A multi-study analysis of variability in calibration coefficients for radiation dose estimation via the dicentric...

Accurate calibration of biological dosimetry methods is crucial for reliable radiation dose assessment in both medical and research contexts. However, discrepancies in calibration coefficients (α, β, c) across various studies impede standardization and the comparability of dose-response curves. This study conducted a systematic analysis of calibration data from 62 studies covering different radiation types (60Co gamma rays, 137Cs gamma rays, and X-rays) with varying energies and dose rates (0.00196-23.85 Gy/min), to explore the sources of variability and their effects on dicentric chromosome yields. Using descriptive statistics, analysis of variance, Kruskal-Wallis tests, and correlation analyses, we found significant differences in α and β coefficients across different dose rate categories for 60Co gamma rays (P < .05). Specifically, the α coefficient increased from 0.022 ± 0.015 at low dose rates (0-0.5 Gy/min) to 0.049 ± 0.021 at higher dose rates (>1 Gy/min). Moreover, no significant differences were detected between the Computer-Assisted Brain Analysis System (CABAS) and Dose Estimate software for estimating coefficients (P > .05 for α, β, c), indicating consistency in the methodological outputs of these software tools. The observed variability was attributed to factors such as radiation quality, experimental protocols, and inter-laboratory differences. These findings highlight the necessity for standardized calibration protocols that take radiation parameters into account. We propose the development of harmonized experimental setups and reference curves to improve comparability across studies, ultimately enhancing the accuracy of biological dosimetry for radiation protection and epidemiological research. In alignment with existing International Atomic Energy Agency and International Organization for Standardization (ISO) guidelines and acknowledging that international ring-trial intercomparisons remain essential for ensuring comparability across laboratories.