Case Report: The Limited Value of Dicentric Analysis in Cases of Suspected Overexposure to a Low X-ray Dose.

Dicentric analysis is used to confirm ionizing radiation exposure and to estimate individual absorbed doses. However, assessing doses below 100 mSv and clearly communicating the findings to the affected person is challenging, partly due to uncertainties in dose estimation. The case described here involves a materials tester who operated two different irradiation devices, one for gamma-ray irradiation and the other for X-ray irradiation, in parallel and was likely overexposed to X rays. A rapid evaluation of his personal dosimeter indicated a value of 5.6 mSv. Dicentric analysis was performed 2.5 months later through manual scoring of up to 3,006 metaphases and automatic evaluation of 8,677 metaphases. The dicentric yields were compared with the decision threshold, the detection limit, and the laboratory's zero-dose reference data. Individual absorbed radiation doses with 95% confidence intervals were estimated, and odds ratios along with probabilities of exposure were calculated using a Bayesian approach. While this scenario is less concerning for acute or long-term health effects, it can still cause psychological stress and legal issues related to occupational safety for the worker involved. This report discusses various options for presenting and interpreting results, as well as the diagnostic value and limitations of dicentric analysis regarding potential low-dose exposures. Although only one person is studied, this case offers valuable insights into the practical application of dicentric analysis.