NUCLEAR CARDIOLOGY APPARATUS AND METHOD

A nuclear cardiology system (M) for use with a scintillation camera for evaluating cardiac function by real time measurement of the variation of radiation from the heart of a patient to whom is administered a radioactive tracer. The camera (C) provides data describing the location of individual counts representing radiation events coming from the patient. The system segregates, in real time, counts corresponding to radiation from an electronically defined region of interest (30) describing an investigated part of the heart, such as the left ventricle. Synchronized by the patient's electrocardiogram, (20) time gated memory circuitry divides each heartbeat into a series of subintervals, and stores indications of the respective amounts of radiation events emanating from the region of interest during each of the subintervals. Calculating circuitry (32, 40) scans the stored information and, based on the maximum and minimum respective radiation amounts detected in the subintervals, computes the fraction of blood ejected by the heart in each beat. A strip chart recorder (12) provides a permanent representation of the curve of radiation from the region of interest, as defined by the indicated series of subinterval radiation amounts.