Analytic correction for scatter in fully 3D PET: statistical issues

Scatter correction methods based on the analytical calculation of the scatter distribution can only estimate scatter from regions outside the field-of-view if transmission and emission scans of these regions exist. The duration of such scans must be short if they are to be acquired in a clinical setting. The effect of scan duration on the accuracy of the scatter estimates is investigated here. It is shown that the correction is insensitive to poor counting statistics in the emission scan, but is strongly affected by poor counting statistics in the transmission scan. Applying an adaptive segmentation algorithm to the transmission data greatly improves performance. Satisfactory scatter estimates are possible with transmission scans as short as one minute.