电离辐射和非电离辐射复合作用的生物学效应

在现实环境中，我们有时可能受到的不止是1种而是2种或多种环境因素的影响，因此，在积极探讨电磁波损伤的规律与机制的同时，电磁波与其他形式的损伤因子，比如与低温、缺氧、射线等的复合效应，也渐渐引起人们的关注，在军事领域，有专家甚至提出了电磁复合伤的概念。其中，电离辐射和非电离辐射的复合效应尤为引人瞩目。     

医用辐射源放射事故的应对

阐述了核事故和放射事故的发生及其危害,列举了医疗应用中的放射事故,分析了放射事故的原因,后果及其对策。     

电离辐射对放射工作人员细胞遗传学的影响

目的 通过对放射工作人员辐射剂量进行监测,探讨电离辐射对放射工作人员细胞遗传学的影响.方法 采用流行病学中队列研究的方法,选取唐山市内1 392名放射工作人员作为观察组,选取无射线接触史且其他条件与观察组具有可比性的143名身体健康者为对照组.分别行一般情况调查、放射剂量测量、微核检测、染色体畸变检测.结果 放射线接触组微核率和染色体畸变率均明显高于对照组.按不同工种分组,观察组微核率和染色体畸变率依照医学放射诊断组、工业探伤组、工业用放射源组、医学放免放疗组的次序呈现出一定程度的递增趋势.按不同工龄分析,＜10、10～ 20和＞20a工龄组的放射工作人员细胞微核异常率分别为10.8％、16.2％、24.8％,对照组为2.1％,差异均有统计学意义(P ＜0.05或0.01);染色体畸变异常率亦随放射工龄的增加而升高.差异均有统计学意义(P＜0.05).随着累积辐射剂量的增加,放射工作人员累积微核异常率、累积染色体畸变异常率也随之增加.结论 电离辐射对放射工作人员健康状况产生一定程度的影响,淋巴细胞微核率和染色体畸变率将会有所增高.从事不同放射工种的放射工作人员受到的辐射损伤不同,放射工作人员受到的辐射损伤与接触射线年限有关,放射工龄越长,累积电离辐射剂量越高,细胞微核率和染色体畸变率越高,其对机体造血系统的损伤越严重,细胞微核率、染色体畸变率与累积辐射剂量均具有一定程度的关联.     

Small doses of ionizing radiation as radiation modifying factor

To investigate the biological effects of small dose ionizing radiation has been acquiring greater importance. The awareness of how and in what direction it show its modifying effects in small doses is an essential scientific basis for developing standards, living conditions under specific environmental conditions. Cultured Hela cells and DEF 4/21 fibroblasts were used to evaluate the biological effects of small-dose ionizing radiation, by examining the conditions under which it showed its modifying effect in small doses (0.1 Gy) in particular. Preexposure to small-dose radiation was shown to alter cell responses to subsequent radiation in large doses. The modifying effects of small-dose radiation turned out to depend on the interval of exposure to small and large doses. Sensitization was recorded at an interval of 2-3 min; an adaptive response was achieved when the interval increased up to 3-5 hours. Upon exposure, intercellular contacts contribute to the modifying effects of small-dose radiation. There was neither effect of sensitization nor adaptive response if single cells were exposed to radiation.     

低剂量电离辐射对放射工作人员细胞遗传学影响

目的 分析低剂量电离辐射对放射工作人员细胞遗传学影响.方法 采用放射场所辐射剂量、个人剂量、细胞遗传学指标检测及流行病学横断面调查研究方法.结果 射线接触组染色体畸变率(0.16%)高于对照组(0.04%),染色体畸变检出率(17.05%)高于对照组(5.1%),微核率(1.0‰)高于对照组(0.2‰),微核检出率(48.06%)高于对照组(12.25%),差异均有统计学意义(x2=8.45,P＜0.01;x2=7.59,P＜0.01;x2=57.23,P＜0.01;x2=32.52,P＜0.01);不同年剂量、累积剂量组染色体畸变率、微核率与对照组比较,差异均有统计学意义;随着个人年剂量、累积剂量水平的增加,染色体畸变率、微核率、微核阳性检出率有增高趋势.结论 长期低剂量电离辐射,对淋巴细胞产生的辐射效应导致的染色体畸变率、微核率的增加并与放射人员个人累积吸收剂量密切相关.     

放射工作人员的辐射防护及健康管理情况调查

目的调查和分析放射工作人员的辐射防护及健康管理情况,为辐射防护及健康管理的开展提供参考资料。方法对84名在读继续教育专升本的放射工作人员,采用自行设计问卷,包括一般资料,安全管理制度、防护用品、辐射安全监督认知情况及致病情况、辐射防护培训、健康管理等开展调查,并对问卷结果进行简要的统计学分析。结果医疗机构证照齐全,辐射防护用品达到89.86%以上,非查部位防护屏蔽为84.06%,辐射安全监督岗位设置、质保和专兼职安全防护人员方面均为68.12%,放射保健津贴66.67%、放射保健休假75.36%,其他方面数据均达到85%以上。结论各级医疗机构基本上能够贯彻辐射防护的政策法规,放射工作人员的辐射防护及健康管理得到有力的保障,但仍需要进一步加强核安全文化素养的教育。     

Deconstructing radiation hormesis

This paper explores some factors that may explain why the possibility of hormesis has not been embraced by the radiation protection community. If shown to be sustainable, hormesis might ameliorate several serious issues plaguing radiation protection including the high economic cost of environmental regulatory compliance and public fear of radiation exposure. Some but not all analyses of data from various sources, including the Japanese survivors of the atomic bombs and residential radon studies, suggest that low levels of ionizing radiation may be beneficial to human health. The evidence, however, has not been viewed as compelling for the following reasons: (1) Data in support of radiation hormesis in human populations is limited and much of it is based on re-evaluation of selected epidemiological data that has been used to test a different hypothesis; (2) Hormetic effects are weak and inconsistent, and are subject to large statistical uncertainties as is the case for carcinogenic effects at small doses; (3) A consensus is lacking on how hormesis should be defined and quantified; and (4) It is unclear how hormesis can be incorporated into the regulatory framework when beneficial health effects exceed the requirement for protection of health.     

回旋加速器辐射防护

本文介绍了几点回旋加速器在机房设计、安装、使用时应该加强的辐射防护知识.     

New technologies in radiation therapy: ensuring patient safety, radiation safety and regulatory issues in radiation oncology

New technologies such as intensity modulated and image guided radiation therapy, computer controlled linear accelerators, record and verify systems, electronic charts, and digital imaging have revolutionized radiation therapy over the past 10-15 y. Quality assurance (QA) as historically practiced and as recommended in reports such as American Association of Physicists in Medicine Task Groups 40 and 53 needs to be updated to address the increasing complexity and computerization of radiotherapy equipment, and the increased quantity of data defining a treatment plan and treatment delivery. While new technology has reduced the probability of many types of medical events, seeing new types of errors caused by improper use of new technology, communication failures between computers, corrupted or erroneous computer data files, and "software bugs" are now being seen. The increased use of computed tomography, magnetic resonance, and positron emission tomography imaging has become routine for many types of radiotherapy treatment planning, and QA for imaging modalities is beyond the expertise of most radiotherapy physicists. Errors in radiotherapy rarely result solely from hardware failures. More commonly they are a combination of computer and human errors. The increased use of radiosurgery, hypofractionation, more complex intensity modulated treatment plans, image guided radiation therapy, and increasing financial pressures to treat more patients in less time will continue to fuel this reliance on high technology and complex computer software. Clinical practitioners and regulatory agencies are beginning to realize that QA for new technologies is a major challenge and poses dangers different in nature than what are historically familiar.     

适形放射治疗后肝损伤的CT表现

目的对原发性肝癌适形放疗后的患者进行CT平扫或增强扫描,观察肿瘤区周围正常肝组织的影像表现,以发现其特征,为与适形放疗后病灶未控或复发提供鉴别依据。方法30例单发肝癌患者采用了适形放疗,36～48Gy8～12次,隔日1次。1～3个月后开始CT复查。结果肿瘤周围15例平扫表现为低密度;增强扫描:无强化,6例;动脉期为低密度,门脉期或延迟期呈强化状态,2例;早期至延迟期均强化,2例。结论照射后,高剂量区CT可表现为低密度,可以出现强化,特征为进行性或持续性强化。     

IAEA activities related to radiation biology and health effects of radiation

The IAEA is involved in capacity building with regard to the radiobiological sciences in its member states through its technical cooperation programme. Research projects/programmes are normally carried out within the framework of coordinated research projects (CRPs). Under this programme, two CRPs have been approved which are relevant to nuclear/radiation accidents: (1) stem cell therapeutics to modify radiation-induced damage to normal tissue, and (2) strengthening biological dosimetry in IAEA member states.