Gamma camera apparatus

• US 6,822,237 B2
• Filed: 06/28/2001
• Issued: 11/23/2004
• Est. Priority Date: 02/28/2001
• Status: Expired due to Fees

• Current Assignee: Anazai Medical Kabushiki Kaisha
• Original Assignee: Anzai Medical Kabushiki Kaisha
• Inventors: Ohwadano, Katsuroh, Inoue, Tomio, Ito, Tadashi, Eguchi, Kenzo, Jimbo, Masao
• Primary Examiner(s): Hannaher, Constantine
• Assistant Examiner(s): LEE, SHUN K
• Application Number:
  US09/892,855
• Publication Number:
  US 20020145114A1
• Time in Patent Office: 1,244 Days
• Field of Search: 250/363.06, 250/370.09, 250/370.11, 250/370.13
• US Class Current: 250/363.06
• CPC Class Codes: G01T 1/1642 using a scintillation crystal and position sensing photodetector arrays, e.g. ANGER cameras
• 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: G01T 1/295 using coded aperture devices, e.g. Fresnel zone plates handling of radiation of particles, e.g. using diaphragms, collimators, diffraction G21K1/00

Abstract

After the position of a collimator with respect to a gamma camera depending on the position of a detection plane in an examinee, gamma rays radiated from the examinee are detected by a scintillation detector via a collimator and a scintillator, and a signal from the scintillation detector is processed by a signal processing circuit and then transferred to an image reconstructing unit, which reconstructs a three-dimensional image of the radiation source in the examinee and displays the three-dimensional image on a display unit.

Claims

1. A gamma camera apparatus for detecting gamma rays emitted from a radioisotope administered to an examinee to construct a three-dimensional image representing a distribution of the radioisotope in the examinee, comprising:

detecting means for detecting gamma rays emitted from the radioisotope in the examinee;

an encoding aperture plate disposed between the examinee and said detecting means;

adjusting means for adjusting the distance from said detecting means to said encoding aperture plate to adjust the position of said encoding aperture plate depending on the depth of an observation position in the examinee; and

processing means for reconstructing a three-dimensional image based on the gamma rays emitted from the radioisotope and detected by said detecting means through said encoding aperture plate,

wherein said encoding aperture plate comprises an M-sequence collimator having a one-dimensional array of apertures over at least one period or an M-array collimator having a two-dimensional array of apertures over at least one period, and

wherein an observation range for a detection plane of said detecting means in the examinee is at most L·

(D+Z)/D where L represents the length of one period of said apertures, Z the distance from said collimator to the observation position in said examinee, and D the distance from said collimator to said detecting means.

2. A gamma camera apparatus according to claim 1, wherein said adjusting means comprises means for adjusting an enlargement ratio α

of said encoding aperture plate with respect to said detecting means as viewed from said observation position in a range from 1.5 to 3.5.

3. A gamma camera apparatus according to claim 1, wherein said detecting means comprises a plurality of semiconductor detecting elements.

4. A gamma camera apparatus according to claim 3, wherein said semiconductor detecting elements are made of CdTe or CdZnTe.

5. A gamma camera apparatus according to claim 1, wherein said detecting means comprises a one-dimensional array of detecting elements.

6. A gamma camera apparatus according to claim 1, wherein said detecting means comprises a two-dimensional array of detecting elements.

7. A gamma camera apparatus according to claim 1, wherein said detecting means comprises a scintillator for converting the wavelength of gamma rays, and a position-sensitive photomultiplier for detecting light obtained by said scintillator.

8. A gamma camera apparatus according to claim 7, wherein said scintillator and said position-sensitive photomultiplier are interconnected by an optical fiber.

9. A gamma camera apparatus according to claim 7, wherein said scintillator is made of a material selected from the group consisting of NaI:

Tl, CsI;

Na, LuSiO₅;

Ce(LSO), (Lu_1-xGd_x)SiO₅;

Ce (LGSO), and YAlO₃.

10. A gamma camera apparatus according to claim 1, wherein said detecting means comprises a scintillator for converting the wavelength of gamma rays, and a plurality of photodiodes for detecting light obtained by said scintillator.

11. A gamma camera apparatus according to claim 1, wherein said encoding aperture plate comprises a collimator having a one-dimensional array of apertures defined according to a rule of an M sequence.

12. A gamma camera apparatus according to claim 1, wherein said encoding aperture plate comprises a collimator having a two-dimensional array of apertures defined according to a rule of an M array.

13. A gamma camera apparatus according to claim 1, further comprising:

image display means for displaying the reconstructed three-dimensional image; and

image supply means for supplying an image to be used in superposed relation to said reconstructed three-dimensional image.

14. A gamma camera apparatus according to claim 13, wherein said image supply means comprises a computerized tomography diagnostic device.

15. A gamma camera apparatus according to claim 13, wherein said image supply means comprises a nuclear medicine diagnostic device.

16. A gamma camera apparatus according to claim 13, wherein said image supply means comprises a magnetic resonance diagnostic device.

17. A gamma camera apparatus according to claim 13, wherein said image supply means comprises a digital camera device.