Enhancement of SPECT images by Fourier filtering the projection image set

Tomographic images from rotating gamma camera systems are often difficult to interpret because of poor contrast and high noise levels. A method is presented for improving the quality of these images by Fourier filtering the projection image set prior to reconstruction. A two-dimensional circularly symmetric Gaussian function is used as the spatial frequency filter. This filter can be optimized to enhance contrast and suppress noise in the projection image set in a straightforward and simple manner from the power spectra of representative projections. Preprocessing of the projections makes it possible to use a ramp reconstruction filter. The resulting tomographic sections show a dramatic improvement in image quality.