A regularized deconvolution-fitting method for Compton-scatter correction in SPECT

A method is presented for estimating the Compton-scatter component within the photopeak for local energy spectra measured by an Anger camera in SPECT. Assuming that the measured energy spectrum is the source scatter energy distribution convolved with a known camera energy-resolution function plus an unscattered spectral component, a least-square inverse operation is performed to recover the source scatter distribution. Since this inverse operation is ill-posed, the regularization technique is applied for stabilization. With the method, scatter fractions similar to those from polynomial spectral fitting (PSF) have been observed for experimentally measured, high-count data with a hot (Tc^99m or I¹³¹) sphere in a cold cylinder, and the inverse (Tc^99m only). The method is also less sensitive to the width of the fitting window. A regularization parameter from 1 to 10 is recommended for practical cases. The shape of a recovered source scatter distribution matches that determined by a high-resolution semiconductor-detector measurement as well as by Monte Carlo simulation