CONSTRUCTION AND VALIDATION OF IN VITRO DOSE-RESPONSE CALIBRATION CURVE USING DICENTRIC CHROMOSOME ABERRATION

Dicentric chromosome assay using a deep learning-based automated system

The dicentric chromosome assay is the "gold standard" in biodosimetry for estimating radiation exposure. However, its large-scale deployment is limited owing to its time-consuming nature and requirement for expert reviewers. Therefore, a recently developed automated system was evaluated for the dicentric chromosome assay. A previously constructed deep learning-based automatic dose-estimation system (DLADES) was used to construct dose curves and calculate estimated doses. Blood samples from two donors were exposed to cobalt-60 gamma rays (0-4 Gy, 0.8 Gy/min). The DLADES efficiently identified monocentric and dicentric chromosomes but showed impaired recognition of complete cells with 46 chromosomes. We estimated the chromosome number of each "Accepted" sample in the DLADES and sorted similar-quality images by removing outliers using the 1.5IQR method. Eleven of the 12 data points followed Poisson distribution. Blind samples were prepared for each dose to verify the accuracy of the estimated dose generated by the curve. The estimated dose was calculated using Merkle's method. The actual dose for each sample was within the 95% confidence limits of the estimated dose. Sorting similar-quality images using chromosome numbers is crucial for the automated dicentric chromosome assay. We successfully constructed a dose-response curve and determined the estimated dose using the DLADES.

ESTABLISHMENT OF THE IN VITRO DOSE-RESPONSE CALIBRATION CURVE FOR X-RAY-INDUCED MICRONUCLEI IN HUMAN LYMPHOCYTES

The cytokinesis-block micronucleus assay has proven to be a reliable technique for biological dosimetry. This study aimed to establish the dose-response curve for X-ray-induced micronucleus. Peripheral blood samples from three healthy donors were irradiated with various doses and scoring criteria by the micronuclei (MN) in binucleated cells. The results showed that the frequency of MN increased with the elevation of radiation dose. CABAS and Dose Estimate software were used to fit the MN and dose into a linear quadratic model, and the results were compared. The linear and quadratic coefficients obtained by the two software were basically the same and were comparable with published curves of similar radiation quality and dose rates by other studies. The dose-response curve established in this study can be used as an alternative method for in vitro dose reconstruction and provides a reliable tool for biological dosimetry in accidental or occupational radiation exposures.