Coincidence detection system for positron emission tomography

Abstract

An arrangement for determing the most likely interaction time corresponding to an observed pulse in a system having statistical processes is provided with a timing arrangement for producing a plurality of timing signals, the timing signals having a predetermined time relationship with respect to one another. A plurality of sampling elements, each having an input for receiving a respectively associated signal vector to be sampled in accordance with at least one of the timing signals, and an output for producing an associated portion of an analog vector signal are additionally provided. A digital memory stores data corresponding to a plurality of weighting coefficient vectors, the weighting coefficient vectors being formed of values corresponding to a predetermined characteristic of the shape of the pulse event and at least one of the statistical processes. Product-forming circuitry produces product signals corresponding to products of the composite analog vector signal and respective one of the plurality of weighting coefficient vectors. The product signals are summed and compared in a threshold crossing detector which detects a threshold crossing of the sum signal.