Comparison of 3D SPECT imaging with a rotating slat collimator and a parallel hole collimator

Besides parallel and converging hole collimators which are frequently used in nuclear medicine, slat collimators can be used for Single Photon Emission Computed Tomography (SPECT). The higher photon collection efficiency, inherent to the geometry of rotating slat collimators results in much lower noise in the data. However, reconstruction of the plane integral data measured by a slat collimator is much more sensitive to noise accumulation compared to traditional SPECT reconstruction from line integrals. It is not a straightforward question whether the initial gain in efficiency will compensate for the larger noise accumulation during reconstruction. Therefore, a comparison of the performance of parallel hole and rotating slat collimation is needed. This study compares SPECT with rotating slat and parallel hole collimation in combination with MLEM reconstruction with accurate system modeling and correction for scatter and attenuation. A contrast-to-noise study revealed an improvement of a factor 3 to 4 for hot lesions and more than a factor of 4 for cold lesion. Rotating slat collimators are thus a valuable alternative for parallel hole collimators.