Ann Lab Med.  2019 Jan;39(1):91-95. 10.3343/alm.2019.39.1.91.

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

• Jang MA
• Han EA
• Lee JK
• Cho KH
• Shin HB
• Lee YK

• KMID: 2420277
• DOI: http://doi.org/10.3343/alm.2019.39.1.91

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 in vitro 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.

Keyword

Chromosome aberration; Cytogenetic dosimetry; X-ray; Dicentric chromosome; Translocation; Correlation

MeSH Terms

Calibration
Chromosome Aberrations
Cytogenetics
In Vitro Techniques*
Particle Accelerators
Radiation, Ionizing
Radiotherapy

Figure

• 

  Fig. 1 Dose-response calibration curves and metaphase images of chromosomal aberrations induced in human lymphocytes by X-ray exposure. (A and B) Dose response curves with the 95% confidence interval delimited by dotted lines. The black dots (●) denotes data points with standard errors of the mean. (A) Dicentric yields, Y=(0.0011±0.0004)+(0.0119±0.0032)D+(0.0617±0.0019)D2, where Y is the dicentric yield, and D is the absorbed dose in Gy. (B) Translocation of chromosomes 1, 2, and 4, Y=(0.0015±0.0004)+(0.0048±0.0024)D+(0.0237±0.0014)D2, where Y is the translocation yield and D is the absorbed dose in Gy. (C) Dicentric chromosomes and their respective fragments are marked with an arrows and arrowheads, respectively. (D) Metaphases with painted chromosomes—1 (red), 2 (green), and 4 (yellow)—and an apparent two-way translocation involving chromosomes 2 and 4 (arrows).

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