A method of generating a filter (40) for a nuclear medicine system (20) where the filter selects valid detected radiation events for image processing. A dataset (60) is provided that is indicative of a plurality of emitted radiation events occurring over a predetermined period of time. Signals representative of the response of a detector to the dataset of the plurality of emitted radiation events are generated. A pattern is determined (66) based on a correlation of a plurality of signals resulting from the response of the detector to a plurality of single radiation events in the dataset. A filter is generated (74) based on the correlation pattern. A method and apparatus of using the generated filter is also disclosed.