基于CBCT的体表标记点辅助配准方法在体部肿瘤放疗摆位中的应用研究

目的:应用基于CBCT(cone beam computed tomography)的体表标记点辅助图像配准方法,提高肿瘤放射治疗摆位验证的工作效率。方法:选取胸部、腹部、盆腔共30例肿瘤放疗患者,定位及治疗摆位时体表粘贴标记点。CBCT扫描验证时,医师、主管技师、技师先进行常规图像配准,后采用体表标记点辅助图像配准,以医师常规图像配准为基础分别进行比较。结果:常规图像配准时,主管技师对比医师在胸部、腹部及盆腔部位的X、Y、Z轴上的差异均无统计学意义;技师对比医师在腹部的X、Y、Z轴上及胸部、盆腔部位的X、Y轴上的差异无统计学意义,在胸部及盆腔部位的Z轴上P值分别为0.006,0.014,有显著意义。标记点辅助图像配准时,医师、主管技师及技师对比医师常规图像配准在胸部、腹部及盆腔部位的X、Y、Z轴上的差异均无统计学意义。图像配准的误差发生率腹部大于胸部及盆腔。医师、主管技师、技师分别与自己对比在胸部、腹部及盆腔部位的图像配准完成时间上P值近似于0,有显著意义。结论:以体表标记点辅助图像配准优于常规图像配准,效率高。     

鼻咽癌X射线模拟定位规范方法

按鼻咽癌放射治疗设野规范。订出X射线模拟定位之规范。以满足鼻咽癌规范设野放疗要求，并不需放疗医师到模拟机房轮候定位，又有利于规范投照及放疗技师素质的提高。     

鼻咽癌的模拟定位技术操作程序

中山大学肿瘤医院放疗科模拟机室自2001年4月开展鼻咽癌常规放疗模拟定位由模拟技师完成,收效明显.文章主要就鼻咽癌模拟定位技术操作程序作一介绍.     

技术员独立应用EPID对盆腔摆位误差监测的可行性

背景与目的:电子实时定位检验成像系统(EPID)是目前应用较多的用于分析放疗质控的工具。本研究比较技术员和医师应用EPID对摆位误差图像分析的差异,探讨技术员独立应用EPID进行摆位误差监测的可行性。方法:2005年5月—2005年8月,接受盆腔放疗12例患者。应用EPID拍摄每天前/后野,两侧野,共得到244组图像,数据由医师和技术员分别分析得到。结果:244组图像分析结果,医师和技术员在左右、前后和头脚3个方向数据分析的差异平均值分别为:(1.0±0.9)mm,(1.0±0.9)mm和(0.8±0.8)mm。两者间差异无显著性。结论:技术员可以应用EPID独立完成对盆腔摆位图像分析,进行误差的监测,为进一步进行自适应性放疗的开展积累经验。     

影响鼻咽癌放疗定位精确度因素分析

[目的]探讨影响鼻咽癌(NPC)放疗精确度的因素.[方法]两组技师每组12人,分别操纵西门子和飞利浦的模拟定位机和直线加速器,每人独立完成1例NPC病人的面膜固定,模拟定位,拍定位片.然后在模拟机下重复摆位及拍片,再到直线加速器上摆位及拍射野验证片.观察重复摆位时激光十字线与摆位标记点的重合情况,以及按解剖骨性标记定位片分别与验证片和重拍的模拟片的误差情况.[结果]①重复摆位时激光十字线与面膜上的摆位标记点模拟机下重复得较好,而治疗机下较差.②骨性标记误差范围在0～6mm之间,两组骨性标志误差在模拟机之间或者治疗机之间的比较总体没有差异(P＞0.05);而在模拟机和治疗机之间的比较却有统计学的差异(P＜0.05).[结论]重复摆位体表标记重合较好时骨性标记也可能存在较大的误差,从模拟机到治疗机之间摆位误差较大,而在模拟机之间的重复摆位误差较小.     

如何保证摆位准确

在肿瘤患者放疗过程中，放疗技师在模拟定位和执行放疗计划时的技术水平及专业态度直接影响治疗效果。在放疗过程中摆位是重要环节，准确的摆位能避免漏照、有效杀伤肿瘤细胞和保护重要的组织和器官，最终使患者的生活质量得到保证。     

低剂量4DCT扫描在肺内孤立性肿瘤模拟定位与靶区构建中的应用价值

目的:探讨低剂量4DCT扫描在肺内孤立性肿瘤模拟定位和靶区构建中的可行性。方法:23例肺内孤立性肿瘤序贯完成常规条件(CON)、低管电压(LV)、低管电流(LA)、低管电压+低管电流(LVA)条件下4DCT扫描模拟定位,基于各序列图像分别进行靶区构建与配准,比较不同扫描条件下肿瘤内运动靶区(IGTV)体积、位置、肿瘤位...     

三维CT模拟定位计划系统的临床应用研究

[目的]通过三维CT模拟定位计划系统的临床应用研究。评价其在放疗听作用。[方法]将螺旋CT,三维激光定位系统和Focus9200三维计划系统通过网络连接,形成放疗科专用的,集影像诊断,图像传送,肿瘤定位和三维计划为一体的三维CT模拟定位计划系统。分别对143例肿瘤病人进行CT模拟定位和治疗计划。[结果]CT模拟定位和X线模拟定位一样可完成从定位到体表标记的全过程,利用CT进行定位,可为靶区的确定,复杂多野照射,适形调强放疗以及立体定向放疗提供更多的图像信息和更高的定位精度,使治疗中心和实际靶中心的重复误差小于1mm。[结论]CT模拟定位可用于大多数肿瘤病人的定位,是实现高精度放疗的必备设备之一。     

PET/CT模拟定位系统在放射治疗中的初步应用

目的:评价PET/CT模拟定位系统在放射治疗中的作用。方法:将PET/CT、三维激光定位系统和Focus3.2.1三维计划系统通过网络连接,形成放疗科专用的三维PET/CT模拟定位计划系统,分别对62例肿瘤患者进行PET/CT模拟定位和治疗计划。结果:通过改造组成的PET/CT模拟定位系统,比CT模拟定位提供更丰富和准确的图像信息,指导靶区GTV的勾画和放疗效果的评价。结论:PET/CT模拟定位系统明显提高放疗的定位精度,是未来放疗治疗定位的发展趋势。     

贯彻卫生部40号令的措施探讨

放射治疗是当今治疗癌症的主要手段之一。从医生的诊断、确定肿瘤大小、定位、制订治疗方案到放疗物理师保证放疗设备各种临床物理参数的正确，以及放疗技师对患者精确摆位、放疗。这些环节的工作好坏直接影响到放射治疗疗效，缺一不可。可以这样认为，放疗医生、放射物理师、放射技师以及与放疗有关的工作人员，共同对患者完成整个治疗的全过程，放射治疗是医学、物理及相关学科所组成的综合性学科。为了保证放射治疗质量，贯彻好物号令，尽快提高我国放疗水平，放射治疗质量保证与质量控制应作为现在乃至今后研究的重要课题，有以下几方面…     

Anatomic foundation of the lateral portal for radiotherapy of nasopharyngeal cancer (NPC)

Basing on 31 normal skulls, the lateral projections of some points relative to the bony structure near the nasopharynx were located under the simulator, followed by drawing it on a sheet of paper with the aid of geometry and trigonometry. Thus, the relation between external and internal structures is shown on the drawn projection, which can serve as the anatomic basis for designing the routine field and improving radiotherapy technique. In the light of data informed by this study and clinical experiences of the authors and others, it was found logical, in radiotherapy of NPC, that large opposing lateral pre-auriculo-cervical portals with their posterior margin extending beyond the external auditory meatus posteriorly be used in order to avoid geographic miss of the uppermost deep cervical lymph nodes usually involved beneath the jugular foramen and posterior portion of the nasopharynx. In addition, the upper margin of the lateral portal must be parallel but superior to the cantho-auditory line, on which the foramen ovale is projected. Actual locating the upper margin should depend on the extent of the intracranial invasion of the tumor as shown by the CT scan.     

图像引导的放射治疗技术

胸腹部肿瘤因呼吸等生理运动处于不断运动的状态,影响成像、治疗计划和治疗过程的精确度。图像引导放疗(IGRT)技术有望解决运动肿瘤的精确治疗问题,它主要分为3个研究方向。其中,呼吸门控放疗开展较早,已经进入临床应用;集成放疗成像系统把定位和治疗设备合二为一,实现常规模拟定位、锥形束CT和实时成像等功能;射束同步放疗技术以四维CT成像技术为基础,控制动态多叶光栅使射束随着肿瘤的运动而不断运动,是最理想的放疗实现模式。     

A French survey on breast radiotherapy techniques for simulation and treatment]

Breast radiotherapy is still in progress. The target volumes - whole breast and lymph nodes - are usually located by clinical palpation and the use of bony landmarks. However computed tomography has allowed a better definition of the deep edge of the volumes and the calculation of 3D dose distributions. A survey of 194 centers has started in June 2005 in France. The questionnaire that was sent included questions about general techniques in breast radiotherapy. Preliminary results on 50 centers showed that patient anatomical data were in the vast majority acquired by a simulator-CT or a CT (for 92%). In the 50 departments, beam placement is done either directly at the simulator (20 centers), or on the TPS (16 centers). Virtual simulation software is used in 8 centers. In about 20% (11) radiotherapy departments, 3D target volumes are contoured and the beams adapted to their shapes.     

放疗网络的临床应用

目的 探讨放疗网络在临床的应用和意义。方法 放疗网络是放疗科内的局域计算机网络，将放疗及与放疗相关的设备通过网络连在一起，对患者资料进行系统管理，对放疗科工作人员按其职能权限进行分工。通过网络系统获得模拟定位机和治疗计划系统的治疗数据，在加速器治疗机上自动设置治疗参数，对每个患者的照射野、照射剂量进行检测和限制。结果 对接受治疗的150例患者进行了从病历号录入、定位、计划、验证和治疗的计算机管理，有7例需要加量治疗的患者，计算机提示并停止原治疗计划，由主管医生修正治疗计划后继续治疗。结论 放疗网络的应用避免了数据传输、人工输入中的误差，是放射治疗临床质量保证和质量控制的工具。     

三次曝光技术在后颈电子线补量中的应用

目的:IP板与自制十字板合用,采用三次曝光照相技术拍摄射野证实片,用于后颈电子线补量照射范围的确定。方法:将自制十字补板和IP板放置在相应位置,分三次曝光拍摄射野证实片,确定电子线后颈量的照射范围,然后在模拟机下同体位拍摄复合定位片,评价照射范围是否符合治疗要求。结果:8例需要后颈电子线补量的病人使用三次曝光方法拍摄射野证实片,经模拟定位机同治疗体位拍摄复合定位片证实,经主管医生确认电子线后颈补量照射野范围均符合治疗要求,PTW 2D-ARRAY729矩阵验证剂量误差符合要求。结论:采用三次曝光技术确定电子线照射野的方法,可用于鼻咽癌及其他口咽部肿瘤治疗时对后颈电子线补量,该方法操作简单方便、实用。     

Radiothérapie guidée par l’image et partage des tâches avec les manipulateurs en électroradiologie : expérience de Clermont-Ferrand

The various image-guided radiotherapy techniques raise the question of how to achieve the control of patient positioning before irradiation session and sharing of tasks between radiation oncologists and radiotherapy technicians. We have put in place procedures and operating methods to make a partial delegation of tasks to radiotherapy technicians and secure the process in three situations: control by orthogonal kV imaging (kV-kV) of bony landmarks, control by kV-kV imaging of intraprostatic fiducial goldmarkers and control by cone beam CT (CBCT) imaging for prostate cancer. Significant medical overtime is required to control these three IGRT techniques. Because of their competence in imaging, these daily controls can be delegated to radiotherapy technicians. However, to secure the process, initial training and regular evaluation are essential. The analysis of the comparison of the use of kV/kV on bone structures allowed us to achieve a partial delegation of control to radiotherapy technicians. Controlling the positioning of the prostate through the use and automatic registration of fiducial goldmarkers allows better tracking of the prostate and can be easily delegated to radiotherapy technicians. The analysis of the use of daily cone beam CT for patients treated with intensity modulated irradiation is underway, and a comparison of practices between radiotherapy technicians and radiation oncologists is ongoing to know if a partial delegation of this control is possible.     

头颈肿瘤立体定向分次照射靶区定位的误差分析

背景与目的:明确靶区定位的精确度是立体定向分次照射质量保证的基本要求。本文主要分析头颈肿瘤立体定向分次照射(fractionatedstereotacticradiotherapy,FSRT)中机械等中心、CT定位、治疗摆位以及CT图像误差等可能引起的靶区定位误差。方法:使用立体定向治疗计划系统、靶点模拟器、头部定位框架检查各个治疗阶段靶区定位的误差。设置任意5个参考点,使用靶点模拟器检查CT定位误差;选取7个不同机器臂架/治疗床角度,定期用胶片检验使用的PhilipsSL-18直线加速器等中心误差大小;用验证片检查治疗摆位误差;对自制模体行CT扫描,分析CT图像伪影可能引起的图像误差。结果:CT定位误差约为(1.5±0.4)mm;在检查的不同机器臂架/治疗床角度中机械等中心最大误差为(1.0±0.6)mm;患者摆位的距离误差为(1.0±0.3)mm;整个治疗过程中靶区定位误差约为(2.1±0.8)mm。结论:立体定向分次照射中需要综合考虑各个阶段中可能对治疗靶区定位产生的影响,误差分析结果可用来确定治疗的计划靶区。     

食管癌后程加速超分割放疗疗效观察

目的:探讨后程加速超分割放射治疗食管癌的疗效.方法:120例食管癌患者分为常规放射治疗组和后程加速超分割组(LCAF),加速组先常规放疗,前后对穿照射40Gy/20次(1次/d,2Gy/次,5次/周),而后复查食管X线片,在模拟机下定位后治疗,剂量为30Gy/20次(1.5Gy/次,2次/d,间隔6-8h,10次/周),2周完成.总剂量:70Gy/40次/6周.比较两种方法治疗效果及不良反应和并发症.结果:常规放射治疗组和LCAF组1年、2年、3 年局控率分别为 41.7%、28.3%、21.7%和66.7%、51.7%、46.7%(P＜0.01).1年、2年、3年生存率分别为46.7%、30%、20%和71.7%、58.3%、46.7%(P＜0.01).食管炎、气管炎、食管狭窄分别为18.3%、16.7%、3.3%和21.7%、21.7%、5%(P＞0.05).结论:后程加速超分割放射治疗食管癌的疗效比常规放射治疗提高了近1倍,虽然急性放疗反应有所增加,但患者均可耐受.     

Bone marrow doses and leukaemia risk in radiotherapy of prostate cancer.

BACKGROUND AND PURPOSE: As more and more patients with prostate cancer are cured and survive with only minor chronic morbidity, other potentially treatment related morbidity, in particular second cancers, becomes an urgent problem which may influence decisions on treatment strategy and treatment plan optimisation. Epidemiological data suggest a radiotherapy associated risk of AML in prostate cancer patients of approximately 0.1% in 10 years. The aim of the study was to determine the range of bone marrow doses from different treatment plans and in different patients in order to develop criteria for optimisation of treatment plans in conformal radiotherapy of prostate cancer to further minimise the small risk of secondary leukaemia. MATERIALS AND METHODS: Doses to the pelvic bone marrow were calculated for eight different plans used in radiotherapy of prostate cancer to determine the variability of bone marrow doses in radiotherapy of prostate cancer. Computer tomography (CT) slices of the entire pelvic region of an Alderson phantom were acquired and transferred to the TPS. Critical bone marrow structures were outlined in each slice. Different treatment plans were evaluated on this phantom and dose-volume histograms (DVH) for the pelvic bone marrow were obtained. Similarly, the DVH for the bone marrow of 14 patients who received conformal radiotherapy for prostate cancer was determined. RESULTS: Mean total bone marrow doses ranged from 3.4 to 5.6 Gy in the phantom study. Approximately 99% of the mean dose to the total bone marrow comes from the dose to bone marrow located in the pelvic bones and lumbar vertebrae. Mean bone marrow doses of 14 patients given the same conformal radiotherapy plan ranged from 3.5 to 7.7 Gy. CONCLUSIONS: No correlation was found between the rectum normal tissue complication probability (NTCP) and the mean bone marrow dose. This means that in the process of treatment planning, exposure to both critical organs, the rectum as well as the bone marrow, should be minimised independently to arrive at the optimal treatment plan.