Evaluation of PET count rate performance.

A proposal is made for the test conditions to evaluate PET count rate performance. This performance depends in a complex manner on the spatial distribution of activity and scattering material. Therefore, a combined body phantom is proposed, which is as simple as possible but which adequately simulates the range of clinical application of a whole body tomograph. Taking into account the special properties of the new block detector design, a comprehensive test procedure is developed. This includes not only the common count rate characteristic, but also checks for the accuracy of randoms estimation and count loss correction schemes, and for the occurrence of pulse pile up. This is done for different source and scatter configurations, simulating brain, cardiac, and abdominal imaging, respectively. Examples are given, based on measurements of the latest generation PET scanners, namely the CT1 PT 931/08-12 and the Scanditronix PC 2048-07WB.