Dose monitoring using the DICOM structured report: assessment of the relationship between cumulative radiation exposure and BMI in abdominal CT

•DICOM-SR was used to implement automatic CT-dose monitoring.•DICOM-SR allowed for a fast and comprehensive analysis of CT dose data.•Radiation exposure for abdominal CT was increased by up to 96% for extremely obese patients.•There were significantly more exceedings of national reference values for obese and extremely obese patients.

AimTo perform a systematic, large-scale analysis using the Digital Imaging and Communication in Medicine structured report (DICOM-SR) to assess the relationship between body mass index (BMI) and radiation exposure in abdominal CT.Materials and methodsA retrospective analysis of DICOM-SR of 3121 abdominal CT examinations between April 2013 and March 2014 was performed. All examinations were conducted using a 128 row CT system. Patients (mean age 61 ± 15 years) were divided into five groups according to their BMI: group A <20 kg/m2 (underweight), group B 20-25 kg/m2 (normal weight), group C 25-30 kg/m2 (overweight), group D 30-35 kg/m2 (obese), and group E > 35 kg/m2 (extremely obese). CT dose index (CTDIvol) and dose-length product (DLP) were compared between all groups and matched to national diagnostic reference values.ResultsThe mean CTDIvol and DLP were 5.4 ± 2.9 mGy and 243 ± 153 mGy·cm in group A, 6 ± 3.6 mGy and 264 ± 179 mGy•cm in group B, 7 ± 3.6 mGy and 320 ± 180 mGy•cm in group C, 8.1 ± 5.2 mGy and 375 ± 306 mGy•cm in group D, and 10 ± 8 mGy and 476 ± 403 mGy•cm in group E, respectively. Except for group A versus group B, CTDIvol and DLP differed significantly between all groups (p<0.05). Significantly more CTDIvol values exceeded national diagnostic reference values in groups D and E (2.1% and 6.3%) compared to group B (0.5%, p<0.05).ConclusionDICOM-SR is a comprehensive, fast, and reproducible way to analyse dose-related data at CT. It allows for automated evaluation of radiation dose in a large study population. Dose exposition is related to the patient's BMI and is increased by up to 96% for extremely obese patients undergoing abdominal CT.