Patent ID: 8294110

Claim:
A method for determining correction factors used to determine energy of an event detected by a gamma ray detector having at least one nonlinear photosensor arranged over a scintillation array of crystal elements, the gamma ray detector using optical multiplexing or analog electronic multiplexing, the method comprising: (a) generating gamma rays having a first predetermined energy value; (b) acquiring, for each of the at least one nonlinear photosensor, at least one output value generated by the at least one nonlinear photosensor in response to receiving scintillation light emitted by at least one crystal in the array of crystal elements in response to arrival of one of the generated gamma rays, which signifies an event; (c) determining a relative position and a total signal value of the event based on the acquired at least one output value of each of the at least one nonlinear photosensor, the relative position being one of a predetermined number of cell locations, the predetermined number of cell locations being greater than a number of crystal elements in the array of crystal elements; (d) storing the total signal value in association with the determined cell location; (e) repeating the acquiring, determining, and storing steps for a plurality of events to generate stored event data; (f) determining, for each cell location, an average total signal value for the first predetermined energy value based on the stored event data; and (g) determining, for each cell location, a correction factor based on the determined average total signal value and the first predetermined energy value.