Uniformity correction of whole body images taken with non-rectangular

Abstract

A head (10) of a nuclear medicine camera has a face defined by scintillation crystal (12) which is non-rectangular. In particular, it has symmetrically clipped corners (16). As the head scans from an initial position (32) to a final position (34), radiation originating from regions (72) and (82) are received by the detector head for a shorter duration than radiation from a corresponding point in the central region, due to the clipped corners. Particularly, for a path (74) that is shorter by 2W.sub.1 than a width W.sub.0 of the central portion, 2W.sub.1 /W.sub.0 fewer counts are received in region (82) from a radiation source of the same strength than would have been received in the central region. An edge enhancement circuit (70 ) boosts the number of radiation events counted in an image memory (54) in pixels corresponding to region (72) by 2W.sub.i /W.sub.0 and in region (82) by W.sub.i /W.sub.0. In the preferred on-line embodiment, the radiation event count adjustment is performed in conjunction with a uniform flood control correction which causes a gate (52) to accept or reject a preselected percentage of the radiation events received at each unit area of the scintillation crystal. The edge enhancement circuit adjusts the uniformity correction factors such that W.sub.i /W.sub.0 or 2W.sub.i /W.sub.0 more radiation events are kept for the edge regions (82, 72).