This study attempts to establish a quantitative link between a patient’s body mass index (BMI), the delivered radiation dose, and the image noise.
The CARE Dose4D computed tomography (CT) acquisitions from 206 patients undergoing “eyes-to-thighs” contrast-enhanced positron emission tomography/CT studies were retrospectively examined. Computed tomography dose index volume (CTDIVOL), mAs, and dose-length product were recorded from the dose report card. The image noise was quantified by evaluating the SD of regions of interest placed over the contrast enhanced aorta.
The multivariate regressions f(BMI2, mAs) and f(BMI2, CTDIVOL) had R2 values of 0.4840 and 0.4802, respectively. Unpaired t tests demonstrate that statistically significant difference in image noise required more than 12.17 kg/m2 of separation between the average BMI values for the groups compared.
The evaluation of image noise with BMI2 and CTDIVOL or mAs is a means to evaluate the consistency of dose modulation software. There is considerable variability in the radiation dose generated by the CARE Dose4D software.