Revision of cytogenetic dosimetry in the IAEA manual 2011 based on data about radio‐sensitivity and dose‐rate findings contributing

Abstract

In order to achieve the goal of rapid response, effective controland protection of life inlarge-scale radiation events, the IAEA Manual 2011 has been revised based on the data of radio-sensitivity, dose-rate findings. Analyze individual differences in radiation sensitivity using 60 Co radiation (0.27 Gy/min). Chromosomal aberrations with different irradiation dose rates were used to establish the biological dose curve and analyze the excess of the "dicentric + ring" caused by the dose rate at each dose point; DAPI-images and Metafer 4 were used to capture metaphase images and make further analysis. The data were collected in 2020, Dicentric + ring/100 Cells was 17.5-43.8, the average value was28.32 ± 6.98. The mean value of Dicentric + ring/100 Cells was 31.37 in males while 25.27 in females, there are significant differences (p < .01). The irradiation dose is dominant, At each dose point, the value of"(dicentric chromosome + centric rings)/cell" is proportional to "dose rate", that is, Y = kx + b, within the dose range of 1-5 Gy, "(dicentric chromosome + centric rings)/ Cell" holds a quadratic linear relationship with dose rate, that is, y = ax 2 + bx + c; The DAPI-images might give you more hints than those of conventional Giemsa-stain.The authors recommend that the IAEA Manual 2011 could be revised based on data of radio-sensitivity and dose-rate, which may contribute to the establishment of a unified dose-response calibration curve and stimulation of potential for automation in cytogenetic biodosimetry. (1) Individual differences of radiosensitivity are very large. (2) At each dose point, "(dicentric chromosome + centric rings)/cell" is proportional to "dose rate", that is, Y = kx + b. (3) "(dicentric chromosome + centric rings)/Cell" is a quadratic linear relationship with dose rate, that is, y = ax 2 + bx + c.(4) We created a "Unity Standard Curve of Biological Dose Estimation". Creating a Unity Standard Curve of Biological Dose, under these circumstances, we can form a joint and rapid response to a nuclear and radiological accident.

Biodosimetry, can it find its way to the nuclear medicine clinic?

“…The foci assay and gene expression assays are faster, since they do not depend on the stimulation of PBLs and can provide results within the first 24 h. In addition, some uncertainties remain a topic of debate, such as the effects of individual differences in radiosensitivity on biological dose-response curves and the influence of radiation dose rate on "Dicentric chromosome + centric rings" in nuclear medicine applications. This led to revisions of the IAEA Manual 2011 in 2022 (131). For the CBMN assay, it must be borne in mind that other genotoxic stresses besides radiation also induce DNA fragmentation, which could appear as MN in the cytoplasm of the cell.…”

“…[131 I]MIBGTemporary myelosuppression lasting 4-6 weeks (<60%) Rarely persistent haematological effects and induction of leukaemia has been reported.…”