CT模拟机质量控制指南

CT模拟机为放射治疗计划设计提供患者的解剖学信息,是进行三维计划设计、剂量计算和计划评估的基础。CT模拟机质量控制的目的是保证模拟定位过程的安全与放射治疗靶区及其周围重要器官的精确勾画,以及提供放疗计划剂量计算所需的准确数据。本指南内容主要涵盖了CT模拟机的机械性能、图像质量、定位流程和辐射防护4个方面的质量控制。     

CT模拟机的质量控制和质量保证检验

虚拟模拟定位过程涉及放射诊断影像、放射治疗计划设计和放射治疗定位等技术.文章主要论述了放射治疗虚拟定位对CT模拟机质量保证工作中影像质量检验和定位精度检验的要求与方法.     

乳腺癌改良根治术后CT模拟定位与模拟机定位的剂量学比较

目的比较乳腺癌改良根治术后CT模拟定位与模拟机定位(或体表画线)剂量学的差异。方法对83例已行乳腺癌改良根治术拟行放射治疗的患者进行CT模拟定位,同时应用模拟机模拟常规治疗计划,根据剂量-体积直方图(DVH),比较患者采用2种治疗计划的患侧及双肺的V5、V10、V20、V30、计划靶区(PTV)接受40 Gy、45 Gy和50 Gy(PTV40、PTV45、PTV50)的体积百分比、PTV>60、PTV>70的体积百分比及靶区内受照最大剂量(MAX)的差异;比较两种定位模式与患者胸壁厚度的关系,并跟踪随访患者放射性肺炎发生情况。结果患者常规治疗患侧及双肺V5、V10、V20、V30以及PTV40、PTV45、PTV50百分比均小于CT模拟定位计划结果,常规治疗PTV>60、PTV>70的百分比及MAX均大于CT模拟定位计划结果。患者平均胸壁厚度为22.9 mm,常规治疗PTV覆盖及正常组织受量与胸壁厚度呈负相关,CT模拟定位PTV覆盖及正常组织受量与胸壁厚度无相关关系。患者3年随访率达90.4%,放射性肺炎发生率为12.0%(9/75)。结论乳腺癌改良根治术后胸壁电子线照射CT模拟定位靶区涵盖优于模拟机定位的常规治疗计划,肺受量常规治疗计划优于CT模拟定位,但放射性肺炎发生率未见提高。在乳腺癌改良根治术后放射治疗中,CT模拟定位较单纯模拟机定位有明显的优越性。     

体表光学图像引导放疗质量控制指南

体表光学图像引导放疗系统（SGRT）是一套采用光学跟踪捕获患者的体表信息,记录和纠正患者分次间、分次内的摆位误差,以提高放疗精度的零辐射图像引导系统。为确保患者的治疗安全,必须对体表光学图像引导放疗系统采取必要的质量控制措施,因此,国家癌症中心/国家肿瘤质控中心组织专家制定了本指南。指南内容涉及：SGRT的定义和基本原理;SGRT的配准算法;SGRT的测量方法和类别;SGRT的质控要求;SGRT的放疗规范。     

体表光学图像引导放疗质量控制指南

体表光学图像引导放疗系统（SGRT）是一套采用光学跟踪捕获患者的体表信息,记录和纠正患者分次间、分次内的摆位误差,以提高放疗精度的零辐射图像引导系统。为确保患者的治疗安全,必须对体表光学图像引导放疗系统采取必要的质量控制措施,因此,国家癌症中心/国家肿瘤质控中心组织专家制定了本指南。指南内容涉及：SGRT的定义和基本原理;SGRT的配准算法;SGRT的测量方法和类别;SGRT的质控要求;SGRT的放疗规范。     

放射治疗记录与验证系统质量控制指南

放疗记录与验证系统(RVS)是一套用于防止医用电子加速器等放疗设备治疗参数设置错误,并且记录所有放疗阶段执行参数的医用计算机软件控制系统。为确保患者的治疗安全,必须对记录与验证系统采取必要的质量控制措施。本指南内容涉及:RVS安装和参数设定过程中的质量控制;RVS的验收测试;RVS在临床使用过程中的持续质量控制;使用RVS过程中的典型错误类型;执行RVS验收测试的具体测试例。     

机载锥形束CT的质量控制

机载锥形束CT主要通过放疗在线获得图象,并根据在线与计划参考图象对比,校正位置误差和离线分析肿瘤及器官运动,以辅助提高和确保精度放疗的效果。因此同样需要规范的质量控制,并定期执行。文章简要介绍目前形成的较为合理规范的机载锥形束CT质量控制内容、基准和执行频度。     

模拟机等中心定位背斜野深度直接测定法探讨

患者在模拟机仰卧位等中心定位，需知背部斜野深度时，可用背斜野深度直接测定法来测量。此方法从理论上来说能解决由于模拟机床板受不透可见光材料的阻挡，致背斜野深度无法后面直接测量的问题，但在实际测量对比中发现，用此有可能存在较大的误差，而不宜在测量等中心背斜野深度时广泛使用。     

放射治疗的质量保证与质量控制

文章主要阐述了放射治疗的质量管理,包括质量保证(QA)、质量控制(QC)、治疗计划和质量改进四个方面.QA是经过周密计划而采取的一系列必要措施,保证放射治疗的整个过程按国际标准安全地执行.QC是采取必要的措施保证QA的执行,并不断修改并进而达到新的QA级水平.     

放射治疗的物理质量控制与质量保证

严格的质量保证（QA）与质量控制（QC）程序是放射治疗取得预期效果的必要条件。放射治疗物理技术的QA内容麻根据病人体位同定、模拟定位影像获取，靶区确定和器官勾画，计划设计与剂量计箅和治疗操作各过程的精度要求制定。而QC则需要对每一过程中所使用设备的稳定性，计划设计的小确定度大小，治疗实施阶段的操作重复性与稳定度等进行测量、校准和修正。文章分析了放射治疗QA／QC的历史发展及其现状．并对我国的QA／QC存在的问题与发展方向作了分析。     

Computed Tomography in Radiotherapy Treatment Planning

Computed tomography (CT) provides in creased accuracy in tumour localisation, patient ouline data and heterogeneity information. This makes the use of CT highly desirable in 2–dimensional treatment planning. Where 3–dimensional (3–D) planning is used computed tomography (or possibly MRI) is essential. Radiotherapy departments must include dedicated CT scanners if they are to attain acceptable accuracy in simulation and treatment planning. The use of modern accelerators and treatment planning systems will be downgraded in the absence of routine CT imaging in a Radiotherapy Department.     

双平面CT 扫描诊断鞍区脊索瘤的价值

 目的　评价轴位加冠状位 CT扫描在诊断鞍区脊索瘤中的作用。方法　回顾性分析 9例经手术证实的脊索瘤的轴位和冠状位 CT扫描资料 ,其中 7例同时行增强扫描。结果　所有病例的病灶中心均位于鞍区 ,其边缘不规则或模糊 ,蝶骨体骨质明显破坏 ,4例鼻咽部有巨大软组织肿块 ,6例患者的瘤体内可见斑片状或不规则块状钙化影。结论　双平面 CT扫描可准确显示肿瘤向颅内侵犯的范围以及骨质破坏的程度 ,在排除鞍区的其它病变后 ,结合临床表现和 CT特征可诊断脊索瘤.     

Computed tomography for radiotherapy planning

Images obtained by X-ray transmission computed tomography (CT) assist in planning external beam radiation therapy. Quantitatively, contiguous transverse tomograms may be used to compute radiation dose distributions, based on patient-specific geometry and density of the tissues irradiated. We present here our clinical experience with a computerized treatment planning system modified for this purpose. The importance of performing a CT examination under conditions which simulate treatment is emphasized, particularly for radiotherapy in the thorax. An approximate method for determining tissue electron densities from CT data of a single scan has been verified for tissues in vivo. These tissue densities are used to compute dose distributions for Cobalt-60 and 25 MV X-ray beams, using the equivalent tissue-air ratio method. Predicted doses have been verified to an accuracy of 2%, using intra-rectal thermoluminescent dosimeters. Three clinical examples, dealing with radiotherapy of the esophagus, the rectum, and the upper half body are discussed. Comparison of dose distributions, corrected for tissue inhomogeneities, to those based on a water-like patient indicate differences in the dose to tumor or to surrounding healthy tissue, which are considered clinically significant.     

CT与MRI对鼻咽癌分期影响的研究

[目的]比较MRI与CT对鼻咽癌侵犯范围检查的差异性和对T分期的影响。[方法]回顾性分析84例治疗前同时或短时间内（不超过2周）行CT和MRI检查并经病理活检证实是鼻咽癌的患者资料,用χ^2检验比较两种检查方法对各解剖部位的检出率。按’92鼻咽癌分期标准,分别以CT加临床体检和MRI加临床体检对患者进行临床分期．用χ^2检验比较这两种方法划分的各期病例数的分布情况。[结果]CT和MRI诊断颅底骨质破坏的发生率分别为11．9％和41．7％,两种检查方法比较有显著性差异（χ2=18．970,P±0．000）。CT和MRI诊断海绵窦受侵犯的发生率分别为8.3％和20．2％,两种检查方法比较差异有显著性（χ2=4．861,P=0．027）。对于T分期,用CT和MRI划分的各期病例数分布情况比较有显著性差异（χ2=16．416,P=0．001）。有31例（36．9％）在CT与MRI之间发生了T分期改变,MRI所划分的中晚期患者（Ⅲ期和Ⅳa期）比CT增多。[结论]MRI对鼻咽癌侵犯颅底骨质和海绵窦的检出率高于CT。MRI可使鼻咽癌的T分期升级。     

Hexabrix 320R for CT. (Computed Tomography) — Patient Tolerance and Image Quality

A total of 367 patients were studied using Hexabrix 320 as intravenous contrast material during CT scanning. Adverse events were recorded and analysed with respect to patient age and risk category. Hexabrix 320 produced adequate image quality in all patients. Whilst minor adverse events were relatively common, only a few moderate adverse events were seen and no severe adverse events were observed. Hexabrix 320 was noted to be very well tolerated in the elderly and well tolerated by the high risk patient.     

International Association for the Study of Lung Cancer Computed Tomography Screening Workshop 2011 report

The International Association for the Study of Lung Cancer (IASLC) Board of Directors convened a computed tomography (CT) Screening Task Force to develop an IASLC position statement, after the National Cancer Institute press statement from the National Lung Screening Trial showed that lung cancer deaths fell by 20%. The Task Force's Position Statement outlined a number of the major opportunities to further improve the CT screening in lung cancer approach, based on experience with cancer screening from other organ sites.The IASLC CT Screening Workshop 2011 further developed these discussions, which are summarized in this report. The recommendation from the workshop, and supported by the IASLC Board of Directors, was to set up the Strategic CT Screening Advisory Committee (IASLC-SSAC). The Strategic CT Screening Advisory Committee is currently engaging professional societies and organizations who are stakeholders in lung cancer CT screening implementation across the globe, to focus on delivering guidelines and recommendations in six specific areas: (i) identification of high-risk individuals for lung cancer CT screening programs; (ii) develop radiological guidelines for use in developing national screening programs; (iii) develop guidelines for the clinical work-up of "indeterminate nodules" resulting from CT screening programmers; (iv) guidelines for pathology reporting of nodules from lung cancer CT screening programs; (v) recommendations for surgical and therapeutic interventions of suspicious nodules identified through lung cancer CT screening programs; and (vi) integration of smoking cessation practices into future national lung cancer CT screening programs.     

规范持久开展质控工作——浙江省临床病理质控中心介绍

浙江省临床病理质控中心成立于1989年,是国内最早实施临床病理质量控制和质量保证工作的省级医疗质量鉴定和评价机构。全文就浙江省临床病理质控的基本概况、主要工作、取得的成绩及目前尚存在的问题进行阐述、分析。