Adaptive correction of scatter and random events for 3D backprojected PET data

Backprojected images offer compact and accurate storage of 3D PET data, and so are potentially very suited to high resolution 3D PET scanners when carrying out fast dynamic scans. However, there are very few methods available for correcting backprojected images for the effects of scatter and random events. Scatter correction methods usually involve experimental measurement of scatter response functions or accurate simulations, and are thus limited by the accuracy of the model used. In contrast, the approach proposed here uniquely adapts a general form of a combined scatter and randoms response function. This method inherently does not rely upon accurate determination of the scatter and randoms response functions, but does however rely upon knowledge of the attenuating object's outline. The technique is able to adapt to different imaging situations, account for detector scatter, and in particular is readily implemented in backprojection space. The method has been implemented for a small volume HIDAC (II) PET scanner.