Image filtering in single-photon emission computed tomography: principles and applications.

Among the factors contributing to optimal image quality in single-photon emission computed tomography (SPECT), image filtering is an important, though mostly subjectively applied, image-processing parameter. We have aimed at giving an overview of current available SPECT filtering options. Current SPECT applications are discussed and practical guidelines to choose optimal filter parameters for a given situation are provided. It is shown that Hann and Butterworth filters allow accurate approximations to most filter types. The authors support the use of limited filter types in an attempt to standardise image-processing approaches, which may lead to better diagnostic compatibility and interpretation of interdepartmental results.