Evaluating the Performance of Multiplane Positron Tomographs Designed for Brain Imaging

The evaluation of a multiplane tomograph designed for brain imaging requires particular attention to certain design parameters that tend to be comprised in such designs. These parameters include resolution uniformity, axial slice thickness uniformity with emphasis on the interplane slices, scatter fraction, accidentals fraction, and system dead time. In addition, the final performance specifications should be relevant to the manner in which the system will actually be employed in the clinic. These specifications should be measured under realistic scatter and count rate conditions using the same reconstruction techniques that are employed in patient imaging. These parameters were evaluated on the NeuroECAT positron tomograph (1,2) and the effect of choice of manner of presentation and type of measurement condition on the apparent performance of the system is shown. The results indicate that clearly defined conditions are a necessity in evaluating the true performance of a positron tomograph.