Establishing Diagnostic Reference Level for Adult Abdomen and Pelvis CT Scans: A Benchmarking Study across BMI Groups

<b>Objective</b> This study aims to establish local diagnostic reference levels (DRLs) for contrast-enhanced computed tomography (CECT) abdomen and pelvis scans in adult patients within the Mangalore region, emphasizing variations in radiation dose metrics across body mass index (BMI) categories. <b>Materials and Methods</b> A prospective multicenter study was conducted across five health care facilities and analyzed data from 500 patients (18-60 years) undergoing multiphase CECT abdomen and pelvis scans. CT dose descriptors, volumetric CT dose index (CTDIvol), and dose length product (DLP) were recorded separately for plain, arterial, and portovenous phases. Descriptive statistics, analysis of variance, and correlation analyses assessed dose variations across BMI categories. <b>Results</b> The 75th percentile CTDIvol and DLP values for the plain phase were 8.30 mGy and 460.50 mGy·cm, respectively. Significant variations in radiation dose indices were observed across BMI groups ( <i>p</i> < 0.001). CTDIvol for the plain phase increased from 7.42 ± 1.41 mGy in underweight individuals to 8.41 ± 1.21 mGy in overweight individuals. Corresponding DLP values ranged from 400.00 to 450.55 mGy·cm. <b>Conclusion</b> The study established DRLs at the 75th percentile, demonstrating lower radiation doses than national and international benchmarks. These results highlight the significance of optimizing doses according to BMI to improve patient safety and the quality of diagnoses.