Dynamically optimized coincidence septa

• US 6,809,321 B2
• Filed: 07/30/2002
• Issued: 10/26/2004
• Est. Priority Date: 07/30/2002
• Status: Active Grant

• Current Assignee: Siemens Medical Solutions USA Incorporated (Siemens AG)
• Original Assignee: Siemens Medical Solutions USA Incorporated (Siemens AG)
• Inventors: Rempel, Trudy D.
• Primary Examiner(s): Hannaher, Constantine
• Application Number:
  US10/207,155
• Publication Number:
  US 20040021081A1
• Time in Patent Office: 819 Days
• Field of Search: 250/363.1, 250/363.03
• US Class Current: 250/363.1
• CPC Class Codes: G01T 1/1648 Ancillary equipment for scintillation cameras, e.g. reference markers, devices for removing motion artifacts, calibration devices adapted for flow studies G01T1/1647
• CPC Class Codes: G21K 1/025 using multiple collimators, e.g. Bucky screens; other devices for eliminating undesired or dispersed radiation

Abstract

Spacing of septa (septa pitch)used in coincidence imaging is varied to maximize imaging count rate in coincidence imaging by PET or Hybrid PET. This is accomplished through use of detector performance indicators, which are used in connection with a processor to determine the point of peak performance. These detector performance indicators can be, but are not limited to single photon count rate, detector dead time or detector busy time.

Claims

1. A PET or Hybrid PET apparatus, which uses septa in coincidence imaging, and adjusts septa spacing, comprising:

a radiation-sensitive detector;

dynamically optimized septa positioned proximate said detector, in which the spacing or pitch of said septa are adjustable to achieve an optimum imaging count rate;

a processor that detects a preselected performance indicator, which is used by said processor to determine the amount of change in the said septa'"'"'s pitch needed to achieve an optimum imaging count rate; and

a drive mechanism that adjusts the pitch of said septa by the amount determined by said processor.

2. The apparatus of claim 1, wherein said radiation-sensitive detector is a gamma scintillation crystal.

3. The apparatus of claim 1, further comprising a controller stage, which controls said drive mechanism in accordance with a drive signal from said processor.

4. The apparatus of claim 3, wherein said controller stage consists of a plurality of independent controllers.

5. The apparatus of claim 3, wherein said controller stage consists of one controller.

6. The apparatus of claim 1, wherein said drive mechanism consists of a plurality of independent drives.

7. The apparatus of claim 1, wherein said drive mechanism consists of a plurality of interlinked drives.

8. The apparatus of claim 1, wherein said septa are inter-plane septa.

9. The apparatus of claim 1, wherein said septa are surface mounted to said radiation-sensitive detector.

10. The apparatus of claim 1, wherein said septa are loaded septa.

11. A method for automatically optimizing imaging count rate in coincidence imaging done by PET or Hybrid PET apparatus, which uses detector performance indicators and a processor to dynamically adjust septa spacing of a pitch-adjustable septa, comprising the steps of:

detecting a performance indicator from imaging data produced by a detector in response to a patient positioned in said detector'"'"'s FOV;

based on detection of said performance indicator, determining the septa spacing, which would be needed for optimum imaging count rate;

relating to a controller stage of the PET or Hybrid PET apparatus the necessary adjustments in said septa spacing to achieve optimum imaging count rate and

physically adjusting the septa spacing based on said necessary adjustment to achieve the optimum imaging count rate.

12. The method of claim 11 where said detector is a gamma scintillation crystal.

13. The method of claim 11 where one of at least three performance indicators, describes peak performance.

14. The method of claim 13, where a peak performance indicator is single photon count rate.

15. The method of claim 13, where a peak performance indicator is detector dead time.

16. The method of claim 13, where a peak performance indicator is detector busy time.

17. A method for manually optimizing imaging count rate in imaging done by PET or Hybrid PET apparatus, which uses detector performance indicators and a processor to dynamically adjust septa spacing of a pitch-adjustable septa in coincidence imaging, comprising the steps of:

detecting a performance indicator from imaging data produced by a detector in response to a patient positioned in said detector'"'"'s FOV;

based on detection of said performance indicators, determining the septa spacing, which would be needed for optimum imaging count rate;

indicating to a user what septa spacing is needed for optimum imaging count rate; and

engaging the appropriate loaded septa in accordance with said indicated septa spacing, which achieves optimum imaging count rate.

18. The method of claim 17, where said detector is a gamma scintillation crystal.

19. The method of claim 17, where one of at least three performance indicators, describes peak performance.

20. The method of claim 19, where a peak performance indicator is single photon count rate.

21. The method of claim 19, where a peak performance indicator is detector dead time.

22. The method of claim 19, where a peak performance indicator is detector busy time.

23. A dynamically adjustable septa device for use in PET or hybrid PET medical imaging, comprising:

a plurality of radiation-impervious septum members;

a plurality of drive mechanisms coupled to respective ones of said septum members; and

at least one controller that actuates said plurality of drive mechanisms to vary the pitch or spacing between each of said plurality of radiation-impervious septum members.