PROBLEM TO BE SOLVED: To provide a device etc., which improves optical sensor gain calibration in a PET system.SOLUTION: An optical sensor gain detection device includes: a detector including an optical sensor which outputs a signal due to a first event occurring in responses to arrival of radioactivity; an after-pulse/dark-pulse detector device which is triggered from the first event and detects an after pulse or dark pulse due to a second event occurring in the optical sensor after the first event, and outputs an indication signal in response to the detected after pulse or dark pulse; an integrator which integrates and outputs the signal output by the optical sensor; a histogram device which is connected to the integrator and after-pulse/dark-pulse detector device and generates a histogram from the integrated signal and the indication signal; and a gain determination device which determines the gain of the optical sensor based upon the generated histogram.
OPTICAL SENSOR GAIN DETECTION METHOD AND OPTICAL SENSOR GAIN DETECTION DEVICE FOR OPTICAL COMBINATION MONITORING OF OPTICAL SENSOR GAIN OF RADIATION DETECTOR AND SCINTILLATION CRYSTAL