Theoretical studies on optimization of tomographic performance of cone-beam collimator for SPECT scintimammography

The major component limiting SPECT performance is the gamma camera collimator. A typical parallel-hole collimator has a low sensitivity yielding noisy tomographic projection images for clinically useful imaging times and radiation dose to the patients. The problem of high noise and low count density, is especially acute in scintimammography due to relatively low uptake in the breast tissue, as compared to the heart and the liver. A practical solution for improved SPECT camera performance in scintimammography might be application of cone-beam collimator (CBC). It offers increased sensitivity in a limited field-of-view (FOV). Disadvantages of CBC include limited and spatially variable FOV, generation of truncation artifacts outside FOV, and more difficult in truly 3D reconstruction. In this paper, we investigate some theoretical aspects of optimization of CBC for applications in SPECT scintimammography.