A method of processing, by a processor of a computer, positron emission tomography (PET) information obtained from a PET detector, including the steps of obtaining a singles event list that includes a plurality of single event entries, each entry corresponding to a single event detected by the PET detector and including a timestamp, energy information, and crystal position information; and determining, based on the timestamp and the crystal position information of each entry and a predetermined coincidence time period, all event pairs within the plurality of single event entries, each event pair consisting of two single events whose respective timestamps differ by less than the predetermined coincidence time period, wherein the determining step determines that an event pair exists when at least two, but no more than k, single events are found within a given time window, wherein k is an integer value greater than or equal to two.