用GR-200A热释光探测器测量医用高能电子线剂量

目的 为掌握GR-200A热释光探测器对电子线剂量测量的最佳条件,了解该探测器在剂量测量中的实用性。方法 使用RTS-200二维扫描水箱、ELEKTA Precise医用电子直线加速器及RGD-3B热释光剂量测量仪等设备进行了相关研究。结果 通过水箱分析医用高能电子线的剂量分布特征,可精确确定GR-200A热释光探测器的剂量测量位点,适于在热释光剂量学研究和应用实践中推广;在准确定位照射下,该探测器对4～8 Mev电子线的能量响应在5％以内、剂量率标准偏差和剂量线性偏差分别为2.3％和4％,可初步实现放射治疗剂量和个人剂量当量Hp(d)的测量。结论GR-200A热释光探测器在医用高能电子线剂量测量中有一定的实用价值。     

LaGrange插值法在测量个人剂量中估计光子能量的应用

GB3100-3102-93"量和单位"对放射工作人员个人剂量监测提出了新的实用量——个人剂量当量Hp(d),文献^[1]研制的过滤型鉴别式热释光个人剂量计解决光子的能量鉴别问题,其基本原理是利用不同过滤情况的热释光读数比值判断出光子的等效能量。     

宁海县放射工作人员个人累积剂量监测结果

宁海县自1989年就对县级单位开展放射工作人员个人累积剂量监测工作,现将1991-2008年放射工作人员个人累积剂量监测情况分析如下。材料与方法 1材料采用热释光个人剂量计（TLD）进行外照射个人累积剂量监测,TLD元件是经过全国比对合格的管状和片状元件。测读仪器设备使用RGD-3B热释光仪和BR2000A型退火炉[1],检测仪器经中国计量科学研究院刻度校正。     

能量鉴别式剂量计在个人剂量监测能力考核中的应用

【目的】了解能量鉴别式剂量计的性能,并分析其对比对个人剂量监测能力考核结果的影响。【方法】对CTLD-J4000型能量鉴别式剂量计进行不同能量光子照射,利用剂量计覆盖的不同密度过滤材料对光子产生不同的过滤作用,拟合读数之比随光子能量的变化曲线来鉴别光子的能量。【结果】鉴别式剂量计读数无过滤/轻过滤比值与厂家参考值的重合性要好于无过滤/重过滤比值,后者在48 keV和83 keV的偏离值较高,分别为12.8%、15.5%。使用平均刻度因子带来的能量响应最大偏差为23.5%。【结论】使用鉴别式剂量计能较好地鉴别出射线能量,从而减少使用平均刻度因子带来的能量响应误差。     

某院肿瘤放射治疗技术人员辐射剂量监测及防护

目的 掌握我科放射治疗工作人员个人受照剂量水平,建立个人剂量档案,进一步保护放射治疗工作人员的健康和提高放射治疗单位辐射防护水平.方法 依据GBZ 128-2002<职业性外照射个人监测规范>、<放射工作人员个人剂量监测方法>,采用热释光(TLD)剂量方法和TLD元件对肿瘤科放射治疗工作人员进行剂量监测.结果 每年各月份人均月平均剂量水平随各月总照射野数工作量的变化情况,以及操作不同放射治疗设备技术员的个人剂量监测结果不同,人均年有效剂量当量稳中有降,2004、2006、2008年的人均年有效剂量当量分别为2.19、1.48和1.33 mSv/a.结论 市级医院基层放射治疗中心通过采取有效措施及加强放射防护,可以使放射工作人员年剂量当量保持在较低水平,确保放射治疗工作人员的健康与安全.     

光子外照射剂量转换系数的比较与分析

目的探讨和分析现行国家标准GBZ/T 144-2002光子外照射剂量转换系数的局限性,以期为其更新提供一些参考。方法将国家标准GBZ/T 144-2002和ICRP 116号出版物剂量转换系数比较。结果二者剂量转换系数(D_T/Ka)整体变化趋势一致,但是肝脏左侧位照射时,ICRP 116号出版物女性、男性剂量转换系数高于GBZ/T 144,能量小于150 keV时,相对变化可超过30%;除了右侧位照射以外,ICRP 116号出版物女性剂量转换系数高于男性,能量在30~200 keV,左侧位照射相对变化超过30%,能量越低差异越大,最大超过100%。女性乳腺前后位照射能量高于4 MeV时,相对变化超过50%。结论不同照射条件下,GBZ/T 144-2002与ICRP 116号出版物器官剂量转换系数的变化趋势相一致,但是当考虑参考体模类型及参考人参数、性别、次级电子以及入射光子能量等时差异较明显,GBZ/T 144需要稍作调整。     

入射体表剂量调查的质量控制

[目的]分析放射诊断受检者入射体表剂量监测用热释光(TLD)检测系统质量控制措施,提高测量结果的可靠性。[方法]在二级标准剂量学实验室对用于入射体表剂量调查的TLD剂量元件照射标准曲线和盲样比对,同时通过标准化的测量程序及设备的定期校正等来控制检测系统的监测质量。[结果]个人剂量与入射体表剂量盲样比对结果评定值与约定真值的偏差均小于±10%;三条标准曲线具有良好的线性(相关系数分别为0.9998、0.9996和0.9999)。[结论]本实验室热释光(TLD)检测系统的质量控制符合国家有关规范要求,监测结果准确可靠,能保障放射诊断受检者入射体表剂量调查的顺利进展。     

参加全国环境累积剂量(TLD元件)监测技术质控考核结果分析

目的 了解四川省环境累积剂量测量系统技术水平,通过比对提高监测能力。方法 依据国家《个人和环境监测用热释光剂量测量系统》(GB 10264-88)对TLD元件监测技术进行质控考核。结果 两组比对剂量评定值与约定真值的绝对偏差均小于10%、两组不确定度均小于10%。结论 四川省环境累积剂量监测技术符合《个人和环境监测用热释光剂量测量系统》标准要求,且仪器稳定性好。     

LiF（Mg,Cu,P）剂量计在个人剂量监测应用中的质量控制

近些年来,热释光剂量计已广泛应用于辐射防护、环境及个人剂量监测等方面。热释光探测元件种类繁多,其中新型的LiF(Mg、Cu,P)探测器对光子具有灵敏度高、组织等效和能量响应好、线性范围宽,几乎无剂量率依赖性以及储存信息稳定等优点,所以在个人剂量监测中应用较多。为加强济南军区放射工作人员个人剂量监测中的质量控制,保证所测数据的可靠性和可比性,我们在本实验室条件下,对使用的仪器和放射工作人员佩戴的个人剂量计性能及试用情况     

放射工作人员个人剂量监测工作的问题及建议

为了了解我县医疗机构放射工作人员的受照剂量和防护水平,为评价放射防护的安全程度、员工的健康状况和放射疾病诊断提供依据。将5年来的监测结果报告如下:1材料与方法1.1材料来源2002—2006年天台县各医疗机构放射工作人员职业外照射个人剂量监测结果报告。1.2方法按GBZ 128-2002《职业性外照射个人监测规范》要求佩戴热释光剂量计(TLD)元件,综合考虑放射工作人员的工作性质、所受剂量的大小、剂量变化程度等因素确定3个月更换TLD元件内芯,并及时将元件内芯送省疾控中心检测,监测周期1年。对检测周期内接受的职业外照射个人剂量小于5 m…     

Synthesis and stereoselective kappa-receptor binding of methylated analogues of GR-89.696

Stereoselective synthesis of all four stereoisomers of methylated analogues 8 of the kappa-receptor agonist GR-89.696 is presented. Starting with orthogonally protected piperazine derivatives (R,R)-4 and (S,S)-4, the reaction sequence involves oxidation, reductive amination and modification of the piperazine nitrogen protective groups. The configuration of the stereocentre in alpha-position to the pyrrolidine moiety is determined by X-ray structure analysis of (R,S)-8. In receptor-binding studies with the radioligand U-69.593, the stereoisomer with (S)-configuration at both stereogenic centres (S,S)-8 displayed the highest kappa-receptor affinity with a K(i)-value of 0.67 nM.     

Optimizing the use of LiF:Mg,Cu,P (GR-200 P) to measure low dose irradiation in nuclear medicine

We undertook a study in order to determine the optimal conditions under which thermoluminescent powder LiF:Mg,Cu,P (GR-200 P) could be used for applications in nuclear medicine and for dosimetric needs. First, we defined the conditions chiefly related to the readout chain, namely the optimal mass of GR-200 material used for each readout, which is between 15 and 30 mg, and the optimal glow curve readout, which corresponds to heating in two phases: a rise in temperature at the rate of 10 degrees C s(-1) up to 150 degrees C followed by a plateau lasting 10 s and then another rise in temperature at the rate of 25 degrees C s(-1) up to 260 degrees C followed by a second plateau lasting 6 s. The optimum conditions for using TL material were also studied: using GR-200 P without annealing and performing two successive readouts of the same sample only led to a 0.1% loss in sensitivity per re-use cycle, and the good reproducibility of measurements was preserved with stable and weak residual TL signal. The response of the sample irradiated at three different dose levels with a 60Co gamma photon beam remained constant over 40 d. Sensitivity was preserved to within +/-4% between a few tenths of a microGy and 1 Gy. Our observations concur with the results of the literature and show how to optimize the conditions for using the GR-200 thermoluminescent dosimeter to measure low doses with a simple procedure that preserves the sensitivity of material.     

Thermoluminescence dosimetric properties of a new thin beta detector (LiF:Mg, Cu, P; GR-200F) in comparison with highly sensitive Al2O3:C beta dosimeters.

There is an increasing need for efficient beta detectors to fulfil ICRU recommendations for new quantities especially in the field of medical physics and retrospective dosimetry. The thermoluminescence properties of thin LiF:Mg, Cu, P (GR-200F) tapes produced in 1998 by Sange Company, People's Republic of China, are investigated and compared with those of highly sensitive thin Al2O3:C beta detectors as regards their applicability in the detection of low energy photons and beta particles. The radiation dose response, minimum detectable dose, reproducibility of measurements and effect of residual signal at low dose are assessed for the possible low level beta dosimetry use. The radiation dose response and photon and beta detection efficiencies are tested underpractical laboratory conditions. The effects of indoor fluorescent light and residual signal after the first read-out are investigated with a view to optimising handling conditions such as post-irradiation and pre-heating treatments for routine dosimetry. The photon energy responses of the detectors are investigated using 150 keV filtered x-rays and 60Co gamma-rays.     

Calcium intake in the elderly: validation of a dietary questionnaire

Epidemiological studies of calcium and osteoporosis have been hampered by the lack of a suitable tool for assessing calcium intake. This report describes a new frequency and amount questionnaire for measuring present and past calcium intake in the elderly. The validity of the questionnaire was tested against two commonly used standards of dietary assessment, five-day duplicate diets and seven-day weighed dietary inventories. The resulting correlation coefficients were, respectively, r = 0.76 and r = 0.69, while that for repeatability was r = 0.84. Furthermore, the questionnaire categorized subjects into thirds of the distribution of intake with almost no gross misclassification. It is suggested that the present findings may be extended to the majority of normal, healthy elderly subjects, implying wide application for the questionnaire in the assessment of calcium intake in the elderly.     

Self-reported health problems among Swedish miners one year after unemployment

Unemployment is considered to be a public health concern sincedeterioration in the health of the unemployed is often anticipated.However, for some groups, such as miners, unemployment mightimprove health due to a cessation of potentially harmful occupationalexposures. This study evaluates the health of 79 miners in oneSwedish iron-ore mine, and 226 age-matched controls from thegeneral population, during one year after the closure of themine. The participants received a questionnaire regarding medicalhistory and subjective symptoms at the beginning of the studyperiod, and after one year. Statistically significant negativeeffects on self-reported health attributable to unemploymentwere not found, although neuropsychiatric symptoms were morecommon among the unemployed miners. The miners reported a statisticallysignificant improvement in grip force (p=0.031). They had asignificantly higher prevalence of symptoms associated withmining related exposures when compared with the population controls;pain in the upper extremities [relative risk (RR)=2.27, 95%confidence interval (Cl)=1.44–3.59), back pain (RR=1.84;Cl=1.237–2.75), vasospastic disease of the fingers (RR=2.05;Cl=1.18–3.57) and obstructive respiratory symptoms (attacksof dyspnea and wheezing: RR=3.67; Cl=1.167–11.6).     

Excès de cas humains et animaux de tularémie en France au cours de l’hiver 2007–2008 : émergence ou phénomène isolé ?

Context

Tularemia is a zoonosis affecting humans and hares in France. We describe the results of surveillance in both species, in 2007 and 2008.

Methods

Human tularemia cases are mandatorily notifiable in France since 2003. In hares, surveillance relies on volunteer hunter associations in all districts of the country. Data from mandatory reports and volunteer surveillance in 2007/2008 were analyzed and compared with previous results.

Results

In 2007/2008, 144 cases were reported in humans and 117 cases in hares. This was a 100% increase compared to previous years. Human cases differed from those of previous years only by the frequency of contact with breeding animals. Human cases without any documented risk exposure were also more frequent.

Conclusion

An increase of tularemia cases occurred in 2007/2008 in both species. Complementary studies are needed to identify the species reservoir in France to understand the causes of this peak of cases.     

深圳公立医院管理体制改革制度设计

深圳公立医院管理体制改革实行政事分开、管办分开,在理事会架构下按法定机构模式组建市医管中心,落实公立医院运营管理自主权.作者从当前公立医院管理体制的弊端入手,介绍了深圳市进行公立医院管理体制改革的基本思路及改革方案设计的主要举措,深入剖析了的改革方案的特点,并对改革效果进行了预测.     

Occupational health hazards in mining: an overview

This review article outlines the physical, chemical, biological, ergonomic and psychosocial occupational health hazards of mining and associated metallurgical processes. Mining remains an important industrial sector in many parts of the world and although substantial progress has been made in the control of occupational health hazards, there remains room for further risk reduction. This applies particularly to traumatic injury hazards, ergonomic hazards and noise. Vigilance is also required to ensure exposures to coal dust and crystalline silica remain effectively controlled.