Volume computed tomography dose index (CTDIvol) and size-specific dose estimate (SSDE) for tube current modulation (TCM) in CT scanning

Background: in the tube current modulation (tcm) technique, tube current ischanged dynamically during the scanning process. to quantify the effect of adynamic tube current, a distinct calculator is needed to estimate the ct outputradiation dose in terms of volume ct dose index (ctdivol) and individual patientdose in terms of size-specific dose estimate (ssde). this study developed a specificcalculator for ct scanning using the tcm technique. materials and methods: thetube current was extracted from the dicom header for every slice, and averagedover the scan length. the water equivalent diameter (dw) and ssde values werecalculated for each tube rotation. the software was retrospectively applied to 57patients who had undergone abdominal and thoracic ct examinations using a multi-detector ct, the somatom emotion 6. results: the differences between thecalculated ctdivol and the ctdivol reported by the ct scanner were 4.4 ± 1.2%and 6.0 ± 2.0% for abdominal and thoracic examinations, respectively. theaverage tube current was found to be linearly correlated with dw with r2values of 0.707 and 0.696 for abdominal and thoracic examinations,respectively. the average tube current was also linearly and stronglycorrelated with the ssde with r2 values of 0.941 and 0.887 for abdominal andthoracic examinations, respectively. conclusion: calculator for estimating ctdivoland ssde specifically for tcm in ct scanning has been successfully developed. thedifference between calculated ctdivol values using this calculator and reportedctdivol values were less than 10%.