Patent Application
20190175939
This invention relates to radiation sensor cables of very small diameter, such that they are suitable for use in medical applications, and in particular the tiny cables can be fitted into urethral and other small diameter catheters.
A scintillator is a special material that exhibits scintillation—the property of luminescence when excited by ionizing radiation. Luminescent materials, when struck by an incoming particle, absorb its energy and scintillate, in other words they reemit the absorbed energy in the form of light.
A scintillation detector or scintillation counter is obtained when a scintillator is coupled to a light sensor such as a photomultiplier tube (PMT), photodiode, PIN diode or CCD-based photodetector. The light sensor will absorb the light emitted by the scintillator and reemit it in the form of electrons via the photoelectric effect. The subsequent multiplication of those electrons (sometimes called photo-electrons) results in an electrical pulse that can be analyzed and provides meaningful information about the particle that originally struck the scintillator. In this way, the original amount of absorbed energy can be detected or counted.
The term “plastic scintillator” typically refers to a scintillating material where the primary fluorescent emitter, called a fluor, is suspended in a solid polymer matrix. While this combination is typically accomplished through the dissolution of the fluor prior to bulk polymerization, the fluor is sometimes associated with the polymer directly, either covalently or through coordination, as is the case with many Li6 plastic scintillators. Polyethylene naphthalate has been found to scintillate without any additives and is expected to replace existing plastic scintillators due to its higher performance and lower price.
The advantages of plastic scintillators include fairly high light output and a relatively quick signal, with a decay time between 2-4 nanoseconds. The biggest advantage of plastic scintillators, though, is their ability to be shaped, through the use of molds or other means, into almost any desired form with a high degree of durability.
In the field of medical radiation therapy, plastic scintillation detectors are used to convert radiation energy into light energy, and the light photons are counted to accurately determine the radiation dose. The scintillating plastic must transfer its photons to a device that can read them, which is commonly done by coupling one or more scintillating fibers to one or more plastic optical fibers (POF). The POF is then connected to a device that can read and analyze the optical output.
This type of sensor is an “active” radiation sensor, not a “passive” radiation sensor. A passive detector is a device that is used to measure levels of ionizing radiation exposure but not in real time. Example includes the Film Badge and the Thermo Luminescent Dosimeter (TLD). The detectors are passive because they need to be “read” at a later stage in order to ascertain the level of exposure recorded. An “active” detector, by contrast, can provide real time information. The sensor described herein gives near real time dosage information, and the delay is much shorter that other active sensors because of the relatively quick signal, with a decay time between 2-4 nanoseconds.
Manufacturing a high volume of such sensor cables is extremely difficult because an accurate and repeatable connection of the plastic scintillator fiber to the plastic optical fiber is required. The problem arises from working with small diameter optical fibers that must be constructed accurately, yet at a low cost and with good durability, reliability and sensitivity.
The current process used to create a sensor cable with a plastic scintillation detector relies on many precise, time-consuming steps, and such cables have thus not reached mainstream use due to the cost of manufacture. First, both ends of the scintillating fiber must be cut and polished. These cuts and polishes are difficult to do because the diameter (1 mm) and length (2 mm) of the scintillation fiber are very small. Next, the optical fiber must be cut, stripped and polished. Then the scintillating fiber is attached to the optical fiber with optical adhesive. A small piece of the optical fiber's jacket can be used to hold the two fibers in place when adhering. This step is challenging due to the small size of the fibers and the need to perfectly align their cores. A black paint or coating is then applied to the distal end of the fiber in order to keep the assembly light tight. The finished assembly is vulnerable to breakage because reliance is placed on the strength of the epoxy bond to hold the assembly together, and on a soft jacket material (PE or PVC) to hold the assembly in alignment. Due to the labor intensive process and time consuming steps, it is very expensive to produce a detector in this fashion, and the process also introduces variability from detector to detector. The current process also uses twist on (FC) or screw on (SMA) metal-bodied fiber connectors at the other end of the sensor cable. Applying these connectors adds more time to the process, and the FC and SMA connectors are expensive.
Therefore, a need exists for a novel manufacturing process and system for a radiation sensor cable to solve these problems. Furthermore, there is a need for a sensor that is of sufficiently small diameter to fit into a urinary catheter for measuring radiation dosage in the urethra when, e.g., when irradiating the prostate.
Generally speaking, the disclosure relates to tiny plastic scintillator detector cables, suitable for use in urinary and other small diameter catheters, methods of fabricating same and various applications therefor. The tiny and inexpensive scintillator detectors are used to assess radiation dosage in real time, and provide a tremendous advance in the field, which heretofore has lacked such tiny, inexpensive detectors for use inside a body cavity at the actual location of the radiation therapy.
Applications include external beam radiation therapy (XRT), stereotactic radiosurgery/stereotactic radiotherapy (SRS/SRT), intensity modulated radiation therapy (IMRT), dynamical arc therapy, tomotherapy treatments, and any similar application where radiation sensing in a small area is needed, including non-medical applications.
In one embodiment, the plastic scintillator detector cable consists of a single, short length of scintillator fiber operably coupled to a suitable length of optic fiber, which has a standard data coupler or connector at the end of the cable opposite the scintillator fiber. The scintillator detector is thus at the distal end of the cable and a suitable data coupler is at the proximal end, and the entirety of the cable is enclosed in a flexible, opaque covering or coating. This sensor is fitted inside a urinary catheter, which preferably includes a urine draining lumen, as well a sensor lumen. The sensor lumen can also include a balloon (e.g., a Foley catheter), provided that the lumen valving is designed to accommodate the cable passing therethrough in a leak proof manner or the ends are bifurcated such that the sensor exit and air inflation means are separate.
In another embodiment, the cable is hardwired directly to a photodetector, thus avoiding connector use. However, a connector is preferred as it allows for quick and easy replacement of damaged cables.
In another embodiment, the cable has at least two separate, but closely juxtaposed, plastic scintillator detectors. The two detectors are parallel, but offset from one another in the longitudinal axis, so that radiation can be simultaneous assessed at two ends of a target, such as on either end of the prostrate or both ends of an irradiated throat area, and the like. However, this embodiment increases the diameter of the cable, and a single detector is preferred for urinary use as providing the smallest possible diameter of ≤3 mm, 2 mm, ≤1 mm or even less. Of course, the connector is excluded from this measurement, as it is much larger, but never enters the body. The diameter of the single sensor cable is approximately 2.8 mm. It uses a 1 mm optical fiber and 1 mm scintillating fiber. The added diameter is due to the fiber jacket, plastic cap and shrink tubing.
In another embodiment, an additional fiber optic cable without plastic scintillator detector can be added thereto, and can serve the function of allowing the subtraction of any background signal, which can arise from the inherent dark current of the PMT or mostly Cerenkov light generated in the fibers. However, these effects are negligible for photon beams, and thus this extra cable is not needed.
Additional plastic scintillation detectors can be added if desired to assess radiation in three or more places along a longitudinal radiation axis. However, single scintillation detectors can also be used where sufficient for the application in question, e.g., where the area to be irradiated is quite small.
Where it is desired to assess radiation levels over more than one axis, e.g., with a larger radiation zone, a second plastic scintillator detector cable can be added, somewhat offset from the first cable (offset in the axis perpendicular to the cable), although this will obviously increase the overall size and cost of the device accordingly.
The scintillator detector can be combined with any medical device suitable for insertion into a body cavity, such as a prostate balloon, vaginal balloon, catheter, needle, brachytherapy—applicator, surgical implements, and the like.
For balloon usage, a small strip of balloon material can be welded to the outer surface thereof, forming a pocket or channel, and the scintillator cable threaded therethrough, thus reliably positioning the detector on the outer surface of the balloon. Alternatively, the cable can be placed inside the balloon and held with one or more spot welds and/or small strips of balloon material or other attachment means.
For solid medical devices, such as brachytherapy applicators, a small tube can be affixed thereto, and the tiny cable threaded inside the small tube, or the cable can be affixed directly to the applicator. Alternatively, a removable balloon can be provided for the applicator, such as is already described. The cable can also be threaded inside a catheter or needle, and other device used to access a body cavity.
The scintillator detector cable has any suitable data connector or adaptor at the proximal end thereof, and is plugged into any existing or dedicated signal detection and computer system for collecting, analyzing and outputting the data collected by the scintillator detector.
Suitable connectors include FDDI, ESCON, SMI, SCRJ, and the like, and will of course vary according to the system that is intended to be used with the scintillator detector cable. The data connectors can be single connectors, even for a dual or triple detector embodiment, but preferably a dual connector is used for the dual detector embodiment, etc., which keeps the cables neat and can prevent plugging sensors into the wrong channels if the connector has asymmetry.
Because the scintillator detector is quite small, novel fabrication methods were developed to allow cost effective, reliable manufacture and assembly therefore. A special cap was therefore designed to allow the scintillator fiber to be reliably connected to the fiber optic cable. This cap is essentially tube shaped with a blind end (a covered or closed end), such that the scintillator fiber fits entirely into the blind end, and the fiber optic cable fits behind it. Thus, the hollow interior closely holds the ends of the two fibers in close juxtaposition (direct contact or “abutting”) without the need for any adhesive between the ends of the two fibers, which greatly improves both sensitivity and reliability. The hollow interior is thus shaped to closely fit the naked fibers, and in many instances will have a circular cross-section, although this can of course vary if the fiber cross section of the cables is varied.
The tube could also have two open ends, but one closed end is preferred as better protecting the fragile fiber, and avoiding a closure step. However, a dual opening cap may be preferred for longer fibers since the dual opening variant can be loaded from either end. The cap can also comprise two components fitted together, e.g., by threadable or snap fits ends, but the unitary construction is the simplest to make and use. Where the tube has an open end, it can be covered with heat shrinkable tubing, a jacket, opaque coating, snap fit lid, or any other means of making it light tight, and preferably water tight. A snap fitting lid can easily be attached to the tube with a small hinge, thus providing a unitary construction that can be made by injection molding, and still allowing tube loading from both ends.
The cap can also be designed with a small extra space left inside for placement of a fiducial marker. In this way, an imaging device, such as a tungsten, gold, barium, carbon or any other radiopaque or reflective pellet can be placed in the tip of the cable and assist in its placement inside the body. Alternatively, the pellet can be placed outside the cap, e.g., on the outer surface or tip thereof. In fact, the cap can be injection-molded with a small snap fit recess into which an imaging pellet can be snap fit, and an optional plug can fitted over the marker if needed.
The blind cap can be affixed to the optical fiber using an optional bead of adhesive at the open end, which will thus only touch the side of the naked optical fiber, or an external clamp can be used, or the blind cap itself can be made of heat shrinkable material for a tight fit. However, we have found that a harder plastic functions best to keep the two cables aligned, and prefer a high impact polystyrene or similar resin for this purpose. Resins may have a hardness of 65 or less, 55 or less, 45 or below, and preferably has 30-40 Shore D.
Alternatively or in addition thereto, an exterior coating of heat shrinkable material can be added thereto for good strength and fit. The shrink tubing covers at least the detector end of the device and protects the detector, while keeping the components together in a tight bundle that remains flexible and can move in all directions. Where the cap is opaque, part of the cap can protrude from the heat shrinkable tubing. The shrink tubing can also cover most or all of the cable, but this will generally not be needed since plastic optical fibers are usually already jacketed, although the heat shrinkable tubing will also function to keep the fibers tightly bundled and thus may be of benefit. A spray on or dip opaque coating or paint is yet another alternative.
Suitable plastics for the blind cap include high impact polystyrene, polybutadiene, acrylonitrile butadiene styrene, polyvinyl chloride, polycarbonate, polyacrylate, polyethylene terephthalate glycol, high density polyethylene, polypropylene, high impact rigid polyvinyl chloride, and polytetrafluoroethylene, and blends and copolymers thereof. Preferred materials are opaque in color to keep the assembly light tight. Alternatively, the cap can be covered in an opaque material and thus plastics with high clarity can be used, such as polycarbonate and polyacrylate.
Also preferred, the blind cap is constructed from a water equivalent plastic so as to not perturb the radiation dosage, and it is known in the art how to assess water equivalence at different energy ranges. Where the plastic is not quite water equivalent, it is known how to apply a scaling factor. See D. Mihailescu and C. Borcia, Water Equivalency Of Some Plastic Materials Used In Electron Dosimetry: A Monte Carlo Investigation, Romanian Reports in Physics, Vol. 58, No. 4, P. 415-425, 2006 (incorporated by reference herein).
A hot knife blade is preferably used for cutting each fiber, thereby eliminating the need for polishing. A soldering iron set to 700° F. may be used with a fine point carbon steel blade having a thickness of 0.0235 inches (0.06 cm). Other hot knifes, temperatures, and blade thicknesses are also contemplated, and it is known how to vary the temperature with the material being used. Many industrial hot-knives are available for use, and cutting blocks that function to ensure a 90° cut are also commercially available. Although a hot knife may be preferred, other cutting methods can be used, including laser, water jet, diamond saw, and the like.
Many suitable jacket plastics are known, and preferably are opaque plastics of low antigenicity or medical grade, although any plastic can be used and combined with an appropriate biocompatible coating. Such materials include low smoke zero halogen (LSFH), polyvinyl chloride (PVC), polyethylene (PE), polyurethane (PUR), polybutylene terephthalate (PBT), polyamide (PA), and the like.
Particularly preferred jacket materials are medical grade polyurethanes due to their lack of plasticizers and which are available in a variety of hardness, ranging from 60 Shore D to 90 Shore A. Particularly preferred are softer plastics of 70-80 Shore A and which give the cable considerably flexibility combined with sufficient strength. However, the polyurethane may need to overlay an opaque plastic, such as black PVC, unless opaque pigments are added thereto or an opaque paint is applied thereto.
Also preferred are cable materials that withstand sterilization procedures, such as autoclaving, gamma irradiation or chemical treatments, although sterilization may be optional if combined with a separately sterilizable balloon that can completely contain the sensor, or if a non-sterile device is needed, e.g., for rectal applications.
The invention can be any of the following embodiments, in any combination thereof:
As used herein, a “simplex sensor cable” refers to a sensor cable having a single sensor. A “duplex” cable has two sensors, typically offset in location. A “triplex” sensor cable would have three scintillators, and so on.
As used herein, a “lumen” is a long hollow conduit that can be used for fluid flow or for housing a cable. A lumen need not have a circular cross-section.
A “tube” as used herein is a long hollow cylinder, having circular cross-section.
As used herein, “real time” dosage detection occurs within one second of a signal being received by the active radiation sensor.
As used herein, “airtight” and “liquid tight” fits are used interchangeably to refer to a tight seal that prevents the escape fluids, whether air or liquid. The balloons in the present disclosure must be air and fluid tight, and by necessity, the locking hubs and some bifurcated ends.
The use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims or the specification means one or more than one, unless the context dictates otherwise.
The term “about” means the stated value plus or minus the usual margin of error of measurement, or plus or minus 10% if no method of measurement is indicated.
The use of the term “or” in the claims is used to mean “and/or” unless explicitly indicated to refer to alternatives only or if the alternatives are mutually exclusive.
The terms “comprise,” “have,” and “include” (and their variants) are open-ended linking verbs and allow the addition of other elements when used in a claim.
The phrase “consisting of” is a closed linking verb and does not allow the addition of any other elements.
The phrase “consisting essentially of” occupies a middle ground, allowing the addition of non-material elements such as labels, instructions for use, and the like.
A better understanding of the invention can be obtained with the following detailed descriptions of the various disclosed embodiments in the drawings, which are given by way of illustration only, and thus are not limiting the invention, and wherein:
The following detailed descriptions are exemplary only and not intended to unduly limit the scope of the claims beyond the plain and ordinary meaning of the terms in the medical art of radiation oncology, and their equivalents.
The parts of
Turning to
The scintillating fibers 2 fit into the fiber caps 3, followed by the naked optic fibers 1B, and a drop of epoxy 4. Heat shrink tubing 5 covers the components, which are shown assembled in
The duplex optical fiber 1 may be a Super Eska 1 mm duplex plastic optical fiber SH4002 available from Mitsubishi Rayon Co., Ltd. of Tokyo, Japan, although other duplex optical fibers are also contemplated. Although duplex optical fibers 1 are shown, it is also contemplated that a single optical fiber may be used or additional fibers can be added. Single fiber sensor cables are preferred for urinary catheters, due to the size limitations.
The scintillating fibers 2 may be a BCF-60 scintillating fiber peak emission 530 NM available from SAINT-GOBAIN CERAMICS & PLASTICS™, Inc. of Hiram, Ohio, although other scintillating fibers are also contemplated.
Fiducial marker 7 is shown outside the cap, but can also be inside the cap.
The fiber cap 3 is shown in more detail in
The use of a pair of plastic optical fibers 1 and pair of scintillator fibers 2 allows a dual detector system using two fibers jacketed together to form a single cable. However, the detectors are still independent and give separate measurements of radiation dosage at each location. The duplex scintillator cable 10 combined with the longitudinally offset positioning of two scintillating fiber tips 2 allows for the detection of two distinct areas of radiation in a single sensor cable device. Additional scintillating fibers and optical cables may be added to the cable for additional detection areas.
The small length of shrink tubing 5 covers the detector end of the device and protects the detectors 2 while keeping the assembly together in a tight bundle. The bundle is allowed to flex and move in all directions. If desired, the shrink tubing can cover a longer length of the cable than is shown herein. Paint or coatings can be used, but shrink tubing may be preferred as easy to assemble, and providing some degree of protection, with a perfect fit. However, where size is critical, a paint or other thin coating may be preferred.
The diameter of the cable herein described is very small, and the device is thus tiny enough to be added to existing medical devices for a variety of radiation applications. Preferably, the cable diameter (excluding the proximal adaptor/connector) is less than 5 mm, and preferably less than 4, 3, or 2 mm. Yet, in spite of its small size, the device is robust and easily manufactured. A single sensor cable is preferably 2 mm or less, 1 mm or less, or even as small as 0.3-0.5 mm in diameter.
A hot knife may be used to make the process more efficient. By cutting each optical fiber distal end 1 and each scintillating fiber 2 with the hot knife blade, the polishing step of the past may be eliminated. The hot knife cuts a smooth and uniform fiber surface with no scraping or cracking, producing light transmittance results on par with polished fibers.
The optical adhesive used in the past may also be omitted from the method and system.
Instead of using adhesive between the exposed optical fiber ends, as is done in the prior art, the optical and scintillating fibers are aligned using the fiber cap 3 and secured by applying optional adhesive 4 only to the open end 31 of the cap 3. The bond is between the cap 3 and the exposed sides of the optical fiber 1 and increases the strength of the assembly and reduces the accuracy needed at the adhesive joint, however the adhesive is optional, as is the shrink tubing.
One embodiment of the assembly process is illustrated in
Step 1: Cut the plastic optical fiber 1 to length using the hot knife at step 100.
Step 2: Cut the plastic scintillation fiber 2 to length using the hot knife system at step 105.
Step 3: Strip back the jackets (if any) on each fiber 1, 2 to a specified length at step 110.
Step 4: Insert the bare scintillation fiber 2 into the scintillating cap 3 at step 115 and gently push until seated at the blind terminus.
Step 5: Insert bare optic fiber 1 into scintillating cap 3. Gently push until the optical fiber 1 is in good contact with the scintillation fiber 2 at step 120.
Step 6: Apply the optional bead of the UV cure epoxy or other adhesive 4 around the open end 31 of the fiber cap 3 where the optical fiber 1 is exposed at step 125. No epoxy 4 contacts the scintillation fiber 2 or the respective abutting ends of the two fibers because only a small amount of adhesive is used.
Step 7: Slide the optional heat shrink tubing 5 over the distal end of the sensor cable 10 so that the edge of the heat shrink 5 is approximately 1 mm away from the distal end of the most distal scintillation cap 3, although it can also completely contain same or more can protrude, as desired. Use a heat gun or oven to shrink down the tubing 5 over the detectors 2 at step 130.
Step 8: Attach an appropriate connector 8 to the proximal end of the cable 10 opposite the detectors 2 at step 135.
The cable is thus fabricated, and can be labeled, packaged, and optionally sterilized, as needed.
The process allows for a much quicker and more accurate assembly than in the past. The cable assembly may be produced in high volumes with excellent repeatability. Variations on the methods are contemplated, and fewer steps are also contemplated.
Urinary catheters are typically made of latex or silicone rubber, although a trend has been made of using polyurethane or carbothane (a polyurethane/polycarbonate copolymer) rather than silicone because it allows for better catheter strength and softness, while still maintaining a large internal diameter. Silicone rubber catheters are believed to be superior to latex catheters, as silicone is more biocompatible, causes less cell death, less likely to become encrusted, and more resistant to bacterial colonization, although latex is low cost. Silastic catheters have decreased incidences of urethritis and, possibly, urethral stricture and can also be used long-term. Polyvinylchloride and polyethylene catheters have a wide lumen enabling a rapid flow rate, are recommended for short-term post-operative use, but cause greater patient discomfort. Pre-lubricated, sterile non-latex catheters coated with polyvinylpyrrolidone, are water absorbent, cause 90%-95% less urethral friction trauma to the urethra, and are also indicated long-term. Other friction reducing agents can be coated on the catheter exteriors.
The catheter can either have one, two or three lumens therein, but preferably has at least two lumens.
The multiple lumens can either be nested (coaxial) or split and split lumens can be made by extrusion or by the merging of separate lumens with e.g., heat, and combinations thereof are also possible (e.g., U.S. Pat. Nos. 3,769,981, 3,634,924, 3,746,003, 4,793,351, 5,167,623, 7,500,982, each incorporated by reference in its entirety).
Inflation lumen 605 provides a passage from the inflation valve 601 to the balloon 609, and balloon port 611 allows air or fluid to be pumped into the balloon when situated inside the bladder, thus preventing accidental egress. This same passage also houses the sensor cable 625, although the passageway bifurcates (608/606 lumens) near the proximal end to give an airtight portal 623 for the cable 625 on one branch, and an inflation means 601 on the other branch.
A second passageway is the urine lumen 607, reaching from urine bag connector 603 to urine port 613, which is usually just shy of the distal tip 615, all of which are situated distal to the balloon. Urine can enter the port 613, travel down the urine lumen 607 and exit the connector 603 to a collection bag (not shown). When inflated, balloon 609 prevents the catheter from withdrawing from the bladder.
Catheter size is expressed in Charriere (Ch) units, which reflects the catheter's outer diameter in millimeters (1 Ch=0.33 mm diameter) or French units (fr=circumference in millimeters). The smallest size of the catheter consistent with effective drainage is used. In the presence of infection or if post-operative bleeding is expected, a larger bore catheter minimizes catheter obstruction. Most urethral catheters are 41-45 cm. long; a shorter catheter (20-25 cm) is more discreet and comfortable in women. Foley catheters typically vary in size from 12 fr to 30 fr (4 to 10 mm) in diameter, with the standard being 14 fr (4.6 mm). The balloon itself varies in size from 5 cc to 30 cc, depending on the needed use, but is typically less than 10 cc. The balloon can either be filled with sterile water or saline or air, but sterile solutions may be preferred in case of accidental leak.
In the embodiment of
In other embodiments, the cable is small enough to fit under a strip of adhesive tape on the outside of the catheter (not shown), but this is not preferred as a less robust and less smooth catheter may result. However, with careful choice of materials and a flatter cross section of the cable or groove on the exterior of the catheter, this may be a viable alternative.
Air pockets should be avoided near the sensor itself, as the radiation may travel faster through air, resulting in errors in dosing. A water or tissue equivalent adhesive can be used to fill air pockets, but preferably, the assemble tolerances are such as to minimize air pockets.
In the small cross section of the catheter, can be seen the inflation lumen 805 and the urine lumen 807 and cable lumen 823. The sensor cable 821 can either be positioned in the inflation lumen 805, or an additional lumen 823 can be provided, as shown here.
As yet another alternative, the balloon and inflation valve can be omitted and the second lumen dedicated to sensor use, as shown in
Any tip can be used with the urinary catheter of the invention, including 815A-Simple urethral catheter; 815B—Open-ended (whistle-tip) catheter; 815C—Coude Catheter (Tiemann); 815D—Wing-tip (Malecot) catheter; or 815E—Mushroom (de Pezzer) catheter; and 815F—simple urethral catheter. However, the Tiemann tip in 815C may be preferred because it is designed to accommodate the enlarged prostate that occurs with benign and metastatic prostate cancers.
If this embodiment is not to be combined with balloon, then outlet 923 need not be air or liquid tight, and thus the position of the sensor can easily be adjusted along the length of the catheter by pulling or pushing on the cable. However, the outlet should still be tight enough to provide a friction fit so that the cable does not easily move on its own. Alternatively, a locking mechanism (e.g., a clamp or snap fit lock) can be provided to hold the cable in place once adjusted.
In the small cross section of the catheter, can be seen the sensor lumen 905, sensor cable 921 therein and the urine lumen 907. Urine port 913, and e.g., Tiemann tip 915C complete the radiation sensor catheter.
Single or “simplex” sensor cables can be built less than one mm in diameter, indeed as small as 0.3-0.5 mm, and thus can easily fit inside a 4 mm catheter, which is the standard size for urinary use. Such cables easily fit inside urinary (or cardiovascular) catheters in the manner shown herein, and thus provide real-time dosage information on radiation treatment of the genitourinary tract, arteries and veins, and especially the prostate. The urinary sensor cable is as described herein, but preferably with just one sensor cable, rather than a dual cable for size constraint reasons. The length of the scintillating fiber can be adjusted for the needs of the treatment. For example, a length of about 2-4 cm or 3 cm may be suitable for monitoring dosage along the entire prostate. However, a smaller fiber of 0.5-1 cm will provide a more localized measurement.
An exemplary simplex sensor cable having a single detector is shown in
In use, the distal tip of the catheter is usually coated with sterile lubricant, the catheter tip is inserted into the urinary meatus (orifice in a female) and the catheter gently fed into the urethra until 1-2 inches past where urine flow is noted. The position of the radiation sensor is ascertained by imaging the fiducial marker, and the position of the catheter and/or sensor adjusted so that the fiducial marker is positioned adjacent to the target treatment area. Preferably, the sensor is positioned to be adjacent the penile bulb, proximal to the prostate. In other instances, the sensor can be placed closer to the prostate.
If necessary, the catheter and/or cable can then be taped in position (e.g., on the patient's leg) to prevent accidental movement of the system. The cables are connected to a separate detector unit, e.g., photodetector. The urine lumen is connected to a collection bag, usually before insertion, and thus is available to collect urine throughout the procedure. Once the system is ready, radiation is applied to the target area, and the medical practitioner can thus monitor dosage in real time. When a target dosage level is reached, the practitioner can then cease the treatment at that target area or otherwise adjust treatment parameters. Balloon catheter use is similar, but includes the step of inflating the balloon portion of the catheter once the bladder has been reached, and deflating before removal.
In order to make assembly of the urinary catheter more efficient and reproducible, a special proximal end adaptor is made that provides the airtight connectors and bifurcation or trifurcation as needed. The simple tube of the catheter can be inserted into this hub, and the same hub used for e.g., urine drainage, inflation and cable entry.
Seal 113b shows e.g., an elastomeric seal 113b, but other one way valving is known and any method of providing an airtight seal or connection can be used, e.g., a one way valve or luer lock. The seal 113b thus will hold a suitable syringe 121, preventing air escape. Locking clip 117 positioned within cable entry portal 115 allows the user to close the clip, thus locking the sensor cable 125 to be locked into position, keeping it in one place during use. If desired, this clip 117 can provide an airtight cable entry point (not shown), but in other embodiments, a second elastomeric seal (not visible herein) or other valving can provide and airtight cable entry point. As yet another alternative, the cable entry portal 115 can connect only with the cable lumen not the air lumen, and thus this entry port need not be airtight.
In
In use, the urinary catheter is assembled if needed by inserting the cable into the catheter via the hub lock, and feeding it up to near the target zone. The catheter with sensor cable is then inserted into the meatus or urethra and taped in place against the leg on reaching the bladder. The syringe is inserted into the hub lock, and the bladder balloon inflated, preventing egress of the catheter at the bladder end of the catheter. Drainage may be allowed throughout if needed, or if a separate draining lumen is not provided, urine can be drained with the syringe before inflation.
The sensor can then be imaged using the fiducial marker, adjusted as needed to e.g., target the prostate, and then the lock or clip 117 closed, preventing the sensor from moving with respect to the catheter. The adaptor or connector is connected to a separate reader device (not described herein), and radiation applied to e.g., the prostate. Dosage can thus be reliably obtained in real time using this active radiation sensor cable.
Locking hub 1220 has a bifurcated end opposite a single end. Single end has an entry port 1221 for airtight insertion of catheter tube 1230. Air entry portal 1224 is fitted e.g., with a spring valve connector 1223, for fluid tight connection to a syringe or other fluid source. A luer lock or other airtight connector could easily replace this spring valve connector. The cable entry port 1222 has a locking connector, in this case a Tuohy Borst connector 1225 (Merit Medical). The Tuohy Borst is a single-use, proprietary valved adapter that provides a leak-proof seal during interventional and diagnostic procedures. The cable can be inserted into the catheter through the connector 1225, and then the valve end 1226 rotated to close the connector down on the cable, thus both locking it in place and providing an airtight seal. Other connectors/locks could be used, however, and this is only one example of an off the self component that can be used, as the air tight feature is not essential in this embodiment. If both bifurcated ends provide airtight seals, then the interior of the hub lock need not have separate fluidic pathways for connection to the two lumens in the catheter tube.
As above, in use the cable is inserted into the hub lock and fed to about an inch of so from the balloon (assuming the prostate is the target). The assembled urinary catheter with radiation sensor cable is then fed into the urethra to the bladder, then a fluid supply is connected to the fluid inlet end of the locking hub, and the balloon inflated, e.g., with sterile saline. Typically, the catheter is taped to the patient's leg, and the adapter plugged into a separate reader. The fiducial marker can then be imaged, and the sensor tip position adjusted as needed, and then again locked into place. This can be done before or after inflation, but preferably is after inflation so that the distal end of the catheter doesn't move. Radiation is applied, and the dosage read from the reader in real time, stopping the treatment when the final dosage level (for that session) is reached. The treatment can thus be monitored and dosage adjusted as needed during treatment.
In some embodiments, the method also includes transferring radiation dosage data to a patient medical record, preferably a non-transitory electronic medical record. In other embodiments, the record is provided as a printout.
In other embodiments, the method includes a non-transitory computer readable medium that stores thereon the medical record, and/or the software needed to analyze the raw data, correcting e.g., for temperature, background radiation, and being capable of providing real time dosage information.
The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated construction can be made within the scope of the present claims without departing from the true spirit of the invention. The present invention should only be limited by the following claims and their legal equivalents.
This application is a Continuation-In-Part to U.S. Patent Application 61/481,503, filed May 2, 2011, U.S. patent application Ser. No. 13/444,584 (U.S. Pat. No. 8,885,986), filed Apr. 11, 2012, and U.S. patent application Ser. No. 14/470,707 (U.S. Pat. No. 8,953,912), filed Aug. 27, 2014. It also claims priority to 62/063,196, filed Oct. 13, 2014. Each of these is incorporated by reference in its entirety for all purposes herein.
| Number | Date | Country | |
|---|---|---|---|
| 62063196 | Oct 2014 | US | |
| 61481503 | May 2011 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13444584 | Apr 2012 | US |
| Child | 14470707 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14881023 | Oct 2015 | US |
| Child | 16259336 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14470707 | Aug 2014 | US |
| Child | 14881023 | US |
