Milacic S
University of Belgrade, Faculty of Medicine, Institute of Occupational Medicine and Radiological Protection, Belgrade, Serbia.
J BUON. 2009 Oct-Dec;14(4):641-6.
To compare the incidence of chromosomal aberrations (CA) in healthy medical workers occupationally exposed to ionizing radiation (IR) and in non-exposed healthy population.
This was a 4-year study with 462 subjects, mean age 42.3 years, occupationally exposed to IR (exposed group - E), and 95 subjects, mean age 35.2 years, not exposed to IR (control group - C), during the same time period and from the same territory. Thermoluminescence dosimeters (TLD) were used for assessment of IR exposure. Modified Moorhead's micro method for peripheral blood lymphocytes and conventional cytogenetic technique of CA was used for analysis of CA. The karyotype of 200 lymphocytes in metaphase was analysed by immersion light microscope.
The average annual absorbed dose measured by TLD was 14.5 mSv in group E and 2.8 mSv in group C exposed to natural level of radioactivity. The incidence of CA was 21.6% in group E and 2.1% in group C (p <0.05), while non-specific chromosomal lesions (gaps, breaks, elongations) were equal in both groups (22%). In group E, the highest incidence was found in nuclear medicine workers (42.6%), then in orthopedic surgeons (27.08%). Highly significant difference (p <0.001) was found in the number of aberrant cells and the sum of CA between group E and C. The sum of CA and the number of aberrant cells were positively correlated with the duration of exposure (p < 0.001), and to a lesser degree with age (p < 0.05) in group E. In group C, this correlation was negative and insignificant. In group E, subjects with duration of occupational exposure (DOE) up to 15 years (subgroup E I=327) had significantly less number of aberrant cells and CA in comparison with the subjects with DOE over 15 years (subgroup E II=135) (p < 0.01).
Long-term occupational exposure to low doses IR contributes to the development and increased frequency of specific CA (like dicentrics), but varies in relation to different working places. The majority of subjects had no other genetic modifications (non-specific chromosomal lesions) affected by low doses of IR.
比较职业性暴露于电离辐射（IR）的健康医务工作者与未暴露的健康人群中染色体畸变（CA）的发生率。
本研究为期4年，共纳入462名平均年龄42.3岁的职业性暴露于IR的受试者（暴露组-E）和95名平均年龄35.2岁、同期同地区未暴露于IR的受试者（对照组-C）。使用热释光剂量计（TLD）评估IR暴露情况。采用改良的Moorhead外周血淋巴细胞微量法和CA的传统细胞遗传学技术分析CA。通过油浸光学显微镜分析中期200个淋巴细胞的核型。
TLD测得的年平均吸收剂量在暴露于天然本底辐射的E组为14.5 mSv，C组为2.8 mSv。E组CA发生率为21.6%，C组为2.1%（p<0.05），而两组非特异性染色体病变（裂隙、断裂、伸长）发生率相同（22%）。在E组中，核医学工作者的发生率最高（42.6%），其次是骨科医生（27.08%）。E组和C组在异常细胞数量和CA总和方面存在高度显著差异（p<0.001）。E组中，CA总和及异常细胞数量与暴露持续时间呈正相关（p<0.001），与年龄的相关性较小（p<0.05）。在C组中，这种相关性为负且不显著。在E组中，职业暴露持续时间（DOE）达15年的受试者（E I亚组=327）与DOE超过15年的受试者（E II亚组=135）相比，异常细胞数量和CA显著较少（p<0.01）。
长期职业性低剂量IR暴露会导致特定CA（如双着丝粒）的发生和频率增加，但因工作场所不同而有所差异。大多数受试者未出现受低剂量IR影响的其他基因改变（非特异性染色体病变）。
