我国医用辐射及其防护标准体系的现状与展望

放射学以及介入放射学、临床核医学、放射肿瘤学等电离辐射的医学应用分支学科,已成为现代医学不可或缺的重要组成部分。医用辐射的发展,使得医用辐射防护成为辐射防护领域影响面最广的重要课题。医用辐射防护涵盖职业照射、医疗照射和公从照射的防护,同时也存在潜在照射防护问题。为有效加强医用辐射防护,必须建立并不断健全医用辐射防护标准３体系。     

上海市放射诊疗发展趋势与医疗照射防护研究

概要归纳与评述了国内外各类放射诊疗迅速发展的动态,以及所致医疗照射应用频率剧增的新进展;进而总结上海市"十一五"期间医疗照射水平调查研究所揭示的新趋势;据此分析提出有效强化医疗照射防护的五方面新启示。显然,X射线诊断、介入放射学、核医学、放射肿瘤学等放射诊疗已成为现代医学不可或缺的重要手段,同时也显著增加了公众因健康体检和疾病诊治需要而接受的各类医疗照射。上海市仅施行X射线诊断业务的医疗机构至2010年已增至1 279家,是1998年的2.1倍多;而拥有的X射线诊断设备总数增加了57.7%,其中X-CT净增131.9%。至2009年,X射线诊断的医疗照射年频率达780.44人次/千人口,比1996年增加58.3%;其中X-CT检查大幅度增加了317.1%。而2008年相比于1996年,临床核医学诊断和放射性核素治疗分别净增了139.4%和210.6%;肿瘤放射治疗则增加了59.9%。上海市率先在我国大陆31省、自治区、直辖市中自主开展了"十一五"期间医疗照射水平的调查研究,适时掌握了各类放射诊疗及其所致医疗照射的发展趋势,从而为有效加强医疗照射防护奠定了坚实基础;并且为合理规划与利用医疗资源提供科学依据;同时很有利于促进放射诊疗事业更加健康地发展以追求趋利避害而造福于民。     

ICRP放射防护基本建议书的演进及其启示

不断演进的国际放射防护委员会（ICRP）的基本建议书,具体阐述了各个历史时期放射防护的总指导方针与原则,是国际组织和世界各国制定放射防护法规与标准的基本依据。ICRP基本建议书的最新更迭是,2007年底出版的第103号出版物——《国际放射防护委员会2007年建议书》取代了其第60号出版物。本文从放射防护体系,防护体系的应用,权重因子和标称危险系数的更新,剂量评价方法,放射防护最优化,医疗照射防护,环境的放射防护等7方面介绍了2007年建议书的更新特点;同时,从更新取决于认识的深化,完善防护体系没有止境,区别对待是重要的防护方针,正确运用剂量限值,培植安全文化等5方面讨论了建议书不断演进的启示。     

国际基本安全标准关于医疗照射防护的新要求

由国际原子机构等６个国际组织共同倡议制定的国际基本安全标准，把医疗照射防护放在相当重要的地位。本文评述了该标准对医疗照射防护的主要要求。国际基本安全标准明确规定有关各方在保证患者防护与安全方面的职责，对医疗照射实施的正当性和防护的最优化提出一系列具体要求，首次用定量的医疗照射指导水平来约束放射诊断与核医学检查的剂量，还提出防范事故性医疗照射的原则等。认真研讨这些规定并紧密结合我国实际吸收应用，必将     

“医疗照射中的放射防护”专题介绍

由于医疗照射是公众所受到的非天然电离辐射中的最主要部分,而近几十年来新的放射性诊断和治疗设备不断出现,并且很快被投入临床使用之中,因此“医疗照射中的放射防护”专题成为了ＩＲＰＡ－１０大会的主要内容。会议中各国学者分别就在放射诊断学（包括介入放射学）、核医学和放射治疗临床工作中,病人与工作人员受照剂量的测量、降低其照射剂量的方法、对健康状况的评价、质量保证／控制工作等等问题发表了各自的论文并进行了广     

放射防护领域的新进展

根据国际辐射单位与测量委员会(ICRU)、联合国原子辐射影响科学委员会(UNSCEAR)和国际放射防护委员会(ICRP)等权威国际组织不断演进的新出版物,归纳揭示出电离辐射量体系、放射生物学效应和放射防护体系等构成放射防护三大重要基础的新进展;同时本文第四部分扼要评述影响面很广的热点课题医疗照射防护的新进展。     

“医疗照射中的放射防护”专题介绍

由于医疗照射是公众所受到的非天然电离辐射中的最主要部分,而近几十年来新的放射性诊断和治疗设备不断出现,并且很快地被投入临床使用之中,因此“医疗照射中的放射防护”专题成为了IRPA-10大会的主要内容。会议中各国学者分别就在放射诊断学(包括介入放射学)、核医学和放射治疗临床工作中,病人与工作人员受照剂量的测量、降低其照射剂量的方法、对健康状况的评价、质量保证／控制工作等等问题发表了各自的论文并进行了广泛的讨论。     

我国放射防护法规与标准体系的新进展

概述建立和健全放射防护法规与标准体系的重要性,总结了我国放射防护法规与标准体系的框架及其新进展。评述了迄今构成此体系主要的4个层次的《中华人民共和国职业病防治法》（2002年5月施行）和《中华人民共和国放射性污染防治法》（2003年10月施行）;《放射性同位素与射线装置安全和防护条例》（2005年12月施行）;《放射性同位素与射线装置安全许可管理办法）（2006年3月施行）和《放射诊疗管理规定》（2006年3月施行）;《电离辐射防护与辐射源安全基本标准》（GB18871-2002,2003年4月实施）等。这些法规与标准是我国放射防护基础结构建设的重要组成,对促进核科学与电离辐射技术的发展及其在各领域的广泛应用具有重要作用。     

“医疗照射中的放射防护”专题介绍

由于医疗照射是公众所受到的非天然电离辐射中的最主要部分 ,而近几十年来新的放射性诊断和治疗设备不断出现 ,并且很快地被投入临床使用之中 ,因此“医疗照射中的放射防护”专题成为了 IRPA-1 0大会的主要内容。会议中各国学者分别就在放射诊断学 (包括介入放射学 )、核医学和放射治疗临床工作中 ,病人与工作人员受照剂量的测量、降低其照射剂量的方法、对健康状况的评价、质量保证 /控制工作等等问题发表了各自的论文并进行了广泛的讨论。     

建立一个环境放射防护体系--来自核能机构辐射防护和公众健康委员会的贡献

1引言 放射防护的基本目的总是为公众和工作人员提供合适的标准,而不过分限制那些增加了辐射照射但能得到利益的实践.在过去的几十年里,开展了很多涉及电离辐射效应的研究工作,其范围从检测单个细胞的辐射效应到检测受不同辐射源照射的大的人群的辐射效应的流行病学研究.使用这些研究所获得的信息来估计辐射照射的后果,同时加以社会和经济的判断,国际放射防护委员会提出了一系列的建议书以构建一个合适的放射防护体系,并保证公众和职业照射工作人员的高标准防护.     

Preparation of Zn/TiO2 powder and its photocatalytic performance for oxidation of P-nitrophenol

Zn-doped TiO2 catalysts were prepared using a sol-gel method and characterized by XPS,UV-Vis, BET, XRD in this study. Under the irradiation of simulant sunlight, the photocatalytic activity for the degradation of p-nitrophenol was studied too. After irradiation for 2.5 h, the degradation percentage of p-nitrophenol could rise to more than 80 %. The results showed that the spectrum absorption band edge of Zn/TiO2 powder does not broaden obviously comparing with pure TiO2 powder. Zinc exists as Zn （11）. When calcined at 973 K, there is a new phase as ZnTiO3 in Zn/TiO2 catalyst. The order of photocatalytic activity of Zn/TiO2 catalysts calcined at different temperatures for p-nitrophenol is 773 K 〉 673 K 〉 873 K 〉 573 K 〉 973 K and the photocatalytic activity of Zn/TiO2 catalyst calcined at 773 K is better than TiO2 catalysts heated at the same temperature, and outclasses that of commercial TiO2 catalyst. It also showed that the photocatalytic degradation of p-nitrophenol follows first-order kinetics under the irradiation of simulant sunlight.     

Current status of radiation therapy for prostate cancer

Radiotherapy for the treatment of prostate cancer has been extensively explored in the past. Along with the comprehensive understanding of the biology of prostate cancer and rapid advances in terms of technology, the out- come of treatment for the patients with prostate cancer has improved. The authors review radiotherapy as the primary treatment for the disease, with particular emphasis on the technological advances from both the radiobiological and radiophysics aspects. Nonconventional fractionated irradiation like hyper- or hypo-fractionation has been imple- mented in the clinic, the final results still need to be confirmed in the future. Technological advances like IMRT, IGRT, in the last two decades have significantly improved the delivery of external radiotherapy to the prostate. This has re- sulted in an overall increase in the total dose that can be safely delivered to the prostate, which has led to modest im- provements in the biochemical outcome. However, establishing the standard therapy for prostate cancer remains con- troversial. It is hoped that the next decades will bring continued advances in the development of biologicals that will further improve current clinical outcomes.     

The control system for SSRF injection and extraction

This paper introduces the injection and extraction control system design for SSRF,which is a distributed control system aimed at stability and reliability of the pulse power supplies,PPS(Personnel Protection System)and MPS(Machine Protection System).The hardware environment is mainly based on PLC(Programmable Logic Con- troller),and ARM(Advanced RISC Machine)is also applied for studying stability of the power supplies.WinCC and EPICS(Experimental Physics and Industrial Control System)have been selected as the platforms of SCADA(Super- visory Control and Data Acquisition).For unifying the interfacing to the control computer,all front-end equipments are connected via Industrial Ethemet.     

水平管内含空气蒸汽强制对流冷凝换热模型研究

为研究含空气蒸汽在水平管内强制对流冷凝换热特性,基于对传热传质过程的分析,建立了管内为环状流与波状流条件下的流动冷凝换热模型。从潜热、显热和液膜3个环节对整个换热过程进行建模,最终得到计算局部冷凝换热系数的理论关系式。模型预测结果与实验数据的对比表明,二者相对偏差在±20%以内,验证了该换热模型的准确性与适用性。通过进一步的研究发现：从换热管入口至出口,随着冷凝的进行,管内换热主要热阻由液膜热阻向气液界面的凝结热阻转变;主流气体对流换热过程基本可忽略。     

Investigations on landmine detection by BF3 detector

Experiments were carried out to investigate the possible use of neutron backscattering for the detection of polyethylene (PE) sample buried in the soil. In detection of landmine by neutrons, the neutron detector and its shield play an important role. In this paper, the effects of graphite, heavy water, polyethylene and boric acid moderators on the flux of back scattered neutrons were investigated. We have also experimentally verified the effect of BF3 detector shield and obtained good agreement with theory.     

Web Services interface of SSRF archive data analysis system

Accelerator database stores various static parameters and real-time data of accelerator. SSRF (Shanghai Synchrotron Radiation Facility) adopts relational database to save the data. We developed a data retrieval system based on XML Web Services for accessing the archive data. It includes a bottom layer interface and an interface applicable for accelerator physics. Client samples exemplifying how to consume the interface are given. The users can browse, retrieve and plot data by the client samples. Also, we give a method to test its stability. The test result and performance are described.     

有效探测面积大于1000 cm2的正比计数器测量系统性能测试

为对自制的活性面积高达1 000 cm²的大面积源进行表面发射率定值,同时作为现有2πα、2πβ表面发射率标准装置能力的扩充,研制了一套内置式大面积2π多丝正比计数器测量系统,并利用活性区直径为8 mm的²⁴¹Am点源及活性区面积为10 cm×15 cm的大面积²⁴¹Am和⁹⁰Sr-⁹⁰Y源对其进行计量学性能测试。结果表明：计数器内计数响应均匀性优于±0.4%,有效探测面积达1 400 cm²;所得²⁴¹Am源高压坪曲线的坪长为1 400 V,坪斜为0.27%/100 V,坪区内计数变化为0.87%;⁹⁰Sr-⁹⁰Y源高压坪曲线的坪长为300 V,坪斜为0.75%/100 V,坪区内计数变化为0.80%;10次测量重复性好于0.4%,8 h内短期稳定性好于0.3%,1 a内长期稳定性好于0.8%。     

Assessment of radioactivity levels in some oil samples from the western desert, Egypt

Distributions of natural gamma-emitting radionuclides were determined in 93 oil samples collected from some petroleum fields in the western desert of Egypt. The radioisotope activities in the area under investigation lay in the range of (21 ± 4) to (38 ± 13) Bq?L-1 for 226Ra, (9 ± 2) to (15 ± 5) Bq?L-1 for 232Th, and (154 ± 28) to (303 ± 54) Bq?L-1 for 40K. The mean values were 27, 12, and 201 Bq?L-1, respectively. Among oils, variations in radionuclide ac- tivities could be on account of differences in TDS, HCO3, and Ba, with high or low pH. In this environment, oil prop- erties differently affected the mobilization of natural radionuclides. The range of 226Ra variation had been compared with available data from other countries. The calculated absorbed dose rate ranged from 22.33 to 32.66 nGy?h-1 in lo- cation (B) and (E) respectively, which was less than the accepted value.     

Preparation and properties of 117m Sn(IV)-TTHMP in in-vitro and in small animals

In this work,TTHMP was synthesized and labelled with 117m Sn.The preparation conditions,stability and lipophilicity of 117m Sn(IV)-TTHMP were investigated.Biodistribution of the complex in rabbits and mice was studied.It was found that the quantity of TTHMP and pH value of the prepararion solution had vital effects on the labeling yield of 117m Sn(IV)-TTHMP.It was also found that 117m Sn(IV)-TTHMP was hydrophilic and stable at room temperature and 37℃ in open air 117m Sn(IV)-TTHMP showed unexpectedly high bone uptake and bone-to-blood ratio in the animals.This made it potentially useful as an reagent for skeletal scintigraphy and radiotherapy of bone tumors.     

The role of AGFA high-energy CR in the calibration and quality control of multileaf collimators （MLC）

Linear accelerators equipped with multileaf collimators （MLC） are becoming more common and are widely used in the intensity-modulated radiotherapy （IMRT）. There is an imperative need to ensure the commissioning specification of the linear accelerators for the sake of quality assurance （QA） and quality control （QC）. This paper is aimed to investigate the role of AGFA high-energy CR （Computed Radiography） in calibrating dynamic multileaf collimators and evaluating the accuracy of the leaf position. The result shows that AGFA high-energy CR can easily and conveniently be used to calibrate MLC and verify its position. Hence, the application of AGFA high-energy CR is proved to be an accurate and time-saving method for routine MLC QC, especially when MLC calibration adjustments are required.