temperatures).
The untethered temperature responsive component assemblies preferentially are positioned on the outer contact surface on the stent structure as described inasmuch as such location provides a factor of safety with respect to the adhesion of the individual components to that contact surface. Should the coupling be damaged, the sensor components are retained by the stent structure itself outside of luminal blood flow.
This outboard positioning of the untethered temperature responsive component assemblies can be arranged with additional redundancy by mounting them, for instance, at diametrically opposite locations upon the stent contact or outer surface.
As noted earlier, essentially all metallic stents which have been implanted are formed of nonmagnetic material in view of the potential involvement of highly magnetic imagining systems, e.g., MRI devices. As a consequence, those pre-implanted stents can be retrofitted in vivo with the temperature sensing aspects of the present invention to permit noninvasive therapeutic procedures for subsequent treatment of restenosis phenomena. The retrofitting approach, in effect, provides for the installation of a temperature responsive component containing stent-like structure diametrically expandable within the preexisting stent.
Referring to
Referring to
By virtue of the intimate association of the secondary stent borne temperature sensor component assemblies 860 and 862 with the stent 850, ΔTstent, the temperature range of the stent 850 about the hyperthermia therapy set point may be maintained within the earlier-described range from about 0.1° C. to about 5° C. and preferably from about 0.1° C. to about 3° C. The intimate association also permits development of the nominal hyperthermia therapy temperature for the stent 850, Tstent within the earlier-noted range of from about 39° C. to 70° C. preferably between about 43° C. and 48° C. A nominal stent heating temperature of 45° C. has been described in publication (53) supra.
See additionally the following publication:
In general the setpoint temperature, TSP, is elected as being effective for inhibiting the proliferation of intimal hyperplasia growth following stent insult. The nominal thermal resistance between the retrofitted stent 850 and the sensor assemblies 860 and 862, TR3 continues to be 5° C./watt and the preferred thermal resistance, TR4 remains 0.5° C./watt. Because of the symmetry of positioning of the temperature sensor assemblies 860 and 862, a balloon evoked placement can be carried out without customized structuring of the secondary stent cylindrical wall as provided in conjunction with the embodiment shown in
The discourse now turns to the procedures associated with the embodiments described above in connection with
Looking to
As an alternate to the procedure thus far described, the secondary stent approach described in conjunction with
Subsequent to the stent positioning phase the patient will be monitored for the occurrence of clinically significant restenosis. As represented at block 902 such checks may be carried out, for instance, using angiography, diagnostic ultrasound, x-ray, or MRI techniques. The procedure then continues as represented at line 904 and block 906 presenting a query as to whether or not evidence of restenosis is present. In the event that it is not, then as represented at line 908, block 910 and line 912 such checks are continued, the patient's cardiac/circulatory function being monitored on a periodical basis. Where evidence of restenosis does exist, then as represented at line 914 and block 916 thermal therapy according to the invention is commenced. As an initial step in the procedure, a marker is placed on the skin of the patient at a location selected for aiding in the positioning of the magnetometer probe 106′ and the ACF heater coil 98′. As represented at line 918 and block 920 the patient is positioned on the table as at 52′ or suitable chair so that the skin locative marker is clearly visible for the noted coil and probe orientation. Then, as represented at line 922 and block 924 the ACF heating coil positioning mode is commenced. In this regard, using the marker at the surface of the patient the heating coil 98′ is located as close as practical to the location of the stent/sensor implant or implants. Then, as indicated by line 926 and block 928, the operator turns on the control feature by actuation of on/off switch 180′ which, in turn, will cause the illumination of green LED 182′. Next, as represented at line 930 and block 932 the operator may select the duty cycles for activating the heater component and the magnetometer. While these intervals may be factory set, the operator may carry out the selection by utilizing switch function 184′. The procedure continues as represented at line 934 and block 936 wherein the operator selects the extent of travel of the table or platform 52′ or a corresponding chair-type support. That selection is made by operator actuation of up/down switches 194′ while observing any corresponding locus of travel value shown at display 196′. The program then continues as represented at line 938 which extends to block 940 providing for the acquisition of the enabling voltage value of the motor control 78′. Following such acquisition, as represented at line 942 and block 944, a determination is made as to whether that enabling voltage Vmc is greater than or equal to three volts. If the determination at block 944 is that the enabling voltage of the table control is not adequate, then as represented at line 946 and block 948, an error message is displayed at the display 204′. The error, in general will indicate that the control leads 84′ from the oscillation system are not properly attached to the console 112′. The program then continues as represented at line 950 and block 952 wherein the display 204′ outputs a display prompt, to wit: “check the lead/cable attachment”. The program then reverts to line 938 as represented at line 954.
In the event of an affirmative determination with respect to the query posed at block 944, then as represented at line 956 and block 958 green LED 210′ is illuminated and the procedure continues as represented at line 960 and block 962. In this regard, the operator carries out what in effect is a “check run” of the oscillation of platform 52′. This check is initiated by actuating button switch 198′. As the patient support assemblage 54′ is activated, the procedure then evaluates the status of the magnetometer 104′. Accordingly, as represented at line 956 and block 958 the magnetometer 104′ is turned on and the system acquires its on and continuity status information. The program then continues as represented at line 968 and block 970 wherein a determination is made as to whether the status of the magnetometer 104′ is ok. In this regard, the peak-to-peak variation of the magnetometer output voltage, VMO is compared with a reference, VFM. Where that condition obtains, then the enablement signal Vc is generated. This signal must be greater than or equal to three volts d.c. to be representative. In the event that the magnetometer status is not ok, then as represented at line 972 and block 974 an error condition is displayed at display 204′ indicating that the magnetometer probe cable 108′ or cable 114′ to console 112′ is not properly attached. The program then continues as represented at line 976 and block 978 to display the prompt to the operator to check the magnetometer cable attachments. The program then returns as represented at line 980 to line 968.
Where the query posed at block 970 is responded to in the affirmative, then as represented at line 982 and block 984, green LED 212′ at console 112′ is illuminated and the program continues as represented at line 986 and block 988. At this juncture in the procedure, the operator will be positioning the magnetometer probe 106′ as close as practical to the stent. This positioning will involve orientation of that probe to achieve a maximum magnetometer signal change with the oscillations of the platform 52′. The program then continues as represented at line 990. Line 990 extends to block 991 providing for the termination of the test run of the support assemblage 54′. This is carried out by operator actuation of the stop button switch 202′ on console 112′. The procedure continues as represented at line 992 and block 993 which provides for operator selection of both therapy duration commencing with the attainment of setpoint temperature, TSP, and the maximum allotted time to attain that temperature, TSP. Selection is carried out by actuation of switches 190′ and 191′ in conjunction with the readout provided at display 192′ (
As represented at line 994 and block 996, the ACF heating assembly 94′ is turned on, and as provided at line 998 and block 1000 a query is posed as to whether the ACF heating unit is enabled both by the development of a requisite on voltage level, VRF as being greater than or equal to three volts and the presence of the earlier-described magnetometer signal Vc as being greater than or equal to three volts. If those ANDed conditions are not met, then as represented at line 1002 and block 1004 an error visual cue is displayed at display 204′ indicating that the control leads 102′ are not properly connected to the control console 112′. The program then continues as represented at line 1006 and block 1008 to display a prompt advising the operator to turn off the ACF heating unit and the cable attachment 102′ extending to the console 112′. The program then reverts to line 994 as represented at line 1008.
Where the query posed at block 1000 results in an affirmative determination, then as represented at line 1012 and block 1014, green LED 211′ is illuminated at console 112′ and the program continues as represented at line 1016. Line 1016 extends to the query posed at block 1018 determining whether the duration for therapy and the maximum time allocated to reach TSP have been set to correct and intended values. Both intervals are set by the operator, employing the up/down switches 190′ and election switch 191′ in conjunction with display 192′ on console 112′. The discussion associated with
Where the query posed at block 1018 is responded to in the affirmative, then as represented at line 1026 and block 1028 a determination is made as to whether the therapy time elapsed indicates zero minutes. This readout is provided at console 112′ at display 222′. In the event that display does not register zero minutes, then as represented at line 1030 and block 1032, reset button switch 224′ is actuated and the program continues as represented at lines 1034 and 1036. Therapy time elapsed having been set at zero, the procedure continues as represented at line 1036 and block 1038. Block 1038 reflects the activity of controller 240 (
In the event the query posed at block 1038 results in an affirmative determination, then as represented at line 1046 and block 1048 hyperthermia therapy is commenced with the operator actuation of the start therapy button switch 220′ at console 112′. With this actuation, as represented at line 1050 and block 1052, the green LED 213′ indicating that therapy is in progress at console 112′ is illuminated and the procedure continues as represented at line 1054 to the query presented at block 1056. Therapy being underway, the program determines whether or not the stop therapy button switch 226′ at console 112′ has been actuated. In the event that such an actuation occurred, then as represented at line 1057 and block 1059, the ACF heating assembly 94′ is turned off as well as the motor control circuit 78′ of the support assemblage 54′. As a visual cue that the therapy is stopped, red LED 228′ is illuminated and, correspondingly, green LEDs 200′ and 213′ are de-energized. The procedure then continues as represented at line 1060 and block 1061 wherein the operator determines whether or not the therapy mode is to be resumed. Where resumption is intended, then as represented at line 1060 and block 1061 the start therapy button switch 220′ is actuated at control console 112′ which, in turn, causes the turning off of red LED 228′ and the turning on of green LEDs 200′ and 213′. This automatically restarts the platform 52′ oscillation and the re-activation of the ACF heating assembly 94′. The program then continues as represented at line 1064 which extends to line 1050. Where the query posed at block 1061 results in a determination that therapy is not to be resumed, then as represented at line 1065 and node 1066, the therapy is ended.
Returning to block 1056, where a determination has been made that the stop therapy switch 226′ has not been actuated, then as represented at line 1067 and block 1068 a determination is made as to whether the target or setpoint temperature, TSP has been reached. This target temperature has been discussed in conjunction with dashed line 142 of
The procedure then continues as represented at line 1078 and block 1080 providing for the illumination of green LED 215′ on console 112′. The program then continues as represented at line 1082. Where the inquiry posed at block 1068 results in a negative determination, then as represented at line 1084 the program reverts to line 1082.
Line 1082 extends to the query posed at block 1086 wherein a determination is made as to whether the therapy time elapsed has reached the value of the preset therapy duration. Where that is not the case, then as represented at line 1088 and block 1090, the time elapsed readout 222′ is updated and the program reverts as represented at line 1092 and node B to line 1054.
In the event the query posed at block 1086 results in an affirmative determination, then, as represented at line 1094 the therapy is completed and the procedure continues as represented at line 1094 and block 1108. Returning to the query at block 1072, where an affirmative determination has been made that the time to setpoint has elapsed before setpoint temperature is reached, then an error condition obtains and is represented at line 1096 and block 1098, an error is displayed at 204′ on console 112′ and the program reverts to line 1094 as represented at line 1100. Line 1194 extends to block 1108 which provides for the deactivation of the active components of the system. In this regard, the ACF heating assembly 94′ is deactivated as is the magnetometer assembly 104′. Control circuit 78′ for the platform support assembly 54′ is deactivated. Therapy complete green LED 214′ is illuminated and green LED 213′ representing therapy in progress is de-energized. The program then continues as represented at line 1110 and block 1112 wherein pertinent data representing the procedure parameters is recorded. It may be recalled that this data can be displayed at display 204′ by the actuation of button switch 206′. The procedure then continues as illustrated at line 1114 extending to node 1116 representing a therapy ended stage.
In the embodiments heretofore described, the patient has been supported upon a moveable platform or chair for the purpose of deriving a relative movement between the temperature sensor components and the magnetometer pick-up. However, this relative movement can be dispensed with, for example, through the utilization of an array of magnetometer pick-ups which is arranged as such that certain of the pick-ups within the array will intercept magnetic field flux lines affected by the sensor components while other somewhat adjacent pick-ups within the array will intercept magnetic field lines which are unaffected by a sensor component, i.e., the field lines will not have intercepted those components. Referring to
Heating of the region of interest 90″ under thermotherapy conditions and, in particular, hyperthermia conditions is provided from the alternating current field heating assembly represented at block 94″. Line power input is represented as being directed to the assembly 94″ at arrow 96″. Substantially focused radiative heating is provided from the ACF heating assembly 94″ by a typical coil-implemented heating component represented at 98″ which is positioned in close proximity to the skin of patient 50″ in the vicinity of a predetermined and earlier marked location of the target tissue volume 90″. Association of the component 98″ with the heating assembly 94″ is represented schematically by line pair 100″. Preferably, the component 98″ may be associated with an induction heating assemblage operating at a lower frequency within the generally identified radio frequency range.
Now looking to the magnetometer-based detection of the earth magnetic field disturbances evoked by the state of permeability of the sensor component at implant 92″, a magnetometer control assembly is represented at block 1122. Assembly 1122 is of a multichannel variety and performs in conjunction with the remotely disposed pick-up or multichannel array or probe 1124, the channels of which are oriented for discerning and/or differentiating magnet field flux lines as they may be affected by the implant or implants at 92″. In effect, the magnetometer sensor array 1124 provides for the measurement of a two-dimensional pattern of magnetic field strength allowing the change in the field strength pattern to be detected as the ferromagnetic sensor 92″ changes from a magnetic to a non-magnetic state—a change which occurs over a narrow temperature range (
While the tissue heating function of assembly 94″ may be carried out simultaneously with the temperature monitoring function of the magnetometer assembly 1122, such coincident operation necessarily requires that the monitoring function be effectively shielded or protected from electromagnetic interference. An approach to avoiding this interference is to intermit the operation of these assemblies in the manner described in connection with
The interactive control functions of the control console 112″ are essentially identical to those described in connection with
In the course of setting up a therapy, certain associated interconnections will be made by the operator. The control system represented by the console 112″ will respond to errors in that setup procedure and provide visual indicia as to error involved and additionally will provide a prompt as to corrective action to be taken. That information is provided at visual display 204″. Display 204″ also will provide a display of pertinent data concerning a completed therapy by operator actuation of momentary on switch 206″. That data also will be recorded automatically in data log memory.
During the course of the setup and subsequent therapeutic operation of the system, an array of visual indicators as to the progress of the procedure as represented generally at 208″ will provide confirmational outputs. In this regard, the illumination of green LED 211″ indicates that an ACF heating assembly 94″ switch located at that unit has been thrown to apply power. Additionally, its illumination indicates that the magnetometer control 1122 monitoring features have indicated that peak-to-peak variations of its control voltages are greater than a reference value. LED 212″, when illuminated, provides for an indication that magnetometer 1122 is in a ready condition. In this regard, its power-on switch will have been actuated to an on condition and its peak-to-peak voltage will have equaled or exceeded a reference voltage value. Next, green LED 213″ is illuminated to provide an indication that therapy is in progress, and green LED 214″, when illuminated, indicates that the therapy duration now has been reached and therapy is completed. Finally, green LED 215″ is illuminated to indicate that the target temperature or setpoint temperature TSP (
Therapy is commenced with the user actuation of the momentary on start therapy switch 220″. During the interval of the therapy, the time elapsed for therapy commencing with the attainment of setpoint temperature, TSP is indicated at display 222″. That display may be reset to zero by actuation of momentary on switch 224″. If, during the progress of the therapeutic performance of the system, the operator deems it advisable to stop the therapy, then the stop therapy switch 226′ is actuated momentarily and the therapy stop red LED 228″ is illuminated.
Concerning the general operation of the control function at console 112″, it may be noted that unless the checking logic of the control system will have functioned to carry out the illumination of the “ready” LED (s) 211″-212″, then the start therapy switch 220″ will not be enabled. In general, error and prompt messages will remain at the display 204″ where the start-up conditions are not satisfied. The control system represented at console 112″ is configured as described above in connection with
Looking to
Next, the method provides a confirmational procedure as represented at line 1156 and block 1158 wherein the imagining and other such instrumentation are used for purposes of ascertaining if the implants are in the proper location with respect to the target tissue. Should the implant positioning not be appropriate, then as represented at loop line 1160, the method reverts to the procedure described in connection with block 1154. Upon an affirmative determination with respect to the query posed at block 1158, then as represented at line 1162 and block 1164 the patient is positioned on the treatment support 1120 so that the earlier located marker or outline on the surface of the patient is visible for the next step in the procedure. That step provides for locating the ACF heating coil or microwave antenna as well as the magnetometer probe 1124 at the proper locations with respect to the skin of the patient. The procedure then continues as represented at line 1166 and block 1168 wherein, guided by the marker at the skin surface of the patient, the heating coil 98″ or microwave antenna is positioned as close as practical with respect to the skin of the patient to the sensor/heater implant(s). The method then continues as represented at line 1170 extending to block 1172 providing for turning on control console 112″ by actuating switch 180″ to, in turn, illuminate green LED 182″. Then, as represented by line 1174 and block 1176, the operator selects the duty cycles. It may be recalled that duty cycle ranges, δt1 and δt2 are set forth in Table 1. As described in conjunction with
Where the query posed at block 1184 is responded to in the affirmative, then as represented at line 1196 and block 1198 green LED 212″ at console 112″ is illuminated and the program continues as represented at line 1200 and block 1202. At this juncture in the procedure, the operator will be positioning the magnetometer probe 1124 as close as practical to the implant(s) in order to obtain a maximum magnetometer signal channel differentiation.
The procedure continues as represented at line 1203 and block 1204 which provides for operator selection of both therapy duration commencing with the attainment of setpoint temperature, TSP , and the maximum allotted time to attain that temperature, TSP. Selection is carried out by actuation of switches 190″ and 191″ in conjunction with the readout provided at display 192″. (
The ACF heating assembly actuation next is addressed as represented at line 1205 and block 1206 providing that the ACF heating assembly 94″ is turned on and, as represented at line 1208 and block 1210, a query is posed as to whether the ACF heating unit is enabled both by the development of a requisite voltage level, VRF as being greater than or equal to, for example, three volts and the presence of the earlier-described magnetometer signal Vc as being greater than or equal to, for example, three volts. If those ANDed conditions are not met, then as represented at line 1212 and block 1214 an error visual cue is displayed at display 204″ indicating that the control leads 102″ are not properly connected to the control console 112″. The program then continues as represented at line 1216 and block 1218 to display a prompt advising the operator to turn off the ACF heating unit and check the cable attachment 102″ extending to the console 112″. The program then reverts to line 1204 as represented at line 1220.
Where the query posed at block 1210 results in an affirmative determination, then as represented at line 1222 and block 1224, green LED 211″ is illuminated and the program continues as represented at line 1226. Line 1226 extends to the query posed at block 1228 determining whether the duration for therapy and maximum time to achieve setpoint temperature have been set to correct and intended values. The times are set by the operator employing the up/down switches 190″ in conjunction with election switch 191″ and display 192″ on console 112″. It may be recalled that for such activities as the temperature controlled dispersion of release agents (see
Where the query posed at block 1228 is responded to in the affirmative, then as represented at line 1236 and block 1238 a determination is made as to whether the therapy time elapsed indicates zero minutes. This readout is provided at console 112″ at display 222″. In the event that this display does not register zero minutes, then as represented at line 1240 and block 1242, reset button switch 224″ is actuated and the program continues as represented at lines 1244 and 1236. With the therapy time elapsed set at zero, the procedure continues as represented at line 1246 and block 1248. Block 1248 reflects the activity of controller 240 (
In the event the query posed at block 1248 results in an affirmative determination, then as represented at line 1256 and block 1258 thermotherapy which may comprise hyperthermia therapy commences with the operator actuation of the start therapy button switch 220″ at console 112″. With this actuation, as represented at line 1260 and block 1262, the green LED 213″ indicating that therapy is in progress at console 112″ is illuminated and the procedure continues as represented at line 1264 to the query at block 1266. Therapy being underway, the program determines whether or not the stop therapy button switch 226″ at console 112″ has been actuated. In the event that such an actuation occurred, then as represented at line 1267 and block 1268, the AC Field heating assembly is turned off. As a visual cue that the therapy is stopped, red LED 228″ is illuminated and, correspondingly, green LED 213″ is de-energized. The procedure then continues as represented at line 1269 and block 1270 wherein the operator determines whether or not the therapy mode is to be resumed. In the event that it is to be so resumed, then as represented at line 1271 and block 1272, in order to resume the therapy mode for the duration of the unlapsed therapy, the start therapy switch 220″ is actuated at control console 112″ which, in turn, causes the turning off of red LED 228″. This automatically activates the ACF heating assembly 94″. The program then continues as represented at line 1273 which extends to line 1260.
Where the query posed at block 1270 results in a determination that therapy is not to be resumed, then as represented at line 1274 and node 1275 the therapy is ended.
Returning to block 1266, where a determination has been made that the stop therapy switch 226″ has not been actuated, then as represented at line 1276 and block 1277, a determination is made as to whether the target or setpoint temperature, TSP, has been reached. This target temperature has been discussed in conjunction with dashed line 142 in connection with
The utilization of an array of magnetometer pick-ups in the manner described in connection with
The discourse now turns to the procedure and control associated with the embodiments described in connection with
As an alternate to the procedure thus far described, the secondary stent approach described in conjunction with
Subsequent to the stent positioning phase the patient will be monitored for the occurrence of clinically significant restenosis. As represented at block 1348 such checks may be carried out, for instance, using angiography, diagnostic ultrasound, x-ray, or MRI techniques. The procedure then continues as represented at line 1350 and block 1352, where a query is presented as to whether or not evidence of restenosis is present. In the event that it is not, then as represented at line 1354, block 1356 and line 1358, such checks are continued, the patient's cardiac/circulatory function being monitored on a periodic basis. Where evidence of restenosis does exist, then as represented at line 1360 thermotherapy according to the invention is commenced. Looking to block 1362 a marker initially is placed on the skin of the patient at a location selected for aiding in the positioning of the magnetometer probe array 1124 and the inductive heater coil 98″. As represented at line 1364 and block 1366, the patient is positioned on the stationary table or chair as at 1120 so that the skin located marker is clearly visible for the noted coil and probe orientation. Then, as represented at line 1368 and block 1370 the heating coil positioning mode is commenced. In this regard, using the marker at the surface of the patient, the heating coil 98″ is located as close as practical to the location of the stent/sensor implant. Then, as indicated by line 1372 and block 1374, the operator turns on the control console 112″ by actuation of on/off switch 180″ which, in turn, will cause the illumination of green LED 182″. Next, as represented at line 1376 and block 1378 the operator may select the duty cycles for activating the heater assembly and the magnetometer. While these intervals may be factory set, the operator may carry out selection by utilizing switch function 184″. It may be recalled that duty cycle ranges δt1 and δt2 are set forth in Table 1.
Next, as represented by line 1380 and block 1382 the procedure evaluates the status of the magnetometer. In this regard, the magnetometer 1122 is turned on and the system acquires its on and continuity status information. The program then continues as represented at line 1384 and block 1386 wherein a determination is made as to whether the status of the magnetometer 1122 is ok. In this regard, the peak-to-peak variation of the magnetometer output voltage is compared with a reference, VFM. Where that condition obtains, then the enablement signal, Vc is generated. This signal must be greater than or equal to, for example, three volts d.c. to be representative. In the event that the magnetometer status is not ok, then as represented at line 1388 and block 1390 an error condition is displayed at display 204″ indicating that the magnetometer probe cable 1126 or the cable 114″ to console 112″ is not properly attached. The program then continues as represented at line 1392 and block 1394 to display a prompt to the operator to check the magnetometer cable attachments. The program then returns as represented at line 1396 to line 1380.
Where the query posed at block 1386 is responded to in the affirmative, then as represented at line 1398 and block 1400 green LED 212″ at console 112″ is illuminated and the program continues as represented at line 1402 and block 1404. At this juncture in the procedure, the operator will be positioning the magnetometer array-type probe 1124 as close as practical to the stent 748 in order to obtain a maximum magnetometer signal channel differentiation.
The procedure continues as represented at line 1406 and block 1407 which provides for operator selection of both therapy duration commencing with the attainment of setpoint temperature, TSP, and the maximum time allotted to attain that temperature. Selection is carried out by actuation of switches 190″ and 191″ in conjunction with the readout provided at display 192″ (
The ACF heating assembly 94″ actuation next is addressed as represented at line 1408 and block 1409. Upon turning on the heating unit, as represented at line 1410 and block 1412 a query is posed as to whether the ACF heating unit is enabled both by the development of a requisite voltage level, VRF as being greater than or equal to, for example, three volts and the presence of the earlier-described magnetometer signal Vc as being greater than or equal to, for example, three volts. If those ANDed conditions are not met, then as represented at line 1414 and block 1416 an error visual cue is displayed at display 204″ indicating that the control leads 102″ are not properly connected to the control console 112″. The program then continues as represented at line 1418 and block 1420 to display a prompt advising the operator to turn off the ACF heating unit and check the cable attachment 102″ extending to the console 112″. The program then reverts to line 1408 as represented at line 1422.
Where the query posed at block 1412 results in an affirmative determination, then as represented at line 1424 and block 1426, green LED 211″ is illuminated and the program continues as represented at line 1428. Line 1428 extends to the query posed at block 1430 determining whether the duration for therapy and the maximum time to achieve setpoint temperature have been set to correct and intended values. These times are set by the operator employing the up/down switches 190″ and election switch 191″ in conjunction with display 192″ on console 112″. It may be recalled that for such activities as the temperature controlled heating dispersion of chemotherapeutic and the like release agents as discussed in connection with
When the query posed at block 1430 is responded to in the affirmative, then as represented at line 1438 and block 1440 a determination is made as to whether the therapy time elapsed indicates zero minutes. This readout is provided at console 112″ at display 222″. In the event that this display does not register zero minutes, then as represented at line 1442 and block 1444, reset button switch 224″ is actuated and the program continues as represented at lines 1446 and 1438. With the therapy time elapsed set at zero, the procedure continues as represented at line 1448 and block 1450. Block 1450 reflects the activity of controller 240 (
In the event the query posed at block 1450 results in an affirmative determination, then as represented at line 1460 and block 1462 thermotherapy which may comprise hyperthermia therapy commences with the operator actuation of the start therapy button switch 220″ at console 112″. With this actuation, as represented at line 1464 and block 1466 the green LED 213″ is energized indicating that therapy is in progress and the procedure continues as represented at line 1468 to the query at block 1470. Therapy being underway, the program determines whether or not the stop therapy button switch 226″ at console 112″ has been actuated. In the event that such an actuation occurred, then as represented at line 1471 and block 1472, the AC field heating assembly is turned off. As a visual cue that the therapy is stopped, red LED 228″ is illuminated and, correspondingly, green LED 213″ is de-energized. The procedure then continues as represented at line 1473 and block 1474 wherein the operator determines whether or not the therapy mode is to be resumed. In the event it is to be so resumed, then as represented at line 1475 and at block 1476 therapy is resumed for the remaining duration of unlapsed therapy or maximum time allotted to reach setpoint temperature, TSP, by actuating the start therapy switch 220″ at control console 112″. This actuation, in turn, causes the turning off of red LED 228″ and automatically activates the AC field heating assembly 94″. The program then continues as represented at line 1477 which extends to line 1464.
Where the query posed at block 1474 results in a determination that therapy is not to be resumed, then as represented at line 1478 and node 1479 the therapy is ended.
Returning to block 1470, where a determination has been made that the stop therapy switch 226″ has not been actuated, then as represented at line 1480 and block 1481, a determination is made as to whether the target or setpoint temperature TSP has been reached. This target temperature has been discussed in conjunction with dashed line 142 in connection with
Where the query posed at block 1484 results in an affirmative determination that the allocated maximum time to reach setpoint has elapsed before that setpoint has actually been reached, then an error condition is at hand and is represented at line 1508 and block 1510, an error condition is displayed at display 204″ and the program continues as represented at lines 1512 and 1506 to the shutdown procedures as above described at block 1522. The program continues as represented at line 1524 and block 1526 wherein pertinent data for the procedure parameters is recorded. It may be recalled that this data can be displayed at display 204″ by actuation of button switch 206″. The procedure then continues as illustrated at line 1528 extending to node 1530 representing a therapy ended stage.
Returning to
The system and method thus far presented has utilized the earth's magnetic field in conjunction with the temperature sensors and magnetometer instrumentation. However, the magnetic field may be applied utilizing an electromagnet.
Looking to
Referring to
Next, the method provides a confirmational procedure as represented at line 1606 and block 1608 wherein imaging and other such instrumentation are used for the purpose of ascertaining if the implants are in the proper location with respect to the target tissue. Should the implant positioning not be appropriate, then as represented at loop line 1610, the method reverts to the procedure described in connection with block 1604. Upon an affirmative determination with respect to the query posed at block 1608, then as represented at line 1612 and block 1614 the patient is positioned on the treatment support such as the table 1120 so that the earlier-located marker or outline on the surface of the patient is visible for the next step in the procedure. Next, as represented at line 1616 and block 1618 the heating coil positioning mode ensues wherein the ACF heating coil or antenna is located at a proper location with respect to the skin of the patient. The procedure then continues as represented at line 1620 and block 1622 providing for turning on the console 112′″ (switch 180′″ illuminating green LED 182′″). Then, as represented by line 1624 and block 1626, the operator selects the duty cycles. It may be recalled that duty cycle ranges δt1 and δt2 are set forth in Table 1. As described in conjunction with the
Where the query posed at block 1664 is responded to in the affirmative, then as represented at line 1676 and block 1678, green LED 212′″ at console 112′″ is illuminated and the program continues as represented at line 1680 and block 1682. At this juncture in the procedure, the operator will be positioning the magnetometer probe 1124′″ as close as practical to the implant(s) in order to obtain a maximum magnetometer signal channel differentiation.
The ACF heating assembly actuation next is addressed as represented at line 1684 and block 1686 providing for turning off the electromagnet 1544 by actuating the stop button switch 1550 on console 112′″.
The ACF heating assembly actuation next is addressed as represented at line 1688 and block 1690 providing that the ACF heating assembly 94′″ is turned on and, as represented at line 1692 and block 1694 a query is posed as to whether the ACF heating unit is enabled both by the development of a requisite voltage level, VRF as being greater than or equal to three volts and the presence of the earlier-described magnetometer signal Vc as being greater than or equal to three volts. If those ANDed conditions are not met, then as represented at line 1696 and block 1698 an error visual cue is provided at display 204′″ indicating that the control leads 102′″ are not properly connected to the control console 112′″. The program then continues as represented at line 1700 and block 1702 to display a prompt advising the operator to turn off the ACF heating unit and check the cable attachment 102′″ extending to the console 112′″. The program then reverts to line 1688 as represented at line 1704.
Where the query posed at block 1694 results in an affirmative determination, then as represented at line 1706 and block 1708, green LED 211′″ is illuminated and the program continues as represented at line 1710. Line 1710 extends to the query posed at block 1712 determining whether the duration for therapy and maximum time allotted for reading setpoint temperature TSP have been set to correct and intended intervals. These intervals are set by the operator employing the up/down switches 190′″ and election switch 191′″ in conjunction with display 192′″ on console 112′″. Where the therapy duration is incorrect, then as represented at line 1714 and block 1716 appropriate adjustment of the control switches 190′″ and 191′″ is made and the program reverts to line 1710 as represented at line 1718.
Where the query posed at block 1712 is responded to in the affirmative, then as represented at line 1720 and block 1722 a determination is made as to whether the therapy time elapsed indicates zero minutes. This readout is provided at console 112′″ at display 222′″. In the event that this display does not register zero minutes, then as represented at line 1724 and block 1726, reset button switch 224′″ is actuated and the program continues as represented at lines 1728 and 1720. With the therapy time remaining set at zero, the procedure continues as represented at line 1730 and block 1732. Block 1732 reflects the activity of controller 240′″ (
In the event the query posed at block 1732 results in an affirmative determination, then as represented at line 1740 and block 1742 thermotherapy, which generally will comprise hyperthermia therapy, commences with the operator actuation of the start therapy button switch 220′″ at console 112′″. With this actuation, electromagnet 1544 automatically is restarted, ACF heater unit 96′″ and the magnetometer 1122′″ are activated. Such actuation of the switch 220′″, will, as represented at line 1744 and block 1746 provide for the illumination of green LED 213′″ indicating that therapy is in progress. The procedure then continues as represented at line 1748 to the query at block 1750 determining whether or not the stop therapy button switch 226′″ at console 112′″ has been actuated. In the event such actuation has occurred, then as represented at line 1751 and block 1752 the AC field heating power assembly is turned off; electromagnet 1544 is stopped; green LED 213′″ is turned off and red LED 228′″ is illuminated as a visual cue that the therapy has been stopped. The procedure then continues as represented at line 1753 and block 1754 at which juncture the operator determines whether or not therapy is to be resumed. In the event that it is to be so resumed, then as represented at line 1755 and block 1756, in order to resume the therapy mode for the duration of the unlapsed therapy, the start therapy switch 220′″ is actuated at control console 112′″ which, in turn, causes the turning off of red LED 228′″. The start therapy switch actuation automatically activates the ACF heating assembly 94′″ as well as the automatic restarting of the electromagnet 1544. The program then continues as represented at line 1757 which extends to line 1744.
Where the query posed at block 1758 results in a determination that therapy is not to be resumed, then as represented at line 1758 and node 1759 the therapy is ended.
Returning to block 1750, where a determination has been made that the stop therapy switch 226′″ has not been actuated, then as represented at line 1760 and block 1761, a query is made as to whether the target setpoint temperature TSP has been reached. This target temperature has been discussed in conjunction with dashed line 142 in connection with
Where the query posed at block 1778 results in an affirmative determination, then the program continues as represented at line 1786 and block 1804. Returning to block 1764, in the event that the maximum time allocated for reaching target temperature TSP, has elapsed before the setpoint temperature has been reached, then an error condition obtains and is represented at line 1788 and block 1790 an error is displayed at display 204′″ and the program continues as represented at lines 1792 and 1786 to block 1804. Block 1804 provides for the deactivation of the active components of the system. In this regard, the ACF heating power system is turned off; electromagnet 1544 is turned off; magnetometer 1122′″ is turned off; therapy completed green LED 214′″ is illuminated; and green LED 213′″ representing therapy in progress is de-energized. The program then continues as represented at line 1806 and block 1808 wherein pertinent data for the procedure parameters is recorded. It may be recalled that this data can be displayed at display 204′″ by the actuation of button switch 206′″. The procedure then continues as illustrated at line 1810 extending to node 1812 representing a therapy ended stage.
As is apparent, the sensor and/or sensor/heater component combination of the invention as combined with a magnetometer based temperature evaluation approach provides the highly desirable, untethered, in vivo thermal treatment of tissue. Such tissue may include bone matter, i.e., boney tissue. In this regard, the sensors may be attached to a bone repair implant or support component such as a rod, plate or screw allowing such an implant then to be raised to a controlled and slightly elevated temperature, for example, in a range of from about 39° C. to about 41° C. The heating can be accomplished by already existing approaches, such as by microwave radiation, or ultrasound. Such mild but targeted and accurately controlled temperature elevations serve to accelerate the rate of bone growth and/or fusion necessary to ultimate bone repair. The untethered nature of the sensors as discussed above, permits an essentially non-invasive repetition of these therapies.
In another embodiment of the invention, a sensor/heater component combination, allows controlled heating of the region directly surrounding a boney injury, wound or tumor site. In this regard, the sensor/heater component combination may be attached to a bone repair implant or support component or a number of sensor/heater component combinations could be placed adjacent to the area to be treated. The sensor/heater component combination allows an implant or the tissue adjacent to sensor/heater component to be heated, raised to a controlled and slightly elevated temperature, with the absolute temperature range depending on a number factors, including but not limited to, the initial body temperature, the duration of heating used, and the stage of healing of the boney tissue, and such additional factors as discussed previously herein.
Implantation of sensors and/or sensor/heater component combination minimizes the potential for infection present with tethered bone stimulation implants, which are susceptible to infection at the site of the tether. Nor does the tissue immediately adjacent to an injured bone need be exposed by invasive surgery. The minimally invasive implantation of the sensor/heater component allows the sensor/heater component combination to remain in place for an extended treatment period. The sensor/heater component combination can be placed such that the target tissue is directly heated. Additional advantages of the sensor/heater component combination, whether used alone, or in conjunction with other heating mechanisms is the ability to readily determine the temperature of the target boney tissue, which cannot be easily done with existing untethered bone growth stimulators. Due to cytotoxic effects if the tissue is overheated, which could damage boney tissue, the ability to monitor the temperature of the target tissue allows therapy that maximizes the therapeutic benefit by maintaining the target tissue in the chosen therapy temperature range.
Hyperthermia can be used as a means for inducing immunity or for treating diseases caused by infectious agents. Particularly for chronic infections that are recalcitrant to treatment with drugs or other existing therapies, an infected individual's immune system could be activated by using hyperthermia to induce infected cells to present immunogenic peptides. In this regard, the sensor/heater component of the present invention could be implanted in tissue that harbors the pathogen. Heating of the tissue sufficient to induce heat shock, as previously described, would cause infected cells to present immunogenic peptides derived from the infectious agent, thus activating the immune system. Those tissues or organs with relatively high numbers of infected cells would be preferred targets for the hyperthermia. Examples of targets include, but are not limited to, the liver or spleen for Mycobacterium tuberculosis infections; lymph nodes for Human Immunodeficiency Virus infections; the liver for Plasmodium or hepatitis virus infections.
The present invention is superior to currently available methods for inducing immunity to infectious agents using HSPs because it offers more precise temperature control of the heat shock than whole organism hyperthermia; focuses the induction of the immune system on a subset of the peptides presented by whole organism hyperthermia; induces an immune response against the actual infectious agent present in the organism, rather than against a non-specific agent that exogenous purified vaccines would produce; and can be used to treat acute infection for which no effective therapy is available.
Since certain changes may be made in the above-described apparatus, method and system without departing from the scope of the invention herein involved, it is intended that all matter contained in the description thereof or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
This application is a divisional of copending U.S. application Ser. No. 10/310,475, and claims the benefit of U.S. Provisional Application No. 60/349,593, filed Jan. 18, 2002, Application for U.S. patent Ser. No. 10/201,363 filed Jul. 23, 2002, and Application for U.S. patent Ser. No. 10/246,347, filed Sep. 18, 2002, and said applications are hereby incorporated by reference.
| Number | Name | Date | Kind |
|---|---|---|---|
| 6635009 | Feucht | Oct 2003 | B2 |
| Number | Date | Country | |
|---|---|---|---|
| 20050125046 A1 | Jun 2005 | US |
| Number | Date | Country | |
|---|---|---|---|
| 60349593 | Jan 2002 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10310475 | Dec 2002 | US |
| Child | 11036276 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10246347 | Sep 2002 | US |
| Child | 10310475 | US | |
| Parent | 10201363 | Jul 2002 | US |
| Child | 10246347 | US |
