Gamma camera

Abstract

A gamma camera having an array of photodetectors arranged to locate a flash of light produced by a scintillator in response to an incident gamma ray photon. A current pulse is produced by each one of the photodetectors in response to each incident gamma ray photon, the amount of charge produced by each one of such photodetectors being a measure of the portion of the energy of the photon detected by such one of the photodetectors. Each integrator produces a voltage which rises from an initial reference level, typically ground potential, to a peak level, such peak voltage level being representative of the amount of charge in the current pulse and hence the peak level of such voltage is a measure of the portion of the energy of the photon detected by such one of the photodetector. The outputs of the integrators are combined to provide X and Y coordinate location signals. The output of the integrator is reset to the initial reference level a predetermined time after the production of the current pulse, such predetermined time corresponding to the time the integrator output is substantially at its peak voltage and has provided a measure of the portion of the energy level of the photon detected by such one of the photodetectors coupled thereto thereby enabling such integrator to properly respond to a current pulse produced by the photodetector in response to succeeding incident gamma ray photon.