Abstract
Discusses two approaches towards improving the sensitivity and enlarging the useful field of view for a rotating positron camera by removing the constraint on phi . Weighted backprojection appears superior in that the camera response is more uniform and the images are less noisy than for the post-reconstruction scaling method. Fourier deconvolution reconstruction may be retained since the response function of the overall system is still shift invariant. In a typical imaging situation, the increase in sensitivity may be as much as a factor of 2.5, which represents a significant improvement when considering the poor statistics of nuclear medicine images. As a consequence of decoupling the sensitivity from the diameter of the field of view, transverse sections through internal organs with dimensions approaching those of the detectors may therefore be accurately imaged with good sensitivity. The weighted backprojection method is now applied in routine clinical imaging (Frey et al., 1984).