Distance-weighted Backprojection: a SPECT Reconstruction Technique

A method of reconstruction of single-photon emission computed tomographic (SPECT) images--distance-weighted filtered backprojection--is described. The quality of SPECT images using the standard filtered backprojection algorithm for data obtained from 360 degrees acquisitions is limited by the loss of spatial resolution with distance, and the attenuation and scatter inherent in the planar images used for reconstruction. In contrast to the standard techniques in which a reconstructed pixel receives equal contributions from 180 degrees opposed views, distance--weighted filtered backprojection applies a variable weighting factor to the data such that the pixel receives greater weight from the closest planar views. Data derived from hot and cold spot phantoms as well as from various clinical studies show better spatial and contrast resolution with this new technique compared with the conventional 360 degrees algorithm.