Relaxed iterative maximum-likelihood expectation maximization for positron emission tomography random coincidence estimation

Abstract

A non-transitory storage medium stores instructions readable and executable by an electronic processor () to perform a method () for estimating singles rates for detectors () of a detector array () of a positron emission tomography (PET) imaging device (). The method includes: obtaining measured delayed coincidence rates for lines of response (LORs) defined by pairs of the detectors of the detector array; and generating estimated singles rates for the detectors of the detector array by an iterative optimization in which each iteration performs an update of estimates of the singles rates for the detectors by operations including: forward projecting the estimates of the singles rates for the detectors to generate estimates of delayed coincidence rates for the LORs; generating quantitative comparisons between the measured delayed coincidence rates for the LORs and the generated estimates of the delayed coincidence rates for the LORs; backprojecting the quantitative comparisons to generate corrections for the singles rates for the detectors; and updating the estimates of the singles rates for the detectors using the generated corrections. The estimated singles rates for the detectors of the detectors array comprise the estimates of the singles rates for the detectors output by the iterative optimization when the iterative optimization satisfies a stopping criterion. This process jointly optimizes the estimated singles rates and randoms estimation.