对计划照射中个人剂量约束的理解

基于对计划照射中个人剂量约束概念的理解,讨论了个人剂量约束在公众照射和职业照射中的应用。在计划照射情况下,公众照射的剂量约束值通常由国家监管机构建立或批准;对于职业照射,鼓励在核能行业组织和核能集团内建立职业照射个人剂量约束值,比审管部门规定具体的约束值可能更合适。     

Release of patients after therapy with unsealed radionuclides

After some therapeutic nuclear medicine procedures with unsealed radionuclides, precautions may be needed to limit doses to other people, but this is rarely the case after diagnostic procedures. Iodine-131 results in the largest dose to medical staff, the public caregivers, and relatives. Other radionuclides used in therapy are usually simple beta emitters (e.g. phosphorus-32, strontium-89, and yttrium-90) that pose much less risk. Dose limits apply to exposure of the public and medical staff from patients. Previously, the ICRP has recommended that a source-related dose constraint for optimisation of a few mSv/episode applies to relatives, visitors, and caregivers at home, rather than a dose limit. The present report recommends that young children and infants, as well as visitors not engaged in direct care or comforting, should be treated a s members of the public (i.e. be subject to the public dose limit.) The modes of exposure to other people are: external exposure; internal exposure due to contamination; and environmental pathways. Dose to adults from patients is mainly due to external exposure. Contamination of infants and children with saliva from a patient could result in significant doses to the child's thyroid. It is important to avoid contamination of children and pregnant women. After radioiodine therapy, mothers must cease breastfeeding immediately. Many types of therapy with unsealed radionuclides are contraindicated in pregnant females. Women should not become pregnant for some time after radioisotope therapy. Technetium-99m dominates discharges to the environment from excreta of nuclear medicine patients, but its short half-life limits its importance. The second largest discharges, iodine-131, can be detected in the environment after medical uses but with no measurable environmental impact. Storing patient's urine after therapy appears to have minimal benefit. Radionuclides released into modern sewage systems are likely to result in doses to sewer workers and the public that are well below public dose limits. The decision to hospitalise or release a patient should be determined on an individual basis. In addition to residual activity in the patient, the decision should take many other factors into account. Hospitalisation often involves a significant psychological burden as well as monetary and other costs that should be analysed and justified. Patients travelling after radioiodine therapy rarely present a hazard to other passengers if travel times are limited to a few hours. Environmental or other radiation-detection devices are able to detect patients who have had radioiodine therapy for several weeks after treatment. Personnel operating such detectors should be specifically trained to identify and deal with nuclear medicine patients. Records of the specifics of therapy with unsealed radionuclides should be maintained at the hospital and given to the patient along with written precautionary instructions. In the case of death of a patient who has had radiotherapy with unsealed radionuclides in the last few months, special precautions may be required.     

公众成员某些放射性核素的食入剂量系数

本文根据ＩＣＲＰ６７号出版物，列出了４６个放射性核素对于３个月婴儿，１、５、１０、１５岁儿童和成人的食入剂量系数，这些核素都是由于人类的活动可能释放到环境中去的具有辐射防护意义的核素。文中还就核素在胃肠道中的吸收分数ｆ＿１、组织权重因子Ｗ＿Ｔ，及生物动力学数据等因素对剂量系数的影响进行了初步讨论。     

核电厂正常运行放射性流出物对婴儿的食入剂量研究

由于有时核电厂址附近自然村婴儿膳食谱的缺乏,使评价核电厂放射性流出物对婴儿的辐射环境影响缺乏完整性。本文参考国际原子能机构(IAEA) 19号报告和国际放射防护委员会(ICRP) 95号报告计算婴儿食入母乳所受的辐射剂量,给出一套婴儿辅食合理的通用膳食谱。研究表明,参考IAEA 19号报告的方法将使评价结果偏小,失去保守性,参考ICRP 95号报告方法更为合理可行。     

ICRU 95号报告:外照射实用量及其对剂量学的影响（英文）

国际放射防护委员会(ICRP)提出了“防护量”这一概念。最常用的防护量,即有效剂量E,用于设定照射限值,并在实用辐射防护中使用,以实现最优化原则。然而,有效剂量不是一个可测量的量,基于此国际辐射单位与测量委员会(ICRU)为外照射的剂量测定提出了一个可测量的量,即实用量,用于估计有效剂量。目前使用的实用量定义于20世纪80年代,当时核工业是职业辐射防护的主要关注点。当前,在其他辐射领域,特别是高能辐射,实用量的不足之处变得很明显：可能高估或低估有效剂量。因此,ICRU和ICRP在全面研究的基础上,为外照射的剂量测定提出了新的实用量,以克服上述缺点。实用量的新定义与防护量(包括有效剂量)的定义更具相关性,特别是使用了相同的仿真体模。当前提出的实用量通过缩小防护量与实用量之间的定义差异简化了辐射防护量体系,并从整体上改进了对有效剂量的估计。本文讨论了提出的新实用量对实际剂量测定的影响。     

空间质子辐射有效剂量测量的闪烁探测器理论设计

有效剂量可解决航天员在空间飞行中所受质子辐射的危害比较与评价问题,在空间辐射危害评价中具有重要应用。为实现空间质子辐射有效剂量监测,针对空间各向同性质子辐射,利用蒙特卡罗程序设计了一种闪烁探测器。通过对探测器结构的特殊设计,在20-400 Me V能量范围内,各向同性质子在该探测器内沉积的能量与国际辐射防护委员会(International Commission on Radiological Protection,ICRP)116号报告提供的质子有效剂量基本成正比。通过探测质子沉积能量来监测质子辐射有效剂量,克服了直接测量有效剂量所存在的困难。对AP8MIN模型地球俘获带质子能谱与随机抽样质子辐射能谱,经数值计算,探测器给出的有效剂量与ICRP116号报告给出的有效剂量的相对偏差均小于±8%。     

Estimation of Radiation Dose with Radionuclides in Nuclear Medicine Application

To study the level of radiation dose on nuclear medicine of radionuclides with estimation method. We chose some diagnostic and therapeutic radionuclide to estimate the dose of internal radiation and external exposure with the estimation model of the dose coefficient method and point source. The results showed that the effective dose that patient suffered in a single diagnostic CNM procedure was up to 1.63 Sv; the single effective dose that A and B medical staffs suffered were 1.48 μSv and 1.15 μSv. The dosage level of some part of Diagnostic radionuclide beyond medical guidance level. The estimation results was slightly larger than the measured effective dose, less than other estimation. Combined with the actual situation, the estimation model can be used as an effective estimation method of the radiation dose level of nuclear medicine radionuclide.     

放射性核素在核医学应用中的辐射剂量估算

采用一种估算方法来研究放射性核素在核医学应用中的辐射剂量水平。选取临床上常用的几种诊疗用放射性核素,分别采用剂量系数法和点源模型估算内照射与外照射剂量。并对比其他估算方法,分析受照剂量存在差异的原因。结果发现,单次核医学诊断所致患者的全身待积有效剂量最高可达1.63 Sv,对A、B类医护人员造成的单次有效剂量分别为1.48 μSv和1.15 μSv。本研究估算结果稍大于实测有效剂量,小于其他估算结果。该估算模型可作为核医学放射性核素辐射剂量水平的一种有效估算方法。     

Protection of the public in situations of prolonged radiation exposure. The application of the Commission's system of radiological protection to controllable radiation exposure due to natural sources and long-lived radioactive residues

This report provides guidance on the application of the ICRP system of radiological protection to prolonged exposure situations affecting members of the public. It addresses the general application of the Commission's system to the control of prolonged exposures resulting from practices and to the undertaking of interventions in prolonged exposure situations. Additionally, it provides recommendations on generic reference levels for such interventions. The report also considers some specific situations and discusses a number of issues that have been of concern, namely: natural radiation sources that may give rise to high doses; the restoration and rehabilitation of sites where human activities involving radioactive substances have been carried out; the return to 'normality' following an accident that has released radioactive substances to the environment; and the global marketing of commodities for public consumption that contain radioactive substances. Annexes provide some examples of prolonged exposure situations and discuss the radiological protection quantities, radiation-induced health effects and aspects of the Commission's system of radiological protection relevant to prolonged exposure. Quantitative recommendations for prolonged exposures are provided in the report. They must be interpreted with extreme caution; Chapters 4 and 5 stress the upper bound nature of the following values: Generic reference levels for intervention, in terms of existing total annual doses, are given as < approximately 100 mSv, above which intervention is almost always justifiable (situations for which the annual dose threshold for deterministic effects in relevant organs is exceeded will almost always require intervention), and < approximately 10 mSv, below which intervention is not likely to be justifiable (and above which it may be necessary). Intervention exemption levels for commodities, especially building materials, are expressed as an additional annual dose of approximately 1 mSv. The dose limit for exposures of the public from practices is expressed as aggregated (prolonged and transitory) additional annual doses from all relevant practices of 1 mSv. Dose constraints for sources within practices are expressed as an additional annual dose lower than 1 mSv (e.g. of approximately 0.3 mSv), which could be approximately 0.1 mSv for the prolonged exposure component. An exemption level for practices is expressed as an additional annual dose of approximately 0.01 mSv.     

An optimal model of the representative habit data for complex environmental exposure systems

The concept of the representative person recommended by the International Commission on Radiological Protection (ICRP) is difficult to apply to dose assessment to the public because the representative habit data could not be determined in advance for general radiation exposure situations. So, a stylized method for constructing habit data of the representative person is needed to ensure consistency and validity of the dose estimation. This paper presents a generalized model of the representative habit data based on optimization by a linear programming technique to handle complex environmental exposure situations such as radioactive waste disposal. The model is devised in such a way that it can fully embody the ICRP's criteria for the representative person by ensuring the upper 5% exposure in the population and it is applicable to general exposure systems. The model was illustrated for Korea's low- and intermediate-level radioactive waste disposal system to show its applicability to complex exposure systems with multiple scenarios and pathways.     

居民由食物所致内剂量估算方法

环境放射性包括天然和人工放射性核素两类。食品是环境放射性进入人体主要途径之一,涉及的人群是比放射性职业人员大得多的广大居民。监测食品环境放射性污染对居民危害过去是依据关键器官的剂量当量率,按ICRP新基本建议书,则是依据有效剂量     

一例239Pu内污染者的剂量评价

ICRP66、67号出版物中对内照射剂量估算中使用的呼吸道模型和Pu在人体内代谢模式进行了较大的修改。本文应用ICRP66、67号出版筇的推荐的Pu在人体内的代谢模型及参数及新呼吸道模型,估算了一例^239Pu内污染者的摄入量和待积有效剂量。     

空勤人员辐射剂量的估算与测定

1991年,ICRP建议将空勤人员列入职业受照人群;2002年,我国颁布实施了《空勤人员宇宙辐射控制标准》。本文介绍航空飞行高度上的辐射环境及空勤人员辐射剂量的估算方法和常用的测量手段,并比较了不同方法的计算和测量结果。     

Annals of the ICRP. A report of: doses to infants from ingestion of radionuclides in mothers' milk

In the present report, ICRP provides information on radiation doses to the infant due to intakes of radionuclides in maternal milk. As in Publication 88 (ICRP, 2001) on doses to the embryo and fetus following intakes of radionuclides by the mother, intakes by female members of the public and female workers are addressed. Acute and chronic intakes are considered at various times before and during pregnancy as well as during the period of breastfeeding. Dose coefficients per unit intake by the mother (Sv/Bq) are given for the selected radionuclides of the same 31 elements for which age-specific biokinetic models were given in Publications 56, 67, 69, and 71 (ICRP, 1989, 1993, 1995a,b). For these elements, doses were calculated for the most radiologically significant natural or artificial radionuclides that might be released into the environment due to various human activities. Dose coefficients are also given in this report for radionuclides of an additional four elements: sodium, magnesium,phosphorus, and potassium. Relevant human and animal data on elemental and radionuclide transfer to milk are reviewed. The biokinetic models for adults given in earlier ICRP publications are adapted to include transfer to milk. Model predictions of fractional transfer of ingested or inhaled activity to milk are discussed in the report, and the corresponding dose coefficients for the infant are compared with dose coefficients for in utero exposure, as given in Publication 88 (ICRP, 2001). Illustrative information is also given on doses to the female breast from radionuclides in breastmilk, and external doses received by the child from radionuclides retained in the tissues of the mother. For the additional elements considered in this report, but not in Publication 88 (ICRP,2001), information is also given on doses to the embryo and fetus following maternal intakes of radioisotopes during or before pregnancy. A CD-ROM is to be issued giving data that will supplement the information given in this report. In addition to the dose coefficients given here, committed equivalent doses to the various organs and tissues of the offspring will be given. Dose coefficients will also be given for inhalation of a range of aerosol sizes for the selected radionuclides of the elements covered by this report.     

美国联邦法规10 CFR 50附录Ⅰ的修订方案及对我国辐射防护审管的启示

本文详细介绍了美国核管理委员会(NRC)对轻水堆的设计目标基准的修订方案和策略,并在此基础上,考虑到我国核电厂址向内陆发展所致公众照射途径的变化,提出了需要明确核动力厂设计目标值的建议,以及应用现行辐射防护相关标准需要关注的问题:(1)ICRP第103号出版物从以前基于过程的实践和干预的方法发展为基于辐射照射情况性质(计划照射、应急照射和现存照射)的方法,应当注意区分不同的照射情况;(2)ICRP第103号出版物在数值上更新了当量剂量和有效剂量的辐射权重因子和组织权重因子,因此,实施剂量评估所采用的剂量转换因子也需要更新。     

Radiation protection lessons learned from the TEPCO Fukushima No.1 NPS accident

Lessons learned from the TEPCO Fukushima No.1 NPS accident are discussed from the viewpoint of radiation protection in the situation of nuclear emergency. It became clear from the discussion that the protective measures should be practiced by taking into account the time profiles of the radiological disaster after the nuclear accident and that the land and coastal sea areas monitoring had to be practiced immediately after the nuclear accident and the communication methods to tell the public about the radiation information and the meaning of protective measures should be developed for mitigation of the sociological aspects of disaster impacts. And it was pointed out from the view point of practicing countermeasures that application of the reference levels, above which it was judged to be inappropriate to plan to allow exposure to occur, played an important role for practicing protective measures in an optimized way and that the quantities and units used for quantifying radiation exposure of individuals in terms of radiation doses have caused considerable communication problems. Finally, the occupational exposures and the public exposures that have been reported so far are shown, and it is concluded that there is no conclusive evidence on low dose exposures that would justify a modification of the radiation risk recommended by the International Commission on Radiological Protection.     

应急照射情况的防护

国际原子能机构(IAEA)在国际放射防护委员会(ICRP)第103号建议书的基础上,完成了《国际电离辐射防护与辐射源安全基本标准》(IBSS)的修订并于2014年发布,原来的实践与干预体系改变为现在的计划照射、应急照射和现存照射三种照射情况。关于应急照射情况的要求主要有:根据与源有关的辐射危险的性质和规模制定应急计划、应急程序和应急安排;参考水平用于应急照射情况下的防护和安全最优化;政府须确保建立和维护一个综合并协调的应急管理体系;对于公众照射,政府须确保在规划阶段制定防护策略并使其正当化和最优化;政府须制定关于管理、控制和记录应急人员在紧急情况下所受剂量的计划。IAEA保护人类和环境安全标准GSR第七部分《核与辐射应急准备和响应安全标准》是基于原安全标准丛书GS-R-2(2002)和IBSS修订发布的,本文给出了在要求、术语、概念等方面的变化。我国现行标准《电离辐射防护与辐射源安全基本标准》等效采用了1996版IBSS,在参考水平、公众应急防护行动准则、应急工作人员的受照控制等方面都与新IBSS不同,应及时开展研究并修订我国标准。     

Age-dependent dose conversion coefficients for external exposure to radioactive cesium in soil

To estimate effective doses for members of the public exposed to external radiation from radioactive cesium (¹³⁴Cs and ¹³⁷Cs) deposited on the ground by the Fukushima nuclear accident, we calculate the conversion coefficients for converting activity concentration to effective dose rate by using the Particle and Heavy Ion Transport Code System. The data were produced from different age groups within the public (newborns; 1-, 5-, 10-, and 15-year-old children; and adults) for the situations in which radioactive cesium is distributed uniformly in the soil over a planar area and at specific depths of 0.0, 0.5, 2.5, 5.0, 10.0, and 50.0 g/cm². On the basis of the results, we also derive the conversion coefficients for exponentially distributed volumetric sources. In addition, we obtain the conversion coefficients that give the effective dose accumulated over the first and second months, the first year, and over a lifetime (50 years) because of the contamination remaining on the ground. These calculations indicate that the conversion coefficients to obtain the effective dose rate are higher for the younger ages compared with adults, but do not exceed the ambient dose equivalent rate. Furthermore, we find that the difference between the calculated effective dose rates according to the International Commission on Radiological Protection 1990 and 2007 Recommendations is small (7% maximum) for a ground contamination of radioactive cesium.     

TLD应用于核模拟辐射剂量测量的几个有关问题

对热释光剂量在核模型辐射剂量测量中所遇到的高剂量率,大剂量,高能量,低能量等特殊情况,谈了对这些问题的考虑及采取的措施。