Variable collimation in radiation detection

• US 20080237482A1
• Filed: 03/28/2007
• Published: 10/02/2008
• Est. Priority Date: 03/28/2007
• Status: Active Grant

• Current Assignee: Orbotech Limited (KLA Corporation)
• Original Assignee: Orbotech Medical Solutions Ltd. (General Electric Company)
• Inventors: Shahar, Arie, El-Hanany, Uri, Gutman, Zeev, Traub, Eliezer, Cherlin, Alexander
• Granted Patent: US 7,663,111 B2
• Time in Patent Office: Days
• US Class Current: 250/394
• CPC Class Codes: A61B 6/037 Emission tomography
• CPC Class Codes: A61B 6/06 Diaphragms
• CPC Class Codes: A61B 6/4258 for detecting non x-ray radiation, e.g. gamma radiation A61B6/037 takes precedence
• CPC Class Codes: G21K 1/025 using multiple collimators, e.g. Bucky screens; other devices for eliminating undesired or dispersed radiation

Abstract

Apparatus for detecting radiation emitted from a number of volume elements of a body. The apparatus includes a first plurality of detector elements, each detector element being configured to output signals indicative of an intensity of radiation that is incident thereon. The apparatus also includes a first plurality of adjustable collimator channels, each adjustable collimator channel being associated with and being positioned between a respective detector element and the body, each adjustable collimator channel having a second plurality of dimensional configurations defining respective different sets of the volume elements from which emitted radiation impinges on the respective detector element. A processor computes a radiation intensity from at least a portion of the volume elements in response to the signals output by the detector elements in at least two of the dimensional configurations of the adjustable collimator channels.

Claims

1. Apparatus for detecting radiation emitted from a number of volume elements of a body, the apparatus comprising:

a first plurality of detector elements, each detector element being configured to output signals indicative of an intensity of radiation that is incident thereon;

a first plurality of adjustable collimator channels, each adjustable collimator channel being associated with and being positioned between a respective detector element and the body, each adjustable collimator channel having a second plurality of dimensional configurations defining respective different sets of the volume elements from which emitted radiation impinges on the respective detector element; and

a processor coupled to compute a radiation intensity from at least a portion of the volume elements in response to the signals output by the detector elements in at least two of the dimensional configurations of the adjustable collimator channels.

2. The apparatus according to claim 1, wherein each adjustable collimator channel comprises a first collimator channel aligned with a second collimator channel and separated therefrom by an adjustable gap.

3. The apparatus according to claim 2, wherein the first collimator channel is aligned with the respective detector element and is separated therefrom by a variable gap.

4. The apparatus according to claim 3, wherein the processor is coupled to adjust at least one of the variable gap and the adjustable gap.

5. The apparatus according to claim 2, wherein the first and second collimator channels comprise different cross-sectional areas.

6. The apparatus according to claim 1, wherein each adjustable collimator channel comprises a third plurality of collimator channels, and wherein the processor is coupled to align one or more of the third plurality of collimator channels with the respective detector element.

7. The apparatus according to claim 1, wherein each adjustable collimator channel comprises a third plurality of collimator channels each having different lengths, and wherein the processor is coupled to align each of the third plurality of collimator channels with the respective detector element.

8. The apparatus according to claim 1, wherein each adjustable collimator channel comprises a cavity which is configured to receive a liquid opaque to the radiation.

9. The apparatus according to claim 8, wherein the liquid comprises mercury.

10. The apparatus according to claim 8, wherein the cavity alters a length of the adjustable collimator channel on receipt of the liquid.

11. The apparatus according to claim 8, wherein the cavity alters a cross-section of the adjustable collimator-channel on receipt of the liquid.

12. The apparatus according to claim 1, wherein the emitted radiation comprises gamma rays.

13. The apparatus according to claim 1, wherein the processor is configured to generate a representation of radioisotopes in the body in response to the radiation intensity.

14. The apparatus according to claim 1, wherein the dimensional configurations comprise a first configuration defining a first set of the volume elements and a second configuration defining a second set of the volume elements, and wherein the first set includes the second set.

15. The apparatus according to claim 14, wherein the first set comprises a first section of a first cone, and wherein the second set comprises a second section of a second cone, the first and the second cones having a common axis of symmetry.

16. The apparatus according to claim 1, wherein the processor is coupled to compute the number of the volume elements in response to the value of the first plurality, the value of the second plurality, and the signals.

17. The apparatus according to claim 16, wherein the processor is coupled to compute the number of the volume elements iteratively, so as to determine a largest number of the volume elements.

18. The apparatus according to claim 16, wherein the number comprises a product of the value of the first plurality and the value of the second plurality.

19. The apparatus according to claim 1, wherein the portion comprises a group of the volume elements selected by an operator of the apparatus.

20. Apparatus for detecting radiation emitted from a body, the apparatus comprising:

a first camera head, comprising a first detector element and a first collimator channel, the first detector element operative to output first signals indicative of a first radiation intensity, the first collimator channel being positioned between the first detector element and the body so as to define a first volume of the body from which emitted radiation impinges on the first detector element;

a second camera head, comprising a second detector element and a second collimator channel, the second detector element operative to output second signals indicative of a second radiation intensity, the second collimator channel being positioned between the second detector element and the body so as to define a second volume of the body from which emitted radiation impinges on the detector element, the second volume being smaller than and included in the first volume; and

a processor coupled to compute a radiation intensity from at least a portion of the body in response to the first signals and the second signals.

21. The apparatus according to claim 20, and comprising a positioning mount operative to set the first camera head in a given position and orientation to measure the first signals and to set the second camera head in the given position and orientation to measure the second signals.

22. The apparatus according to claim 20, wherein the first volume comprises a first conic volume, and the second volume comprises a second conic volume concentric with the first conic volume.

23. The apparatus according to claim 20, and comprising a positioning mount operative to set the first collimator channel in a first position and orientation with respect to the first detector element so as to measure the first signals and to set the second collimator channel in a second position and orientation with respect to the second detector element so as to measure the second signals.

24. The apparatus according to claim 23, wherein the first collimator channel is fixedly coupled to the second collimator channel, and wherein the first collimator channel and the second collimator channel are comprised in a common configurable collimator of the first and second camera heads.

25. The apparatus according to claim 20, wherein at least one of the first and second collimator channels has a plurality of dimensional configurations defining respective different sets of volume elements of the body from which the radiation is emitted.

26. A method for detecting radiation emitted from a number of volume elements of a body, comprising:

providing a first plurality of detector elements, each detector element being configured to output signals indicative of an intensity of radiation that is incident thereon;

positioning a first plurality of adjustable collimator channels between a respective detector element and the body, each adjustable collimator channel having a second plurality of dimensional configurations defining respective different sets of the volume elements from which emitted radiation impinges on the respective detector element; and

computing a radiation intensity from at least a portion of the volume elements in response to the signals output by the detector elements in at least two of the dimensional configurations of the adjustable collimator channels.

27. The method according to claim 26, wherein each adjustable collimator channel comprises a first collimator channel aligned with a second collimator channel and separated therefrom by an adjustable gap.

28. The method according to claim 27, wherein the first collimator channel is aligned with the respective detector element and is separated therefrom by a variable gap.

29. The method according to claim 28, and comprising adjusting at least one of the variable gap and the adjustable gap.

30. The method according to claim 27, wherein the first and second collimator channels comprise different cross-sectional areas.

31. The method according to claim 26, wherein each adjustable collimator channel comprises a third plurality of collimator channels, and comprising aligning one or more of the third plurality of collimator channels with the respective detector element.

32. The method according to claim 26, wherein each adjustable collimator channel comprises a third plurality of collimator channels each having different lengths, and comprising aligning each of the third plurality, of collimator channels with the respective detector element.

33. The method, according to claim 26, wherein each adjustable collimator channel comprises a cavity which is configured to receive a liquid opaque to the radiation.

34. The method according to claim 33, wherein the liquid comprises mercury.

35. The method according to claim 33, wherein the cavity alters a length of the adjustable collimator channel on receipt of the liquid.

36. The method according to claim 33, wherein the cavity alters a cross-section of the adjustable collimator channel on receipt of the liquid.

37. The method according to claim 26, wherein the emitted radiation comprises gamma rays.

38. The method according to claim 26, and comprising generating a representation of radioisotopes in the body in response to the radiation intensity.

39. The method according to claim 26, wherein the dimensional configurations comprise a first configuration defining a first set of the volume elements and a second configuration defining a second set of the volume elements, and wherein the first set includes the second set.

40. The method according to claim 39, wherein the first set comprises a first section of a first cone, and wherein the second set comprises a second section of a second cone, the first and the second cones having a common axis of symmetry.

41. The method according to claim 26, and comprising computing the number of the volume elements in response to the value of the first plurality, the value of the second plurality, and the signals.

42. The method according to claim 41, wherein computing the number comprises computing the number iteratively, so as to determine a largest number of the volume elements.

43. The method according to claim 41, wherein the number comprises a product of the value of the first plurality and the value of the second plurality.

44. The method according to claim 26, wherein the portion comprises a group of the volume elements selected by an operator of the method.

45. A method for detecting radiation emitted from a body, comprising:

positioning a first collimator channel between a first detector element and the body so as to define a first volume of the body from which emitted radiation impinges on the first detector element, the first detector element being operative to output first signals indicative of a first radiation intensity;

positioning a second collimator channel between a second detector element and the body so as to define a second volume of the body from which emitted radiation impinges on the second detector element, the second detector element being operative to output second signals indicative of a second radiation intensity, the second volume being smaller than and included in the first volume; and

computing a radiation intensity from at least a portion of the body in response to the first signals and the second signals.

46. The method according to claim 45, and comprising setting the first collimator channel and the first detector element in a given position and orientation to measure the first signals and setting the second collimator channel and the second detector element in the given position and orientation to measure the second signals.

47. The method according to claim 45, wherein the first volume comprises a first conic volume, and the second volume comprises a second conic volume concentric with the first conic volume.

48. The method according to claim 45, and comprising positioning the first collimator channel in a first position and orientation with respect to the first detector element so as to measure the first signals and positioning the second collimator channel in a second position and orientation with respect to the second detector element so as to measure the second signals.

49. The method according to claim 48, wherein the first collimator channel is fixedly coupled to the second collimator channel, and wherein the first collimator channel and the second collimator channel are comprised in a common configurable collimator.

50. The method according to claim 45, wherein at least one of the first and second collimator channels has a plurality of dimensional configurations defining respective different sets of volume elements of the body from which the radiation is emitted.

51. Apparatus for detecting radiation emitted from a body, the apparatus comprising:

a detector element, which is operative to output signals indicative of an intensity of radiation that is incident thereon;

an adjustable collimator channel, positioned between the detector element and the body so as to define a volume of the body from which emitted radiation impinges on the detector element, and having at least a first configuration in which the emitted radiation impinges on the detector element from a first volume and a second configuration in which the emitted radiation impinges on the detector element from a second volume smaller than and included in the first volume; and

a processor coupled to compute a radiation intensity from at least a portion of the volume in response to the signals output by the detector element in at least the first and second configurations of the adjustable collimator channel.

52. A method for detecting radiation emitted from a body, comprising:

outputting, from a detector element, signals indicative of an intensity of radiation that is incident on the detector element;

positioning an adjustable collimator channel between the detector element and the body so as to define a volume of the body from which emitted radiation impinges on the detector element, the adjustable collimator channel having at least a first configuration in which the emitted radiation impinges on the detector element from a first volume and a second configuration in which the emitted radiation impinges on the detector element from a second volume smaller than and included in the first volume; and

computing a radiation intensity from at least a portion of the volume in response to the signals output by the detector element in at least the first and second configurations of the adjustable collimator channel.