【作者】 张烜；

【导师】 周宝森；

【作者基本信息】 中国医科大学 ， 流行病学与卫生统计学， 2004， 硕士

【摘要】 前言 电离辐射的医学应用中，职业暴露具有低水平、持续性的特点，流行病学研究揭示暴露于职业照射的人群恶性肿瘤如白血病、皮肤癌等发病风险较高。近年来介入放射学迅速发展，因其操作特殊性不易采取放射防护措施而使职业人员剂量负荷增加，目前国外有报道超剂量照射导致介入放射工作人员身体损害的事件，而国内研究对该人群职业效应尚未给予足够关注。借助细胞遗传学手段，观察职业人员的生物细胞遗传毒性效应，可以反映辐射所致随机性效应的风险以及个体对辐射的敏感度。因此，调查该人员职业暴露水平现状，研究其潜在或已导致的生物效应风险，以及二者之间的关系，对于保护职业人群健康、制定采取辐射防护措施、控制潜在照射危险、促进电离辐射医学实践的正当化有着重要的意义。 方法 采用现场模拟实时测试和热释光剂量计测量方法相互补充，调查和估算职业暴露水平；采用外周血淋巴细胞微核率等指标评价辐射所致细胞遗传毒性效应。经过整群抽样，选取辽宁省开展介入放射工作的省级医院的189名放射工作人员作为研究对象，利用多元逐步回归等统计学方法研究职业暴露水平和细胞遗传学指标的关系。 结果 1、暴露水平调查 通过对抽样的医疗单位现场调查测试，采用现场模拟实时测试和热释光剂量计测量的两种方法结果基本一致，可根据实际情况和研究需要加以选择。本研究给出了各主要部位平均水平并进行了归一化，其中以手部的剂量水平为最高。最近连续两年的个人剂量监测结果显示，介入放射工作者暴露水平显著高于其他医学放射工作者，平均水平相差近十倍。介入放射学职业暴露水平的复杂性表现在两个方面:①不同使用场所、不同操作方式、不同设备、不同工种之间个体接受的剂量水平不同;②对单一个体而言，躯体各器官或各部位(如眼晶体、左右手、下肢等)剂量水平不同。 2、暴露效应研究 ’在辐射效应的研究方面，白细胞计数、眼晶体检查等生理指标和体征未提示介人放射工作者和其他医学工作者间存在明显差异，微核试验结果揭示二者间显著差异，但未发现其明显的剂量反应关系。通过对不同性别间暴露水平和微核试验结果的比较，提示女性微核试验对辐射更为敏感;多元回归结果提示，年龄因素也对微核形成有一定促进作用。讨论 本实验所研究的介人放射学工作者其职业暴露水平显著高于普通医学放射工作者，但暴露水平低于国内报道的一般水平，这是由于本实验所抽取的研究对象为省级较大规模的医疗单位，放射防护管理和措施较为得力。据笔者分析，介人放射职业人群总体中暴露水平差异很大，介人放射学职业暴露整体情况较为严峻，因此对其应给予高度关注，尽快采取措施进行干预，控制和降低暴露水平，减少恶性职业疾患的发生。本实验中，介入放射学工作者微核率显著高于非介人工作者，但研究对象暴露水平与微核试验结果的剂量反应关系不明确，有可能是在低剂量水平下，众多的混杂因.素的干扰作用影响较大所致。经统计学分析，女性微核试验对辐射较男性敏感，随年龄增加，微核率也有上升趋势。但利用微核试验评价辐射所致危害效应是可行的，并且该指标还可以反应出个体对辐射的敏感性以及其他因素对辐射效应的联合作用，应进一步研究其它因素的影响作用。结论1、介人放射学工作者职业暴露水平显著高于其他医学放射工作者，应予重点关注2、微核率在不同剂量暴露水平中有显著差异，但剂量反应关系不明显3、女性微核试验对电离辐射较为敏感，微核率与年龄正相关。更多还原

【Abstract】 IntroductionThe occupation exposure which arises from ionizing irradiation in medicine is in low level and durative. It was suggested that the occupation exposure population have a higher risk in malignancy such as leukaemia and dermal cancer by epidemiological studies. While intervention radiology has developed rapidly, occupation exposure has increased without effective radiation protection measures due to the particularity of operations. It was reported that injuries to intervention radiologist occurred in excessive dosage exposure overseas, but the domestic research has not given enough attention to the occupational health effect. With the aid of the cytogenesis method, observations of cell genetic toxic effects in occupation population may reflect the risk of stochastic effect from radiation as well as the individual radiosensitivity. So, it is important to investigate the latent or existent biological effect of the occupation exposure and the relations among them regarding the protection occupation crowd health, radiation protection measure established, latent radiation danger controlling, ionization radiation practice promotion in medicine.MethodUsing real -time simulated survey on the scene and thermoluminescent do-simeters (TLD) measuring technique, occupation exposure level was investigated. Micronucleus (MN) assay in peripheral lymphocyte was used to appraise cell genetic toxic effect from ionizing radiation. 189 radiation workers from large - scale hospitals in Liaoning Province was cluster sampled to study the relation between occupation exposure dose and cytogenetie index by multi - varianceslinear regression.ResultReal - time simulated survey on the scene is close to TLD dose meter measuring result. Dosage in several positions was calculated and modified to unitary. It showed that hands received the most dosage than other organs. The dosage of intervention radiologists was nearly ten times higher than the other radiologists. The complexity of exposure dosage in intervention radiologists can be shown in two aspects: (1) the difference of individual dosage varies in different places, operative methods, equipments and the types of work; (2)the dosage of different organs and parts of body (e. g. lens, hands, lower limbs) varies individual-iy- ’ .White blood cell counting and eye lens checking did not indicate significant difference between intervention radiologists and other radiologists, but MN assay did, although no significant dose - effect relation was shown. Dosage and MN frequency comparison between male and female indicated MN assay was more sensitive in female. Multi - variance linear regression showed MN frequency was related to age.DiscussionIn this study, the exposure dosage of intervention radiologist was significantly higher than other radiologist, but it is generally lower than other studies in China. The reason was that the sample objects in this study were picked from large - scale hospital in which more effective measure was carried out for radiation protection. In fact, the radiation exposure on intervention radiologists was more serious, measure should be taken to control and decrease exposure dosage. In this study, MN frequencies in intervention radiologists was significantly higher than non - intervention radiologists. However, the relation between exposure level and MN frequency was not well defined. It may be caused by greater disturbance of many confused factors in lower dosage level. According to the resultsof statistical analysis, the response to MN assay is more sensitive in female than in male. With the increase of age, the MN frequency tends to increase. It is advisable to evaluate the harm caused by radiation with MN assay. And this index can also be used to reflect the individual radiosensitivity and the combined effect of other factors. Further study is needed to evaluate the effects of other factors.Inclusion1. Occupational exposu更多还原