Linac neutron therapy and imaging

• US 20030155530A1
• Filed: 11/26/2002
• Published: 08/21/2003
• Est. Priority Date: 01/14/2000
• Status: Abandoned Application

• Current Assignee: Gino Fallone, Nabil Adnani
• Original Assignee: Gino Fallone, Nabil Adnani
• Inventors: Adnani, Nabil, Fallone, Gino
• Application Number:
  US10/169,845
• Publication Number:
  US 20030155530A1
• Time in Patent Office: Days
• US Class Current: 250/491.1
• CPC Class Codes: A61N 2005/109 Neutrons
• CPC Class Codes: A61N 5/10 X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy A61N5/01 takes precedence
• CPC Class Codes: G21K 5/04 with beam-forming means
• CPC Class Codes: H05H 3/06 Generating neutron beams targets for producing nuclear reactions H05H6/00; neutron sources G21G4/02

Abstract

A high energy electron accelerator (LINAC) can be employed for neutron-based therapy and imaging methods. Methods and systems are described for producing a thermal neutron image of a subject using a LINAC. Methods are also described for treating diseased tissues by neutron capture therapy or neutron capture enhanced photon therapy using a LINAC.

Claims

1. A method for producing thermal neutrons in a target tissue comprising:

(a) producing a beam comprising photons and fast neutrons from a high energy electron accelerator;

(b) passing the beam through a shield to minimise the photon content of the beam;

(c) directing the resulting beam on to the tissue, whereby at least a portion of the fast neutrons of the beam are reduced in energy to produce thermal neutrons in the tissue.

2. The method of claim 1 wherein the shield comprises the closed collimator jaws of the accelerator.

3. The method of claim 1 wherein the shield comprises a block of a photon-absorbing material positioned in the path of the beam.

4. The method of claim 3 wherein the block is positioned within the treatment head of the accelerator.

5. The method of claim 3 wherein the photon-absorbing material comprises lead, tungsten or bismuth.

6. An apparatus comprising a high energy electron accelerator adapted to emit a monodirectional beam of photons and fast neutrons and a moveable shield located in the path of the emitted beam to minimise the photon content of the beam while permitting emission of a fast neutron beam.

7. The apparatus of claim 6 wherein the shield comprises the closed collimator jaws of the accelerator.

8. The apparatus of claim 6 wherein the shield comprises a block of a photon-absorbing material positioned in the path of the beam.

9. The apparatus of claim 8 wherein the block is positioned within the treatment head of the accelerator.

10. The apparatus of claim 8 wherein the photon-absorbent material comprises lead, tungsten or bismuth.

11. A method for producing a thermal neutron image of an object, wherein the object has a low capacity for thermalising fast neutrons comprising:

(a) producing a beam comprising photons and fast neutrons from a high energy electron accelerator;

(b) passing the beam through a shield to minimise the photon content of the beam;

(c) directing the resulting beam, through a medium for thermalising fast neutrons, on to the object; and

(d) detecting thermal neutrons which pass through the object, to produce an image of the object.

12. The method of claim 11 wherein the shield comprises the closed collimator jaws of the accelerator.

13. The method of claim 11 wherein the shield comprises a block of a photon-absorbing material positioned in the path of the beam.

14. The method of claim 13 wherein the block is positioned within the treatment head of the accelerator.

15. The method of claim 13 wherein the photon-absorbing material comprises lead, tungsten or bismuth.

16. The method of any of claims 11 to 15 wherein the thermalising medium is water.

17. A system for producing a thermal neutron image of an object, wherein the object has a low capacity for thermalising fast neutrons, comprising:

(a) a high energy electron accelerator;

(b) a shield to minimise photon emission from the accelerator;

(c) a medium for thermalising fast neutrons emitted by the accelerator;

(d) a thermal neutron detector.

18. The system of claim 17 wherein the shield comprises the closed collimator jaws of the accelerator.

19. The system of claim 17 wherein the shield comprises a block of a photon-absorbing material positioned in the path of the beam.

20. The system of claim 19 wherein the block is positioned within the treatment head of the accelerator.

21. The system of claim 19 wherein the photon-absorbing material comprises lead, tungsten or bismuth.

22. The system of any of claims 17 to 21 wherein the thermalising medium is water.

23. The system of any of claims 17 to 22 wherein the thermal neutron detector comprises a photographic film in contact with a prompt neutron/photon conversion agent, the detector being positioned with the film closer to the object than the conversion agent.

24. The system of any of claims 17 to 22 wherein the thermal neutron detector comprises a delayed neutron/photon conversion agent.

25. The system of claim 23 wherein the prompt neutron/photon conversion agent comprises gadolinium.

26. The system of claim 25 wherein the agent is Gd-157 enriched gadolinium.

27. The system of claim 24 wherein the delayed neutron/photon conversion agent is indium or dysprosium.

28. The system of claim 17 wherein the thermal neutron detector comprises an electronic radiation detector having an active detecting surface and a layer comprising a prompt neutron/photon conversion agent over the active detecting surface.

29. A method for producing a thermal neutron image of a human or non-human animal subject comprising:

(a) producing a beam comprising photons and fast neutrons from a high energy electron accelerator;

(b) passing the beam through a shield to minimise the photon content of the beam;

(c) using the resulting beam to irradiate the human or non-human animal subject, whereby at least a portion of the fast neutrons of the beam are reduced in energy to produce thermal neutrons in the subject; and

(d) detecting thermal neutrons which pass through the human or non-human animal subject to produce an image of the subject.

30. The method of claim 29 wherein the shield comprises the closed collimator jaws of the accelerator.

31. The method of claim 30 wherein the shield comprises a block of a photon-absorbing material positioned in the path of the beam.

32. The method of claim 31 wherein the block is positioned within the treatment head of the accelerator.

33. The method of claim 31 wherein the photon-absorbing material comprises lead, tungsten or bismuth.

34. A system for producing a thermal neutron image of a human or non-human animal subject comprising:

(a) a high energy electron accelerator;

(b) a shield to minimise photon emission from the accelerator; and

(c) a thermal neutron detector.

35. The system of claim 34 wherein the shield comprises the closed collimator jaws of the accelerator.

36. The system of claim 34 wherein the shield comprises a block of a photon-absorbing material positioned in the path of the beam.

37. The system of claim 36 wherein the block is positioned within the treatment head of the accelerator.

38. The system of claim 36 wherein the photon-absorbing material comprises lead, tungsten or bismuth.

39. The system of any of claims 34 to 38 wherein the thermal neutron detector comprises a photographic film in contact with a prompt neutron/photon conversion agent, the detector being positioned with the film closer to the object than the conversion agent.

40. The system of any of claims 34 to 38 wherein the thermal neutron detector comprises a delayed neutron/photon conversion agent.

41. The system of claim 39 wherein the prompt neutron/photon conversion agent comprises gadolinium.

42. The system of claim 41 wherein the agent is Gd-157 enriched gadolinium.

43. The system of claim 40 wherein the delayed neutron/photon conversion agent is indium or dysprosium.

44. The system of claim 34 wherein the thermal neutron detector comprises an electronic radiation detector having an active detecting surface and a layer comprising a prompt neutron/photon conversion agent over the active detecting surface.

45. A method of treating a diseased tissue in a human or non-human animal subject, the method comprising the steps of:

(a) providing a subject having a diseased tissue in need of treatment;

(b) incorporating a thermal neutron capture agent into the diseased tissue;

(c) producing a beam of fast neutrons from a high energy electron accelerator; and

(d) irradiating the subject with the fast neutron beam,

whereby the energy level of at least a portion of the fast neutrons is reduced within the subject to yield thermal neutrons and the capture agent, on interaction with the thermal neutrons, emits radiation to destroy the diseased tissue.

46. The method of claim 45 wherein the subject is a human subject.

47. The method of claim 45 or 46 wherein the thermal neutron capture agent comprises a prompt neutron/photon conversion agent.

48. The method of claim 47 wherein the prompt neutron/photon conversion agent is gadolinium.

49. The method of claim 48 wherein the agent is Gd-157 enriched gadolinium.

50. The method of claim 45 or 46 wherein the thermal neutron capture agent is a neutron/high LET particle conversion agent.

51. The method of claim 50 wherein the neutron/high LET particle conversion agent is boron-10.

52. The method of any of claims 45 to 51 wherein the tissue is a tumour.

53. A method of treating a diseased tissue in a human or non-human animal subject, the method comprising the steps of:

(a) providing a subject having a diseased tissue in need of treatment;

(b) incorporating a thermal neutron capture agent into the diseased tissue;

(c) producing a beam of photons and fast neutrons from a high energy electron accelerator;

(d) irradiating the subject with the beam,

whereby the energy level of at least a portion of the fast neutrons is reduced within the subject to produce thermal neutrons and the capture agent, on interaction with the thermal neutrons, emits radiation which, together with the photons, destroys the diseased portion of the tissue.

54. The method of claim 53 wherein the subject is a human subject.

55. The method of claim 53 or 54 wherein the thermal neutron capture agent comprises a prompt neutron/photon conversion agent.

56. The method of claim 55 wherein the prompt neutron/photon conversion agent is gadolinium.

57. The method of claim 56 wherein the agent is Gd-157 enriched gadolinium.

58. The method of claim 53 or 54 wherein the thermal neutron capture agent is a neutron/high LET particle conversion agent.

59. The method of claim 58 wherein the neutron/high LET particle conversion agent is boron-10.

60. The method of any of claims 53 to 59 wherein the tissue is a tumour.

61. A method for producing a fast neutron image of subject comprising:

(a) producing a beam comprising photons and fast neutrons from a high energy electron accelerator;

(b) passing the beam through a shield to minimise the photon content of the beam;

(c) irradiating the subject with the resulting beam; and

(d) detecting fast neutrons which pass through the subject to produce an image of the subject.

62. The method of claim 61 wherein the shield comprises the closed collimator jaws of the accelerator.

63. The method of claim 61 wherein the shield comprises a block of a photon-absorbing material positioned in the path of the beam.

64. The method of claim 63 wherein the block is positioned within the treatment head of the accelerator.

65. The method of claim 63 wherein the photon-absorbing material comprises lead, tungsten or bismuth.

66. A phantom comprising:

a base of a material of low capacity to interact with thermal neutrons;

a plurality of cylinders supported within the base, each cylinder being selected to simulate the thermal neutron absorption capacity of a tissue of a human or non-human animal subject.

67. The phantom of claim 66 wherein the cylinders are arranged around the periphery of the base, the phantom further comprising a core comprising an array of cadmium bars.

68. The phantom of claim 67 wherein the cadmium bars are arranged in four quadrants, and wherein the bars within each quadrant are spaced apart by a different distance.

69. The phantom of claim 68 comprising:

a plurality of vials containing a first concentration of a capture agent;

a plurality of vials each containing a different concentration of a capture agent higher than the first concentration;

a vial containing water;

a plurality of cylinders, each cylinder being of a plastic material of different hydrogen content; and

a plurality of cylinders comprising a material selected from the group consisting of cadmium, Teflon, gadolinium or boron.