TLD和仿真盆腔模型核查宫颈癌后装治疗三维剂量分布的研究

目的探讨用JR1152F型热释光剂量计(TLD)和仿真人体盆腔模型核查宫颈癌腔内后装治疗三维剂量分布的可行性。方法测定JR1152-F-型TLD(规格1mm×1mm×6mm)用于铱-192剂量测量的升温程序、剂量线性响应范围和重复性,并对TLD剂量计及热释光剂量仪(FJ427-A1)进行剂量刻度,仿真人体盆腔模型分成6段、每一层面关键器官上设置若干直径1mm、长6mm的测试孔,孔中放入直径1mm、长6mm小铅条,插入宫腔管施源器,模拟机下拍摄X光定位片,取出铅条,测试孔内放入TLD剂量计,用microSelectronHDR后装治疗计划系统(TPS)设计腔内放疗模拟计划,给予A点剂量200cGy次,计算出各测试点的理论值和重建精度,按计划进行腔内后装照射,用热释光剂量仪对受照后的TLD剂量计进行重复测量。结果TLD剂量计剂量线性范围在300cGy内,相关系数0.997,重复性好于±4%,A点、B点、F点、膀胱和直肠剂量参考点实测剂量与TPS计算值符合较好,误差分别在±3.60%、±0.9%、±7.8%、±7.1%、6.4%内。结论用JR1152-F型TLD和仿真人体盆腔模型核查宫颈癌腔内后装治疗三维剂量分布准确、可靠。     

基于CT图像的三维后装腔内治疗计划系统的研制

目的:开发一种新的适合于临床应用的基于CT图像的三维后装腔内治疗计划系统。方法:对插三个硬管的仿真人体盆腔体模和插二个软管的鼻咽癌患者进行CT扫描,以Microsoft Visual C 为开发工具,对CT图像进行dicom解析,提取有用的信息,然后重建施源管的三维坐标,并给出驻点的三维坐标,接着程序实现源外剂量分布计算方法和剂量优化算法,最后在CT层面生成等剂量线,采用VTK技术进行三维显示。结果:本系统能依临床预设的参考剂量点,逆向计算驻点的驻留时间,生成符合临床要求的等剂量面,三维显示等剂量体与正常组织的空间关系。结论:为临床医生提供一种具有三维剂量分布显示的人机交互布源的基于CT图像的三维后装腔内治疗计划系统,克服目前国内普遍使用的基于X线片的二维后装计划系统的不足。目前本系统正临床测试,效果良好。     

基于CT定位的三维一体化后装治疗系统的开发和临床应用

本文介绍了基于CT定位的三维一体化后装治疗系统的开发及在中晚期宫颈癌治疗中的临床应用。该系统以我院目前成熟的二维一体化后装治疗系统为构建基础,将基于CT的三维成像系统、影像传输系统、治疗计划系统、后装治疗系统有机结合,从而实现施源器置放、三维成像、靶区勾画、治疗计划制定及后装治疗的精确、迅速完成,对于中晚期宫颈癌的治疗具有重要的临床价值。     

前列腺癌调强放疗重复CT模拟定位的作用

目的:探讨前列腺癌调强放疗重复CT模拟定位的作用。方法:前列腺癌调强放疗首次CT模拟定位后行CT扫描,在模拟定位工作站确定靶体积中心(等中心)做体表标记。于放射治疗4周左右进行重复CT模拟定位,扫描前用激光灯核对原等中心标记,记录等中心数值后进行CT扫描。在模拟定位工作站录入记录的原等中心数值传输至治疗计划系统,与首次CT模拟定位的图像融合后进行对比分析。结果:首次CT与重复CT图像融合后测量靶区位移的平均误差左右(RL)方向为1.9mm;头脚(SI)方向为2.8mm;前后(AP)方向为3.1mm。危及器官膀胱和直肠的最大剂量分别增加0.5～3.7Gy、0.9～5.0Gy;平均剂量分别增加0.7～4.9Gy、0.6～5.4Gy;最小剂量分别增加0.3～1.3Gy、0.6～2.8Gy。结论:前列腺癌调强放疗重复CT模拟定位便于对比分析靶区和危及器官的位移和对剂量的影响,为及时调整治疗计划提供依据。     

4D锥形束CT引导下的肺癌立体定向放射治疗的临床研究

目的 探讨肺癌患者放射治疗中的定位、靶区勾画、计划设计、计划评估、计划验证等流程的准确性,着重研究利用Monaco 5.11.01计划系统制定的立体定向放射治疗(SBRT)计划及其结果,为肺癌SBRT提供参考意见。方法 利用热塑膜和真空垫对患者进行体位固定后,行大孔径4D CT扫描,将扫描图像传输至Monaco 5.11.01计划系统勾画靶区,然后制定预计划;将预计划传输至X线容积影像(XVI)系统并在医用电子直线加速器上扫描4D锥形束CT(CBCT)图像,回传扫描图像至Monaco 5.11.01计划系统,结合4D CT图像最终确定计划靶区范围,制定SBRT计划;治疗前,用ArcCheck模体验证计划。结果 4D CT结合4D CBCT图像,采用Monaco 5.11.01计划系统精确勾画能够有效解决靶区运动问题;患侧肺的V₂₀、V₅均随靶区处方剂量、靶区体积增加而增加,且对处方剂量的变化敏感度更高;当靶区体积<10 cm³时,计划设计较难达到美国放射肿瘤协作组(RTOG)要求;3%/3 mm、3%/2 mm、2...     

鼻咽癌调强放疗剂量验证的探讨

目的探讨逆向调强适形放疗（IMRT）的剂量学验证方法,保证接受治疗患者剂量的准确性。方法随机抽取30例鼻咽癌患者,进行CT定位扫描,然后把图像传输至核通PLATO三维逆向治疗计划系统,并设计出均分野（七野）治疗计划。利用固体水模板在治疗计划系统中建立三维等效模体,将待验证的IMRT计划套于模体内,分别计算出每野在模体中的剂量分布,选取模体中感兴趣平面上的每野剂量分布,传输至MAPCHECK验证软件系统,在加速器下进行二维剂量模拟照射并与计划系统计算的结果相比较,验证相对剂量和绝对剂量。结果采用DTA方法,剂量位置限定在3%/3mm标准条件下,所有射野中相对量的通过率在85%～100%之间,绝对量的平均通过率在80.7%～100%之间。结论剂量学验证是IMRT临床实施的可靠保证,使用MAPCHECK分析软件进行剂量验证具有适时、方便、快捷的特点,免去了胶片验证法中冲洗、扫描胶片的过程,也减少了大部分的系统误差。因此,MAPCHECK分析软件如今已成为我院剂量验证的常规工具。     

CT-电子密度转换曲线的采集校正及对治疗计划剂量计算的影响

目的:为提高放疗精度,建立CT-电子密度转换曲线,确定对放射治疗计划剂量计算的影响。方法:利用CT电子密度模体,对模拟定位CT机的CT值进行检测。比较人体不同组织的CT值,建立CT-电子密度转换曲线。根据各组织的相对电子密度对组织不均匀性剂量进行校正,并分析照射剂量MU数值的变化。结果:在同一定位扫描参数下,不同位置的等效密度组织CT值均有变化:高密度组织CT值变化较大,近床面的等效密度组织CT值变化均大于远床面的等效密度组织。不同的CT-电子密度转换曲线其MU数值相差均<20%,调强放疗(intensity modulated radiation therapy,IMRT)较大,三维适形放射治疗(3-dimensional conformal radiation therapy,3DCRT)和调强放疗各偏差值相同。结论:对治疗计划系统数据进行采集录入时,应正确合理地输入一条CT-电子密度转换曲线,以保证治疗计划剂量计算的精度。     

模拟定位机影像工作站在三维适形放射治疗计划射野位置验证中的应用

目的 探讨模拟定位机的影像工作站在三维适形放射治疗(3D-CRT)计划射野位置验证中的应用价值。方法 在影像工作站上比较模拟定位机的验证野影像和治疗计划系统的验证野数字重建影像(DRR),测量摆位误差。结果 254例患者的放疗计划通过模拟定位机进行了射野的位置验证。位置校正后,头颈部肿瘤患者的放疗计划在x轴、y轴、z轴方向上的误差分别为(-1.0±1.0)mm,(-1±2)mm,(2±1)mm;胸腹部肿瘤患者为(1±2)mm,(0±2)mm,(3±1)mm;盆腔肿瘤患者为(1±1)mm,(1±2)mm,(2±2)mm。位置校正后,各放疗计划的误差都能够控制在允许范围内。结论 模拟定位机的影像工作站可以对放疗计划进行射野位置验证,减少摆位误差。     

ArcCHECK-3DVH剂量验证系统在宫颈癌容积旋转调强放射治疗三维剂量验证中的应用

目的探讨ArcCHECK-3DVH剂量验证系统在宫颈癌容积旋转调强放射治疗(VMAT)三维剂量验证中的应用。方法选取2021年1—12月于医院行VMAT的20例宫颈癌术后患者,利用ArcCHECK-3DVH剂量验证系统进行计划验证,比较ArcCHECK-3DVH剂量验证系统重建剂量与治疗计划系统(TPS)计算剂量的三维γ通过率,以及计划靶区(PTV)的98%体积受量(D_98%)、2%体积受量(D_2%)、平均剂量(D_mean)与危及器官剂量参数。结果20例宫颈癌患者的PTV和危及器官的整体3 mm/3%γ通过率为(93.58±2.9)%。PTV和危及器官的ArcCHECK-3DVH剂量验证系统重建剂量均大于TPS计算剂量。PTV的D_98%、D_2%和D_mean的ArcCHECK-3DVH剂量验证系统重建值与TPS计算值的差异分别为(0.95±0.80)%、(2.93±1.38)%和[2.0(1.42,2.17)]%,均小于3%,且差异有统计学意义(P<0...     

采用仿真头模及剂量计检验X刀治疗脑室肿瘤的剂量分布研究

目的 采用美国Kodak-omat XTL-2剂量胶片,LiF(Mg,Cu,P)CR-200ATLD和仿真人体头模,检验X刀放射治疗脑室肿瘤剂量分布的可行性。方法 仿真头模以3 cm厚做横向(水平面)切开,共切成四片,取其中二、三片(即A片和B片),每一层面关键器官上设置若干直径1 cm,长0.5 cm的测试孔,孔中放入TLD剂量计,每间隔10 mm一个测点。测量采用临床常用的二种不同治疗照射方案,计算出各测试点的理论实验值及重建精度。结果 TLD剂量计的测量结果在5%以内符合,剂量胶片的测量结果在3%以内符合,均能满足放射治疗的剂量学要求。结论 可见采用LiF(Mg,Cu,P)CR-200A TLD计,Kodak-omat XTL-2剂量胶片及仿真人体头模检验X刀治疗脑室肿瘤的剂量分布准确、可靠。     

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.     

The occurrence of antimicrobial substances in toilet,sink and shower drainpipes of clinical units: A neglected source of antibiotic residues

Antibiotics represent one of the most important drug groups used in the management of bacterial infections in humans and animals. Due to the increasing problem of antibiotic resistance, assurance of the antibacterial effectiveness of these substances has moved into the focus of public health. The reduction in antibiotic residues in wastewater and the environment may play a decisive role in the development of increasing rates of antibiotic resistance. The present study examines the wastewater of 31 patient rooms of various German clinics for possible residues of antibiotics, as well as the wastewater of five private households as a reference.To the best of our knowledge, this study shows for the first time that in hospitals with high antibiotic consumption rates, residues of these drugs can be regularly detected in toilets, sink siphons and shower drains at concentrations ranging from 0.02?μg·L^?1 to a maximum of 79?mg·L^?1. After complete flushing of the wastewater siphons, antibiotics are no longer detectable, but after temporal stagnation, the concentration of the active substances in the water phases of respective siphons increases again, suggesting that antibiotics persist through the washing process in biofilms. This study demonstrates that clinical wastewater systems offer further possibilities for the optimization of antibiotic resistance surveillance.     

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.     

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.     

Manufacture and use of nanomaterials: current status in the UK and global trends

This paper provides an overview of the production and use of nanomaterials (NMs), particularly in the UK. Currently, relatively few companies in the UK are identifiable as NM manufacturers, the main emphasis being the bulk markets in metals and metal oxides, and some niche markets such as carbon nanotubes and quantum dots. NM manufacturing in the UK does not reflect the global emphasis on fullerenes, nanotubes and fibres. Some assumptions have been made about the types of NM that are likely to be imported into the UK, which currently include fullerenes, modified fullerenes and other carbon-based NMs including nanotubes. Many university departments, spin-offs and private companies have developed processes for the manufacture of NMs but may only be producing small quantities for research and development (R&D) purposes. However, some have the potential to scale up to produce large quantities. The nanotechnology industry in the UK has strong R&D backup from universities and related institutions. This review has covered R&D trends at such institutions, and appropriate information has been added to a searchable database. While several companies are including NMs in their products, only a few (e.g. manufacturers of paints, coatings, cosmetics, catalysts, polymer composites) are using nanoparticles (NPs) in any significant quantities. However, this situation is likely to change rapidly. There is a need to collect more information about exposure to NPs in both manufacturing and user scenarios. As the market grows, and as manufacturers switch from the micro- to the nanoscale, the potential for exposure will increase. More research is required to quantify any risks to workers and consumers.     

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.     

Effects of nitrogen dioxide on red blood cells of rats: Changes in components of red cell membranes during in vivo exposure to NO2

Red cell membranes, prepared from red blood cells of rats exposed to 4, 10, or 20 ppm nitrogen dioxide (NO₂) for 1 to 10 days, were examined for evidence of changes in membrane components. Appreciable changes were not found in contents of phospholipid and cholesterol during exposure to 10 ppm NO₂. By contrast, protein content altered with the time of exposure. Moreover, changes in protein composition were observed by employing sodium dodecyl sulfate — polyacrylamide gel electrophoresis. Twenty-four-hour exposure to NO₂ at the concentration above 10 ppm resulted in a marked increase in the percentage of lysophosphatidylethanolamine (LysoPE) to the total phospholipids. The prolonged exposure to 10 ppm NO₂ gave rise to a further increase in LysoPE, whereas the percentage of phosphatidylethanolamine (PE) showed a gradual decrease. A 1-day exposure to 4.0 ppm NO₂ also caused an increase in sialic acid content and decreases in those of PE and hexose. In addition to contents of these components the percentage of LysoPE increased 5 days after exposure and the elevated values were maintained up to the end of exposure period. These results demonstrate that red blood cells in circulation exhibit different membrane properties in terms of lipid and carbohydrate composition during 10 days of exposure to 4.0 ppm NO₂.     

Investigating clusters in the workplace and beyond

Clusters of disease are common and occur in the workplace and in the general community. They often arouse considerable concern among the population. Investigations have sometimes lead to exciting new knowledge, but in general the investigation of clusters is difficult and often unrewarding, especially for community clusters. In the workplace, investigations are more likely to find associations and even new causes, but still many clusters remain enigmatic. Despite this, there are many reasons for investigating clusters, including allaying community concern and identifying uncontrolled exposures. A structure for investigating clusters in the workplace is suggested.