Implantable radiation therapy device having controllable radiation emission

• US 6,471,631 B1
• Filed: 05/22/2000
• Issued: 10/29/2002
• Est. Priority Date: 11/27/1998
• Status: Expired due to Term

• Current Assignee: Syntheon LLC
• Original Assignee: Syntheon LLC
• Inventors: Jahrmarkt, Scott L., Slater, Charles R., Smith, Kevin W., Smith, Scott T.
• Primary Examiner(s): Lacyk, John P.
• Application Number:
  US09/575,431
• Time in Patent Office: 890 Days
• Field of Search: 600/1-8
• US Class Current: 600/8
• CPC Class Codes: A61N 2005/1005 with asymmetrical radiation pattern
• CPC Class Codes: A61N 2005/1024 Seeds
• CPC Class Codes: A61N 5/1027 Interstitial radiation therapy

Abstract

An implantable radiation therapy device includes a biocompatible radiotranslucent outer capsule containing a radiation shielding element and a radioactive isotope at least partially shielded by the shielding element. When the device is at or below body temperature, radiation is prevented or limited from being transmitted through the outer capsule by the shielding element. When non-ambient energy is applied to the device, the shielding element and radioactive isotope are reconfigured such that an increased level of radiation is transmitted through the outer capsule and emitted by the device.

Claims

1. An implantable radiation therapy device, comprising:

a) a biocompatible outer capsule having a wall adapted to transmit radiation therethrough;

b) a radioactive material located inside said outer capsule and emitting radiation; and

c) control means inside said capsule for controllably altering an amount of said radiation transmitted through said outer capsule,

wherein said radioactive material and said control means are irremovable from inside said capsule without opening said capsule.

2. An implantable radiation therapy device according to claim 1, wherein:

said control means operates to increase the amount of radiation transmitted through said outer capsule.

3. An implantable radiation therapy device according to claim 1, wherein:

said control means includes a radiopaque shield movable between first and second configurations, wherein in said first configuration said radiopaque shield prevents a first amount of said radiation from reaching said outer capsule, and in said second configuration said radiopaque shield permits a greater amount of said radiation from reaching said outer capsule.

4. An implantable radiation therapy device according to claim 1, wherein:

said control means includes a shape memory alloy.

5. An implantable radiation therapy device according to claim 1, wherein:

said control means includes one of a spring and a pressurized fluid.

6. An implantable radiation therapy device according to claim 1, wherein:

said control means includes a collapsible sleeve.

7. An implantable radiation therapy device according to claim 1, wherein:

said radioactive material includes a carrier with radioactive elements suspended therein.

8. An implantable radiation therapy device according to claim 7, wherein:

said carrier melts at a temperature between body temperature and a relatively higher temperature which does not exceed a temperature will cause severe damage to body tissue.

9. An implantable radiation therapy device according to claim 1, wherein:

said radioactive material is liquid at body temperature.

10. A radiation therapy device implantable within a human body, comprising:

a) a biocompatible outer capsule having a wall adapted to transmit radiation therethrough;

b) a radioactive material located inside said outer capsule; and

c) a radiopaque shield located inside said outer capsule,

wherein when said device is in a first state, said radiopaque shield and said radioactive material are configured to allow a first amount of radiation transmission through said outer capsule, and

wherein upon application of non-ambient energy to said device, said device enters into a second state in which said radioactive material and said radiopaque shield are otherwise configured to permit a second amount of radiation transmission through said outer capsule, said second amount being different than said first amount,

wherein when said device is implanted in the human body, said non-ambient energy is appliable without physical contact between said device and an instrument controllable from outside the human body.

11. An implantable radiation therapy device according to claim 10, wherein:

said first amount is substantially zero.

12. An implantable radiation therapy device according to claim 10, wherein:

said second amount is greater than said first amount.

13. An implantable radiation therapy device according to claim 10, wherein:

in said first state, said radiopaque shield substantially surrounds said radioactive material.

14. An implantable radiation therapy device according to claim 10, further comprising:

d) an inner capsule provided in said outer capsule, said inner capsule being made of a radiopaque material, and including at least one opening and defining an interior,

wherein in said first state, said radioactive material is substantially provided in said interior of said inner capsule, and in said second state said radioactive material is at least partially located outside said interior of said inner capsule.

15. An implantable radiation therapy device according to claim 14, wherein:

said inner capsule is held coaxial in said outer capsule.

16. An implantable radiation therapy device according to claim 14, wherein:

said radioactive material includes a carrier having radioactive elements suspended therein.

17. An implantable radiation therapy device according to claim 14, wherein:

said radioactive material is in a liquid state at body temperature, and said radiation therapy seed further comprises,

e) a means for preventing said radiopaque material from flowing through said at least one opening when said seed is in said first state.

18. An implantable radiation therapy device according to claim 17, wherein:

said means for preventing comprises a meltable plug which melts upon application of said non-ambient energy.

19. An implantable radiation therapy device according to claim 16, wherein:

said carrier melts at a temperature between body temperature and a relatively higher temperature which does not exceed a temperature will cause severe damage to body tissue.

20. An implantable radiation therapy device according to claim 19, wherein:

said carrier is one of liquid, wax, a polymer, and metal.

21. An implantable radiation therapy device according to claim 16, further comprising:

e) means for moving said carrier from said interior through said at least one opening in said inner capsule, and into a space between said inner capsule and said outer capsule.

22. An implantable radiation therapy device according to claim 21, wherein:

said means for moving is one of a spring element and a pressurized fluid.

23. An implantable radiation therapy device according to claim 10, wherein:

said radioactive material is liquid at body temperature.

24. An implantable radiation therapy device according to claim 10, further comprising:

a covering over said radioactive material, said covering having a surface on which said radiopaque shield is provided,

said radioactive material adapted to melt upon application of said non-ambient energy, and said covering is at least one of elastic and heat-shrinkable, such that when said non-ambient energy is applied to said seed, said radioactive material melts and said covering contracts forcing said melted radioactive material from said cover to at least partially surround said radiopaque material.

25. A radiation therapy device implantable within a human body, comprising:

a) an implantable container having a wall adapted for the transmission of radiation therethrough;

b) a radioactive isotope which emits radiation and which is provided in said container; and

c) a movable shield provided in said container for increasing the radiation transmitted through said container relative to the radiation emitted by said isotope when an amount of energy is applied to said device,

wherein when said device is implanted in the human body, said amount of energy is appliable without physical contact between said device and an instrument controllable from outside the human body.

26. An implantable radiation therapy device according to claim 25, wherein:

said amount of energy is heat at a temperature above body temperature.

27. An implantable radiation therapy device according to claim 25, further comprising:

d) a member having a portion upon which said isotope is provided,

wherein said shield is a substantially radiopaque shape memory metal extended over and covering said member, and adapted to move and expose said portion of said member on which said isotope is provided when said energy is applied to said shaped memory metal.

28. An implantable radiation therapy device according to claim 25, wherein:

said shield comprises a substantially radiopaque portion on a plurality of shape memory members, each also having a portion upon which said isotope is provided, said plurality of members arranged in said container such that said portion having said isotope is substantially prevented from emitting radiation through said container without substantial interference from said substantially radiopaque portions,

wherein said shape memory members include a predisposition to at least one of bend, rotate and twist upon application of said amount of energy such that said portions upon which said isotope is provided at least partially surround said radiopaque portions.

29. An implantable radiation therapy device according to claim 28, wherein:

said shape memory members are each in the form of an elongate rod and comprised of a substantially radiopaque material, and said isotope is provided along a longitudinal portion of each said shape memory member.

30. An implantable radiation therapy device according to claim 28, wherein:

said shape memory members are each in the form of longitudinal strip having first and second sides, each being predisposed to bend along a longitudinal axis over said first side, said first side being provided with a substantially radiopaque material and said second side being provided with said radioactive isotope,

wherein upon application of said amount of energy said members at least partially bend about said longitudinal axis such that said portions on which said isotope is provided are substantially exposed and unshielded by said radiopaque material.

31. A radiation therapy device implantable within a human body, comprising:

a) an implantable container having a wall adapted for the transmission of radiation therethrough;

b) a radioactive isotope which emits radiation and which is provided in said container; and

c) a movable element provided in said container which moves when an amount of energy is applied to said device,

wherein when said device is implanted in the human body, said amount of energy is appliable without physical contact between said device and an instrument controllable from outside the human body.

32. An implantable radiation therapy device according to claim 31, wherein:

said movable element includes a radiopaque portion.

33. An implantable radiation therapy device according to claim 31, wherein:

said movable element includes said radioactive isotope.

34. An implantable radiation therapy device, comprising:

a) a biocompatible outer capsule having a wall adapted to transmit radiation therethrough;

b) a radioactive material located inside said outer capsule and emitting radiation; and

c) control means for controllably altering an amount of said radiation transmitted through said outer capsule, said control means including a collapsible sleeve.

35. An implantable radiation therapy device, comprising:

a) a biocompatible outer capsule having a wall adapted to transmit radiation therethrough;

b) a radioactive material located inside said outer capsule and emitting radiation, said radioactive material including a carrier with radioactive elements suspended therein and said carrier melting at a temperature between body temperature and a relatively higher temperature which does not exceed a temperature will cause severe damage to body tissue; and

c) control means for controllably altering an amount of said radiation transmitted through said outer capsule.

36. An implantable radiation therapy device, comprising:

a) a biocompatible outer capsule having a wall adapted to transmit radiation therethrough;

b) a radioactive material located inside said outer capsule and emitting radiation, said radioactive material being in a liquid state at body temperature; and

c) control means for controllably altering an amount of said radiation transmitted through said outer capsule.

37. An implantable radiation therapy device, comprising:

a) a biocompatible outer capsule having a wall adapted to transmit radiation therethrough;

b) a radioactive material located inside said outer capsule;

c) a radiopaque shield located inside said outer capsule; and

d) an inner capsule provided in said outer capsule, said inner capsule being made of a radiopaque material, and including at least one opening and defining an interior,

wherein when said device is in a first state, said radiopaque shield and said radioactive material are configured to allow a first amount of radiation transmission through said outer capsule, said radioactive material being substantially provided in said interior of said inner capsule, and

wherein upon application of non-ambient energy to said device, said device enters into a second state in which said radioactive material and said radiopaque shield are otherwise configured such that said radioactive material is at least partially located outside said interior of said inner capsule to permit a second amount of radiation transmission through said outer capsule, said second amount being different than said first amount.

38. An implantable radiation therapy device, comprising:

a) a biocompatible outer capsule having a wall adapted to transmit radiation therethrough;

b) a radioactive material located inside said outer capsule, said radioactive material being in a liquid state at body temperature; and

c) a radiopaque shield located inside said outer capsule,

wherein when said device is in a first state, said radiopaque shield and said radioactive material are configured to allow a first amount of radiation transmission through said outer capsule, and

wherein upon application of non-ambient energy to said device, said device enters into a second state in which said radioactive material and said radiopaque shield are otherwise configured to permit a second amount of radiation transmission through said outer capsule, said second amount being different than said first amount.

39. An implantable radiation therapy device, comprising:

a) a biocompatible outer capsule having a wall adapted to transmit radiation therethrough;

b) a radioactive material located inside said outer capsule;

c) a radiopaque shield located inside said outer capsule; and

d) a covering over said radioactive material, said covering having a surface on which said radiopaque shield is provided,

wherein when said device is in a first state, said radiopaque shield and said radioactive material are configured to allow a first amount of radiation transmission through said outer capsule,

and wherein said radioactive material adapted to melt upon application of said non-ambient energy, and said covering is at least one of elastic and heat-shrinkable, such that when said non-ambient energy is applied to said seed, said radioactive material melts and said covering contracts forcing said melted radioactive material from said cover to at least partially surround said radiopaque material so that said device enters into a second state in which a second amount of radiation transmission is permitted through said outer capsule, said second amount being different than said first amount.

40. An implantable radiation therapy device, comprising:

a) a container having a wall adapted for the transmission of radiation therethrough;

b) a radioactive isotope which emits radiation and which is provided in said container; and

c) a movable shield provided in said container for increasing the radiation transmitted through said container relative to the radiation emitted by said isotope when heat at a temperature above body temperature applied to said device.

41. An implantable radiation therapy device, comprising:

a) a container having a wall adapted for the transmission of radiation therethrough;

b) a radioactive isotope which emits radiation and which is provided in said container;

c) a member having a portion upon which said isotope is provided; and

d) a movable shield provided in said container for increasing the radiation transmitted through said container relative to the radiation emitted by said isotope when an amount of energy is applied to said device,

wherein said shield is a substantially radiopaque shape memory metal extended over and covering said member, and adapted to move and expose said portion of said member on which said isotope is provided when said energy is applied to said shaped memory metal.

42. An implantable radiation therapy device, comprising:

a) a container having a wall adapted for the transmission of radiation therethrough;

b) a radioactive isotope which emits radiation and which is provided in said container; and

c) a movable shield provided in said container for increasing the radiation transmitted through said container relative to the radiation emitted by said isotope when an amount of energy is applied to said device, said shield comprising a substantially radiopaque portion on a plurality of shape memory members, each also having a portion upon which said isotope is provided, said plurality of members arranged in said container such that said portion having said isotope is substantially prevented from emitting radiation through said container without substantial interference from said substantially radiopaque portions,

wherein said shape memory members include a predisposition to at least one of bend, rotate and twist upon application of said amount of energy such that said portions upon which said isotope is provided at least partially surround said radiopaque portions.

43. An implantable radiation therapy device, comprising:

a) a container having a wall adapted for the transmission of radiation therethrough;

b) a movable element provided in said container which moves when an amount of energy is applied to said seed,

c) a radioactive isotope which emits radiation, said movable element including said radioactive isotope.