The Role of CT-Based Attenuation Correction and Collimator Blurring Correction in Striatal Spect Quantification
Figure 2
“Bias-noise” curves: plot of root mean squared coefficient of variation (RMSCOV) versus average recovery (AR) for phantom data (a and b) or versus the average specific uptake ratio (aSUR) for patient data (c and d). (a) give the results when using no correction for collimator blurring, the default value (9.4 mm FWHM) for the constant collimator blurring correction, and the measured depth dependent collimator blurring correction (method 1, see text). (d) give the results when using the optimized values for the constant collimator blurring correction or the depth dependent collimator blurring correction (method 2, see text). In the latter figures, we added the case when no correction for collimator blurring is performed to help in the comparison with the top figures. (abbreviations: ct: nonuniform attenuation correction using a CT-based attenuation map; ell: uniform attenuation correction using an ellipse approximating the scalp; p0, pc, pd: no, constant, and depth dependent correction for collimator blurring, resp.; FWHM: full width at half maximum).
