CT模拟在放射治疗中的应用

三维ＣＴ模拟定位计划系统 (ＣＴｓｉｍｕｌａｔｉｏｎａｎｄ 3Ｄｔｒｅａｔｍｅｎｔｐｌａｎｎｉｎｇｓｙｓｔｅｍ ,3ＤＣＴ -Ｓｉｍ)是将放射治疗定位专用螺旋ＣＴ、激光定位系统和三维治疗计划系统三者通过网络连接 ,形成集影像诊断、图像传送、肿瘤定位和治疗计划为一体的高精度肿瘤定位计划系统。本院从 1999年 2月在国内率先开展了这一先进技术 ,并已对 143例各类肿瘤进行了ＣＴ模拟定位和三维治疗计划 ,现将其技术特点和在放射治疗中的应用报道如下。1　材料与方法1.1　设备 :螺旋ＣＴ基本同于诊断用螺旋ＣＴ ,但要求机架孔径 >70ｃ…     

乳腺癌放射治疗的剂量分割研究进展

放射治疗在乳腺癌的治疗中起重要作用，目前常用的剂量分割方法是1．8-2Gy／次，1次／d，5d／周，术后放射治疗的总剂量为45-50Gy，总疗程约为5周；很多单位对于高危区域，如保乳手术后的瘤床区还进行局部推量。在乳腺癌前瞻性随机对照研究中，放射治疗大部分是采用这一方案，如美国的NSABP、RTOG、欧洲的EORTC和DBCG等系列研究，其疗效通过长期观察得到了证实，表现为乳腺癌根治术后放射治疗可将局部区域复发率降低2／3，保乳术后放射治疗可以使局部控制率达到与根治术相似的疗效。虽然在世界范围内这一方案得到了广泛使用，但仍有很多应用非常规剂量分割方案治疗乳腺癌的尝试，笔者就此做一综述。     

食管癌放射治疗CT模拟和常规模拟定位的对比

目的　对比食管癌放射治疗中CT模拟和常规模拟定位的优劣。方法　对10例食管胸段癌病例,同时行CT模拟定位和常规模拟定位。全部设机架角为0°、120°、240°的等中心3个野,照射野长度为所见病灶上下各扩大3?cm。常规模拟野宽度分别为前野6?cm,后斜野5?cm,CT模拟野宽为大体肿瘤区（GTV）最大径外扩大10?mm。对以上二种定位方法所描述靶区大小、等中心位置、照射野大小的差异和剂量分布情况进行对比分析。结果　二种定位方法等中心点位置在X、Y、Z3个轴上分别相差（4.2±2.6）、（3.4±2.7）、（15.4±10.6）?mm。二者的照射野大小差异有显著性意义［宽（6.0±1.1）?cm对（5.3±0.5）?cm,t=3.54,P<0.01;长（12.8±3.0）?cm对（16.4±4.1）?cm,t=6.17,P<0.01］。GTV完全被90%等剂量线所包括的计划中CT定位有10例、常规定位只有1例;脊髓最大受照剂量低于计划75%的,CT定位只有2例而常规定位有7例。结论　CT模拟定位较常规模拟定位更充分显示肿瘤外侵范围并反映其非对称生长,但在确定病灶长度时不如后者;用CT定位时常规食管吞钡X射线片仍有重要的参考价值。     

调强放射治疗的临床应用

随着计算机技术和放射治疗计划系统的飞速发展，放射治疗技术日新月异，相继出现了三维适形放射治疗（three-dimensional radiotherapy，3D-CRT）和调强放射治疗（intensity modulated radiotherapy，IMRT）。3D-CRT的目的是使放射治疗的三维高剂量分布与靶区的三维形状一致，以保护靶区周围的正常组织。     

乳腺癌放射治疗CT模拟定位技术

CT模拟定位系统为Picker公司的ACOPlan软件系统和PQ5000螺旋CT组成.病人用真空袋固定体位,于治疗体位下在PQ5000CT上行定位扫描获得图像资料;在ACQplan系统上用视束观(BEV)并借助有关轮廓线及各种断面和三维立体图像于数字重建图像(DRR)设计照射野.技术一采用锁骨上野上半野及切线野前半野及二个等中心,辅以转床和挡块消除锁骨上野和切线野的交叉.技术二采用锁骨上半野及切线1/4野、用同一等中心,有适形挡块挡去肺组织.二种定位方法均准确可行,技术二因为只有一个等中心点,治疗摆位更加方便,但因为采用的下半野长度经常超出了楔形板的长度,故无法使用楔形板,会使胸壁的剂量分布均匀度受到一定程度的影响.     

乳腺癌调强放射治疗方法的研究现状

全乳根治性放射治疗作为早期乳腺癌保留乳房综合治疗的主要手段之一 ,传统上采用以切线野为主的技术 ,获得了较满意的局部控制率和长期美容效果 ,心肺等器官放射治疗并发症发生率较低[1] 。但在部分乳房体积大或胸廓外形特殊的患者中仍存在某些缺陷 :全乳靶区内剂量分布不够均匀 ,心脏、肺等危及器官局部受到过量照射。调强放射治疗(intensitymodulatedradiationtherapy,IMRT)可对射野内各点的输出剂量按要求进行调制 ,从而使靶区三维剂量分布更加适形 ,显著改善靶区剂量均匀性同时减少周围器官的照射 ,有望进一步减少并发症 ,提高生活质…     

PET/CT在乳腺癌临床治疗决策中的应用

PET是利用肿瘤组织与正常组织的生物学特点的差异而成像的功能显像方法.目前,临床上应用最广泛的放射性示踪剂是葡萄糖结构类似物2-18F-脱氧葡萄糖(18F-FDG),PET与CT的结合使肿瘤复杂的分子代谢变化与解剖结构的准确定位相结合,从而为肿瘤的准确诊断和明确分期提供了更精确的影像资料.     

CT在立体定向放射治疗中的新用途

目的　探讨CT在立体定向放射治疗中的新作用。方法　在某些情况下 ,用配备 3D激光定位的CT模拟机替代框架定位的可能性 ,3 0例头、体部肿瘤患者分别采用框架系统与CT模拟技术与相应的GREAT立体TPS与A thens三维TPS经光缆联网。各自独立设计治疗计划和定位坐标。结果　在相同条件下 , 5cm、4cm、3cm ,剂量误差分别为 1%、1.5 %、2 %。等剂量曲线及DVH图相似。定位误差在头部无差异 ,在体部小于 + 1mm。结论　CT无框架定位技术与可替代框架定位系统用于立体定向放射治疗的定位。     

CT模拟定位在食管癌放射治疗中的应用

目的 探讨食管癌放射治疗时利用CT模拟定位的疗效。方法 对103例食管癌病例用CT模拟定位，全部病例以肿瘤中心为照射野的等中心点，照射野长度为肿瘤上、下缘放大3cm，野宽为肿瘤边缘外放1cm，总剂量为Dr60Gy-70Gy/次，5次/周，6-7周内完成。结果 103例病例近期疗效显示完全缓解率达55.3%，部分缓解率为37.9%，1、3年生存率分别为73.4%和56.1%。在己死亡的42例中，因局部失败只占38.1%，而远移和淋巴结转移占54.8%。结论 利用CT模拟定位，以肿瘤中心为射野等中心点对食管癌进行外照射，可明显提高局部控制率，提高生存率，在巳死亡的病例中，远处转移和淋巴结转移的比例明显上升。     

放射治疗乳腺癌的模拟定位技术

放射治疗乳腺癌的模拟定位技术李德锐陈志坚关键词乳腺肿放射治疗模拟定位中图号Ｒ７３７．９乳腺癌放疗在技术上应符合下列要求：（１）避免靶区漏照，又应尽量避免野间射线扩散重叠以减少正常组织的损伤；（２）摆位和照射技术必须简便，重复性好。由于多野连接和射线束...     

CT-Sim技术在乳腺癌放射治疗中的应用

用大恒STAR 2 0 0 0三维放射治疗系统、GE双螺旋CT、国产北医BJ 6B型加速器对乳腺癌患者实施精确定位、虚拟计划设计、射野间无缝连接照射 ,可提高患者重复摆位的精度 ,定位时间短 ,射野间衔接好 ,患者皮肤反应轻 ,放射性肺炎发生率明显下降。     

乳腺癌术后辅助放疗研究的进展

放射治疗在乳腺癌综合治疗中发挥着重要的作用.随着乳腺癌临床-病理、肿瘤生物学特性研究的深入,化疗/内分必治疗的规范化应用,对传统乳腺癌术后辅助放疗的指征与方式、方法受到质疑,学者应重新认识.鉴于放射治疗在理念、原则、技术等方面都在不断的变化,放疗要有目标性而不是传统的包括区域淋巴结在内的大野照射,旨在提高肿瘤局部控制率和生存率的同时如何减少或避免放射损伤.为规范乳腺癌术后辅助放疗,本文综述近年来相关的临床研究,提出乳腺癌术后各部位辅助放疗的指征、技术方法及剂量.     

The survival of inoperable breast cancer treated with radiotherapy and radiotherapy followed by mastectomy

Forty-five patients with locally advanced breast carcinoma were treated by radiotherapy. Twelve of them became operable and were operated. After 3 and 4 years in comparable clinical stage the rate of metastases in the nonoperated group was 78.6% and in the operated 75%. The survival after 3 and 4 years in comparable clinical stages was similar. In more advanced stages the survival was worse. Considering the trauma of mastectomy and the similar survival obtained in our material, an international trial should be performed to decide whether inoperable breast cancer becoming operable after radiotherapy should be operated.     

CT planning for breast cancer

Radiotherapy to the affected breast or chest wall is well established as an integral part of postoperative management of breast cancer. However, it is known to be associated with increased cardiac and pulmonary morbidities and mortalities. Modern technologies, such as CT planning, have shown to improve treatment planning by accurately delivering optimal doses to the target volumes, while minimizing doses to sensitive structures, thus reducing potential treatment‐related adverse effects. The purpose of this study is to report on our experiences with CT planning of adjuvant radiotherapy for breast cancer.     

Radiation-induced malignancies following radiotherapy for breast cancer

With advances in diagnosis and treatment, breast cancer is becoming an increasingly survivable disease resulting in a large population of long-term survivors. Factors affecting the quality of life of such patients include the consequences of breast cancer treatment, which may have involved radiotherapy. In this study, we compare the incidence of second primary cancers in women who received breast radiotherapy with that in those who did not (non-radiotherapy). All women studied received surgery for their first breast cancer. Second cancers of the lung, colon, oesophagus and thyroid gland, malignant melanomas, myeloid leukaemias and second primary breast cancers were studied. Comparing radiotherapy and non-radiotherapy cohorts, elevated relative risks (RR) were observed for lung cancer at 10-14 years and 15 or more (15+) years after initial breast cancer diagnosis (RR 1.62, 95% confidence interval [CI] 1.05-2.54 and RR 1.49, 95% CI 1.05-2.14, respectively), and for myeloid leukaemia at 1-5 years (RR 2.99, 95% CI 1.13-9.33), for second breast cancer at 5-10 years (RR 1.34, 95% CI 1.10-1.63) and 15+ years (RR 1.26, 95% CI 1.00-1.59) and oesophageal cancer at 15+ years (RR 2.19, 95% CI 1.10-4.62).     

Tattoo allergy in patients receiving adjuvant radiotherapy for breast cancer

Tattooing is routinely employed prior to radiotherapy treatment but allergies to tattoos are rare. New information on the incidence of tattoo allergy at St George Hospital is presented with details of two clinical cases. The literature on tattoo allergy has been unable to estimate the incidence of allergic reaction to tattoos because the total number of patients treated is unknown and not all patients were followed up. Our radiation oncology population for the first time has provided a known denominator, but wide confidence intervals prevent an accurate estimate of the incidence. Salient issues about tattoo allergy are highlighted based on a review of the published literature from 1966 to 1998.     

Lactation following conservation surgery and radiotherapy for breast cancer

A 38-year-old woman with early stage invasive breast cancer was treated with wide excision of the tumor, axillary lymph node dissection, and breast irradiation. Three years later, she gave birth to a normal baby. She attempted breast feeding and had full lactation from the untreated breast. The irradiated breast underwent only minor changes during pregnancy and postpartum but produced small amounts of colostrum and milk for 2 weeks postpartum. There are only a few reports of lactation after breast irradiation. These cases are reviewed, and possible factors affecting breast function after radiotherapy are discussed. Because of scant information available regarding its safety for the infant, nursing from the irradiated breast is not recommended.     

Cancer risk after radiotherapy for breast cancer

Among women with breast cancer, we compared the relative and absolute rates of subsequent cancers in 1541 women treated with radiotherapy (RT) to 4570 women not so treated (NRT), using all registered in the Swiss Vaud Cancer Registry in the period between 1978 and 1998, and followed up to December 2002. Standardised incidence ratios (SIRs) and the corresponding 95% confidence intervals (CIs) were based on age- and calendar year-specific incidence rates in the Vaud general population. There were 11 lung cancers in RT (SIR = 1.40; 95% CI: 0.70-2.51) and 17 in NRT women (SIR = 0.76; 95% CI: 0.44-1.22), 72 contralateral breast cancers in RT (SIR = 1.85; 95% CI: 1.45-2.33) and 150 in NRT women (SIR = 1.38; 95% CI: 1.16-1.61), and 90 other neoplasms in RT (SIR = 1.37; 95% CI: 1.10-1.68) and 224 in NRT women (SIR = 1.05; 95% CI: 0.91-1.19). Overall, there were 173 second neoplasms in RT women (SIR = 1.54, 95% CI: 1.32-1.78) and 391 among NRT women (SIR = 1.13, 95% CI: 1.02-1.25). The estimates were significantly heterogeneous. After 15 years, 20% of RT cases vs 16% of NRT cases had developed a second neoplasm. The appreciable excess risk of subsequent neoplasms after RT for breast cancer must be weighed against the approximately 5% reduction of breast cancer mortality at 15 years after RT.     

早期乳腺癌保乳术后的放疗时机

早期乳腺癌保留乳房手术加放疗的疗效与根治术相同。对术后放疗时机的问题有一些回顾性和随机性研究,但无明确结论,近期的一些随机研究尚需要长期随访。总的来说,对于无需术后化疗的病人应尽早放疗,建议手术放疗间隔最好不超过8周。术后放疗、化疗顺序对疗效无显著影响,先放疗或先化疗均可以。对于腋窝淋巴结转移数较多的远地转移高危病人,术后可先做辅助化疗,但放疗不应延迟到术后7个月以后。如果手术切缘阳性,放疗应尽早开始。同步放化疗可以在不延迟放化疗的基础上提高局部疗效,但疗效提高有限,同时会增加急性和晚期毒副作用,不宜作为常规治疗。特殊病人需要使用时,应选择有效低毒的化疗方案,以降低治疗带来的急性毒副作用和晚期并发症。缩短放疗总时间对需要化疗的病人可以缩短手术到化疗的时间间隔,目前可行的方式有大分割放疗和乳腺瘤床同步补量技术。缩短放疗总时间是否能对疗效改善有影响,有待于临床资料证实。