浙江省放射物理质量控制和质量保证状况分析

按照《浙江省医院肿瘤放射治疗质量保证管理规定》条例和浙江省放射物理质量控制检查评分标准,自1996年至2006年对全省的放疗单位进行放射物理质控检查,范围涉及放射治疗设备、人员、剂量检测、摆位操作规范等,汇总分析检查结果数据。浙江省的放疔设备配置呈合理规范化发展。加速器、模拟机、放射治疗计划系统、剂量设备成为肿瘤中心的基本必备设备。全省放射治疗机的输出剂量误差保持在3％以内,其它主要性能指标均达到国家标准。28家医院治疗摆位准确性检查合格率达93％。2006年全省放疗单位物理师的数量较1996年增加6倍,但仍有少数单位缺乏专职物理师。     

肝癌放疗研究进展

随着影像技术的发展和放疗技术的不断进步,图像引导的放疗技术、呼吸运动相关的器官运动追踪技术的应用以及对部分肝体积放疗耐受剂量的重新认识,肝癌实施精确放疗,大剂量照射,明显提高了肝癌放疗的疗效,由此对放疗在肝癌中的治疗作用及地位有了新的认识。全文对近年来肝癌的放射耐受量、适形放射治疗、立体定向放射治疗、放疗联合血管介入栓塞治疗、功能影像对肝癌放疗疗效的潜在优势以及存在问题和展望作一综述。     

肺部肿瘤的精确放射治疗研究进展

目前肺部肿瘤的放射治疗已进入精确放疗时代。实施精确放疗的具体方法主要包括:调强放疗(intensity modulated radiotherapy,IMRT)、图像引导放射治疗(image-guided radiotherapy,IGRT)和体部立体定向放射治疗(stereotactic body radiotherapy,SBRT)。在实施精确放疗过程中,对于以下问题:患者体位固定、肺部肿瘤运动的控制、影像技术的使用、PTV边界、剂量的处方和报道、射野的安排、剂量体积的控制和治疗的实施等,应给予充分的考虑和注意,以确保精确放疗能够精确执行。     

多模医学图像引导的非小细胞肺癌放疗研究新进展

放射治疗是目前非小细胞肺癌的主要治疗手段之一,在放疗过程中,利用功能影像与CT解剖影像相结合,不但提高了肿瘤靶区的勾画精度,而且,还能利用功能影像显示的靶区细胞的生物学特性,进行生物功能图像引导的剂量雕刻（dose painting）治疗,这是放射治疗发展过程的一个重要转折点.对局部晚期非小细胞肺癌而言,采用累及野照射的方式优于选择性淋巴结照射.利用4D-CT图像引导的个体化靶区勾画、锥形束CT（cone beam CT,CBCT）图像引导放疗和自适应放疗（adaptive radiation therapy,ART）技术的应用,进一步提高了非小细胞肺癌放疗的精度,可望减少放射性肺炎等正常组织损伤、提高肿瘤控制率和改善疗后生存质量.     

前列腺癌IMRT的质量保证现状及进展

适形调强放射治疗（IMRT）是“精确定位、精确计划、精确治疗”的体现，要求在整个治疗过程做到严格的质量保证，对患者选择、定位和治疗的摆位、照射剂量的验证均提出了更高的要求，包括电子射野影像系统、兆伏级锥形束CT、超声等仪器在质量保证过程中的准确应用，并对相对剂量和绝对剂量验证中各种方法有严格的选择。     

基于诊断CT影像组学对食管癌放疗疗效早期评估

目的 探讨分析诊断级CT图像特征预测食管癌放疗效果的可行性。方法 33例接受调强放疗的Ⅰ-Ⅳ期食管癌患者;治疗期间采用CT-on-rail影像系统获取CT图像,MIM图像系统获取大体肿瘤、脊髓和无照射组织(NIT)的容积、CT平均值、标准差、斜度等影像特征数据,并观察其变化。根据治疗后3个月随访结果将患者分为有效组(完全缓解+部分缓解)24例、无效组(无变化+进展)9例。采用自行设计Matlab软件动态分析组间差异。结果 33例患者的肿瘤容积、CT平均值随照射剂量增加而逐渐减小,有效组、无效组容积和CT平均值分别减少42.46%、21.76%和5.76HU和3.66HU,有效组下降幅度较无效组更显著(P<0.005);无效组的斜度随放疗剂量增加而下降,有效组的斜度变化趋势则相反,两组变化值分别为0.503和-0.450(P=0.034);脊髓和NIT随照射剂量增加无变化。结论 分析放疗期间食管癌患者CT图像的特征数据可能早期预测放疗疗效。     

现代放射治疗的多维度特征及其智能化发展

现代放射治疗在肿瘤治疗中发挥重要作用，新型放疗手段和各种学科融合层出不穷，是越来越活跃的领域。随着图像引导、自适应放射治疗、人工智能集成、重粒子治疗和Flash超高剂量率等先进技术快速发展，现代放疗呈现出多种特点：放射治疗的复杂性和多元性，放疗数据的多样性和多模态，放疗技术的高精度、快捷性、实时性和功能性，以及放疗技术的多学科融合、人工智能化。人工智能在肿瘤放疗靶区和危及器官智能化自动化勾画、建立放射治疗计划模型、建立远程智能化质控系统的应用正如火如荼。这些现代放疗的多维度、多模态、大数据的独有特征，以及基于“互联网＋放疗”、“人工智能放疗”和“共享放疗”的新服务模式，推动放疗技术向着数字化、自动化、智能化的方向进步和发展。     

放射治疗的质量保证和质量控制(二)——临床方面

放射治疗是一个复杂的临床治疗过程。放射治疗的质量保证涉及到放射治疗医生、放射物理人员、放疗技术员及有关机器维修的工程技术人员等各方面的工作。质量保证的目的是使用各种措施,使治疗过程中的每个环节的质量保持准确稳定,并使之     

人工智能在肿瘤放射治疗中的应用

目的 对以深度学习为代表的人工智能在肿瘤放射治疗全程中的应用现状进行归纳,并对目前其存在的问题和发展前景进行阐述。方法 以“放射治疗、人工智能、深度学习、自动勾画、质量保证、图像配准”等为中文关键词,“radiotherapy, artificial intelligence, deep learning, automatic contouring, quality assurance, image registration”等为英文关键词,在PubMed、CNKI数据库中检索2012-2023发表的相关文献。纳入标准：(1)人工智能在放疗图像配准和自动勾画中的应用;(2)人工智能在放疗计划制定中的应用;(3)人工智能在放疗质量保证及疗效预测中的应用。排除标准：与放射治疗相关性较低。结果 人工智能中的深度学习技术在放射治疗的多个环节中扮演重要角色,尤其在医学图像处理方面,现有研究证明深度学习在图像合成与配准、靶区自动勾画领域可以减少放射科医生的工作量并提高结果的一致性。然而在放射治疗计划和质量保证中的应用仍需要进一步开发和临床验证以充分发挥其潜力。结论 人工智能与放射治疗的结合已经初步...     

20例鼻咽癌自适应放疗应用探讨

目的:使用我院Elekta Synergy医用直线加速器自带XIO三维适形调强放射治疗计划系统计算在不同放疗阶段及不同影像条件下对放疗计划的影响，探讨自适应放射治疗（ART）的可行性及实用性。方法:收集2013年8月至2014年10月共20例鼻咽癌患者资料，获取每例患者的第1次放射治疗时、放疗至17次时的千伏级锥形束CT(kV-cone beam)kV-实时CT(CBCT)影像。同时，获取在同一治疗条件下的传统扇形束CT(FBCT)图像。使用XIO三维适形调强放射治疗计划系统行三维的剂量显示、剂量体积直方图（DVH）及TPC/NTCP计划评估工具，在不同视野面进行放疗计划实时比较。进行不同放疗阶段下两种影像系统的放疗计划差异比较。结果:在不同放疗阶段下，两种影像系统的放疗计划差异性小（P＜0.05），它们在同一放疗阶段的靶区及危及器官剂量差异均在1.5%以内、DVH显示两者有较好的一致性。结论:我院Elekta Synergy医用直线加速器的kV-CBCT影像可以用来做放疗计划设计，ART在我院有可行性及一定的实用性。     

兆伏锥形束CT在放疗中的应用

兆伏锥形束CT(MVCBCT)在体内有金属移植物时可以消除金属对散射线的影响,提高图像质量,便于勾画靶区,纠正摆位误差,并且可以监测治疗期间患者解剖结构的变化.通过放射治疗过程中的MVCBCT图像进行剂量监测和计算,可了解肿瘤退缩、患者体重减轻等对靶区和正常组织所受剂量的影响,更为重要的是可在其图像上进行图像引导放射治疗的研究.     

Optimising the dosimetric quality and efficiency of post-prostatectomy radiotherapy: a planning study comparing the performance of volumetric-modulated arc therapy (VMAT) with an optimised seven-field intensity-modulated radiotherapy (IMRT) technique

Purpose: The purpose of this study was to compare and evaluate radiotherapy treatment plans using volumetric modulated arc therapy (VMAT) and intensity modulated radiotherapy (IMRT) for post‐prostatectomy radiotherapy. Methods and Materials: The quality of radiotherapy plans for 10 patients planned and treated with a seven‐field IMRT technique for biochemical failure post‐prostatectomy were subsequently compared with 10 prospectively planned single‐arc VMAT plans using the same computed tomography data set and treatment planning software. Plans were analysed using parameters to assess for target volume coverage, dose to organs at risk (OAR), biological outcomes, dose conformity and homogeneity, as well as the total monitor units (MU), planning and treatment efficiency. Results: The mean results for the study population are reported for the purpose of comparison. For IMRT, the median dose to the planning target volume, V_95% and D_95% was 71.1 Gy, 98.9% and 68.3 Gy compared with 71.2 Gy, 99.2% and 68.6 Gy for VMAT. There was no significant difference in the conformity index or homogeneity index. The VMAT plans achieved better sparing of the rectum and the left and right femora with a reduction in the median dose by 7.9, 6.3 and 3.6 Gy, respectively. The total number of monitor units (MU) was reduced by 24% and treatment delivery time by an estimated 3 min per fraction without a significant increase in planning requirements. Conclusions: VMAT can achieve post‐prostatectomy radiotherapy plans of comparable quality to IMRT with the potential to reduce dose to OAR and improve the efficiency of treatment delivery.     

État des lieux de la radiothérapie adaptative en 2019 : de la mise en place à l’utilisation clinique

Intensity modulated radiotherapy combined with image guided radiotherapy has led to increase the precision of external beam radiotherapy. However, intra or inter-fraction anatomical variations are frequent during the treatment course and can cause under-dosing of the target volume and/or over-dosing of the organs at risk. Several adaptive radiotherapy (ART) strategies can be defined to compensate these anatomical variations. The purpose of this article is to provide an overview of available ART strategies: offline, online, hybrid (library of treatment plans) or in real-time, while considering the arrival of MR-Linac devices in radiotherapy departments. The tools required to these ART strategies such as auto-segmentation, deformable image registration, calculation of the daily dose or dose accumulation, are also described. Implementing an ART strategy requires a rigorous quality assurance process, at each stage and on the entire workflow, as well as prior organization and training from of all the trades. A strong multidisciplinary involvement is finally required in order to ensure ART treatments.     

医诺尔放射治疗信息系统（RTIS －Yino）在放射治疗中的应用

目的：探讨医诺尔放射治疗信息系统（RTIS －Yino）在肿瘤放射治疗中的应用。方法：利用医诺尔放射治疗信息系统（RTIS －Yino）将放射治疗相关设备组成局域网络,系统管理患者数据,对放疗科工作人员分配不同的职责与权限。通过网络获取患者信息、影像信息和治疗数据,实现自动对患者治疗数据检测及限制。结果：400例患者完成了从信息录入、CT 模拟定位、计划设计与验证、位置验证和放射治疗的系统管理,计算机提示有13例患者需要加量治疗,经主管医生和物理师核定后继续治疗。结论：医诺尔放射治疗信息系统（RTIS －Yino）应用方便、准确,节省人力,为放射治疗提供良好的质量保证（QA）和质量控制（QC）。     

瓦里安iX加速器kV级CBCT图像环状伪影故障排除

影像引导系统中软硬件故障都有可能造成环状伪影图像,硬件老化引起此现象较为常见,故障排除应优先检查基础硬件有无明显故障,后采集OBI本底图像确认坏点状态,若有坏点未被屏蔽可按步骤通过更新图像处理坏点补偿时所调用的Pixel Correction Maps补偿坏点并进行图像校准,若仍无法修复可考虑更换探测板。锥形束CT影像引导系统是现代放疗中体位方向和摆位精度的重要验证方式,是放疗安全性和精准性的有力保障。应充分了解其老化规律,定期保养设备和验证图像质量,才能保证设备正常运行。     

A quantitative image quality comparison of four different image guided radiotherapy devices.

PURPOSE: A study to quantitatively compare the image quality of four different image guided radiotherapy (IGRT) devices based on phantom measurements with respect to the additional dose delivered to the patient. METHODS: Images of three different head-sized phantoms (diameter 16-18 cm) were acquired with the following four IGRT-CT solutions: (i) the Siemens Primatom single slice fan beam computed tomography (CT) scanner with an acceleration voltage of 130 kV, (ii) a Tomotherapy HI-ART II unit using a fan beam scanner with an energy of 3.5 MeV and (iii) the Siemens Artíste prototype, providing the possibility to perform kV (121 kV) and MV (6 MV) cone beam (CB) CTs. For each device three scan protocols (named low, normal, high) were selected to yield the same weighted computed tomography dose index (CTDI(w)). Based on the individual inserts of the different phantoms the image quality achieved with each device at a certain dose level was characterized in terms of homogeneity, spatial resolution, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and electron density-to-CT-number conversion. RESULTS: Based on the current findings for head-sized phantoms all devices show an electron density-to-CT-number conversion almost independent of the imaging parameters and hence can be suited for treatment planning purposes. The evaluation of the image quality, however, points out clear differences due to the different energies and geometries. The Primatom standard CT scanner shows throughout the best performance, especially for soft tissue contrast and spatial resolution with low imaging doses. Reasonable soft tissue contrast can be obtained with slightly higher doses compared to the CT scanner with the kVCB and the Tomotherapy unit. In order to get similar results with the MVCB system a much higher dose needs to be applied to the patient. CONCLUSION: Considering the entire investigations, especially in terms of contrast and spatial resolution, a rough tendency for decreasing image quality can be given: Primatom, Artíste prototype kVCB, Tomotherapy, Artíste prototype MVCB.     

The use of an aSi-based EPID for routine absolute dosimetric pre-treatment verification of dynamic IMRT fields.

BACKGROUND AND PURPOSE: In parallel with the increased use of intensity modulated radiation treatment (IMRT) fields in radiation therapy, flat panel amorphous silicon (aSi) detectors are becoming the standard for online portal imaging at the linear accelerator. In order to minimise the workload related to the quality assurance of the IMRT fields, we have explored the possibility of using a commercially available aSi portal imager for absolute dosimetric verification of the delivery of dynamic IMRT fields. PATIENTS AND METHODS: We investigated the basic dosimetric characteristics of an aSi portal imager (aS500, Varian Medical Systems), using an acquisition mode especially developed for portal dose (PD) integration during delivery of a-static or dynamic-radiation field. Secondly, the dose calculation algorithm of a commercially available treatment planning system (Cadplan, Varian Medical Systems) was modified to allow prediction of the PD image, i.e. to compare the intended fluence distribution with the fluence distribution as actually delivered by the dynamic multileaf collimator. Absolute rather than relative dose prediction was applied. The PD image prediction was compared to the corresponding acquisition for several clinical IMRT fields by means of the gamma evaluation method. RESULTS AND CONCLUSIONS: The acquisition mode is accurate in integrating all PD over a wide range of monitor units, provided detector saturation is avoided. Although the dose deposition behaviour in the portal image detector is not equivalent to the dose to water measurements, it is reproducible and self-consistent, lending itself to quality assurance measurements. Gamma evaluations of the predicted versus measured PD distribution were within the pre-defined acceptance criteria for all clinical IMRT fields, i.e. allowing a dose difference of 3% of the local field dose in combination with a distance to agreement of 3 mm.     

Thermoluminescent dosimeters (TLD) quality assurance network in the Czech Republic.

INTRODUCTION: The Czech thermoluminescent dosimeters (TLD) quality assurance network was established in 1997. Its aim is to pursue a regular independent quality audit in Czech radiotherapy centres and to support state supervision. MATERIALS AND METHODS: The audit is realised via mailed TL dosimetry. The TLD system consists of encapsulated LiF:Mg,Ti powder (type MT-N) read with Harshaw manual reader model 4000. Basic mode of the TLD audit covers measurements under reference conditions, specifically beam calibration checks for all clinically used photon and electron beams. Advanced mode consists of measurements under both reference and non-reference conditions using a solid multipurpose phantom ('Leuven phantom') for photon beams. The radiotherapy centres are instructed to deliver to the TLD on central beam axis absorbed dose of 2 Gy calculated with their treatment planning system for a particular treatment set-up. The TLD measured doses are compared with the calculated ones. Deviations of +/-3% are considered acceptable for both basic and advanced mode of the audit. RESULTS: There are 34 radiotherapy centres in the Czech Republic. They undergo the basic mode of the TLD audit regularly every 2 years. If a centre shows a deviation outside the acceptance level, it is audited more often. Presently, most of the checked beams comply with the acceptance level. The advanced TLD audit has been implemented as a pilot study for the present. The results were mostly within the acceptance limit for the measurements on-axis, whereas for off-axis points they fell beyond the limit more frequently, especially for set-ups with inhomogeneities, oblique incidence and wedges. CONCLUSIONS: The results prove the importance of the national TLD quality assurance network. It has contributed to the improvement of clinical dosimetry in the Czech Republic. In addition, it helps the regulatory authority to monitor effectively and regularly radiotherapy centres.     

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。