Evaluation of scatter correction using a single isotope for simultaneous emission and transmission data - Phantom and clinical patient studies

Photon scatter is one of the most important factors degrading the quantitat ive accuracy of SPECT images. Many scatter correction methods have been pro posed. The single isotope method was proposed by us. Aim: We evaluate the s catter correction method of improving the quality of images by acquiring em ission and transmission data simultaneously with single isotope scan. Metho d: To evaluate the proposed scatter correction method, a contrast and linea rity phantom was studied. Four female patients with fibromyalgia (FM) syndr ome and four with chronic back pain (BP) were imaged. Grey-to-cerebellum (G /C) and grey-to-white matter (G/W) ratios were determined by one skilled op erator for 12 regions of interest (ROIs) in each subject. Results: The line arity of activity response was improved after the scatter correction (r = 0 .999). The y-intercept value of the regression line was 0.036 (p <0.0001) a fter scatter correction and the slope was 0.954. Pairwise correlation indic ated the agreement between nonscatter corrected and scatter corrected image s. Reconstructed slices before and after scatter correction demonstrate a g ood correlation in the quantitative accuracy of radionuclide concentration. G/C values have significant correlation coefficients between original and corrected data. Conclusion: The transaxial images of human brain studies sh ow that the scatter correction using single isotope in simultaneous transmi ssion and emission tomography provides a good scatter compensation. The con trasts were increased on all 22 ROIs. The scatter compensation enhanced det ails of physiological lesions.