Correction for spatial variations of deadtime of a monolithic scintillator based detector in a medical imaging system

Abstract

A nuclear medicine imaging system includes the capability to correct for the deadtime, including the capability to correct for spatial variations in deadtime across the imaging surface of a detector. The imaging system includes one or more radiation detectors, each using a large, monolithic scintillation crystal. Each detector has deadtime associated with it. A given detector is used to acquire an energy profile of a patient based on emission radiation. The detector includes a number of timing channels. The energy profile is used to select a zone influence map indicating the extent of spatial overlap in response between the various timing channels. Emission data of the patient is then acquired during an emission scan. During acquisition of the emission data, a rate meter assigned to each timing channel samples the number of counts associated with each timing channel to acquire deadtime data. A unique deadtime function is provided for each unique zone represented in the zone influence map, including each region of overlap. The deadtime data acquired from the rate meters are then applied to the deadtime functions to correct the emission data for deadtime on a pixel-by-pixel basis. An image is generated based on the deadtime-corrected data.