Table 5.

Effects of Scanning Parameters on Dose and Risk, Quantified by Using Coefficient of Variation across Protocols

Note.—Coefficient of variation = (standard deviation × 100%)/mean. The coefficients of variation represent averages across patients. They had standard deviations across patients of less than 5%, except for the effect of collimation on colon dose, where the average coefficient of variation had a standard deviation of 15% both before and after the colon dose was normalized by CTDI_vol. As an example, to quantify the effect of bow tie filter on the lung dose of a given patient, coefficient of variation was calculated by using the lung dose values of that patient from protocols A, B, and C, which differed only in terms of bow tie filter choice.