Patent ID: 6927396

Claim:
An apparatus for processing gamma ray events, the apparatus comprising: a pixilated crystal array, each pixel of the crystal array responsive to a gamma ray received thereby for outputting a pixel signal related to the energy of the received gamma ray; means responsive to each pixel signal for outputting a first threshold signal and second threshold signal related to a position of each pixel in the crystal array when the pixel signal has a predetermined relation to a reference signal; means responsive to each pixel signal and its related first and second threshold signals for outputting a counter value when the pixel signal has a predetermined relation to the first and second threshold signals; an event counter having an array of registers, each of which is related to one of the pixels of the crystal array, with the event counter responsive to each counter value for incrementing a value of the register related to the pixel of the crystal array outputting the pixel signal related to the counter value; and means for displaying the values in the registers as an image.