Single photon emission computed tomography system

• US 6,525,320 B1
• Filed: 04/14/2000
• Issued: 02/25/2003
• Est. Priority Date: 04/14/1999
• Status: Expired due to Term

• Current Assignee: HighBrook Holdings, LLC
• Original Assignee: Jack E. Juni
• Inventors: Juni, Jack E.
• Primary Examiner(s): Hannaher, Constantine
• Assistant Examiner(s): Gabor, Otilia
• Application Number:
  US09/549,435
• Time in Patent Office: 1,047 Days
• Field of Search: 250/363.04, 250/363.03, 250/363.05, 250/363.1, 250/496.1, 250/497.1, 250/498.1, 250/370.09
• US Class Current: 250/363.04
• CPC Class Codes: A61B 6/037 Emission tomography
• CPC Class Codes: G01T 1/1642 using a scintillation crystal and position sensing photodetector arrays, e.g. ANGER cameras

Abstract

A single photon emission computed tomography system produces multiple tomographic images of the type representing a three-dimensional distribution of a photon-emitting radioisotope. The system has a base including a patient support for supporting a patient such that a portion of the patient is located in a field of view. A longitudinal axis is defined through the field of view. A detector module is adjacent the field of view and includes a photon-responsive detector. The detector is an elongated strip with a central axis that is generally parallel to the longitudinal axis. The detector is operable to detect if a photon strikes the detector. The detector can also determine a position along the length of the strip where a photon is detected. A photon-blocking member is positioned between the field of view and the detector. The blocking member has an aperture slot for passage of photons aligned with the aperture slot. The slot is generally parallel to the longitudinal axis. A line of response is defined from the detector through the aperture. A displacement device moves either the detector module or the photon-blocking member relative to the other so that the aperture is displaced relative to the detector and the line of response is swept across at least a portion of the field of view.

Claims

1. A single photon emission computed tomography system for producing multiple tomographic images of the type representing a three-dimensional distribution of a photon-emitting radioisotope, said system comprising:

a base including a patient support for supporting a patient such that a portion of the patient is located in a field of view, a longitudinal axis being defined through said field of view;

a detector module adjacent said field of view, said module including a photon-responsive detector, said detector being an elongated strip with a central axis disposed generally parallel to said longitudinal axis, said detector being operable to detect if a photon strikes the detector, said detector further being operable to determine a position along the length of said elongated strip where a photon is detected;

a photon-blocking member disposed between said field of view and said detector, said blocking member having an aperture slot defined therethrough for passage of photons aligned with said aperture slot, said slot being generally parallel to said longitudinal axis, a line of response being defined from the detector through said aperture;

a collimating assembly including at least two spaced apart collimating vanes of photon-attenuating material, said collimating vanes including only vanes that are generally parallel to each other and generally perpendicular to said longitudinal axis, each of said vanes being disposed between said detector and said field of view; and

a displacement actuator for moving one of said detector module and said photon-blocking member relative to the other of said detector and said photon-blocking member such that said aperture is displaced relative to said detector and said line of response is swept across at least a portion of said field of view.

2. The system of claim 1, wherein said collimating vanes are disposed between said photon-blocking member and said detector.

3. The system of claim 1, wherein a radiolucent material is disposed in the spaces between said vanes.

4. The system of claim 1, wherein said displacement actuator is operable to move said photon-blocking member relative to said detector module.

5. The system of claim 1, wherein said longitudinal axis is generally vertical and said patient support comprises an adjustable seat with means for moving said seat relative to said field of view.

6. The system of claim 1, wherein said elongated detector comprises a solid state detector having a plurality of solid state detector elements disposed along its length, each element operable to detect if a photon strikes said element.

7. The system of claim 1, wherein said elongated detector comprises a strip of scintillation material having a first and second end, said strip further having a front face directed toward said field of view for receiving photons and a rear face directed away from said field of view, said scintillation material operable to create a flash of light when a photon strikes said material.

8. The system of claim 7, wherein said elongated detector further comprises a first light detector disposed adjacent said first end of said scintillation material and a second light detector disposed adjacent said second end of said scintillation material, said light detectors operable to detect said flash of light created by said scintillation material when said material is struck by a photon.

9. The system of claim 7, said elongated detector further comprising a mask of photon attenuating material covering a portion of said front face of said scintillation material such that a vertical strip of said face is not covered by said mask.

10. The system of claim 7, wherein said front face of said scintillation material has a width less than a width of said rear face such that said scintillation material has a generally trapezoidal cross section.

11. A single photon emission computed tomography system for producing multiple tomographic images of the type representing a three-dimensional distribution of a photon-emitting radioisotope, said system comprising:

a base including a patient support for supporting a patient such that a portion of the patient is located in a field of view, a longitudinal axis being defined through said field of view;

a detector assembly at least partially surrounding said field of view, said assembly including a plurality of photon-responsive detectors spaced apart along said assembly, each detector comprising an elongated strip with a central axis disposed generally parallel to said longitudinal axis, each detector being operable to detect if a photon strikes said detector, each detector further being operable to determine a position along the length of said elongated strip where a photon is detected;

a photon-blocking member disposed between said detectors and said field of view, said member having a plurality of aperture slots defined therethrough at intervals along said member for passage of photons aligned with said aperture slots, each of said slots being generally parallel to said longitudinal axis, a line of response for each of said detectors being defined from said detector through the nearest aperture;

a collimating assembly including at least two spaced apart collimating vanes of photon-attenuating material, said collimating vanes including only vanes that are generally parallel to each other and generally perpendicular to said longitudinal axis, each of said vanes being disposed between said detectors and said field of view; and

displacement actuator for moving one of said detector module and said photon-blocking member relative to the other of said detector module and said photon-blocking member such that said apertures are displaced relative to said detectors and said lines of response are swept across at least a portion of said field of view.

12. The system of claim 11, wherein said detectors are arranged generally in an arc and said photon-blocking member is generally arcuate.

13. The system of claim 12, wherein said arc of detectors and said arcuate photon-blocking member extend in a range between 180 and 360 degrees.

14. The system of claim 12, wherein said arc of detectors and said photon-blocking member are concentric.

15. The system of claim 11, wherein said collimating vanes are disposed between said photon-blocking member and said detectors.

16. The system of claim 11, wherein a radiolucent material is disposed in the spaces between said vanes.

17. The system of claim 11, wherein said displacement actuator is operable lo move said photon-blocking member relative to said detector module.

18. The system of claim 11, wherein said patient support comprises an adjustable seat with means for moving said seat relative to said field of view.

19. The system of claim 11, wherein each of said elongated detectors comprises a solid state detector having a plurality of solid state detector elements disposed along its length, each element operable to detect if a photon strikes said element.

20. The system of claim 11, wherein each of said elongated detectors comprises a strip of scintillation material having a first and second end, each strip further having a front face directed toward said field of view for receiving photons and a rear face directed away from said field of view, said scintillation material operable to create a flash of light when a photon strikes said material.

21. The system of claim 20, wherein each of said elongated detectors further comprises a first light detector disposed adjacent said first end of said scintillation material and a second light detector disposed adjacent said second end of said scintillation material, said light detectors operable to detect said flash of light created by said scintillation material when said material is struck by a photon.

22. The system of claim 20, each of said elongated detectors further comprising a mask of photon attenuating material covering a portion of said front face of said scintillation material such that a vertical strip of said face is not covered by said mask.

23. The system of claim 20, wherein said front face of said scintillation material has a width less than a width of said rear face such that said scintillation material has a generally trapezoidal cross section.

24. A single photon emission computed tomography system for producing multiple tomographic images of the type representing a three-dimensional distribution of a photon-emitting radioisotope, said system comprising:

a base including a patient support for supporting a patient such that a portion of the patient is located in a field of view, the field of view being sufficiently large to contain the chest of an adult human, a longitudinal z-axis being defined through the field of view;

a generally arcuate detector assembly adjacent to the field of view, said detector assembly extending generally arcuately at least 180 degrees about the field of view between a first end and a second end, said first and second ends being spaced apart so as to define an entry opening to the field of view, the entry opening being sufficiently large to allow the chest of the adult human to pass therethrough, the detector assembly comprising a plurality of photon-responsive detectors arranged along the arcuate detector assembly, the detectors being stationary with respect to the base,

the photon-responsive detectors each comprising an elongated 1-dimensional strip detector having a longitudinal axis generally parallel to the z-axis, said detector being operable to detect if a photon strikes the detector and to determine the z-axis position of the photon strike, but not being operable to determine the position in an axis perpendicular to the z-axis;

a generally arcuate photon-blocking member disposed between the field of view and said detectors, said blocking member having a plurality of aperture slots defined therethrough at intervals along said member for passage of photons aligned with said aperture slots, a line of response for each of said detectors being defined from said detector through the nearest of said aperture slots;

a collimating assembly disposed between the field of view and said detectors, said collimating assembly including a plurality of spaced apart generally parallel collimating vanes, said collimating assembly including only vanes which are generally perpendicular to the z-axis; and

a displacement actuator operable to move said photon-blocking member relative to said detectors such that said aperture slots are displaced relative to said detectors and said lines of response are swept across at least a portion of the field of view.