CA2334138A1 - Radiation source - Google Patents
Radiation source Download PDFInfo
- Publication number
- CA2334138A1 CA2334138A1 CA002334138A CA2334138A CA2334138A1 CA 2334138 A1 CA2334138 A1 CA 2334138A1 CA 002334138 A CA002334138 A CA 002334138A CA 2334138 A CA2334138 A CA 2334138A CA 2334138 A1 CA2334138 A1 CA 2334138A1
- Authority
- CA
- Canada
- Prior art keywords
- sleeve
- thread
- isotope
- liquid
- seal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 230000005855 radiation Effects 0.000 title claims abstract description 82
- 239000007788 liquid Substances 0.000 claims abstract description 52
- 230000002285 radioactive effect Effects 0.000 claims abstract description 33
- 239000011248 coating agent Substances 0.000 claims abstract description 26
- 238000000576 coating method Methods 0.000 claims abstract description 26
- 238000001704 evaporation Methods 0.000 claims abstract description 26
- 230000008020 evaporation Effects 0.000 claims abstract description 20
- 238000001959 radiotherapy Methods 0.000 claims abstract description 17
- 238000000034 method Methods 0.000 claims description 37
- 230000009471 action Effects 0.000 claims description 14
- 239000004094 surface-active agent Substances 0.000 claims description 13
- 238000004873 anchoring Methods 0.000 claims description 12
- 238000007747 plating Methods 0.000 claims description 8
- 230000007480 spreading Effects 0.000 claims description 6
- 238000007789 sealing Methods 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 4
- OAICVXFJPJFONN-OUBTZVSYSA-N Phosphorus-32 Chemical group [32P] OAICVXFJPJFONN-OUBTZVSYSA-N 0.000 claims description 3
- 229940097886 phosphorus 32 Drugs 0.000 claims description 3
- 238000005553 drilling Methods 0.000 claims description 2
- 238000001035 drying Methods 0.000 claims description 2
- 235000011007 phosphoric acid Nutrition 0.000 claims description 2
- 238000009736 wetting Methods 0.000 claims description 2
- 229920000297 Rayon Polymers 0.000 abstract description 2
- 239000002964 rayon Substances 0.000 abstract description 2
- 229920006122 polyamide resin Polymers 0.000 abstract 1
- 238000009826 distribution Methods 0.000 description 7
- 239000008188 pellet Substances 0.000 description 5
- 230000037361 pathway Effects 0.000 description 4
- 230000002526 effect on cardiovascular system Effects 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 238000003780 insertion Methods 0.000 description 3
- 230000037431 insertion Effects 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 125000006850 spacer group Chemical group 0.000 description 3
- 239000002775 capsule Substances 0.000 description 2
- 210000004351 coronary vessel Anatomy 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229920001721 polyimide Polymers 0.000 description 2
- 239000009719 polyimide resin Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000009827 uniform distribution Methods 0.000 description 2
- APOYTRAZFJURPB-UHFFFAOYSA-N 2-methoxy-n-(2-methoxyethyl)-n-(trifluoro-$l^{4}-sulfanyl)ethanamine Chemical compound COCCN(S(F)(F)F)CCOC APOYTRAZFJURPB-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000008280 blood Substances 0.000 description 1
- 210000004369 blood Anatomy 0.000 description 1
- 210000000748 cardiovascular system Anatomy 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000013013 elastic material Substances 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000002513 implantation Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 238000004890 malting Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
- A61N5/00—Radiation therapy
- A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
- A61N5/1001—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy using radiation sources introduced into or applied onto the body; brachytherapy
- A61N5/1002—Intraluminal radiation therapy
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
- A61N5/00—Radiation therapy
- A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
- A61N5/1001—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy using radiation sources introduced into or applied onto the body; brachytherapy
- A61N2005/1019—Sources therefor
- A61N2005/1021—Radioactive fluid
Abstract
A radiation source (10) for invasive medical treatment, such as intra-coronary radiotherapy or other such intravascular radiotherapy, is described. The radiation source (10) includes a thread (14) extending longitudinally within a sleeve (12). The sleeve (12) is a hollow circular cylinder, sealed at either end (20, 24), made from a polyamide resin, and is configured such that it is sufficiently flexible enough to be used for intravascular radiotherapy. A
plurality of laser drilled holes (16) are configured in an evenly spaced pattern along the sleeve (12), and promote uniform liquid evaporation from within the sleeve (12). The thread (14) is comprised of twelve rayon filaments (26) wound in a helical fashion, which extend longitudinally through the sleeve (12), and are anchored in the seals (18, 22) at either end (20, 24) of the sleeve (12). A radioactive isotope is formed into a coating on surfaces within the sleeve (12).
plurality of laser drilled holes (16) are configured in an evenly spaced pattern along the sleeve (12), and promote uniform liquid evaporation from within the sleeve (12). The thread (14) is comprised of twelve rayon filaments (26) wound in a helical fashion, which extend longitudinally through the sleeve (12), and are anchored in the seals (18, 22) at either end (20, 24) of the sleeve (12). A radioactive isotope is formed into a coating on surfaces within the sleeve (12).
Description
RADIATION SOURCE
BACKGROUND OF THE INVENTION
This invention relates generally to invasive medical radiotherapy and, more particularly, to a radiation source for use in invasive medical treatment, and to a method for making it.
Physicians now use radiation to treat an increasing number of medical problems. One form of radiation treatrnent involves the insertion of a radiation source into a patient's body to irradiate a limited area of the body for a controlled period of time. Typically, a surgeon inserts a longitudinal radiation source into die patient's body through a lumen of an implanted guide catheter. This procedure often requires a radiation source to exhibit both high flexibility and an effectively high level of radioactivity, particularly for cardiovascular radiotherapy. Furtlermore, the radiation source must provide consistent levels of radiation over its entire length.
During implantation, the radiation sotuce might be required to travel through tortuous pathways within a patient's body, such as the coronary arteries.
Furthermore, the area requiring treatment might be characterized by tortuous twists and bends. A radiation source must therefore be sufficiently flexible to navigate such pathways without injuring the patient or damaging itself.
Once the radiation source has been inserted into the patient's body, the total dosage of radiation will be determined by the level of radioactivity of the radiation source, and by the length of time the targeted tissue is exposed to die radiation source. Radiation sources having higher radiation levels provide for shorter exposure times, which lowers both the time duration of a procedure and the level of risk involved in the procedure. This risk is particularly important in situations where die guide catheter causes significant obstruction to the profusion of the blood.
However, existing technologies provide for higher levels of radioactivity at the expense of flexibility, thus placing an upper limit on the radiation levels available for treating torhious pathways.
A limiting factor on the design of such radiation sources is the risk of overexposing a patient to radiarion due to inconsistent levels of radiation along the length of the radiation source. The radiation source is brought into close proximity with portions of the patient's body, and a particularly "hot" portion of the radiation source can therefore overexpose an adjacent portion of the patient's body.
Likewise, longitudinal sections having a lower than desired radiation level can provide lower than desired levels of radiation treatment. Thus, the radiation level along a radiation source must be kept as longitudinally consistent as possible. It is known that longitudinal uniformity is important, and that a preferred level of uniformity is a maximum 10% variation.
It is known, for example, that a radiation source can be formed in a cavity within a wire or within a tube (also known as a ribbon), and can include a plurality of rigid pellets, made from a radioactive isotope, that are embedded at intervals along the wire with spacers positioned between the pellets. The spacers function to give this source wire some flexibility despite the presence of die rigid pellets. The flexibility is restricted, however, to the areas between the pellets.
Furthermore, the pellets form a series of nonuniform radiation hot spots, causing tissue around the source wire to be irradiated unevenly. Longer spacers improve the source wire's flexibility, however they cause the distribution of radiation to be less uniforn~
and less continuous, and thus a trade off must be made between flexibility and radiation uniformity.
It has been suggested flat an isotope could be carried in a liquid, and passed into, and then out of a passage in a catheter. However, when the catheter assumes a strongly bent position, such as in a tortuous passage, a portion of the passage could change in cross-sectional shape, and the quantity of the isotope that could be located in that portion would vary. Thus, the catheter would lave local radiation levels that vary wide die bent shape of the catheter, and would not maintain a uniform radiation level distribution.
Accordingly, there has existed a definite need for an invasive medical treatment radiation source, where the radiation source exhibits high flexibility and high levels of radioactivity, the radioactivity being distributed in a uniform and continuous fashion throughout the radiation source. The present invention satisfies these and oilier needs, and provides further related advantages.
SUMMARY OF THE INVENTION
The present invention provides a radiation source for invasive medical treatment, where the radiation soiuce exhibits high flexibility and high levels of radioactivity, the radioactivity being distributed in a uniform and continuous fashion throughout the radiation source, and a method of malting the radiation source.
The present invention further provides a related method of employing the radioactive isotope for invasive medical treatment. The invention has potential use in a wide range of applicatlons, such as intravascular radiotherapy and oncology.
A radiation source for invasive medical treatment, embodying the present invention, features a hollow sleeve (e.g., a tube or cylinder) and a coating of a radioactive isotope distributed on surfaces in the interior of the sleeve.
Tlis radiation source provides for the irradiation of tissue, within a patient's body, along long and tortuously curved pathways in the body, such as coronary arteries. It further provides for a substantially even level of irradiation along the full length of irradiated tissue.
The invention also features a struchire, e.g., a thread with filaments wound in a helical pattern, within the sleeve, that is configured to distribute a liquid throughout the sleeve by capillary action. This feature advantageously provides for the uniform spreading of the isotope, while born in a liquid, throughout the sleeve. The struchire preferably extends from a first seal at a first end of a sleeve, to a second seal at a second end of the sleeve. The helical filaments may cause the fluead to follow a pig-tailed, coiled path down the sleeve. The thread and seals promote even capillary spreading of the liquid, providing even distribution of a liquid-born isotope, and thus serving as a fiirther means for distributing the liquid-born isotope throughout the sleeve. The pig-tailed thread may further enhance the capillary action.
A fiuther feature of the invention is drat die sleeve is configured to promote liquid evaporation from within the sleeve at a consistent rate throughout the sleeve. This feature can comprise a plurality of holes in die sleeve, which are positioned at approximately equal intervals along the sleeve's length and spaced at approximately symmetric locations around die sleeve's circumference. The holes can be any form of orifice, such as circular or oval openings, slits that open under internal pressure, or even the pores in a porous material having large enough pores to allow evaporation. This feature advantageously allows for the uniform evaporation, along the length of the sleeve, of a liquid that bears'the isotope. The evaporation causes the surfaces distributed throughout the interior of the sleeve to be plated with a uniform coating of the precipitated isotope.
Additionally, die invention features a coating of a surfactant along surfaces in the interior of the sleeve. The surfactant reduces surface tension of die fluid, to promote uniform spreading of a liquid throughout the sleeve, through capillary action.
Other feahires and advantages of the invention will become apparent from the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings, wl>ich illustrate, by way of example, the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of a source configured to receive a radioactive isotope, embodying features of the present invention.
FIG. 2 is a cross-sectional side view of die source depicted in FIG. l, taken along line 2-2 of FIG. 1.
FIG. 3 is an elevarional view of the source depicted in FIG. l, being held in a device configured to hold the source, the source being in the process of contacting a drop of a liquid-borne radioactive isotope.
FIG. 4 is an elevational view of the source depicted in FIG. 1, inserted in a patient's cardiovascular system through a vide catheter for cardiovascular radiotherapy.
S
pETAILED DESCRIPTION C~F THE PREFERRED FMRODIMENTS
With reference now to the illustrative drawings, and particularly to FIGS.
1 and 2, there is shown one embodiment of a "source" 10 configured to receive a radioactive isotope for invasive medical treatment, such as intracoronary radiotherapy, or other such intravascular radiotherapy, according to the present invention.
The source includes a foundation, preferably in the form of a hollow sleeve 12, and most preferably including a fluead 14 extending longihidinally witlin the sleeve.
This foundation includes surfaces for receiving a coating of a radioactive isotope.
Preferably, the isotope is precipitated from an evaporating liquid and plated onto the surfaces. The sleeve and thread provide capillary forces to draw a drop of liquid-borne radioactive isotope into the sleeve and distribute it tluoughout the sleeve, such that it plates on surfaces within the sleeve.
The sleeve I2 is preferably in die form of a hollow circular cylinder, defining a longitudinal axis. The sleeve is preferably made from a polyimide resin, or other such elastic material that is resistant to radiation degradation. The diameter and wall thickness of the sleeve are selected to be sufficiently flexible for intravascular radiotherapy. Preferably, the sleeve's length is substantially greater than its diameter to provide for irradiation of an extended length of tissue in a narrow vessel.
For example, the sleeve's length might be greater dean 1 inch, while the sleeve's diameter is less than 0.02 inches.
The hollow sleeve 12 defines a plurality of holes 16 connecting tle interior siuface of the sleeve to the exterior surface of the sleeve. The holes, in groups of six, are longitudinally spaced at equal intervals along the length of the sleeve. Each group of six holes is symmetrically spaced around die circiunference of the sleeve at a given longitudinal location. Longihidinally consecutive groups of holes are WO 99/62590 PCT/US99/1260$
circumferentially offset by 30° from each other. The holes are confi~~red in an evenly spaced pattern that promotes liquid evaporation from within the sleeve at a reasonably consistent rate throughout the length and circumference of the sleeve. Thus, the holes provide a means of coating surfaces throughout the interior of the sleeve with a substantially uniform plating of the isotope, such that the sleeve is appropriate for evenly irradiating nearby tissue.
A first seal 18 caps tle sleeve 12 at a first end 20, preferably sealing that end to prevent liquid flow through that end. A second seal 22 caps the sleeve at a second end 24, preferably sealing that end to prevent liquid flow duough that end. The seals, like die sleeve, are preferably made from a polyimide resin. The thread includes two ends, which are anchored in the hwo seals, respectively. T1e seals thus maintain the ends of the thread in alignment with flee capped ends of the sleeve, and prevent liquid flow through those ends:
The thread 14 extends longih~dinally through the sleeve 12 from tle sleeve's first end 20 to its second end 24. The longitudinal cross-section of the thread (see FIG. 2) defines an area that is preferably consistent along the length of the thread, preferably filling roughly 25% to 30% of tire sleeve's volume. The thread i4 is preferably comprised of approximately twelve rayon filaments 26 wound in a helical fashion, as depicted in FIG. 1. Thread of this nahire can be found as strands within larger dreads.
While this embodiment includes a thread 14, other embodiments can be provided will other alternative structures within the sleeve, such as a unitary thread or a rigid stnicttrre. These stnrchires preferably provide for the distribution of a liquid duoughout the sleeve, such as by capillary forces. These stmcW res also preferably provide plating surfaces throughout the sleeve flat are configured for a predetermined distribution of precipitated isotope. Preferably, the predetermined distribution of the isotope is an approximately uniform distribution along the length of the sleeve.
Both the sleeve 12 and the thread 14 include a coating of a surfactant, such as Phironic Surfactant type 68, manufactured by BAST. The surfactant lowers surface tension of a liquid vv~itlun the sleeve, promoting uniform spreading of the liquid fluoughout the sleeve by capillary action.
The invention includes a related method of employing a radioactive isotope for invasive medical treatment. In this inventive method, the sleeve 12 is formed in its desired diameter and thickness. Laser drilling is preferably used to form the holes 16 in the sleeve.
The tluead 14 is inserted into the sleeve 12, and die first seal 18 is formed, anchoring the first end of the dread to the first end 20 of the sleeve. The first seal is formed by heating the end of the sleeve and thread to approximately 80° C to 100° C, preferably in a column of heated gas, to solidify the ends of the sleeve and thread into a unitary seal. Prior to insertion, the thread may be passed through a drop of adhesive in order to stiffen it, easing the its insertion into the sleeve 12.
With only one seal formed, the sleeve 12 and thread 14 are wet (preferably by dunking in water) and then dried. This wetting and drying preshrinks the thread prior to forming the second seal 22, and thus avoids potential warping during later steps of the process.
The second seal 22 is then formed, anchoring the second cnd of the thread 14 to the second end 24 of the sleeve 12. As with the first seal, the second seal is formed by heating the end of the sleeve and thread, preferably in a column of Heated gas, to solidify the ends of the sleeve and thread into a unitary seat.
The sleeve and the thread are then wet (preferably by dunking) with a surfactant. The surfactant is dried to complete the formation of the source.
The surfactant, coating stcrfaces widun the sleeve, promotes capillary action within the sleeve. This is particularly important in low luimidity environments when static electricity might be a problem.
To plate a coating of a radioactive isotope on the surfaces within the sleeve 12, the radioactive isotope is provided while borne in a liquid. The radioactive isotope is preferably Phosphorus-32 (P-32), which has a high specific activity, and the liquid is preferably water. Wlule a number of Phosphonis-32 radionuclide solutions may he used, preferably the solution is radioactive orthophosphoric acid (H,PO,) in water. The provision of a highly concentrated liquid-borne radioactive isotope allows a higher level of radioactivity per unit of liquid, and tlys produces a radiation source with higher levels of radiation.
Referring now to FIGS. 1 to 3, the first end 20 of the completed radiation source's sleeve 12 is placed into a retaining device 28, which holds the source without covering a significant number of t1e source's holes 16. The retaining device is preferably configured with a follow cylinder having an inner dia~aeter conforming to the outer diameter of the sleeve, providing for a friction grip on tl~e source.
The source I0, held by the retaining device 28, is brought into contact with the liquid-borne radioactive isotope. Preferably, the source is positioned below a drop 32 of the liquid-borne radioactive isotope, and is moved up into contact with the drop. The drop contacts the source in the source's central portion, hetw~een tl~e ends <) 20, 24 of the sleeve 12, and most preferably at the approximate longitudinal midpoint of t1e sleeve. The drop is preferably of a correct volume to approximately fill the sleeve. The drop is preferably suspended from a syringe. A preferred apparatus, including a syringe and a retaining device 28, for use with the invention is described in the concurrently filed and commonly assigned patent application, entitled METHOD
AND APPARATUS FOR CONCCNTRATING A SOLUTE IN SOLUTION WITH A
SOLVENT, having application Serial No. , which is uicorporated herein by reference.
Upon contact, die drop 32 of the liquid-borne radioactive isotope enters the sleeve 12 through flee holes 16. As the drop enters the sleeve, capillary forces draw the liquid from the middle of the sleeve to the ends 20, 24 of the sleeve, spreading the drop uniformly tlu'oughout the sleeve. Both the thread 14 and the coating of surfactant encourage the capillary action, improving the distribution of the liquid.
The source 10, containing the drop of liquid, is heated to cause the evaporation of the liquid. The heat can optionally be provided by the same heat source that was used to form die seals 18, 22 at the ends of the sleeve 12. The evaporating liquid leaves a radioactive precipitated isotope residue plated within the sleeve, completing the radiation source.
The thread 14 and the sleeve 12 have consistent surfaces throughout tl~e interior of the sleeve, providing for a consistent volume of the liquid throughout tt~e sleeve, and thus providing for uniform plating of the precipitated isotope.
The uniformly spaced holes 16, and the watertight seals 18, 22 further encourage uniformity in the plating of the precipitated isotope. While heating the source is the preferred method of evaporation, other methods can be used. For example, altering the WO 99/62590 PCT/CfS99/12608 air pressure, or even leaving die source exposed to die unaltered atmosphere, would be alternate methods of evaporating die liquid.
As seen in FIG. 4, the completed radiation source, comprising the sleeve 12 and its contents, is then sealed within a cavity in a wire 34, using a water-tight seal, to create a radiation source wire. The source wire is subsequently inserted into a guide catheter 36, which is positioned within a cardiovascular vessel 38 in a patient's body.
Because the radiation source is highly flexible, it can pass through, and be positioned in torhmus regions 40 of the vessel, to irradiate the tissue 42 to be treated.
The positioned radiation source thus employs a radioactive isotope for invasive medical treatment.
The sealed source wire 34 provides a mechanism to quickly and safely insert and locate the radiation source through a guide catheter 36 within a patient's body. The watertight seal protects the patients body from direct contact with the isotope. Additional safety is gained by the isotope's being plated on surfaces in t1e interior of the sleeve 12, and thus not being prone to leaking out. Tlis protection is in addition to die protection provided by the guide catheter, which typically isolates a patient's body from radiation sources.
Wlile the above method of employing a radioactive isotope for invasive medical ireaiment is preferable, other methods are within the scope of the invention.
For example, the source can be formed with only one end of the sleeve sealed, and the drop can first contact the thread or the sleeve at the oilier end of the sleeve. Such an arrangement might be advantageous if the liquid-borne isotope is provided in a container, and is not conveniently dispensed in drops.
WO 99/62590 PCT/US99/12b08 Furthermore, it would be within the scope of the' invention to use structures other than the tluead to encourage the liquid to wick, under capillary forces, throughout die sleeve: Indeed, the invention can be practiced without the thread or the seals, however it might be more dif6.cult to obtain uniform distribution of the isotope in such embodiments.
An alternate method of treating a patient, wluch is within the scope of the present invention, includes providing the radiation source, sealing the radiation source wifliin a water tight capsule, and implanting the capsule into the patient's body. This method would generally be more appropriate for a radiation source having very low levels of radiation, or possibly having an isotope with a short half life.
From the foregoing description, it will be appreciated that the present invention provides a source configtued to receive a radioactive isotope, forming a radiation source for invasive medical treatment. It further provides a related method of employing a radioactive isotope for invasive medical treatment. The radiation source is flexible, and can carry a radioactive isotope having a High level of radioactivity dishibuted uniformly along its length.
While a particular form of the invention has been illustrated and described, it will be apparent that various modifications can be made without departing from the spirit and scope of the invention. Thus, although the invention has been described in detail with reference only to the preferred embodiments, those having ordinary skill in the art will appreciate that various modifications can be made without departing from the invention. Accordingly, the invention is not intended to be limited, and is defined with reference to the following claims.
BACKGROUND OF THE INVENTION
This invention relates generally to invasive medical radiotherapy and, more particularly, to a radiation source for use in invasive medical treatment, and to a method for making it.
Physicians now use radiation to treat an increasing number of medical problems. One form of radiation treatrnent involves the insertion of a radiation source into a patient's body to irradiate a limited area of the body for a controlled period of time. Typically, a surgeon inserts a longitudinal radiation source into die patient's body through a lumen of an implanted guide catheter. This procedure often requires a radiation source to exhibit both high flexibility and an effectively high level of radioactivity, particularly for cardiovascular radiotherapy. Furtlermore, the radiation source must provide consistent levels of radiation over its entire length.
During implantation, the radiation sotuce might be required to travel through tortuous pathways within a patient's body, such as the coronary arteries.
Furthermore, the area requiring treatment might be characterized by tortuous twists and bends. A radiation source must therefore be sufficiently flexible to navigate such pathways without injuring the patient or damaging itself.
Once the radiation source has been inserted into the patient's body, the total dosage of radiation will be determined by the level of radioactivity of the radiation source, and by the length of time the targeted tissue is exposed to die radiation source. Radiation sources having higher radiation levels provide for shorter exposure times, which lowers both the time duration of a procedure and the level of risk involved in the procedure. This risk is particularly important in situations where die guide catheter causes significant obstruction to the profusion of the blood.
However, existing technologies provide for higher levels of radioactivity at the expense of flexibility, thus placing an upper limit on the radiation levels available for treating torhious pathways.
A limiting factor on the design of such radiation sources is the risk of overexposing a patient to radiarion due to inconsistent levels of radiation along the length of the radiation source. The radiation source is brought into close proximity with portions of the patient's body, and a particularly "hot" portion of the radiation source can therefore overexpose an adjacent portion of the patient's body.
Likewise, longitudinal sections having a lower than desired radiation level can provide lower than desired levels of radiation treatment. Thus, the radiation level along a radiation source must be kept as longitudinally consistent as possible. It is known that longitudinal uniformity is important, and that a preferred level of uniformity is a maximum 10% variation.
It is known, for example, that a radiation source can be formed in a cavity within a wire or within a tube (also known as a ribbon), and can include a plurality of rigid pellets, made from a radioactive isotope, that are embedded at intervals along the wire with spacers positioned between the pellets. The spacers function to give this source wire some flexibility despite the presence of die rigid pellets. The flexibility is restricted, however, to the areas between the pellets.
Furthermore, the pellets form a series of nonuniform radiation hot spots, causing tissue around the source wire to be irradiated unevenly. Longer spacers improve the source wire's flexibility, however they cause the distribution of radiation to be less uniforn~
and less continuous, and thus a trade off must be made between flexibility and radiation uniformity.
It has been suggested flat an isotope could be carried in a liquid, and passed into, and then out of a passage in a catheter. However, when the catheter assumes a strongly bent position, such as in a tortuous passage, a portion of the passage could change in cross-sectional shape, and the quantity of the isotope that could be located in that portion would vary. Thus, the catheter would lave local radiation levels that vary wide die bent shape of the catheter, and would not maintain a uniform radiation level distribution.
Accordingly, there has existed a definite need for an invasive medical treatment radiation source, where the radiation source exhibits high flexibility and high levels of radioactivity, the radioactivity being distributed in a uniform and continuous fashion throughout the radiation source. The present invention satisfies these and oilier needs, and provides further related advantages.
SUMMARY OF THE INVENTION
The present invention provides a radiation source for invasive medical treatment, where the radiation soiuce exhibits high flexibility and high levels of radioactivity, the radioactivity being distributed in a uniform and continuous fashion throughout the radiation source, and a method of malting the radiation source.
The present invention further provides a related method of employing the radioactive isotope for invasive medical treatment. The invention has potential use in a wide range of applicatlons, such as intravascular radiotherapy and oncology.
A radiation source for invasive medical treatment, embodying the present invention, features a hollow sleeve (e.g., a tube or cylinder) and a coating of a radioactive isotope distributed on surfaces in the interior of the sleeve.
Tlis radiation source provides for the irradiation of tissue, within a patient's body, along long and tortuously curved pathways in the body, such as coronary arteries. It further provides for a substantially even level of irradiation along the full length of irradiated tissue.
The invention also features a struchire, e.g., a thread with filaments wound in a helical pattern, within the sleeve, that is configured to distribute a liquid throughout the sleeve by capillary action. This feature advantageously provides for the uniform spreading of the isotope, while born in a liquid, throughout the sleeve. The struchire preferably extends from a first seal at a first end of a sleeve, to a second seal at a second end of the sleeve. The helical filaments may cause the fluead to follow a pig-tailed, coiled path down the sleeve. The thread and seals promote even capillary spreading of the liquid, providing even distribution of a liquid-born isotope, and thus serving as a fiirther means for distributing the liquid-born isotope throughout the sleeve. The pig-tailed thread may further enhance the capillary action.
A fiuther feature of the invention is drat die sleeve is configured to promote liquid evaporation from within the sleeve at a consistent rate throughout the sleeve. This feature can comprise a plurality of holes in die sleeve, which are positioned at approximately equal intervals along the sleeve's length and spaced at approximately symmetric locations around die sleeve's circumference. The holes can be any form of orifice, such as circular or oval openings, slits that open under internal pressure, or even the pores in a porous material having large enough pores to allow evaporation. This feature advantageously allows for the uniform evaporation, along the length of the sleeve, of a liquid that bears'the isotope. The evaporation causes the surfaces distributed throughout the interior of the sleeve to be plated with a uniform coating of the precipitated isotope.
Additionally, die invention features a coating of a surfactant along surfaces in the interior of the sleeve. The surfactant reduces surface tension of die fluid, to promote uniform spreading of a liquid throughout the sleeve, through capillary action.
Other feahires and advantages of the invention will become apparent from the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings, wl>ich illustrate, by way of example, the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of a source configured to receive a radioactive isotope, embodying features of the present invention.
FIG. 2 is a cross-sectional side view of die source depicted in FIG. l, taken along line 2-2 of FIG. 1.
FIG. 3 is an elevarional view of the source depicted in FIG. l, being held in a device configured to hold the source, the source being in the process of contacting a drop of a liquid-borne radioactive isotope.
FIG. 4 is an elevational view of the source depicted in FIG. 1, inserted in a patient's cardiovascular system through a vide catheter for cardiovascular radiotherapy.
S
pETAILED DESCRIPTION C~F THE PREFERRED FMRODIMENTS
With reference now to the illustrative drawings, and particularly to FIGS.
1 and 2, there is shown one embodiment of a "source" 10 configured to receive a radioactive isotope for invasive medical treatment, such as intracoronary radiotherapy, or other such intravascular radiotherapy, according to the present invention.
The source includes a foundation, preferably in the form of a hollow sleeve 12, and most preferably including a fluead 14 extending longihidinally witlin the sleeve.
This foundation includes surfaces for receiving a coating of a radioactive isotope.
Preferably, the isotope is precipitated from an evaporating liquid and plated onto the surfaces. The sleeve and thread provide capillary forces to draw a drop of liquid-borne radioactive isotope into the sleeve and distribute it tluoughout the sleeve, such that it plates on surfaces within the sleeve.
The sleeve I2 is preferably in die form of a hollow circular cylinder, defining a longitudinal axis. The sleeve is preferably made from a polyimide resin, or other such elastic material that is resistant to radiation degradation. The diameter and wall thickness of the sleeve are selected to be sufficiently flexible for intravascular radiotherapy. Preferably, the sleeve's length is substantially greater than its diameter to provide for irradiation of an extended length of tissue in a narrow vessel.
For example, the sleeve's length might be greater dean 1 inch, while the sleeve's diameter is less than 0.02 inches.
The hollow sleeve 12 defines a plurality of holes 16 connecting tle interior siuface of the sleeve to the exterior surface of the sleeve. The holes, in groups of six, are longitudinally spaced at equal intervals along the length of the sleeve. Each group of six holes is symmetrically spaced around die circiunference of the sleeve at a given longitudinal location. Longihidinally consecutive groups of holes are WO 99/62590 PCT/US99/1260$
circumferentially offset by 30° from each other. The holes are confi~~red in an evenly spaced pattern that promotes liquid evaporation from within the sleeve at a reasonably consistent rate throughout the length and circumference of the sleeve. Thus, the holes provide a means of coating surfaces throughout the interior of the sleeve with a substantially uniform plating of the isotope, such that the sleeve is appropriate for evenly irradiating nearby tissue.
A first seal 18 caps tle sleeve 12 at a first end 20, preferably sealing that end to prevent liquid flow through that end. A second seal 22 caps the sleeve at a second end 24, preferably sealing that end to prevent liquid flow duough that end. The seals, like die sleeve, are preferably made from a polyimide resin. The thread includes two ends, which are anchored in the hwo seals, respectively. T1e seals thus maintain the ends of the thread in alignment with flee capped ends of the sleeve, and prevent liquid flow through those ends:
The thread 14 extends longih~dinally through the sleeve 12 from tle sleeve's first end 20 to its second end 24. The longitudinal cross-section of the thread (see FIG. 2) defines an area that is preferably consistent along the length of the thread, preferably filling roughly 25% to 30% of tire sleeve's volume. The thread i4 is preferably comprised of approximately twelve rayon filaments 26 wound in a helical fashion, as depicted in FIG. 1. Thread of this nahire can be found as strands within larger dreads.
While this embodiment includes a thread 14, other embodiments can be provided will other alternative structures within the sleeve, such as a unitary thread or a rigid stnicttrre. These stnrchires preferably provide for the distribution of a liquid duoughout the sleeve, such as by capillary forces. These stmcW res also preferably provide plating surfaces throughout the sleeve flat are configured for a predetermined distribution of precipitated isotope. Preferably, the predetermined distribution of the isotope is an approximately uniform distribution along the length of the sleeve.
Both the sleeve 12 and the thread 14 include a coating of a surfactant, such as Phironic Surfactant type 68, manufactured by BAST. The surfactant lowers surface tension of a liquid vv~itlun the sleeve, promoting uniform spreading of the liquid fluoughout the sleeve by capillary action.
The invention includes a related method of employing a radioactive isotope for invasive medical treatment. In this inventive method, the sleeve 12 is formed in its desired diameter and thickness. Laser drilling is preferably used to form the holes 16 in the sleeve.
The tluead 14 is inserted into the sleeve 12, and die first seal 18 is formed, anchoring the first end of the dread to the first end 20 of the sleeve. The first seal is formed by heating the end of the sleeve and thread to approximately 80° C to 100° C, preferably in a column of heated gas, to solidify the ends of the sleeve and thread into a unitary seal. Prior to insertion, the thread may be passed through a drop of adhesive in order to stiffen it, easing the its insertion into the sleeve 12.
With only one seal formed, the sleeve 12 and thread 14 are wet (preferably by dunking in water) and then dried. This wetting and drying preshrinks the thread prior to forming the second seal 22, and thus avoids potential warping during later steps of the process.
The second seal 22 is then formed, anchoring the second cnd of the thread 14 to the second end 24 of the sleeve 12. As with the first seal, the second seal is formed by heating the end of the sleeve and thread, preferably in a column of Heated gas, to solidify the ends of the sleeve and thread into a unitary seat.
The sleeve and the thread are then wet (preferably by dunking) with a surfactant. The surfactant is dried to complete the formation of the source.
The surfactant, coating stcrfaces widun the sleeve, promotes capillary action within the sleeve. This is particularly important in low luimidity environments when static electricity might be a problem.
To plate a coating of a radioactive isotope on the surfaces within the sleeve 12, the radioactive isotope is provided while borne in a liquid. The radioactive isotope is preferably Phosphorus-32 (P-32), which has a high specific activity, and the liquid is preferably water. Wlule a number of Phosphonis-32 radionuclide solutions may he used, preferably the solution is radioactive orthophosphoric acid (H,PO,) in water. The provision of a highly concentrated liquid-borne radioactive isotope allows a higher level of radioactivity per unit of liquid, and tlys produces a radiation source with higher levels of radiation.
Referring now to FIGS. 1 to 3, the first end 20 of the completed radiation source's sleeve 12 is placed into a retaining device 28, which holds the source without covering a significant number of t1e source's holes 16. The retaining device is preferably configured with a follow cylinder having an inner dia~aeter conforming to the outer diameter of the sleeve, providing for a friction grip on tl~e source.
The source I0, held by the retaining device 28, is brought into contact with the liquid-borne radioactive isotope. Preferably, the source is positioned below a drop 32 of the liquid-borne radioactive isotope, and is moved up into contact with the drop. The drop contacts the source in the source's central portion, hetw~een tl~e ends <) 20, 24 of the sleeve 12, and most preferably at the approximate longitudinal midpoint of t1e sleeve. The drop is preferably of a correct volume to approximately fill the sleeve. The drop is preferably suspended from a syringe. A preferred apparatus, including a syringe and a retaining device 28, for use with the invention is described in the concurrently filed and commonly assigned patent application, entitled METHOD
AND APPARATUS FOR CONCCNTRATING A SOLUTE IN SOLUTION WITH A
SOLVENT, having application Serial No. , which is uicorporated herein by reference.
Upon contact, die drop 32 of the liquid-borne radioactive isotope enters the sleeve 12 through flee holes 16. As the drop enters the sleeve, capillary forces draw the liquid from the middle of the sleeve to the ends 20, 24 of the sleeve, spreading the drop uniformly tlu'oughout the sleeve. Both the thread 14 and the coating of surfactant encourage the capillary action, improving the distribution of the liquid.
The source 10, containing the drop of liquid, is heated to cause the evaporation of the liquid. The heat can optionally be provided by the same heat source that was used to form die seals 18, 22 at the ends of the sleeve 12. The evaporating liquid leaves a radioactive precipitated isotope residue plated within the sleeve, completing the radiation source.
The thread 14 and the sleeve 12 have consistent surfaces throughout tl~e interior of the sleeve, providing for a consistent volume of the liquid throughout tt~e sleeve, and thus providing for uniform plating of the precipitated isotope.
The uniformly spaced holes 16, and the watertight seals 18, 22 further encourage uniformity in the plating of the precipitated isotope. While heating the source is the preferred method of evaporation, other methods can be used. For example, altering the WO 99/62590 PCT/CfS99/12608 air pressure, or even leaving die source exposed to die unaltered atmosphere, would be alternate methods of evaporating die liquid.
As seen in FIG. 4, the completed radiation source, comprising the sleeve 12 and its contents, is then sealed within a cavity in a wire 34, using a water-tight seal, to create a radiation source wire. The source wire is subsequently inserted into a guide catheter 36, which is positioned within a cardiovascular vessel 38 in a patient's body.
Because the radiation source is highly flexible, it can pass through, and be positioned in torhmus regions 40 of the vessel, to irradiate the tissue 42 to be treated.
The positioned radiation source thus employs a radioactive isotope for invasive medical treatment.
The sealed source wire 34 provides a mechanism to quickly and safely insert and locate the radiation source through a guide catheter 36 within a patient's body. The watertight seal protects the patients body from direct contact with the isotope. Additional safety is gained by the isotope's being plated on surfaces in t1e interior of the sleeve 12, and thus not being prone to leaking out. Tlis protection is in addition to die protection provided by the guide catheter, which typically isolates a patient's body from radiation sources.
Wlile the above method of employing a radioactive isotope for invasive medical ireaiment is preferable, other methods are within the scope of the invention.
For example, the source can be formed with only one end of the sleeve sealed, and the drop can first contact the thread or the sleeve at the oilier end of the sleeve. Such an arrangement might be advantageous if the liquid-borne isotope is provided in a container, and is not conveniently dispensed in drops.
WO 99/62590 PCT/US99/12b08 Furthermore, it would be within the scope of the' invention to use structures other than the tluead to encourage the liquid to wick, under capillary forces, throughout die sleeve: Indeed, the invention can be practiced without the thread or the seals, however it might be more dif6.cult to obtain uniform distribution of the isotope in such embodiments.
An alternate method of treating a patient, wluch is within the scope of the present invention, includes providing the radiation source, sealing the radiation source wifliin a water tight capsule, and implanting the capsule into the patient's body. This method would generally be more appropriate for a radiation source having very low levels of radiation, or possibly having an isotope with a short half life.
From the foregoing description, it will be appreciated that the present invention provides a source configtued to receive a radioactive isotope, forming a radiation source for invasive medical treatment. It further provides a related method of employing a radioactive isotope for invasive medical treatment. The radiation source is flexible, and can carry a radioactive isotope having a High level of radioactivity dishibuted uniformly along its length.
While a particular form of the invention has been illustrated and described, it will be apparent that various modifications can be made without departing from the spirit and scope of the invention. Thus, although the invention has been described in detail with reference only to the preferred embodiments, those having ordinary skill in the art will appreciate that various modifications can be made without departing from the invention. Accordingly, the invention is not intended to be limited, and is defined with reference to the following claims.
Claims (52)
1. A source for carrying a radioactive isotope, comprising:
a hollow longitudinal sleeve; and a structure, within the sleeve, configured to distribute a liquid longitudinally throughout the sleeve by capillary action.
a hollow longitudinal sleeve; and a structure, within the sleeve, configured to distribute a liquid longitudinally throughout the sleeve by capillary action.
2. The source of claim 1, wherein the sleeve is configured to promote liquid evaporation from widen the sleeve at a consistent rate longitudinally throughout die sleeve.
3. The source of claim 2, and further comprising a first seal at a first end of the sleeve.
4. The source of claim 3, and further comprising a second seal at a second end of the sleeve.
5. The source of claim 2, wherein the sleeve's configuration to promote liquid evaporation comprises a plurality of holes defined in the sleeve.
6. The source of claim 5, wherein the plurality of holes are openings positioned at approximately equal intervals longitudinally along the sleeve, and wherein the plurality of holes are spaced at approximately symmetric locations around the circumference of the sleeve.
7. The source of claim 6, and further comprising a first seal at a first end of the sleeve and a second seal at a second end of the sleeve.
8. The source of claim 1, wherein the structure configured to distribute a liquid is a thread extending longitudinally within the sleeve.
9. The source of claim 8, wherein the thread includes a plurality of filaments.
10. The source of claim 9, wherein the thread is anchored to a first end of the sleeve;
and the thread is anchored to a second end of the sleeve.
and the thread is anchored to a second end of the sleeve.
11. The source of claim 10, wherein the plurality of filaments extend along the sleeve in a helical configuration.
12. The source of claim 8, wherein the lengths of the thread and the sleeve are substantially longer than the diameter of the sleeve, and wherein the thread and the sleeve are sufficiently flexible to be used in intracoronary radiotherapy.
13. The source of claim 1, wherein the source includes one or more surfaces within the sleeve, the surfaces being coated with a surfactant.
14. The source of claim 1, and further comprising:
a first seal at a first end of the sleeve; and a second seal at a second end of the sleeve;
wherein the sleeve defines a plurality of holes to promote liquid evaporation from within the sleeve at a consistent rate longitudinally throughout the sleeve;
wherein the plurality of holes are openings positioned at approximately equal intervals longitudinally along the sleeve;
wherein the plurality of holes are spaced at approximately symmetric locations around the circumference of the sleeve;
wherein the structure configured to distribute the radioactive isotope is a thread extending longitudinally within the sleeve, the thread including a plurality of filaments;
wherein the first seal anchors the thread to the first end of the sleeve;
wherein the second seal anchors the thread to the second end of the sleeve;
and wherein the thread and the sleeve are sufficiently flexible to be used in intracoronary radiotherapy.
a first seal at a first end of the sleeve; and a second seal at a second end of the sleeve;
wherein the sleeve defines a plurality of holes to promote liquid evaporation from within the sleeve at a consistent rate longitudinally throughout the sleeve;
wherein the plurality of holes are openings positioned at approximately equal intervals longitudinally along the sleeve;
wherein the plurality of holes are spaced at approximately symmetric locations around the circumference of the sleeve;
wherein the structure configured to distribute the radioactive isotope is a thread extending longitudinally within the sleeve, the thread including a plurality of filaments;
wherein the first seal anchors the thread to the first end of the sleeve;
wherein the second seal anchors the thread to the second end of the sleeve;
and wherein the thread and the sleeve are sufficiently flexible to be used in intracoronary radiotherapy.
15. A radiation source for invasive medical treatment, comprising:
a longitudinal foundation; and a coating of a radioactive isotope on the foundation.
a longitudinal foundation; and a coating of a radioactive isotope on the foundation.
16. The radiation source of claim 15, wherein:
the foundation is a hollow longitudinal sleeve; and the coating of a radioactive isotope is plated on surfaces in the interior of the sleeve.
the foundation is a hollow longitudinal sleeve; and the coating of a radioactive isotope is plated on surfaces in the interior of the sleeve.
17. The radiation source of claim 16, wherein the sleeve is configured to promote liquid evaporation from within the sleeve at a consistent rate longitudinally throughout the sleeve.
18. The radiation source of claim 17, wherein the sleeve defines a plurality of holes to promote evaporation.
19. The radiation source of claim 17, and further comprising a first seal at a first end of the sleeve, and a second seal at a second end of the sleeve.
20. The radiation source of claim 16, and further comprising a structure, within the sleeve, configured to distribute a liquid longitudinally throughout the sleeve by capillary action.
21. The radiation source of claim 20, wherein the structure configured to distribute a liquid is a thread extending longitudinally within the sleeve, the thread including a plurality of filaments.
22. The radiation source of claim 21, wherein the thread is anchored to a first end of the sleeve and to a second end of the sleeve, and wherein the plurality of filaments extend along the sleeve in a helical configuration.
23. The radiation source of claim 16, wherein the length of the sleeve is substantially longer than the diameter of the sleeve, and wherein the thread is sufficiently flexible to be used in intracoronary radiotherapy.
24. The radiation source of claim 16, and further comprising:
a thread extending longitudinally within the sleeve, the thread including a plurality of filaments extending along the sleeve in a helical configuration, the thread being configured to distribute a liquid longitudinally throughout the sleeve by capillary action; and a first seal anchoring the thread at a first end of the sleeve, and a second seal anchoring the thread at a second end of the sleeve;
wherein the sleeve defines a plurality of holes to promote liquid evaporation from within the sleeve at a consistent rate longitudinally throughout the sleeve;
wherein the plurality of holes are openings positioned at approximately equal intervals longitudinally along the sleeve;
wherein the lengths of the thread and the sleeve are substantially longer than the diameter of the sleeve; and wherein the thread and the sleeve are sufficiently flexible to be used in intracoronary radiotherapy.
a thread extending longitudinally within the sleeve, the thread including a plurality of filaments extending along the sleeve in a helical configuration, the thread being configured to distribute a liquid longitudinally throughout the sleeve by capillary action; and a first seal anchoring the thread at a first end of the sleeve, and a second seal anchoring the thread at a second end of the sleeve;
wherein the sleeve defines a plurality of holes to promote liquid evaporation from within the sleeve at a consistent rate longitudinally throughout the sleeve;
wherein the plurality of holes are openings positioned at approximately equal intervals longitudinally along the sleeve;
wherein the lengths of the thread and the sleeve are substantially longer than the diameter of the sleeve; and wherein the thread and the sleeve are sufficiently flexible to be used in intracoronary radiotherapy.
25. The radiation source of claim 15, and further comprising a wire containing the foundation in a cavity within the wire, wherein the wire provides a watertight seal around the foundation.
26. The radiation source of claim 25, wherein:
the foundation is a hollow longitudinal sleeve; and the coating of a radioactive isotope is plated on surfaces in the interior of the sleeve.
the foundation is a hollow longitudinal sleeve; and the coating of a radioactive isotope is plated on surfaces in the interior of the sleeve.
27. The radiation source of claim 26, and further comprising a first seal at a first end of the sleeve, and a second seal at a second end of the sleeve, wherein the sleeve defines a plurality of holes to promote liquid evaporation from within the sleeve.
28. The radiation source of claim 26, and further comprising a thread extending longitudinally within the sleeve, configured to distribute a liquid throughout the sleeve by capillary action, wherein the thread is anchored to a first end of the sleeve and to a second end of the sleeve.
29. The radiation source of claim 26, and further comprising:
a thread extending longitudinally within the sleeve, configured to distribute a liquid longitudinally throughout the sleeve by capillary action, the thread including a plurality of filaments extending along the sleeve in a helical configuration;
a first seal anchoring the thread at a first end of the sleeve; and a second seal anchoring the thread at a second end of the sleeve;
wherein the sleeve defines a plurality of holes to promote liquid evaporation from within the sleeve; and wherein the thread and the sleeve are sufficiently flexible to be used in intracoronary radiotherapy.
a thread extending longitudinally within the sleeve, configured to distribute a liquid longitudinally throughout the sleeve by capillary action, the thread including a plurality of filaments extending along the sleeve in a helical configuration;
a first seal anchoring the thread at a first end of the sleeve; and a second seal anchoring the thread at a second end of the sleeve;
wherein the sleeve defines a plurality of holes to promote liquid evaporation from within the sleeve; and wherein the thread and the sleeve are sufficiently flexible to be used in intracoronary radiotherapy.
30. The radiation source of claim 15, wherein the radioactive isotope is Phosphorus-32.
31. A method of employing a radioactive isotope for invasive medical treatment, comprising:
providing a longitudinal foundation; and coating the foundation with precipitated isotope.
providing a longitudinal foundation; and coating the foundation with precipitated isotope.
32. The method of claim 31, wherein:
the provided foundation is a hollow longitudinal sleeve; and the step of coating the foundation includes coating surfaces distributed longitudinally throughout in the interior of the sleeve with precipitated isotope.
the provided foundation is a hollow longitudinal sleeve; and the step of coating the foundation includes coating surfaces distributed longitudinally throughout in the interior of the sleeve with precipitated isotope.
33. The method of claim 32, and further comprising sealing the sleeve, coated with the isotope, within a cavity in a wire, using a water-tight seal.
34. The method of claim 32, wherein the step of coating with the isotope includes contacting the isotope, borne in a liquid, with the sleeve, such that capillary action will longitudinally distribute the liquid-borne isotope throughout the sleeve, and wherein the step of coating with the isotope further includes evaporating the liquid to cause plating of the isotope within the sleeve.
35. The method of claim 34, wherein the isotope, borne in a liquid, is radioactive orthophosphoric acid in water.
36. The method of claim 34, and further comprising coating surfaces in the interior of the sleeve with a surfactant prior to the step of contacting the isotope with the sleeve.
37. The method of claim 34, wherein the sleeve defines a plurality of holes to promote liquid evaporation from within the sleeve.
38. The method of claim 37, wherein the sleeve includes a first seal at a first end of the sleeve and a second seal at a second end of the sleeve, and wherein the sleeve contacts the liquid-borne isotope with a central portion of the sleeve.
39. The method of claim 34, and further providing a thread extending longitudinally within the sleeve.
40. The method of claim 39, and further comprising:
anchoring the thread to a first end of the sleeve;
wetting and drying the thread to preshrink the thread; and anchoring the preshrunk thread to a second end of the sleeve;
wherein the thread includes a plurality of filaments extending along the sleeve in a helical configuration; and wherein the sleeve defines a plurality of holes to promote liquid evaporation from within the sleeve.
anchoring the thread to a first end of the sleeve;
wetting and drying the thread to preshrink the thread; and anchoring the preshrunk thread to a second end of the sleeve;
wherein the thread includes a plurality of filaments extending along the sleeve in a helical configuration; and wherein the sleeve defines a plurality of holes to promote liquid evaporation from within the sleeve.
41. The method of claim 40, and further comprising:
laser drilling a plurality of holes in the sleeve to promote liquid evaporation from within the sleeve;
providing a thread extending longitudinally within the sleeve, wherein the lengths of the thread and the sleeve are substantially longer than the diameter of the sleeve, and wherein the thread and the sleeve are sufficiently flexible to be used in intracoronary radiotherapy; and coating surfaces in the interior of the sleeve with a surfactant prior to the step of contacting the isotope with the sleeve;
wherein the step of anchoring the thread to the first end of the sleeve includes providing the sleeve with a first seal that anchors the thread, wherein the step of anchoring the thread to the second end of the sleeve includes providing the sleeve with a second seal that anchors the thread; and wherein the liquid-borne isotope contacts a central portion of the sleeve in the step of contacting the isotope with the sleeve.
laser drilling a plurality of holes in the sleeve to promote liquid evaporation from within the sleeve;
providing a thread extending longitudinally within the sleeve, wherein the lengths of the thread and the sleeve are substantially longer than the diameter of the sleeve, and wherein the thread and the sleeve are sufficiently flexible to be used in intracoronary radiotherapy; and coating surfaces in the interior of the sleeve with a surfactant prior to the step of contacting the isotope with the sleeve;
wherein the step of anchoring the thread to the first end of the sleeve includes providing the sleeve with a first seal that anchors the thread, wherein the step of anchoring the thread to the second end of the sleeve includes providing the sleeve with a second seal that anchors the thread; and wherein the liquid-borne isotope contacts a central portion of the sleeve in the step of contacting the isotope with the sleeve.
42. The method of claim 41, wherein the lengths of the thread and the sleeve are substantially longer than the diameter of the sleeve, and wherein the thread and the sleeve are sufficiently flexible to be used in intracoronary radiotherapy.
43. The method of claim 32, and further comprising inserting the sleeve, coated with the isotope, into a patient's body;
wherein the step of coating with the isotope includes contacting the isotope, borne in a liquid, with the sleeve, such that capillary action will distribute the liquid-borne isotope throughout the sleeve; and evaporating the liquid to cause plating of the isotope within the sleeve.
wherein the step of coating with the isotope includes contacting the isotope, borne in a liquid, with the sleeve, such that capillary action will distribute the liquid-borne isotope throughout the sleeve; and evaporating the liquid to cause plating of the isotope within the sleeve.
44. The method of claim 43, and further comprising coating surfaces in the interior of the sleeve surfactant prior to the step of contacting the isotope with the sleeve, wherein the provided sleeve defines a plurality of holes to promote liquid evaporation from within the sleeve.
45. The method of claim 43, wherein the sleeve includes a first seal at a first end of the sleeve and a second seal at a second end of the sleeve, and wherein the sleeve contacts the liquid-borne isotope with a central portion of the sleeve.
46. The method of claim 43, and further comprising:
providing a thread extending longitudinally within the sleeve;
anchoring the thread to a fist end of the sleeve;
preshrinking the thread; and anchoring the preshrunk thread to a second end of the sleeve;
wherein the thread includes a plurality of filaments extending along the sleeve in a helical configuration.
providing a thread extending longitudinally within the sleeve;
anchoring the thread to a fist end of the sleeve;
preshrinking the thread; and anchoring the preshrunk thread to a second end of the sleeve;
wherein the thread includes a plurality of filaments extending along the sleeve in a helical configuration.
47. The method of claim 43, and further comprising sealing the sleeve, coated with the isotope, within a cavity in a wire, using a water-tight seal.
48. The method of claim 31, wherein the isotope, borne in a liquid, is a Phosphorus-32 radionuclide solution.
49. A radiation source employing a radioactive isotope for invasive medical treatment, comprising:
a hollow sleeve; and means for coating surfaces throughout in the interior of the sleeve with a plating of the isotope.
a hollow sleeve; and means for coating surfaces throughout in the interior of the sleeve with a plating of the isotope.
50. The radiation source of claim 49, wherein the means for coating includes a means for distributing a liquid-borne isotope throughout the sleeve.
51. The radiation source of claim 49, wherein the means for coating includes a means for evaporating a liquid-borne isotope within the sleeve to cause tire plating of the isotope.
52. The radiation source of claim 49, wherein the means for coating includes a means for reducing surface tension to promote uniform spreading of a liquid longitudinally throughout the sleeve, through capillary action.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US09/090,892 | 1998-06-04 | ||
| US09/090,892 US6053858A (en) | 1998-06-04 | 1998-06-04 | Radiation source |
| PCT/US1999/012608 WO1999062590A2 (en) | 1998-06-04 | 1999-06-04 | Radiation source |
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| Publication Number | Publication Date |
|---|---|
| CA2334138A1 true CA2334138A1 (en) | 1999-12-09 |
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|---|---|---|---|
| CA002334138A Abandoned CA2334138A1 (en) | 1998-06-04 | 1999-06-04 | Radiation source |
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| EP (1) | EP1083970A2 (en) |
| JP (1) | JP2002516730A (en) |
| AU (1) | AU4334499A (en) |
| CA (1) | CA2334138A1 (en) |
| WO (1) | WO1999062590A2 (en) |
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| ATE170708T1 (en) | 1994-06-10 | 1998-09-15 | Schneider Europ Gmbh | MEDICINAL DEVICE FOR THE TREATMENT OF A PART OF BODY VESSEL USING IONIZATION RADIATION |
| EP0688580B1 (en) | 1994-06-24 | 2000-10-04 | Schneider (Europe) GmbH | Medical appliance for the treatment of a portion of body vessel by ionising radiation |
| US6234951B1 (en) | 1996-02-29 | 2001-05-22 | Scimed Life Systems, Inc. | Intravascular radiation delivery system |
| US6416457B1 (en) | 2000-03-09 | 2002-07-09 | Scimed Life Systems, Inc. | System and method for intravascular ionizing tandem radiation therapy |
| US6302865B1 (en) | 2000-03-13 | 2001-10-16 | Scimed Life Systems, Inc. | Intravascular guidewire with perfusion lumen |
| US6746661B2 (en) * | 2000-11-16 | 2004-06-08 | Microspherix Llc | Brachytherapy seed |
| EP1545705A4 (en) * | 2000-11-16 | 2010-04-28 | Microspherix Llc | Flexible and/or elastic brachytherapy seed or strand |
| US6875165B2 (en) * | 2001-02-22 | 2005-04-05 | Retinalabs, Inc. | Method of radiation delivery to the eye |
| US6787786B2 (en) | 2001-06-12 | 2004-09-07 | North American Scientific, Inc. | Thin radiation source and method of making the same |
| US7074291B2 (en) * | 2001-11-02 | 2006-07-11 | Worldwide Medical Technologies, L.L.C. | Delivery system and method for interstitial radiation therapy using strands constructed with extruded strand housings |
| US7060020B2 (en) | 2001-11-02 | 2006-06-13 | Ideamatrix, Inc. | Delivery system and method for interstitial radiation therapy |
| AU2005214040B2 (en) * | 2004-02-12 | 2011-03-31 | Neo Vista, Inc. | Methods and apparatus for intraocular brachytherapy |
| US7563222B2 (en) | 2004-02-12 | 2009-07-21 | Neovista, Inc. | Methods and apparatus for intraocular brachytherapy |
| US8187159B2 (en) | 2005-07-22 | 2012-05-29 | Biocompatibles, UK | Therapeutic member including a rail used in brachytherapy and other radiation therapy |
| US7736293B2 (en) * | 2005-07-22 | 2010-06-15 | Biocompatibles Uk Limited | Implants for use in brachytherapy and other radiation therapy that resist migration and rotation |
| CA2629648A1 (en) * | 2005-11-15 | 2007-05-24 | Neovista Inc. | Methods and apparatus for intraocular brachytherapy |
| US7988611B2 (en) | 2006-05-09 | 2011-08-02 | Biocompatibles Uk Limited | After-loader for positioning implants for needle delivery in brachytherapy and other radiation therapy |
| US20090216063A1 (en) * | 2008-01-29 | 2009-08-27 | Biocompatibles Uk Limited | Bio-absorbable brachytherapy strands |
| US7878964B1 (en) | 2006-09-07 | 2011-02-01 | Biocompatibles Uk Limited | Echogenic spacers and strands |
| US7874976B1 (en) | 2006-09-07 | 2011-01-25 | Biocompatibles Uk Limited | Echogenic strands and spacers therein |
| EP2296756A1 (en) | 2008-06-04 | 2011-03-23 | Neovista, Inc. | Handheld radiation delivery system for advancing a radiation source wire |
| US10967198B2 (en) * | 2019-05-29 | 2021-04-06 | Arnold Herskovic | Brachytherapy stent configurations |
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| US5084002A (en) * | 1988-08-04 | 1992-01-28 | Omnitron International, Inc. | Ultra-thin high dose iridium source for remote afterloader |
| US4861520A (en) * | 1988-10-28 | 1989-08-29 | Eric van't Hooft | Capsule for radioactive source |
| US5176617A (en) * | 1989-12-11 | 1993-01-05 | Medical Innovative Technologies R & D Limited Partnership | Use of a stent with the capability to inhibit malignant growth in a vessel such as a biliary duct |
| US5833593A (en) * | 1995-11-09 | 1998-11-10 | United States Surgical Corporation | Flexible source wire for localized internal irradiation of tissue |
| US5871436A (en) * | 1996-07-19 | 1999-02-16 | Advanced Cardiovascular Systems, Inc. | Radiation therapy method and device |
-
1998
- 1998-06-04 US US09/090,892 patent/US6053858A/en not_active Expired - Fee Related
-
1999
- 1999-06-04 AU AU43344/99A patent/AU4334499A/en not_active Abandoned
- 1999-06-04 EP EP99955231A patent/EP1083970A2/en not_active Withdrawn
- 1999-06-04 WO PCT/US1999/012608 patent/WO1999062590A2/en not_active Application Discontinuation
- 1999-06-04 CA CA002334138A patent/CA2334138A1/en not_active Abandoned
- 1999-06-04 JP JP2000551843A patent/JP2002516730A/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| AU4334499A (en) | 1999-12-20 |
| EP1083970A2 (en) | 2001-03-21 |
| JP2002516730A (en) | 2002-06-11 |
| US6053858A (en) | 2000-04-25 |
| WO1999062590A3 (en) | 2000-10-12 |
| WO1999062590A2 (en) | 1999-12-09 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |