Comparing the performance of two gamma cameras under high counting rates: principles and practice

The performance of two large Anger cameras at high counting rates was compared, and the principles for measuring the relevant parameters, especially deadtime loss and coincidence artifacts, are discussed. The results demonstrate the importance of the following factors: modern pulse-shaping circuitry with short paralyzable deadtime, and anti-pileup circuit, and uniform energy information within the field of view, which requires separate summing matrices for energy and position. Elaborate testing of the specifications should be carried out before purchase of a gamma camera.