1. A system for identifying non-functioning pixels in positron emission tomography (PET) imaging, said system comprising: a pixel identification processor configured to: receive data describing scintillation events localized to a plurality of pixels of a PET scanner; generate a count map histogram from the received data, the count map histogram mapping each of the pixels to a count of scintillation events localized to the pixel; and identify one or more non-functioning pixels from the count map histogram; store unique identifiers of the identified non-functioning pixels in a pixel memory for use during pixel compensation; and compare the identified non-functioning pixels against previously identified non-functioning pixels of the pixels memory; wherein a newly identified non-functioning pixel is only used for pixel compensation after it has been identified as non-functioning in a predetermined number of scans.