| 摘要 |
PROBLEM TO BE SOLVED: To stably process a photoelectric multiplying tube(PMT) output signal and prevent the deterioration of a camera image by outputting an electric signal obtained by photoelectrically converting a scintillation light as a digital signal. SOLUTION: The scintillation light emitted from a scintillator 29 byγ-ray is incident on a plurality of digital PTM 31. The PTM 31 photoelectrically converts this light, and A/D converts and outputs its analog electric signal after it is subjected to a processing such as integration, sample/hold or the like by a signal processing circuit 31a. This digital signal is inputted to an electronic circuit board 33 through a cable 32. In the circuit board 33, the sensitivity of the PMT 31 is regularly made constant by a deterioration-with-age correcting circuit, and the deterioration of a camera image is suppressed. The output characteristic of the PMT 31 is corrected by a nonlinear correcting circuit. This signal is transmitted to a processing device through a frame 2 and a cable, and the processing device forms a gamma camera image, or the distribution image of a radioactive isotope within a subject, and indicates it on a display.
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