食管癌束流调强与三维适形放疗计划设计的比较

食管癌的三维适形放疗与束流调强放疗正日益受到肿瘤治疗临床与放射物理界的关注。本文综合国内外最新研究结果就目前食管癌的适形放疗计划的评价指标,以及三维适形和束流调强放疗各参数及计划的优化与评价作一综述。     

Comparison of treatment plans involving intensity-modulated radiotherapy for nasopharyngeal carcinoma

PURPOSE: To compare intensity-modulated radiotherapy (IMRT) treatment plans with conventional treatment plans for a case of locally advanced nasopharyngeal carcinoma. METHODS AND MATERIALS: The study case was planned using two types of IMRT techniques, as well as a three-dimensional conformal radiotherapy technique (3D-CRT), and a traditional treatment method using bilateral opposing fields. These four plans were compared with respect to dose conformality, dose-volume histogram (DVH), dose to the sensitive normal tissue structures, and ease of treatment delivery. RESULTS: The planned dose distributions were more conformal to the tumor target volume in the IMRT plans than those in the conventional plans. With similar dose coverage of the clinical target volume (CTV), defined as delivery of minimum of 60 Gy to >/= 95% of CTV, the IMRT plans achieved better sensitive normal tissue structure sparing, while concomitantly delivering a minimum dose of 68 Gy to >/= 95% of the gross tumor volume (GTV) at a higher dose per fraction. CONCLUSIONS: Compared to conventional techniques, IMRT techniques provide improved tumor target coverage with significantly better sparing of sensitive normal tissue structures in the treatment of locally advanced nasopharyngeal carcinoma. With improvement of the delivery efficiency, IMRT should provide the optimal treatment for all nasopharyngeal carcinoma. Further studies are needed to establish the true clinical advantage of this new modality.     

Comparison of inverse-planned three-dimensional conformal radiotherapy and intensity-modulated radiotherapy for non-small-cell lung cancer

PURPOSE: Lungs are the major dose-limiting organ during radiotherapy (RT) for non-small-cell lung cancer owing to the development of pneumonitis. This study compared intensity-modulated RT (IMRT) with three-dimensional conformal RT (3D-CRT) in reducing the dose to the lungs. METHODS: Ten patients with localized non-small-cell lung cancer underwent computed tomography (CT). The planning target volume (PTV) was defined and the organs at risk were outlined. An inverse-planning program, AutoPlan, was used to design the beam angle-optimized six-field noncoplanar 3D-CRT plans. Each 3D-CRT plan was compared with a series of five IMRT plans per patient. The IMRT plans were created using a commercial algorithm and consisted of a series of three, five, seven, and nine equidistant coplanar field arrangements and one six-field noncoplanar plan. The planning objectives were to minimize the lung dose while maintaining the dose to the PTV. The percentage of lung volume receiving >20 Gy (V20) and the percentage of the PTV covered by the 90% isodose (PTV90) were the primary endpoints. The PTV90/V20 ratio was used as the parameter accounting for both the reduction in lung volume treated and the PTV coverage. RESULTS: All IMRT plans, except for the three-field coplanar plans, improved the PTV90/V20 ratio significantly compared with the optimized 3D-CRT plan. Nine coplanar IMRT beams were significantly better than five or seven coplanar IMRT beams, with an improved PTV90/V20 ratio. CONCLUSION: The results of our study have shown that IMRT can reduce the dose to the lungs compared with 3D-CRT by improving the conformity of the plan.     

IMRT或3DCRT计划评估——适形指数(CI)

目的 推荐一组适形指数用于判断IMRT或3DCRT计划中靶区和OAR受量是否满足临床剂量处方的要求。方法 从已治NSCLC的IMRT或3DCRT计划中随机抽取30例计划,按文中定义的新适形指数进行评估分析,根据评估结果选出其中待改进的计划并对其制定2个改进方案,评估改进前后计划组参数值以及靶区和OAR剂量学参数的差异并配对t检验差异。结果 30例计划中处方剂量线(面)包裹的体积比PTV体积大25%,即处方剂量线(面)包裹的体积中只有75%体积是靶区,而大约有25%PTV的正常肺组织会受到和靶区一样的剂量,30例计划中95%靶区都受到了处方剂量,虽然有5%靶区受量低于处方剂量,但仍然能保证几乎100%靶区受到了90%处方剂量;两改进组与原计划组相比,方案(1)与原临床计划组在CI₂、CI₄、CI₅、CI₆和HI中都相近(P=0.240~0.780),CI₁和CI₃不同(P=0.002、0);PTV的D_max、D_min、D_mean和正常肺组织V₅、V₂₀,心脏V₃₀、V₄₀及脊髓D_max都近似(P=0.211~0.964);方案(2)与原临床组在CI₂、CI₄和CI₅中都相近(P=0.308、0.308、0.106),在CI₁、CI₃、CI₆和HI不同(P=0.001~0.014);PTV的D_max、D_min、D_mean和正常肺组织V₅、V₂₀及脊髓D_max都不同(P=0.008~0.036),心脏V₃₀、V₄₀近似(P=0.083、0.080)。结论 文中推荐的适形指数方法定量评估了计划中靶区适形度及OAR中接受处方剂量情况,有利于设计出更高水平的个性化计划。     

中心型非小细胞肺癌三维适形放疗与调强放疗治疗计划比较

目的:对比研究中心型非小细胞肺癌(NSCLC)三维适形放疗(3D-CRT)和正向调强(fIMRT)及逆向调强(iIMRT)放疗计划特点,为中心型NSCLC放疗计划制定提供指导.方法:选择拟行根治性放疗的21例中心型NSCLC患者进行3D-CRT、fIMRT和iIMRT治疗计划设计,对3种治疗计划的相关剂量学参数进行比较.结果:3D-CRT、fIMRT 和iIMRT治疗计划的适形指数(CI)差异有统计学意义,P=0.000;均匀性指数(HI)差异也有统计学意义,P=0.032.全肺V20和全肺平均受照剂量(MLD)差异均无统计学意义,P值分别为0.896和0.926;全肺V10和全肺V35组间差异均有统计学意义,P值分别为0.001和0.022;全肺V15和全肺V30组间差异为临界值,P值分别为0.058和0.051.心脏Dmean组间差异无统计学意义,P=0.989;心脏V40组间差异也无统计学意义,P=0.934.食管V45组间差异无统计学意义,P=0.708.脊髓Dmax组间差异无统计学意义,P=0.216.结论:对中心型NSCLC而言,采用iIMRT可以获得更好的靶区适形度,但iIMRT计划的剂量均匀性优势并不显著.iIMRT对中心型NSCLC正常肺组织的影响需要辨证看待,其并没有显著降低全肺V20和MLD而且增加了全肺V10、V15及键侧肺V5、V10、V15,但其显著降低了全肺V30.iIMRT没能使中心型NSCLC患者心脏、食管及脊髓受照剂量显著下降.     

Three-dimensional conformal radiotherapy for paranasal sinus carcinoma: clinical results for 25 patients

PURPOSE: To assess local control, survival, and clinical and dosimetric prognostic factors in 25 patients with locally advanced maxillary or ethmoid sinus carcinoma treated by three-dimensional conformal radiotherapy (RT). MATERIALS AND METHODS: Surgery was performed in 22 patients and was macroscopically complete in 16. Seven patients received chemotherapy (concomitant with RT in four). The following quality indexes were defined for the 95% and 90% isodoses: tumor conformity index, normal tissue conformity index, and global conformity index. RESULTS: The median radiation dose to the planned treatment volume was 63 Gy, with a minimal dose of 60 Gy, except in 2 patients whose cancer progressed during RT. The maximal doses tolerated by the structures involved in vision were respected, except for tumors that involved the optic nerve. After a median follow-up of 25 months, 14 local tumor recurrences developed. The major prognostic factors were central nervous system involvement by disease and the presence of nonresectable tumors. The radiation dose and tumor conformity index value were not significant prognostic indicators. Two patients died of acute infectious toxicity, and two developed late ipsilateral ocular toxicity. CONCLUSIONS: Improving local control remains the main challenge in RT for paranasal tumors.     

自动和逆向3DCRT与逆向IMRT计划剂量学比较

目的 比较自动3DCRT、逆向3DCRT、逆向IMRT计划的剂量学差异。方法 选取2014—2015年间单一靶区肺癌10例和颅内肿瘤10例,经网络传输至RayStation4.5TPS。采用自动3DCRT、逆向3DCRT和逆向IMRT方法分别对20例病例进行治疗计划设计,3种PTV和OAR剂量体积限制条件一致、射野数相同,比较3种计划的等剂量分布、靶区和OAR剂量参数。采用多相关变量和双相关变量分布分析。结果 肺癌病例中IMRT计划D_98%、D_50%、D_2%、CI和HI均优于逆向3DCRT和自动3DCRT计划(P=0.007、0.001、0.002、0.000、0.000);自动3DCRT计划的CI优于逆向3DCRT计划(P=0.000),3种计划中心脏D₃₃、脊髓D_max和D_{1 cm³}、双肺的各参数受量均相近(P=0.702、0.237、0.163、0.739、0.908、0.832、0.886、0.722、0.429、0.840、0.702);颅内肿瘤病例中逆向IMRT和自动3DCRT计划的CI优于逆向3DCRT计划(P=0.002、0.034),其他靶区参数相近(P=0.648、0.783、0.256、0.931),3种计划全脑受量各参数相近(P=0.446、0.755、0.772、0.0266、0.440、0.290、0.939)。结论 单一靶区肺癌和颅内肿瘤病例中,与逆向3DCRT技术相比,自动3DCRT技术可提高靶区CI;与逆向IMRT技术相比,对OAR保护相近,考虑到3DCRT的简便性和低成本,自动3DCRT技术可以作为一种新放疗技术进行推广。     

宫颈癌术后盆腔三维适形与调强放疗剂量学与技术的研究

目的 研究宫颈癌术后盆腔三维适形放疗(3DCRT)和调强放疗(IMRT)技术建立方法,进行三维剂量学研究,找出适合临床应用的最佳方案.方法 选择宫颈癌根治性全子宫切除术及盆腔淋巴结清扫术后具有术后盆腔放疗指征的10例患者行下列研究:(1)放疗最佳体位(俯卧位或仰卧位)比较;(2)放疗时膀胱充盈状况与正常组织受照体积相关性研究;(3)放疗射野移动误差测定和靶区勾画;(4)3DCRT及IMRT计划设计及优化比较.结果 采用俯卧位固定方式患者治疗中心点的摆位误差在前后、头脚及左右方向的误差均在5 mm以内,而采用仰卧位误差均>5mm,两者差异有统计学意义.俯卧位、膀胱充盈状态时膀胱受照体积百分比较之膀胱处于排空状态时为小,且小肠和结肠受照体积百分比较之膀胱处于排空状态时为小.俯卧位、膀胱充盈状态时射野片显示放疗过程中射野移动的总误差为(7.4±1.6)mm.采用95%可信区间,CTV至PTV的外放边界可定为1cm.3DCRT 3、4、5和6个射野下PTV适形指数分别为0.46、0.67、0.68和0.68,4个以上射野数目的增加不再显著改善靶区分布和减少正常组织受照体积百分比.IMRT 5、7、9、11和13个射野下PTV适形指数分别为0.75、0.83、0.84、0.85和0.85,9个以上增加射野数目不再显著改善靶区分布和减少正常组织受照体积百分比.结论 宫颈痛术后盆腔放疗者俯卧位固定方式因摆位误差小而优于仰卧位固定方式,膀胱处于充盈状态因可使膀胱及肠道受照体积百分比减少而优于膀胱排空状态.对宫颈癌术后盆腔3DCRT和IMRT计划的三维剂量学研究表明,3DCRT以4个射野数计划为优,IMRT以9个射野数计划为优.     

鼻腔副鼻窦恶性肿瘤术后放疗临床分析

目的 探讨影响鼻腔副鼻窦恶性肿瘤术后放疗效果与预后的因素.方法 95例鼻腔副鼻窦恶性肿瘤接受术后放疗,生存率计算采用Kaplan-Meier法,生存率差异检验采用Logrank法,多因素分析采用Cox模型.结果 1,3,5,10年总生存率分别为84.2%、50.5%、44.2%和20.0%.单因素分析显示,性别、年龄、手术方法和肿瘤剂量与生存率无相关性;而临床分期、病理类型与生存率相关.多因素分析显示,临床分期、病理类型是影响预后的独立因素.视力障碍、听力障碍、口干是治疗的主要毒副作用.结论 临床分期、病理类型是影响鼻腔副鼻窦恶性肿瘤术后放疗效果和预后的重要因素,术后放疗能够提高鼻腔副鼻窦恶性肿瘤的疗效.     

Ⅱ和Ⅲ期胸段食管癌术后预防性三维放疗疗效分析

目的 分析三维适形放疗(3DCRT)或调强放疗(IMRT)技术对Ⅱ、Ⅲ期胸段食管癌根治术后预防性放疗的疗效及不良反应。方法 2004—2009年间本院行食管鳞状细胞癌根治术患者 251例,术后病理分期为Ⅱ期 95例、Ⅲ期 156例。3DCRT的 20例,IMRT的 231例,中位剂量60 Gy。采用Kaplan-Meier法计算生存率并Logrank法检验和单因素预后分析,Cox回归模型多因素预后分析。结果 随访率为98.8%,随访满3、5年者分别为159、57例。全组1、3、5年生存率分别为90.8%、56.1%、45.8%。Ⅱ_a、Ⅱ_b、Ⅲ期的 5年生存率分别65.0%、53.8%、38.4%(χ²=7.30,P=0.026)。淋巴结阴性与阳性的 5年生存率分别64.9%、40.4%(χ²=7.04,P=0.008)。单因素分析显示病理分期、淋巴结是否转移、肿瘤分化程度、脉管瘤栓为影响预后因素(χ²=7.30、7.04、8.34、9.40,P=0.026、0.008、0.004、0.002),多因素分析显示肿瘤分化程度、淋巴是否结转移、脉管瘤栓为影响预后因素(χ²=6.86、5.27、4.24,P=0.009、0.022、0.040)。主要失败原因中血道转移 58例、锁骨上淋巴结转移 14例、腹腔淋巴结转移 17例、胸腔内复发 31例。主要晚期不良反应中≥2级吻合口狭窄 5例、大出血 8例。结论 3DCRT或IMTR技术对食管癌根治术后预防性放疗明显降低放疗部位复发率和提高生存率且不良反应低。Ⅲ期和有淋巴结转移食管癌术后患者应预防性放疗。     

Comparison of intensity-modulated radiotherapy with conventional conformal radiotherapy for complex-shaped tumors

Purpose: Conformal and intensity-modulated radiotherapy (IMRT) plans for 9 patients were compared based on characterization of plan quality and effects on the oncology department.

Methods and Materials: These clinical cases, treated originally with conformal radiotherapy (CRT), required extraordinary effort to produce conformal treatment plans using nonmodulated, shaped noncoplanar fields with multileaf collimators (MLCs). IMRT plans created for comparison included rotational treatments with slit collimator, and fixed-field MLC treatments using equispaced coplanar, and noncoplanar fields. Plans were compared based upon target coverage, target conformality, dose homogeneity, monitor units (MU), user-interactive planning time, and treatment delivery time. The results were subjected to a statistical analysis.

Results: IMRT increased target coverage an average of 36% and conformality by 10%. Where dose escalation was a goal, IMRT increased mean dose by 4–6 Gy and target coverage by 19% with the same degree of conformality. Rotational IMRT was slightly superior to fixed-field IMRT. All IMRT techniques increased integral dose and target dose heterogeneity. IMRT planning times were significantly less, whereas MU increased significantly; estimated delivery times were similar.

Conclusion: IMRT techniques increase dose and target coverage while continuing to spare organs-at-risk, and can be delivered in a time frame comparable to other sophisticated techniques.     

胸上段食管癌三维适形和调强放疗剂量学对比研究

目的 筛选胸上段食管癌不同适形和调强放疗计划优选方案.方法 8例胸上段食管癌cT模拟后参考食管钡餐造影和食管镜结果勾画GTV,按统一标准外扩CTV和PTV,实施3、4、6个野适形治疗计划和3、4、5、7、9、11个野IMRT计划和s-IMRT计划,以95%PTV体积获得6000 cGy处方剂量进行归一,分析各治疗计划靶区剂量分布和危及器官受量,进行剂量学对比研究.结果 3套适形计划之间,PTV剂量参数和体积参数均相近(P＞0.05);6个野适形计划全肺V20高于4个野(P＜0.05),3、6个野适形计划MLD也高于4个野(P＜0.05).6套调强治疗计划中,3个野IMRT计划PTV D100低于9、11个野IMRT计划(P＜0.05);4个野IMRT计划IV高于9、11个野IMRT计划(P＜0.05);9、11个野IMRT计划PTV适形指数CI、剂量参数D95、体积参数V100和V95较57个野IMRT和s-IMRT计划无明显优势(P＞0.05);各IMRT计划之间危及器官受量相近(P＞0.05).胸上段食管癌4个野适形计划PTV CI、PTV剂量参数和体积参数均低于5、7个野IMRT计划和s-IMRT计划(P＜0.05);4个野适形计划全肺V20均高于5、7个野IMRT计划和s-IMRT计划(P＜0.05).结论 胸上段食管癌三维适形放疗中4个野适形计划可为优选方案,调强放疗中5、7个野IMRT计划和s-IMRT计划可为优选方案.胸上段食管癌5、7个野IMRT计划和s-IMRT计划优于4个野适形计划.     

Clinical and dosimetric study of radiotherapy for glioblastoma: three-dimensional conformal radiotherapy versus intensity-modulated radiotherapy

Journal of Neuro-Oncology - We aimed to compare three-dimensional conformal radiotherapy (3D-CRT) with intensity-modulated radiotherapy (IMRT) for the treatment of glioblastoma. Retrospective study...     

Conformal three-dimensional photon radiotherapy for paranasal sinus tumors.

BACKGROUND: Tumors in the nasal cavity and paranasal sinus are difficult to treat with radiotherapy. Usually, in addition to a two- or three-field photon technique, an interorbital electron field is required. This may result, however, in severe over- or underdosage, the latter being especially detrimental when occurring in the main tumor bulk. METHODS AND RESULTS: We present a conformal three-dimensional treatment technique that provides sufficient interorbital dose with photons only while sparing the eyes, optic nerves and chiasm, and may be considered for selected tumors in this region.     

上颌窦恶性肿瘤三维适形放疗疗效分析

为了观察三维适形放射治疗（3DCRT）上颌窦恶性肿瘤的临床疗效,对26例上颌窦恶性肿瘤患者采用3DCRT,30～54d剂量为（60～70）Gy／（13～40）次。随访时间为1、2及3年。结果治疗有效率100％,1、2及3年生存率分别为100％（26／26）、84．6％（22／26）及76．9％（20／26）。初步研究结果提示,3DCRT是上颌窦恶性肿瘤有效无创治疗手段。     

食管癌全程三维适形放射治疗的临床研究

目的:探讨食管癌全程三维适形放射治疗(3DCRT)结合后程加速超分割放射治疗的疗效及放疗毒副反应.方法:将98例食管鳞癌患者随机分为观察组和对照组,观察组(48例)全程行3DCRT,先常规分割照射,2 Gy/次,5次/周,30～36 Gy后改为加速超分割放疗,1.3 Gy/次,2次/d,总剂量60～66 Gy,6～6.5周完成.对照组(50例)常规放疗,2 Gy/次,5次/周,总剂量60～70 Gy,6～7周完成.观察两组患者的临床疗效、放疗毒副反应.结果:1、2、3年原发肿瘤的局部控制率和生存率与对照组比较,观察组明显提高,分别为87.5%、70.8%、58.3%比60.0%、42.0%、32.0%和89.6%、68.8%、56.3%比58.0%、44.0%、26.0%,差异均有统计学意义,P值均<0.05;观察组急性放射反应发生率与对照组比较略高,但两组差异无统计学意义,P>0.05.结论:全程3DCRT结合后程加速超分割放疗治疗食管癌的疗效优于常规放射治疗,并且放射性毒性可耐受.     

Outcomes and prognostic factors of conformal radiotherapy versus intensity-modulated radiotherapy for nasopharyngeal carcinoma

Introduction

This study retrospectively compared outcomes and prognostic factors of nasopharyngeal carcinoma (NPC) treated with conformal radiotherapy (CRT) and intensity-modulated radiotherapy (IMRT).

Materials and methods

The treatment records of 182 patients treated with IMRT and 198 patients treated with CRT from April 2005 to December 2007 in our hospital were reviewed. The clinical characteristics, treatment outcomes (including survival analysis and acute and late toxicity), and prognostic factors of the two groups were compared.

Results

The 4-year local?Cregional control (LRC), distant metastasis-free survival (DMFS), disease-free survival (DFS), and overall survival (OS) of the IMRT and CRT groups were 93.6 and 85.3?%, 79.1 and 73.6?%, 74.7 and 65.0?%, and 83.5 and 72.1?%, respectively. The acute radiation dermatitis and xerostomia of the two groups were significantly different (P?<?0.05). In the IMRT group, OS between different T stages could not be well separated. Multivariate analysis revealed that, in the CRT group, the clinical stage and T and N stages were significant prognostic factors for OS, DMFS, and DFS and that T stage was a significant prognostic factor for LRC. In the IMRT group, T and N stages had no predictive value for outcomes.

Conclusions

Compared with CRT, IMRT has a better prognosis and less adverse effects. For IMRT, T stage was not a significant prognostic factor for LRC, DMFS, DFS, or OS. An effective treatment strategy is needed for distant control. With the increasing use of IMRT and continued modulation of treatment strategies for NPC, the current staging system faces great challenges.     

Assessment of extended-field radiotherapy for stage IIIC endometrial cancer using three-dimensional conformal radiotherapy, intensity-modulated radiotherapy, and helical tomotherapy

PURPOSE: To perform a dosimetric comparison of three-dimensional conformal radiotherapy (3D-CRT), intensity-modulated radiotherapy (IMRT), and helical tomotherapy (HT) plans for pelvic and para-aortic RT in postoperative endometrial cancer patients; and to evaluate the integral dose (ID) received by critical structures within the radiation fields. METHODS AND MATERIALS: We selected 10 patients with Stage IIIC endometrial cancer. For each patient, three plans were created with 3D-CRT, IMRT, and HT. The IMRT and HT plans were both optimized to keep the mean dose to the planning target volume (PTV) the same as that with 3D-CRT. The dosimetry and ID for the critical structures were compared. A paired two-tailed Student t test was used for data analysis. RESULTS: Compared with the 3D-CRT plans, the IMRT plans resulted in lower IDs in the organs at risk (OARs), ranging from -3.49% to -17.59%. The HT plans showed a similar result except that the ID for the bowel increased 0.27%. The IMRT and HT plans both increased the IDs to normal tissue (see Table 1 and text for definition), pelvic bone, and spine (range, 3.31-19.7%). The IMRT and HT dosimetry showed superior PTV coverage and better OAR sparing than the 3D-CRT dosimetry. Compared directly with IMRT, HT showed similar PTV coverage, lower Ids, and a decreased dose to most OARs. CONCLUSION: Intensity-modulated RT and HT appear to achieve excellent PTV coverage and better sparing of OARs, but at the expense of increased IDs to normal tissue and skeleton. HT allows for additional improvement in dosimetry and sparing of most OARs.