Weight-Specific Dose Estimates in Chest and Abdominopelvic Ct: A Practical Complementary Approach to Aapm 204 Size-Based Methods Publisher



Jamshidi MH ; Orangi B ; Nia NZ ; Johar N ; Deevband MR ; Miri A ; Tahmasbi M
Source: Radiation Physics and Chemistry Published:2026

Abstract

Volume CT dose index (CTDIvol) and dose-length product (DLP) reflect scanner output but do not account for patient size, limiting accuracy in estimating radiation dose. To address this, the AAPM introduced the size-specific dose estimate (SSDE), adjusting CTDIvol based on patient body dimensions. This study evaluates the relationship between patient weight and radiation dose in non-contrast abdominopelvic and chest CT scans. Data from 366 patients were analyzed (age, weight, and scan parameters). SSDE was calculated according to AAPM Report 204, using the effective diameter derived from anterior-posterior and lateral measurements. Correlations between SSDE, effective diameter, and patient weight were assessed. An exponential model was developed to estimate a weight-specific dose estimate (WSDE) from patient weight and CTDIvol, and the results were compared with AAPM-based SSDE trends. Patient weight showed moderate correlations and stronger associations with CTDIvol and SSDE than effective diameter. In abdominopelvic CT, the correlation coefficient (R2) between CTDIvol and weight was 0.6334 (vs. 0.4436 for effective diameter), and between SSDE and weight was 0.4483 (vs. 0.2714 for effective diameter), with p-values <0.05. The exponential equations enabled WSDE calculation, demonstrating moderate-to-strong correlation with effective diameter–based SSDE (R2 > 0.75 in chest CT). Agreement analysis showed a mean absolute percentage error of approximately 10% for chest CT and 26% for abdominopelvic CT. These findings indicate that WSDE follows dose–size trends consistent with AAPM methodology but does not replace image-based SSDE. The WSDE method provides a practical complementary approach for population-level dose monitoring when anatomical measurements are unavailable. © 2026 Elsevier Ltd.