Abstract
<title>Abstract</title> <p>Background Conventional gastrointestinal (GI) contrast radiography remains an essential diagnostic modality in many low- and middle-income countries where fluoroscopic facilities are unavailable or limited. Repeated radiographic acquisitions during barium examinations may increase radiation exposure to radiosensitive organs and contribute to stochastic radiation risks. However, comprehensive organ dosimetry and radiological risk data for these procedures remain scarce in Northwestern Nigeria. Objective To evaluate organ-specific absorbed doses, effective dose, and radiation-induced lifetime cancer incidence and mortality risks associated with barium swallow, barium meal, and barium enema examinations performed using conventional radiographic systems in selected hospitals in Northwestern Nigeria. Methods A multicentre prospective cross-sectional study was conducted among adult patients undergoing clinically indicated gastrointestinal contrast examinations at Yauri General Hospital, Usmanu Danfodiyo University Teaching Hospital (UDUTH), and MedStop Diagnostic and Clinical Centre. Patient demographics and exposure parameters, including tube potential (kVp), tube current–time product (mAs), focus-to-skin distance (FSD), focus-to-detector distance (FDD), beam area, and number of acquired images, were prospectively recorded. Organ absorbed doses, effective dose, and lifetime cancer incidence and mortality risks were estimated using Monte Carlo-based CALDose_X version 5.0, employing the MASH and FASH voxel phantoms. Statistical analyses were performed using IBM SPSS Statistics version 26.0. Results Significant inter-procedural and inter-centre variations were observed. MedStop recorded the highest exposure settings for a barium swallow (88.08 kVp; 39.04 mAs), whereas a barium enema required the greatest number of radiographic acquisitions (8.35 images). During barium swallow, the thyroid received the highest absorbed dose (6.81 mGy), followed by the thymus (4.84 mGy), while the maximum skin entrance dose reached 12.07 mGy. A barium enema produced the highest doses to the gallbladder wall (3.31 ± 0.75 mGy), colon wall (1.96 ± 0.47 mGy), pancreas (1.70 ± 0.43 mGy), and skin entrance (6.73 ± 1.31 mGy). Effective doses ranged from 0.32 ± 0.09 mSv (female barium swallow, UDUTH) to 1.06 ± 0.43 mSv (male barium swallow, MedStop), whereas barium enema and barium meal recorded 0.74 ± 0.18 mSv and 0.50 ± 0.17 mSv, respectively. The highest lifetime cancer incidence (9.56 ± 4.52 per 100,000) and mortality risk (6.87 ± 3.05 per 100,000) occurred among male barium swallow patients at MedStop. Effective doses were 17.0–84.13% lower than previous African reports. Conclusions Conventional gastrointestinal contrast radiography in Northwestern Nigeria was associated with relatively low effective doses but considerable variability in organ absorbed doses, particularly in the thyroid, skin, gallbladder, colon, and pancreas. Although estimated radiation-induced cancer risks remained low, institutional differences indicate opportunities for further optimization. These findings support the establishment of regional diagnostic reference levels (DRLs), standardized imaging protocols, and strengthened quality assurance programs to improve patient radiation protection.</p>