Dose Estimation Curves Following In Vitro X-ray Irradiation Using Blood From Four Healthy Korean Individuals

Abstract

Cytogenetic dosimetry is useful for evaluating the absorbed dose of ionizing radiation based on analysis of radiation-induced chromosomal aberrations. We created two types of dose-response calibration curves for dicentric chromosomes (DC) and translocations (TR) induced by X-ray irradiation, using an electron linear accelerator, which is the most frequently used medical device in radiotherapy. We irradiated samples from four healthy Korean individuals and compared the resultant curves between individuals. Aberration yields were studied in a total of 31,800 and 31,725 metaphases for DC and TR, respectively, obtained from 11 X-ray irradiation dose-points (0, 0.05, 0.1, 0.25, 0.5, 0.75, 1, 2, 3, 4, and 5 Gy). The dose-response relationship followed a linear-quadratic equation, Y=C+αD+βD², with the coefficients C=0.0011 for DC and 0.0015 for TR, α=0.0119 for DC and 0.0048 for TR, and β=0.0617 for DC and 0.0237 for TR. Correlation coefficients between irradiation doses and chromosomal aberrations were 0.971 for DC and 0.6 for TR, indicating a very strong and a moderate correlation, respectively. This is the first study implementing cytogenetic dosimetry following exposure to ionizing X-radiation.

Evaluating the Cumulative Impact of Ionizing Radiation Exposure With Diagnostic Genetics

“…I have scrutinized the salient article by Jang et al [1] with great interest. Using the most advanced cytogenetic dosimetry techniques, the authors successfully evaluated the in vitro damaging impact of ionizing radiation on human chromosomes.…”

“…According to the U.S. Department of Energy, doses below 100 mGy are defined as low-dose radiation [10]. Accordingly, among the 11 X-ray single-dose points used by Jang et al [1], only 0.05 Gy and 0.1 Gy belong to low-dose radiation. Given that clinical investigators are seeking to improve diagnostic imaging with low or zero radiation, the potential future application of the cytogenetic analysis proposed by Jang et al [1] should be explored for such cumulative low-dose radiation detection.…”

“…Human lymphocytes can be applied to both genomic sequencing and chromosomal aberrations. Therefore, it would also be interesting for Jang et al [1] to expand their research to studying the relation between these two types of alterations.…”

“…Overall, Jang et al [1] provide a valuable tool for investigating cytogenetic dosimetry by analyzing chromosomal morphological changes of peripheral lymphocytes from healthy adults. I further propose that this laboratory technique can be applied to clinical investigations, especially for evaluating the cumulative effects of low-dose radiation.…”

Correspondence: Response to “Evaluating the Cumulative Impact of Ionizing Radiation Exposure With Diagnostic Genetics”

“…We appreciate the opportunity to respond to the Letter to the Editor by Professor Wang [1] regarding our article reporting dose estimation curves following in vitro X-ray irradiation using blood from four healthy Korean individuals [2]. Professor Wang raises an important scientific issue in the original research paper, namely, clinical application of cytogenetic dosimetry for low-dose exposure to ionizing radiation (IR) <100 mGy.…”