Purpose: This study attempts to establish a quantitative link between a patient’s body mass index (BMI), the delivered radiation dose, and the image noise.
Methods: 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.
Results: The multivariate regressions f(BMI2, mAs) and f(BMI2, CTDIVOL) had R 2 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.
Conclusions: 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.
From the * Department of Radiology, University of Minnesota, Minneapolis, MN; † Department of Radiology, University of Kentucky, Lexington, KY; ‡ Division of Biostatistics and Clinical and Translational Science Institute, University of Minnesota; and § Department of Emergency Medicine, Hennepin County Medical Center, Minneapolis, MN.
Received for publication November 7, 2012; accepted December 17, 2012.
Reprints: Cory P. Daignault, MD, Department of Radiology, University of Minnesota, MMC 292, 420 Delaware St SE, Minneapolis, MN 55455 (e-mail: firstname.lastname@example.org).
The authors have no conflicts of interest to report.