Elimination of Loss of Resolution at Depth in Single-Photon Nuclear Images

The use of a high purity germanium gamma camera capable of assigning the interaction point of a gamma-ray unambiguously to a 2×2mm2 element, together with the use of matched square-hole tantalum tube collimators, permits the application of a weighted backprojection technique to reconstruct images that do not show the loss of spatial resolution associated with distance between the object and collimator surface. The technique converges, and images with improved definition are obtained.