Estimating an acquisition-specific NEC curve for PET acquisitions

NEC (or NECR) analysis is a valuable tool in understanding PET image quality and imaging performance. NEC is often expressed as a function of activity level, measured in the course of a decay series acquisition. In patient imaging a series of acquisitions is generally unavailable, and the NEC curve cannot be appreciated. This work uses the prompt and delayed coincidence event rates measured in a PET data frame, plus the measurements of system deadtime made in the course of that acquisition, to determine the shape of the NEC curve. This will allow, for instance, analysis of the image quality effects of changing the activity concentration in the patient, either by changing the injected dose or the delay to scan start.