Patent Application
20100185099
1. Field of the Invention
The invention relates generally to a system and a method for therapy and diagnosis in a subject. More particularly, the system and method relate to a system and method for tumor therapy and diagnosis in a human or animal. Even more particularly, the invention relates to a system and method for photodynamic therapy (PDT) and/or photothermal therapy (PTT) and/or photodynamic diagnosis (PDD) of a site on and/or in a body, wherein electromagnetic non-ionizing radiation is conducted to the site for reaction with the radiation, wherein the system comprises at least one operation mode selector element for distribution of radiation from at least one source of radiation to a reaction site, and/or from the reaction site to at least one radiation sensor, respectively, and wherein the reaction site generally is a tumor site with a tumor, such as a malignant tumor.
2. Description of the Related Art
Within the field of medical therapy of tumor diseases, a plurality of treatment modalities has been developed for the treatment of malignant tumor diseases: operation, cytostatic treatment, treatment with ionizing radiation (gamma or particle radiation), isotope therapy and brachytherapy employing radioactive needles are examples of common treatment modalities. In spite of great progress within therapy, the tumor diseases continue to account for much human suffering, and are responsible for a high percentage of deaths in western countries. A relatively new treatment modality, photodynamic therapy, commonly abbreviated PDT, provides an interesting complement or alternative in the treatment field. A tumor-seeking agent, normally referred to as a precursor or sensitizer, is administered to the body intravenously, orally or topically. It generally accumulates in malignant tumors to a higher extent than in the surrounding healthy tissue. The tumor area is then irradiated with non-thermal red light, normally from a laser, leading to excitation of the sensitizer to a more energetic state. Through energy transfer from the activated sensitizer to the oxygen molecules of the tissue, the oxygen is transferred from its normal triplet state to the excited singlet state. Singlet oxygen is known to be particularly toxic to tissue; cells are eradicated and the tissue goes in necrosis. Because of the localization of the sensitizer to tumor cells a unique selectivity is obtained, where surrounding healthy tissue is spared. The clinical experiences, using in particular haematoporphyrin derivative (HPD) and delta aminolevulinic acid (ALA) have shown good results.
Sensitizers may also exhibit a further useful property; to yield a characteristic fluorescence signal when the substance is excited with visible or ultraviolet radiation. This signal clearly appears in contrast to the endogenous fluorescence of the tissue, which is also called autofluorescence, and is used to localize tumors and for quantifying the size of the uptake of the sensitizer in the tissue.
The limited penetration in the tissue of the activating radiation is a big drawback of PDT. The result is that only tumors less than about 5 mm in thickness can be treated by surface irradiation. In order to treat thicker and/or deep-lying tumors, interstitial PDT (IPDT) can be utilized. Here, light-conducting optical fibers are brought into the tumor using, e.g., a syringe needle, in the lumen of which a fiber has been placed.
In order to achieve an efficient treatment, several fibers have been used to ascertain that all tumor cells are subjected to a sufficient dose of radiation so that the toxic singlet state is obtained. It has been shown to be achievable to perform dose calculations of the absorptive and scattering properties of the tissue. E.g., in the Swedish patent SE 503 408 an IPDT system is described, where six fibers are used for treatment as well as for measurement of the light flux which reaches a given fiber in the penetration through the tissue from the other fibers. In this way an improved calculation of the correct light dose can be achieved for all parts of the tumor.
According to the disclosure of SE 503 408, the light from a single laser is divided into six different parts using a beamsplitter system comprising a large number of mechanical and optical components. The light is then focused into each of the six individual treatment fibers. One fiber is used as a transmitter while the other fibers are used as receivers of radiation penetrating the tissue. For light measurement light detectors are mechanically swung into the beam path which thus is blocked, and the weak light, which originates from the fibers that collected the light which is administered to the tissue, is measured.
However, such open beam paths result in a strongly lossy beamsplitting and the resulting losses of light drastically impair the light distribution as well as the light measurement. Furthermore, such a system must often be adjusted optically, which is also an important drawback in connection with clinical treatments. The system is also large and heavy and difficult to integrate into a user-friendly apparatus. Moreover, it is difficult to control the power of the light sent into each individual fiber, which makes the measurement results unreliable.
EP-A1-0523417 discloses a pipeline switch for distribution of radioactive emitters and/or test objects for radiotherapy, i.e. radioactive radiation treatment of a body. The emitters or test objects are conveyed within pipelines on flexible wires movable within the conduit. First pipes for conveying the flexible wires to the switch are on the one hand connected to a moveable switch element and second pipes further conveying the flexible wires to the body connected to a second, stationary switch element. The two switch elements are moveable relative each other and different constellations of pipelines are thus possible. However, when changing from one constellation to another, the flexible wire has to be retracted between each switching process, otherwise the relative movement of the switch element is obstructed. Switching times and treatment times are thus very long. Furthermore, the pipelines are not suitable for conducting radiation themselves, they just provide external protection and guidance to the flexible wires conveyed therein. The construction is also bulky and not suited for small optical fibers. Moreover, the arrangement of the disclosure is not suited for diagnosis, only for therapy, and no interactive co-operation is disclosed.
EP-A2-0280397 discloses a sterilizable endoscope having a central coherent fiber bundle for carrying an image to a viewing means. The fiber bundle is surrounded by light fibers. The proximate end of the endoscope is provided with a coupling means for aligning the optical fiber bundle with the optical system of the viewing means and for providing an interface with light transmitting means to transmit light from a light source along the light fibers to a body cavity to be inspected. The device can be used for detection of cancer cells and treatment thereof by phototherapy. A dye is attached to the tissue being examined and subsequently exposed to an exciting laser light frequency. Cancer cells will emit fluorescent light at a characteristic fluorescence frequency. The fluorescence light is detected and displayed on the video monitor and light with the same frequency as this fluorescent light is then transmitted through the light fibers to the cell for phototherapy treatment. However, only the use of a single wavelength light source is disclosed, it is thus not possible to have multiple diagnostics performed without manually exchanging the light source. Moreover, it is not possible to switch between different constellations of the light fibers, i.e. all fibers always have the same function (light in or light out). The coupling means mentioned in EP-A2-0280397 is only used to adjust the path of light through a two-part endoscope when it is assembled prior to use. In addition, different fibers are used for directing therapeutic light to a cancer location and to direct diagnostic light back through the endoscope. No distribution is performed between different operating modes. This solution offers for instance neither interactive treatment nor tomographic mapping of tumors.
WO-A1-02074339 discloses a device and method for photodynamic diagnosis of tumor tissue by using fluorescent cobalamins. These fluorescent cobalamins are used as diagnostic and prognostic markers (a) to distinguish cancer cells and tissues from healthy cells and tissues, and (b) to determine if an individual responds positively to chemotherapy using cobalamin-therapeutic bioconjugates. An apparatus is disclosed that includes a camera coupled to the proximal end of a surgical telescopic device. The surgical telescopic device is used for illuminating tissue with non-white light and detecting the emitted fluorescence for diagnostic purposes. The use of a dual light sources including a red (non-white) and a white light source is disclosed. The white light source is used for conventional illumination of the tissue. A switch is mentioned for switching between the alternative light sources. The switch might be voice-actuated, mechanically-operated (foot pedal), optically-operated, or electronically-operated. The switch is not described in more detail, except that a mirror or prism under mechanical or electromechanical control can be used to switch between the two light sources. Alternatively, a light source with two physically separated outputs is disclosed. In this case the light input to the surgical telescopic device has to be moved between the two outputs in order to switch illumination source for the tissue. The device is not suitable for therapy. Therapy has to be performed conventionally by a surgeon removing the cancerous tissue detected by means of fluorescence. Therefore, this device is not suited for interactive diagnosis and therapy. Furthermore, there is no indication for a switch suitable for switching between different modes of diagnosis or therapy. Furthermore, the disclosed device offers only substantially superficial diagnosis or treatment, interstitial tissue cannot be diagnosed or treated. The device is also limited to existing body cavities and has the drawback that endoscopic probes are bulky and large compared to single optical fibers.
EP-A2-0195375 discloses a catheter for laser angiosurgery. The device is used for detecting atherosclerotic plaque deposits by means of detecting fluorescent light as a reaction on excitation light sent through the catheter comprising optical fibers for this purpose. The same fiber may be used for sending excitation light to the plaque and for receiving fluorescent light from the plaque. When plaque is detected, it may be removed by sending high energy light through selected fibers in the catheter. However, this system is not suited for diagnosis or treatment of tumors. Fibers to be illuminated are selected by purely mechanical arrangements either moving the light source or the fibers in order to align the two towards each other. This device is also bulky compared to single fibers, similar to the above mentioned endoscope, bound to existing body cavities and works substantially superficial. Furthermore it is not selective, i.e. all tissue aimed at is destroyed, independently if it is noxious or healthy.
Thus, there is a need for a new compact device allowing distributing of radiation in a system for PDD, PDT and PTT for implementing a smart way of performing interactive interstitial treatment. One solution would be to use smart mechanical constructions for switching between different operating modes avoiding e.g. the lossy beamsplitters and allowing e.g. automatic calibration.
Such a mechanical solution to the above mentioned problems has been proposed in PCT/SE02/02050, wherein a distributor for radiation having two discs rotating relative each other is described. The radiation distributor couples optical fibers between different operating modes by rotational movement of fibers in these discs relative each other. For switching between several light sources to one fiber going to the patient, an assembly with a total of four discs is described. There is a need to further reduce the size of the described solution in order to further minimize the size of the system.
However, although these purely mechanical constructions are improvements to the above described known IPDT system and although the above described problems are solved, these mechanical solutions have other limitations, related to e.g. mechanical inertia limiting the switching time between the different modes of a therapy and diagnosis system such as an interactive interstitial treatment system. There is also a desire to remove at least a certain number of mechanical switching elements in order to minimize costs for service. However, sometimes it is not economically defendable to replace all mechanical systems.
Thus, there is a need for a new system and/or compact device allowing distributing of radiation in a system for therapy and diagnosis in a human or animal, wherein the therapy and diagnosis comprises PDD, PDT and PTT, and wherein the system provides an optimal relationship between advantages such as reliable measurements, optimum of flexibility, cost-effectiveness, production efforts, but also that e.g. multiplexing, as described below, is possible.
The present invention overcomes the above identified deficiencies in the art and solves at least the above identified problems by providing a system and a method according to the appended patent claims, wherein a very practical and efficient implementation of interactive IPDT is achieved in that different radiation measurements for diagnostics and dosimetry can be performed in an integrated and simple way. An important application of the invention is interactive, interstitial photodynamic therapy, and/or interactive photothermal tumor therapy. According to the invention, the size of a system using existing radiation distributors, such as described in PCT/SE02/02050 is further reduced. Furthermore, the invention is improving the prior art by providing alternative solutions to the problems and drawbacks associated with the systems according to the prior art. Moreover, the system according to the invention combines the advantages of purely mechanical and purely non-mechanical solutions in a new and synergetic way. Non-mechanical elements have several advantages. Among others, these advantages comprise: high switching speed between different system operation modes (diagnosis, photodynamic therapy, thermal therapy); compactness and stability of the system; excellent radiation parameters; long life of the system due to no mechanical wear of the components and due to many more switching cycles during a life-cycle of the elements of the system, and low noise offering comfort to the user and patient, etc. In combination with mechanical distributors for radiation, non-mechanical elements for distribution of radiation also provide increased flexibility.
The term “radiation” used hereinafter in this specification refers to radiation suitable for the field of the invention, i.e. for photodynamic therapy (PDT) and/or photothermal therapy (PTT) and/or photodynamic diagnosis (PDD). More specifically this radiation is “optical” radiation, i.e. non-ionizing electromagnetic radiation within the wavelength-range of infrared (IR), visible or ultraviolet light. This also concerns radiation sources, radiation conductors, radiation sensors, radiation switches etc. within the scope of the embodiments and claims defining the invention, i.e. these sources, conductors or sensors for “radiation” are adapted to generate, conduct, measure, etc. the above-mentioned radiation.
According to one aspect of the invention, a system for therapy and/or diagnosis of a human or animal comprises at least one first radiation source for emission of a diagnostic radiation, at least one first radiation conductor adapted to conduct radiation to a site at or in said human or animal, at least one second radiation source for emission of a therapeutic radiation through at least one of said radiation conductors to said site, and at least one radiation detector, wherein at least one coupling element for coupling of radiation couples radiation from at least the first radiation source to the site and/or from said second radiation source to said site and/or from said site to said detector. The coupling elements are combinations of at least one translatory distributor comprising at least one translatory element being arranged in such a manner that radiation is coupled in different constellations by translatory movement of said translatory element between pre-determined positions, wherein radiation conductors are attached to said translatory element, and at least one rotary distributor comprising two rotary elements being arranged in such a manner that radiation is coupled in different constellations by rotational movement of said rotary element between pre-determined positions, wherein radiation conductors are attached to said elements, and at least one operation mode selector means for directing either said therapeutic radiation or said diagnostic radiation to said site through said at least one first radiation conductor.
As already mentioned, the system combines the advantages of non-mechanical elements with the advantages of mechanical elements in an optimal way. Among others, these advantages of radiation elements comprise: high switching speed between different system operation modes (diagnosis, photodynamic therapy, thermal therapy); compactness and stability of the system; excellent radiation parameters; long life of the system due to no mechanical wear of the components and due to many more switching cycles during a life-cycle of the elements of the system. Examples of the advantages of mechanical elements comprise: easy manufacturing; inexpensive; readily available technology; efficient radiation transmission; low crosstalk. Yet a further advantage is an adaptation to effective consideration of power management and compatibility of the system components. In general, the radiation used for therapy has a much higher effect/power than the diagnostic radiation, with at least a factor 10 in difference. The elements for switching/coupling this radiation have to be adapted to this effect. In general it is more cost-effective to use mechanical solutions for high power applications. Thus, the combination of elements suggested by the present application has a surprising synergetic effect that one does not realize immediately. Yet a further advantage is that according to one embodiment, the system is made more simple by using a therapeutic radiation source also for diagnostic radiation, thus saving a diagnostic radiation source. Finally switching times are provided that offer a convenient and comfortable treatment of a patient.
In order to explain the invention in more detail, a number of embodiments of the invention will be described below with reference to the appended drawings, wherein
Different embodiments of the system according to the invention are now described with reference to the drawings. In order to simplify the description of the embodiments, reference numerals for similar elements shown in the drawings are not repeated throughout all the figures.
Evenly distributed holes 513 lying on a circle are arranged in both discs (not shown in the Figs.) for fixation of radiation conductors 6, 6′, 7a, 7a′. Preferably the diameter of the holes is 0.1-0.7 mm in case the radiation conductors are optical fibers directly attached to the disc. In order to attain a high precision, allowing the radiation conductors to be arranged exactly face to face, the holes of the two discs can be drilled together, e.g. with a centering tube. Alternatively, high precision cutter or drilling machines may be used for producing the discs or any other mechanical elements mentioned in this description. Then the common axis 2 is utilized arranged through centrally located holes 512 of the discs 3,4. It is thus possible to achieve a very high precision when making the series of holes.
By employing discs drilled together, radiation conductors can be fixed in said discs, wherein an extra, thinner disc then can be turned slightly, preferably spring-loaded, so that all radiation conductors are simultaneously pinched in their positions without the need for any glue or other fixation means. Alternatively, the diameter of the holes is made larger than the diameter of the radiation conductors, wherein the holes can be dressed with an appropriate piece of tubing, or the ends of the radiation conductors can be supplied with a fitted hose. Alternatively, the ends of the radiation conductors can be flared or flanged into the holes or the holes may be equipped with appropriate SMA connector or other type of connectors for receiving radiation conductors. The same principle applies to the holes and fixation of radiation conductors in the translatory radiation distributors as described with reference to the following embodiments.
Preferably the radiation conductors are optical fibers, wherein different types of hoses or flexible tubes containing a radiation-conducting material are included. The radiation conductors should have such a length and be arranged in such a way that the discs can be turned a full turn (+−180 degrees) without problems. The direction of movement may be reversed to avoid the radiation conductors forming a spiral. The same principle applies to the translatory elements disclosed in this description, wherein the radiation conductors connected to the translatory elements should have such a length that the function of the translatory elements or the radiation conductors is not negatively influenced. Moreover, the length of the radiation conductors should be sufficiently long, that the positioning of the distal ends of the patient radiation conductors are not negatively influenced.
According to this embodiment of the invention, a plurality of first radiation conductors 6 in a system for PDD, PDT and PTT are arranged in turnable disc 3 for conduction of radiation to and from a reaction site 200 (shown e.g. in
The holes 513 in the fixed disc as well as in the turnable disc are arranged on a circular line, wherein the circle radius on one disc equals the circle radius on the other disc. The holes on one disc are equally distributed along the circle line with an angular separation of v1=(360/n1) degrees, where n1 equals the number of holes, and the holes of the other disc are equally distributed along the circle line with an angular separation v2 equaling (360/n2) degrees. The first ends of the first radiation conductors 6 are fixed in the holes of the turnable disc 3, and first ends of the second radiation conductors 7a are fixed in the holes of the fixed disc 4. In order to make the holes, and thereby the radiation conductors in both discs connectable to each other in different constellations by turning of the turnable disc 3, n2 is selected to be a multiple of n, in such a way that n2 is obtained as an integer larger or equal to 1. Suitably the number of holes in the fixed disc is chosen from two to more than six, e.g. two, three, four, five, six, seven, eight, nine or ten.
According to the currently described embodiment, six holes are arranged in the turnable disc 3 and twelve holes are arranged in the fixed disc 4. With six first radiation conductors 6 the angular separation of the holes will accordingly become 60 degrees in the turnable disc 3 and with twelve holes arranged in the fixed disc 4 the angular separation will become 30 degrees for the second radiation conductors 7a.
The coupling of diagnostic radiation from diagnostic radiation sources 9a to a single radiation conductor 7a′ is accomplished by means of a radiation combiner 310. For switching to a diagnostic operation mode, the therapeutic radiation sources (not shown in
In order to facilitate the comprehension of the invention the following description of a preferred embodiment of the distributor of the system according to
Thus, the turnable or rotatable disc 3, as well as the fixed disc 4, have six holes 513 for corresponding second radiation conductors, and, for disc 4, in addition, six further holes for second radiation conductors being connected to therapeutic radiation sources (not shown in
By turning the turnable disc 3 the first and the second radiation conductors become connectable to each other in different constellations. An exact positioning of the opposing radiation conductors in the distributor 1 is facilitated by arranging means for stopping the turnable disc 3 in pre-determined angular positions, for instance, grooves may be arranged in the axis 2 for catching a spring-loaded ball arranged in the turnable disc 3 (not shown in the Figs.) or an angular detector on the rotatable disc can be used. Alternatively electronic regulation using stepper motors or servomotors may be used for this purpose, also in combination with then “seventh hole” method described below.
In order to allow a fast and efficient switching between a diagnostic operation mode and a therapeutic operation mode, every second of the second radiation conductors of the distributor 1 according to the invention, are divided into a first and into a second series. Both series of holes are arranged on the same circle, but displaced by 30 degrees with regard to each other. A specific radiation conductor in the first series of every other second radiation conductor is arranged for emitting radiation from at least one radiation source. The other, non specific radiation conductors in the first series of second radiation conductors are arranged for conduction of radiation to at least one radiation sensor 12. The second series of every other second radiation conductor is for therapeutical purposes arranged to emit radiation to the reaction site 200 from at least one radiation source.
The radiation conductors are preferably optical fibers, which in the distributor 1 shown in
With reference to
By turning the turnable disc 3 by 30 degrees the fibers 6 which are optically coupled to the tissue of the patient can be employed for therapy as well as diagnostics and measurements. One radiation conductor 7a′ out of every second radiation conductor fixed on disc 4 is in the diagnostic operation mode connected to different radiation sources for diagnostics, while the other five radiation conductors 7a receive signals, which are related to the interaction of these radiation sources with the tissue. Radiation conductors (not shown in
Since intensity as well as spectral resolution is of interest, the distal ends of these five radiation conductors 7a are arranged in a slit-like arrangement so that they overlap the entrance slit and/or constitute the entrance slit of the radiation sensor 12, which may be a compact spectrometer or other type of detector and is supplied with a two-dimensional detector array or one to several one dimensional detector arrays. The recording range of the spectrometer is preferably within the range of approximately 400 to 900 run. Each of the radiation conductors 7a can of course be connected to an individual radiation detector 12 in the form of a spectrometer or another type of detector, e.g. a compact integrated spectrometer.
The assembly 1 is shown with the two discs 3,4 on a common axle 2 and the combiner 310 for coupling different diagnostic radiation sources. In this way a compact and robust construction is obtained for switching between the diagnostic radiation sources.
Preferably one of the radiation sources 9a is a laser of the same wavelength as the ones utilised for the laser irradiation for photodynamic tumor therapy, but could be of lower output power.
Certain of the radiation sources 9a are utilised in order to study how radiation (light) of the corresponding wavelength is penetrating through the tissue of the tumor. When radiation from a radiation source is transmitted through the particular radiation conductor via combiner 310 and the discs 4, 3 into the tissue, one radiation conductor 6′ of the first radiation conductors 6, which is the one opposing the radiation conductor 7a′, will function as a transmitter in the tumor, and the other five radiation conductors 6 in the tumor will act as receivers and collect the diffuse flux of radiation reaching them. The radiation collected is again conducted via the discs 3, 4 and via radiation conductors 7a to the radiation sensor 12 and five different radiation intensities can be recorded on the detector/detectors/detector array.
When the turnable disc 3 is turned by 60 degrees, the next radiation conductor 6 to the patient will get the role as transmitter, and the five others become the receivers for a new radiation distribution. After four further turns of the turnable disc 3, each by 60 degrees to the following radiation conductor 6 in the patient, radiation flux data for all remaining combinations of transmitters/receivers have been recorded. Thus, in total 6×5=30 measurement values are obtained and can be used as input data for a tomographic modeling of the radiation dose build up in the different parts of the tumor during the course of the treatment. Furthermore, by switching through the three radiation sources 9a, by means of switching the appropriate radiation source on or off, these 30 measurement values are multiplied by the number of radiation sources, resulting in 90 tomographic measurement values.
In addition to a specific wavelength, radiation from a white light source and/or broadband light emitting diodes and/or line light sources can be coupled into the particular active radiation conductor in radiation distributor 1. On passage through the tissue to the receiving radiation conductor 6 in the patient, the well-defined spectral distribution of the radiation source will be modified by the tissue absorption. Then, oxygenated blood yields a different signature than non oxygenated blood, allowing a tomographic determination of the oxygen distribution utilizing the thirty different spectral distributions which are read out, five spectra at a time in the six possible different constellations on rotation of the turnable disc 3 during a diagnostic investigation. Such a determination of the oxygenation in the tumor is important, since the PDT process requires access to oxygen in the tissue.
Finally, a light source for red, blue/violet or ultraviolet light, e.g. a laser, can be coupled to the particular active radiation conductor in radiation distributor 1. Then fluorescence is induced in the tissue, and a sensitizer administered to the tissue displays a characteristic red fluorescence distribution in the red/near-infrared spectral region. The strength of the corresponding signal allows an approximate quantification of the sensitizer level in the tissue.
Since the short wavelength light (ultraviolet or blue/violet light) has a very low penetration into the tissue, the induced fluorescence will only be measured locally at the tip of the radiation conductor. For this task there is in this case for the corresponding radiation source 9a at the distal end of the particular radiation conductor 17 a beamsplitter 18, connected via the radiation conductor 17 and which is preferably a dichroic beamsplitter, transmitting the exciting radiation but reflecting the red-shifted fluorescence radiation. This reflected radiation is focused into the distal end of a conveying radiation conductor 19, the other end of which is connected to the radiation sensor 12, which records the fluorescence radiation distribution. A suitable self-contained fluorosensor is described in Rev. Sci. Instr. 71, 3004 (2000). Such a system with dichroic beamsplitters may also in a similar way be implemented by means of the other distributor system as shown in
By rotating the turnable disc 3, the fluorescence that is a specific function of the concentration of the sensitizer, can be measured sequentially at the tips of the six radiation conductors 6. Since the sensitizer is bleached by the strong red treatment radiation, being particularly strong just around the tip of the radiation conductor 6 conducting radiation to the patient, it is essential to make this measurement before the start of the treatment.
If the tips of the radiation conductors 6 in addition are treated with a material, the fluorescence properties of which are temperature dependent, sharp fluorescence lines are obtained upon excitation, and the intensity of the lines and their relative strength depend on the temperature of the tip of the radiation conductor 6, being employed for treatment. Examples of such materials are salts of the transition metals or the rare earth metals. Thus also the temperature can be measured at the six positions of the six radiation conductors, one at a time. The measured temperatures can be utilised to find out if blood coagulation with an associated radiation attenuation has occurred at the tip of the radiation conductor 6, and for studies regarding the utilization of possible synergy effects between PDT and thermal interaction. Since the lines obtained are sharp, they can be lifted off the more broad-banded fluorescence distribution from the tissue.
The concentration of the sensitizer can for certain substances be measured in an alternative way. Then the red radiation used for the radiation propagation studies is used to induce near-infrared fluorescence. This fluorescence penetrates through the tissue to the tips of the receiving radiation conductors 6, 120, 142, and are displayed simultaneously as spectra obtained in the radiation sensor 12. A tomographic calculation of the concentration distribution can be performed based on in total thirty measurement values.
After diagnostic measurements and calculations have been performed, the fibers 6 optically coupled to the tissue of the patients can be utilised for therapy by rotation of the turnable disc 3 by 30 degrees. Therapeutic radiation sources are thus coupled to the patient fibers 6. The therapeutic radiation sources are preferably laser sources with a wavelength, which is adapted to the absorption band of the sensitizer. At the photodynamic tumor treatment a dye laser or a diode laser is preferably used, with a wavelength which is selected with regard to the sensitizer employed. For PhotoErin® the wavelength is 630 nm, for delta aminolevulinic acid (ALA) it is 635 nm and for phthalocyanines it is around 670 nm. The individual lasers are regulated during the treatment to a desirable individual output power. If desired, they may have built-in or external monitoring detectors.
The therapeutical treatment can be interrupted and new diagnostic data can be processed in an interactive method until an optimal treatment has been reached. This method can include synergy between PDT and hyperthermia, where an increased temperature is reached at increased fluxes of laser radiation. The whole process is controlled using a computer, which does not only perform all the calculations but also is utilised for regulation.
This present embodiment has the advantages of being cheap, all diagnostic radiation sources may be switched on at the same time or multiplexed, there is little risk of “blooming” (detector in permanent saturation) of the radiation detector 12, there is no moving element or mechanical part for switching between the detector radiation sources, optical fibers with large diameters may be used, and the system has low radiation losses, i.e., it has a sound “photoneconomics”.
The coupling of diagnostic radiation from diagnostic radiation sources 144-146 to a single radiation conductor 160 is accomplished by means of an radiation combiner 310. For switching to a diagnostic operation mode, the therapeutic radiation sources 101 are switched off and subsequently one of the three diagnostic radiation sources 144-146 is activated. Thus, diagnostic radiation is conducted to combiner 310, where the radiation from the active diagnostic radiation source is coupled to the output of the combiner leading via the radiation conductor 160 to a transversal radiation distributor 110,111, where it is coupled to one of radiation conductors 120 going to a tumor site 200 in a patient.
A first translatory distributor B for radiation comprises two, in close proximity to each other lying, longitudinal translatory elements 110, 111 made of, e.g., 1 cm thick steel, however lower thicknesses are possible, as mentioned above. The longitudinal translatory elements are hereby arranged in such a manner that they may move translatory relative to each other in such a manner that a plurality of radiation conductors 160 or 102, 131 respectively, such as optical fibers, being attached to holes in the first translatory element 110 are coupled to a second plurality of fibers 120, 431a-431e respectively, being attached to holes in the second translatory element 111, 470 by appropriately positioning the two elements relative to each other. The system 400 shown in
In the diagnostic position radiation is coupled to at least one radiation detector 430. The diagnostic part of system 400 comprises three diagnostic radiation sources 144-146, which are coupled to a single output radiation conductor 160 by means of an radiation combiner, in such a manner that an active diagnostic radiation source is coupled to radiation conductor 160 and further to the site in the patient to be treated via translatory radiation distributor B. This diagnostic operation mode will be described in more detail below. Furthermore a plurality of diagnostic radiation sources may be used simultaneously. In this case several diagnostic radiation sources may be modulated, so that the diagnostic radiation may be detected simultaneously by means of e.g. a lock-in method or by multiplexing the signals, wherein the therapeutic radiation preferably, but not necessarily, is shut off in diagnostic operation mode.
Main radiation distributor B comprises two translatory elements 110, 111. The two translatory elements 110, 111 are displaceable with relation to the other translatory element, as indicated by the arrows 305,306. The displacement is controlled in such a manner that a plurality of radiation conductors 120 lead radiation to and from a tumor site 200 in a patient. Main radiation distributor B switches between the diagnostic operation modes and the therapeutic operation mode. The radiation conductors 120 leading to and from the patient are fixed to the translatory element 111. The translatory element 110 of the main radiation distributor B comprises a (3N−1) to N radiation distributor, wherein N is the number of radiation conductors 120 to/from the patient fixed in translatory element 111 and (3N−1) is the number of radiation conductors fixed in translatory element 110 of which N are radiation distributors 102 coupled to radiation sources 101 and 2 (N−1) are radiation distributors 131 coupled to radiation detector 430, and one, 160, is coupled to the diagnostic radiation sources 144-146 via combiner 310.
In the therapeutic operation mode, B is adjusted translatory in such a manner that treatment radiation originating from the radiation sources 101 is coupled to radiation conductors 102. These radiation conductors, preferably light guides or optical fibers, are coupled to translatory displacement element 110. Element 110 is aligned with translatory displacement element 111 in such a manner that the radiation from radiation sources 101 is coupled to radiation conductors 120 and further to the treatment site 200 in the patient.
In diagnostic operation mode the at least one active diagnostic radiation source 144-146 is coupled to fiber 160 by means of combiner 310. Main radiation distributor B is in diagnostic operation mode adjusted such that one of the N patient fibers 120 is coupled to a diagnostic radiation conducting radiation conductor 160, as illustrated in
A further translatory radiation distributor C having elements 470, 471 is used for minimizing the number of radiation conductors leading to detector 430. Distributor C comprises two translatory elements 470, 471. The two translatory elements 470, 471 are displaceable with relation to the other translatory element respectively. A plurality of (N−1) radiation conductors 431a-431e, corresponding to the (N−1) radiation conductors conducting diagnostic radiation from the patient, are fixed to the translatory element 470 and lead to the detector 430. 2*(N−1) radiation conductors 131 lead from the translatory element 110 to the translatory element 471. Radiation distributor C is adjusted in such a manner that only the active (N−1) radiation conductors of the plurality of conductors 131 are coupled to the detector 430 through radiation conductors 431. Alternatively, the translatory element 471 may be integrated with the translatory element 110 and the translatory element 470 may be integrated with the translatory element 111 (not shown in the Figs.). In this way, the one and same translator may be used for therapy and diagnostic measurements.
N=6 and n=3 in the exemplary embodiment given above. However, other numbers of N and n are equally possible.
For calibration purposes of at least the mechanical part of a system according to embodiments of the present invention comprising at least one mechanical radiation distributor, a 7th hole may be present in translator 111 or similar elements. Preferably this hole is located exactly between two fibers 120 on translator 111, with reference to the linear translator shown in
This embodiment has the advantages of avoiding torsion of the radiation conductors, there occurs no “blooming” of the detectors, and it allows a compact and flat implementation including a very compact layout of a device for performing the method according to the invention. Furthermore, there is no moving element or mechanical part for switching between the detector radiation sources, optical fibers with large diameters may be used, and the system has low radiation losses, i.e. it has a sound “photon economy”.
The combiner 330 may be a fiber combiner commercially available from, e.g., Polymicro Technologies.
As a basis for the radiation switch 320 one may use a commercially available radiation fiber switch from Piezosystem Jena Inc. The working principle of the combiner 330 is described below in more detail. The combiner 330 may also be based upon a commercially available fiber combiner from Polymicro Technologies. The combiner is connected to two source radiation conductors 360 and 361 one detection radiation conductor 363, and one patient radiation conductor 362, wherein radiation is mainly transmitted along these radiation conductors in the directions as indicated by arrows on the corresponding radiation conductors shown in
Furthermore the diagnostic radiation sources 310 may be modulated, so that the diagnostic radiation may be detected simultaneously by means of, e.g., a lock-in technique or by multiplexing the signals, wherein the therapeutic radiation is preferably shut off in diagnostic operation mode.
Diagnostic measurements may be made simultaneously according to the present embodiment by multiplexing the diagnostic radiation sources. As shown in
Alternatively, the radiation conductors in part 150 are attached to part 150 with a different interval space between the radiation conductors than the interval space of radiation conductors 122 in element 451. In this case, element 150 has to be moved eighteen times. However, this has the advantage that the diagnostic radiation sources do not need to be switched off between the measurements, as two of the three radiation conductors in element 150 are alternatingly disconnected from radiation conductors 122 (by translatory displacement) and only one radiation conductor 122 conducts radiation to the corresponding module 325.
This embodiment allows a very compact construction, it is very cheap to implement and there is only one moving part and no torsion in the radiation guides.
For calibration purposes of the system according to the invention, the overall performance of the system is recorded prior to the treatment by direct measurements on a calibrated tissue phantom made of, e.g., a sterile intralipid-water solution and/or a sterile solid phantom made of, e.g., Delrin®. The performance of the therapeutic radiation sources may either be monitored by internal and/or external power meters.
The radiation switches described may work according to different principles. One is the switching by direct radiation conductor movement actuated by piezoelectric movement of the radiation conductor in relation to output radiation conductor. Another is the switching by microradiation beam deflection, which may be based on micromechanical components, such as microprisms or mirrors or by acousto-optical means, deflecting an optical beam to different output/input fibers. The switching and beam deflection is based on optical principles without mechanical movement of components such as prisms or mirrors. Examples of non-mechanical switching principles are for instance beam deflection by an acousto-optical means based on sound generated Bragg deflection, or acousto magnetic means, or by an electrically controlled variation of the refractive index of a material through which the beam travels, thereby deflecting an optical beam to different output/input fibers. Examples for materials having a variable refractive index suitable for electro-optical switches are e.g. LiNbO3, LiTaO3, GaAs, HgS, CdS, KDP, ADP or SiO2. The Agiltron™ company provides commercially available optical switches of this type, namely the CrystaLatch™ Solid-State Fiber Optic Switch family or the NanoSpeed™ Optical Switch Series.
The therapeutic radiation sources are preferably laser sources with a wavelength, which is adapted to the absorption band of the sensitizer. At the photodynamic tumor treatment a dye laser or a diode laser is preferably used, with a wavelength which is selected with regard to the sensitizer employed. For PhotoErin® the wavelength is 630 nm, for delta-aminolevulinic acid (ALA) it is 635 nm and for phthalocyanines it is around 670 nm. The individual lasers are regulated during the treatment to a desirable individual output power. If desired, they may have built-in or external monitoring detectors.
The therapeutical treatment can be interrupted and new diagnostic data can be processed in an interactive method until an optimal treatment has been reached. This method can include synergy between PDT and hyperthermia, where an increased temperature is reached at increased fluxes of laser radiation. The whole process is controlled using a computer, which does not only perform all the calculations but also is utilised for regulation.
The radiation distributors described are preferably driven by stepper motors/servomotors in order to move between the different constellations.
Naturally, diagnosis and therapy may also be performed at the same time, if so desired. With an appropriate number of radiation conductors going to the tumor, for instance the above mentioned six radiation conductors for therapeutic irradiation plus four radiation conductors for simultaneously diagnosing the effect of the therapeutic light, it is possible to directly regulate therapy in real-time. This is of particular interest when performing therapy on sensitive organs that are not to be damaged by the therapeutic optical radiation. Of course it is a goal to only destroy tumor tissue. In the given example, the six radiation conductors illuminate the tumor tissue into which the distal ends of the six radiation conductors are placed. The four diagnostic radiation conductors are also placed into the tumor tissue at appropriate locations and pick up both the excitation radiation from the therapeutic radiation conductors scattered in the tumor tissue and the fluorescent radiation resulting in the tumor tissue. This picked-up radiation may be analyzed in a spectrometer and be used for regulating the therapeutic radiation source. These, for example, four extra radiation conductors can be placed in-between the six radiation conductors for therapeutic irradiation. When the six radiation conductors are connected to the radiation sources by means of the above-described arrangements, the four extra radiation conductors are suitably automatically connected to the radiation detector, e.g. because of the arrangement of the translatory slides or rotating discs.
The present invention has been described above with reference to specific embodiments. However, other embodiments than the preferred above are equally possible within the scope of the appended claims, e.g. different shapes of the translatory elements, different radiation coupler elements than those described above or other elements described in this description than those described above, performing the above method by hardware or software, fluorescence or temperature measurements described in one embodiment, etc. Moreover, the translatory elements may be further minimized by using micromechanical technologies for constructing the elements. Thus, one realization of the elements may be provided by a Micro-Electro-Mechanical System (MEMS) produced by microfabrication technology. The elements described may work according to different principles. One is the switching by direct fiber movement actuated by piezoelectric movement of the fiber in relation to output fibers. Another is the switching by microoptical beam deflection, which may be based on micromechanical components, such as microprisms or mirrors deflecting an optical beam to different output/input fibers. Piezosystem Jena Inc or Pyramid Optics Inc. provide suitable components based on the latter micromechanical principles.
Furthermore, the term “comprises/comprising” when used in this specification does not exclude other elements or steps, the terms “a” and “an” do not exclude a plurality and a single processor or other units may fulfill the functions of several of the units or circuits recited in the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 0301406-5 | May 2003 | SE | national |
| 0301410-7 | May 2003 | SE | national |
| 0301411-5 | May 2003 | SE | national |
This application is a continuation of U.S. application Ser. No. 10/556,919, filed on Dec. 4, 2006, which is a National Phase filing of PCT/SE04/00758. This application also claims priority to Provisional Applications 60/470,856; 60/470,854; and 60/470,855. The content of U.S. application Ser. No. 10/556,919 is hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 60470856 | May 2003 | US | |
| 60470854 | May 2003 | US | |
| 60470855 | May 2003 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10556919 | Dec 2006 | US |
| Child | 12689182 | US |
