title: Attenuation compensation in single-photon emission tomography: a comparative evaluation.
abstract: Attenuation of photons in single-photon emission tomography (SPECT) makes three-dimensional reconstruction of unknown radioactivity distributions a mathematically intractable problem. Approaches to approximate SPECT reconstruction range from ignoring the effect of photon attenuation to incorporating assumed attenuation coefficients into an iterative reconstruction procedure. We have developed a computer-based simulation method to assess the relative effectiveness of attenuation compensation procedures. The method was used to study four procedures for myocardial SPECT using an infarct-avid radiopharmaceutical, Tc-99m stannous pyrophosphate. Reconstructions were evaluated by two criteria: overall (sum-of-squares) accuracy, and accuracy of lesion sizing. For moderate- to high-contrast studies there were no significant differences among the reconstructions by either evaluation criterion; for low contrast ratios the iterative method produced lower sum-of-squares criterion; for low contrast ratios the iterative method produced lower sum-of-squares error. We conclude that the additional expense of the iterative method is not justified under the conditions of this study. The approach used here is a convenient tool for evaluating specific SPECT reconstruction alternatives.
mesh_terms: D006801:Humans; D008433:Mathematics; D008961:Models, Structural; D009203:Myocardial Infarction / Q000000981:diagnostic imaging; D013667:Technetium; D016698:Technetium Tc 99m Pyrophosphate; D014003:Tin Polyphosphates; D014055:Tomography, Emission-Computed / Q000379:methods*
chemical_list: D014003:Tin Polyphosphates; C017742:technetium Tc 99m stannous pyrophosphate; D016698:Technetium Tc 99m Pyrophosphate; D013667:Technetium