Improved scatter correction for SPECT images: a Monte Carlo study

We propose the extended triple energy window (ETEW) method that improves quantitation and contrast in SPECT images. ETEW is a modification of the triple energy window (TEW) method which corrects for scatter by using abutted scatter rejection windows, which can overestimate or underestimate scatter. ETEW is compared to TEW using Monte Carlo simulated data for point sources as well as hot and cold spheres in a cylindrical water phantom. Various main energy window widths were simulated. Both TEW and ETEW improved image contrast and recovery coefficients. Estimated scatter components by TEW were not proportional to the true scatter components when main energy window widths of 10%, 15%, and 20% were simulated. ETEW resulted in scatter that was directly proportional to the true scatter. ETEW improves image quantitation and quality of SPECT image data by more accurately correcting for scatter.