早期乳腺癌保乳术后4种放疗技术的剂量参数比较

目的：比较早期乳腺癌保乳术后常规切线野（TW）、野中野调强（FIF - IMRT）、切线逆向调强（T -IMRT）和容积调强（VMAT）4种放射治疗技术的靶区和危及器官的剂量参数。方法：15例左侧早期（pT1-2 N0 M0）乳腺癌患者保乳术后接受放疗。CT 模拟定位扫描后勾画靶区和危及器官,在同一患者 CT 影像上分别做 TW、FIF - IMRT、T - IMRT 和 VMAT 4种治疗计划设计。PTV 剂量为50Gy,V47.5≥95%。4种计划的剂量限制相同。在剂量-体积直方图中读取4种计划靶区剂量的分布参数,心脏、双侧肺脏及对侧乳腺受照剂量和体积,对各参数的均数进行比较,并比较4组平均机器跳数差异。结果：4种计划都满足 V47.5≥95%。VMAT 与 T - IMRT、FIF - IMRT 和 TW 计划相比,明显提高了靶区适行指数（CI,P ﹤0.05）。VMAT、T - IMRT和 FIF - IMRT 与 TW 相比,明显改善了靶区均匀性指数（HI,P ﹤0.05）。VMAT 增加了危及器官（心脏和同侧肺脏）V 5、V10和 V20的受照射体积,但是没有增加﹥ V30的照射体积。VMAT 明显增加了右侧乳腺和右侧肺脏照射剂量（P ﹤0.05）,T - IMRT 和 FIF - IMRT 明显降低了右侧乳腺和右侧肺脏照射剂量（P ﹤0.05）。VMAT 与T - IMRT、FIF - IMRT 和 TW 相比,明显增加了机器跳数（P ﹤0.05）。结论：早期乳腺癌保乳术后放射治疗4种计划比较,VMAT 明显提高了靶区的适行性和均匀性,增加了正常组织的受照射剂量和机器跳数,延长了治疗时间。T - IMRT 和 FIF - IMRT 也提高了靶区的适行性和均匀性,降低了正常组织的受照射剂量。     

乳腺癌术后胸壁切线野与容积弧形调强技术的剂量学比较

目的:分析比较乳腺癌术后胸壁辅助放疗采用容积弧形调强技术与传统的胸壁切线野的剂量学差异。方法:随机选择需要放射治疗的乳腺癌患者10例,左右侧各5例,采用Eclipse计划系统为每位患者分别设计传统的胸壁切线野与容积弧形调强两套放射治疗计划,处方剂量均为DT50Gy/25次。用剂量体积直方图(DVH)比较靶区、心脏和肺受照射剂量和体积等参数的差异。结果:2种技术均能满足胸壁靶区剂量分布要求。与常规切线野相比,容积弧形调强技术使左侧乳腺癌患者的心脏平均V30由15.87%减少到1.58%(P=0.00),心脏平均V10由22.41%增加到37.82%(P=0.00);左肺平均V20由25.72%减少到11.35%(P=0.00),左肺平均V30由22.79%减少到4.23%(P=0.00)。右侧乳腺癌患者右肺平均V20由28.23%减少到13.55%(P=0.00),右肺平均V30由25.31%减少到5.77%(P=0.00),右肺平均V10由33.26%增加到42.08%(P=0.01)。无论左、右侧乳腺癌,容积弧形调强技术对于身体的低剂量照射范围均大于传统切线野。结论:乳腺癌术后胸壁辅助放疗采用容积弧形调强技术相对于传统的胸壁切线野,能明显减少心脏和肺的高剂量受照体积,却增加了低剂量区范围。     

深吸气屏气技术在左侧乳腺癌保乳术后动态容积旋转调强放疗中的剂量学分析

目的:比较深吸气屏气(deep inspiration breath-hold,DIBH)和自由呼吸(free breathing,FB)两种呼吸模式在左侧乳腺癌保乳术后动态容积旋转调强（volumetric modulated arc therapy,VMAT）放疗中的剂量学差异,探寻左侧乳腺癌保乳术后放疗最佳呼吸模式。方法:选取11例左侧乳腺癌保乳术后女性患者,分别在DIBH-CT和FB-CT图像上设计切线弧t-VMAT计划。结果:DIBH呼吸模式下心脏V5、V10、V20、V30、Dmean、左冠状动脉前降支Dmean、左肺Dmean、右肺V5、Dmean及右侧乳腺V5、Dmean均低于FB呼吸模式,且差异均有统计学意义（P均＜0.05）,其中心脏、左冠状动脉前降支LAD及左肺平均剂量分别下降26.2%、47.7%和11.8%。结论:DIBH呼吸模式显著降低了心脏及左冠状动脉前降支等危及器官的受照剂量,采用t-VMAT计划缩短了深吸气屏气技术的治疗时间,提高了患者舒适度,更好的保证治疗顺利进行。     

深吸气屏气在乳腺癌放射治疗中应用的研究进展

放射治疗是乳腺癌综合治疗的重要环节,但其心肺剂量则易导致放射性心脏病等并发症的发生。因此,如何减少心脏剂量、降低放疗并发症成为乳腺癌精准放疗的研究重点。深吸气屏气是一类呼吸控制方法,其应用于放疗可减少心肺等危及器官的受照剂量,以期减少放射性心脏损伤、改善患者远期预后。本文旨在概述乳腺癌放疗引起的心脏毒性及保护方法,深吸气屏气技术的剂量优势及应用,为临床和科研工作提供思路及方向。     

深吸气屏气技术在左侧乳腺癌术后放疗中的应用（附41例）

目的:探讨深吸气屏气(deep inspiration breath hold，DIBH)技术在左侧乳腺癌术后放射治疗中的剂量学优势。方法:对澳门镜湖医院在2016年4月至2017年12月期间连续收治的41例左侧乳腺癌患者，接受术后放疗的资料进行总结，比较DIBH和自由呼吸（free breath，FB）两种呼吸模式下放疗的剂量学差异，包括靶区适形性（conformity index，CI）和均匀性（homogeneity index，HI）参数，肺、心脏、左侧冠状动脉前降支（LAD）以及右侧乳腺剂量比较。结果:DIBH和FB两种模式下心脏的平均剂量、左侧冠状动脉前降支平均剂量、左肺V20有显著性差别，分别是（4.92±1.93）Gy vs （6.53±2.30）Gy（P<0.001）、（18.71±9.00）Gy vs （27.21±8.81）Gy（P<0.001）、（23.42±6.67）% vs （28.03±8.68）%（P<0.001）。单纯全乳/胸壁放疗与全乳/胸壁+区域淋巴结放疗两组在DIBH模式下，左肺V20下降的百分比分别为16.53%和24.86%，差异有统计学意义（P<0.05）。DIBH和FB的靶区适形性和均匀性均无差异。结论:采用DIBH可以显著减少心脏、冠状动脉和肺等重要器官的照射。无论是单纯乳腺/胸壁放疗还是合并区域淋巴结放疗，采用DIBH技术均可以临床获益。     

乳腺癌改良根治术后内乳淋巴结放疗患者VMAT与IMRT计划剂量学比较

目的 探讨容积调强弧形治疗(VMAT)和固定野动态调强放疗(IMRT)在左侧乳腺癌改良根治术后需辅助放疗并内乳淋巴结照射患者的剂量学差异。方法 对20例左侧乳腺癌患者制定VMAT和IMRT两种放疗计划。通过剂量体积直方图计算靶区和危及器官剂量学参数。对分类变量行χ²或Fisher′s精确概率法检验,连续变量根据正态性采用配对t检验或秩和检验。结果 IMRT靶区均匀性指数比VMAT高(P<0.05)。VMAT治疗时间较IMRT更短(P<0.01)。VMAT患侧肺V20Gy、V30Gy优于IMRT (P<0.05)。VMAT在冠脉左前降支Dmean、Dmax和心脏V30Gy、V40Gy、Dmean、Dmax优于IMRT (P<0.01)。食管DmeanVMAT优于IMRT (P<0.05),但健侧肺V5Gy、V10Gy和食管DmaxIMRT优于VMAT (P<0.05)。结论 VMAT可以显著减少心脏、健侧肺、脊髓、食管照射剂量,缩短治疗时间。对于左侧乳腺癌根治术后需辅助放疗并照射内乳淋巴结的患者,VMAT技术比IMRT技术可以更好保护正常组织。     

左侧乳腺癌保乳术后放疗对病人心肌钙蛋白的影响

目的:探讨左侧乳腺癌保乳术后切线野放疗、调强放疗对心肌钙蛋白(cTnT)的影响.方法:采用酶联免疫吸附(ELISA)法分别测定10例调强放疗(IMRT)组、10例切线野(CWTF)组、10例胸部以外部位放疗对照组患者放疗前后cTnT的变化.应用计算机治疗计划系统对IMRT计划、CWTF计划进行对比.结果:所有放疗病人放疗前cTnT均在正常范围,放疗后均显著性升高; CWTF组与IMRT组相比有显著性差异(P=0.02).与PWTF计划相比,IMRT计划的剂量分布适形度高(P=0.02),心脏、左肺受到照射的剂量显著降低(P=0.01).结论:左侧乳腺癌保乳术后IMRT技术可降低心脏受量,cTnT可作为放疗损伤标记物.     

左侧乳腺癌保乳术后调强放疗的剂量学研究

目的分析左侧乳腺癌保乳术后调强放疗(IMRT)靶区以及心脏、同侧肺的照射剂量分布情况。方法对保乳术后接受调强放疗的37例左侧乳腺癌患者采取CT定位并行调强放射治疗,采用IMRT及3D-CRT 2种照射计划,总剂量均为50 Gy,1次/d,5 d/周,共照射25次。观察比较两种计划的剂量学差异。结果 IMRT计划D95剂量高于3D-CRT计划,而IMRT的V105%、V110%、HI明显低于3D-CRT,具有统计学差异(P<0.05)。IMRT的肺V20、V30、V40以及心脏V5、V30、V40均显著低于3D-CRT的,具有统计学差异(P<0.05)。15例患者左侧乳腺体积超过500 cm3,22例小于500 cm3,经比较发现,两组患者IMRT计划的D95、V105、V110、HI比较无显著差异。结论 IMRT靶区剂量更接近于处方剂量,靶区剂量分布较3D-CRT更均匀,有更好的适形性,能更好地保护肺脏、心脏等周围组织,而且IMRT放射治疗受CTV影响较小,靶区内剂量均匀性较好。     

宫颈癌调强放射治疗靶区设计的临床研究

目的探讨宫颈癌盆腔调强放射治疗（IMRT）的计划靶区变化对危险器官受照容积百分比的影响。方法常规体外和腔内放射治疗的10例IIb～Ⅲb宫颈癌患者,放疗前行CT扫描并勾画靶区,临床靶区（CTV）包括子宫、宫颈、阴道等原发肿瘤区域及髂总、髂外、髂内、闭孔、骶前淋巴结等区域及其周围组织,计划靶区（PTV）以CTV为基础向外放不同距离形成PTVA、PTVB、PTVC和PTVD,通过DVH图与传统前后两野等中心照射技术对比,了解随着计划靶区的变化,危险器官受照容积的变化。结果膀胱和小肠接受30GY、40GY、45GY剂量的容积采用IMRT技术均小于前后两野照射技术,随着靶区的扩大,受照容积随之增加（P=0．000）。但是,与前后两野对比,IMRT计划并非均能很好地保护直肠,靶区向后扩大≤10mm,直肠受照容积的变化才具有统计学差异（P=0．001）,靶区扩大至15mm时,直肠受照容积无论是低剂量或是高剂量IMRT计划均大于前后两野照射。结论采用IMRT技术代替常规体外放疗能减少膀胱、小肠和直肠受照容积,其优势随着计划靶区的扩大而减少,靶区的精确勾画和定位的高度重复性,以及对内在器官运动的了解,是IMRT的基础。     

乳腺癌保乳术后调强放疗与常规放疗的剂量学比较

 目的　探讨早期乳腺癌保乳术后全乳适形调强放射治疗（IMRT）的剂量学优势。方法　选择10例接受保乳手术的Tis~2N0M0早期乳腺癌病例,其中左侧乳腺癌6例,右侧乳腺癌4例,应用三维治疗计划系统（3D-TPS）为每位患者设计两种全乳放射治疗计划,即切线野常规计划与IMRT计划,处方剂量均为50 Gy／25次。用剂量体积直方图（DVH）来比较两种计划中计划靶体积（PTV）、危及器官（OARS）的剂量学差异。结果　靶区覆盖率在两种计划中相似,分别为97.83 %、97.61 %,与常规计划相比IMRT计划的PTV接受＜95 %处方剂量与＞103 %处方剂量的体积百分比之和（IHI） 从25.42 %减少到2.71 %,PTV接受至少105 %处方剂量照射的体积百分比（V105 %）从25.79 %减少到1.08 %,IMRT计划改善IHI和减少V105 %的平均值,在PTV较大的患者中更明显。左侧乳腺癌患者心脏的平均剂量（Dmean）从6.72 Gy减少到4.95 Gy、心脏接受30 Gy照射的体积百分比（V30）从7.23 %减少到1.04 %。所有患者同侧肺的Dmean从9.19 Gy减少到7.65 Gy、至少接受20 Gy 照射的体积百分比（V20）从22.34 %减少到20.18 %。对侧乳腺Dmean从5.12 Gy减少到3.52 Gy,对侧肺Dmean从2.76 Gy减少到1.79 Gy。右侧患者肝脏Dmean从7.23 Gy减少到1.04 Gy。结论　全乳IMRT的剂量学优势主要是在保证靶区覆盖率的前提下,显著改善了靶区剂量分布的均匀性,并在一定程度上降低OARS的受照剂量与容积,乳房体积大的病例可以通过IMRT获得更好的剂量学结果。     

Dosimetric comparison between IMRT and VMAT in patients undergoing internal mammary lymph node radiotherapy after modified radical mastectomy

Objective To investigate the dosimetric differences in volumetric-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) in patients receiving adjuvant radiotherapy and internal lymph node irradiation after left-sided modified radical mastectomy. Methods VMAT and IMRT radiotherapy plans were established for 20 patients undergoing left-sided modified radical mastectomy. The dosimetric parameters of the target area and organs at risk were calculated by the dose volume histogram. The categorical variables were tested by χ² or Fisher′s exact probability test. The continuous variables with normal distribution were analyzed by paired-t test or rank-sum test. Results Among the two radiotherapy techniques, the homogeneity index of IMRT was significantly higher than that of VMAT (P<0.05). The time of VMAT treatment was significantly shorter than that of IMRT (P<0.01). VMAT was superior to IMRT in V20Gy and V30Gy of the affected lung (both P<0.05). VMAT was superior to IMRT in the left anterior descending coronary artery Dmean, Dmax, and heart V30Gy, V40Gy, Dmean and Dmax(all P<0.01). The esophageal Dmean in the VMAT group was superior to that in the IMRT group (P<0.05). The V5Gy and V10Gy of the contralateral lung and the Dmax of the esophagus in the IMRT group were significantly better compared with those in the VMAT group (all P<0.05). Conclusions VMAT can significantly reduce the dose of the heart, contralateral lung, spinal cord, esophagus and other vital organs, and shorten the treatment time. For patients who need adjuvant radiotherapy and internal mammary lymph node irradiation after left-sided modified radical mastectomy, VMAT technology can better protect normal tissues than IMRT.     

Postmastectomy Radiation Therapy Planning After Immediate Implant-based Reconstruction Using the European Society for Radiotherapy and Oncology-Advisory Committee in Radiation Oncology Practice Consensus Guidelines for Target Volume Delineation

AimsTo evaluate how common radiation therapy techniques perform in the setting of the new European Society for Radiotherapy and Oncology-Advisory Committee in Radiation Oncology Practice (ESTRO-ACROP) delineation recommendations for immediate breast reconstruction (IBR).Materials and methodsSeven Danish radiation therapy centres and six international European centres participated in this project. Two breast cancer cases (one left-sided and one right-sided) with a retropectoral implant were chosen for radiation therapy planning using deep-inspiration breath-hold. Target volumes were delineated according to ESTRO-ACROP delineation recommendations. The centres were asked to plan the cases using any radiation therapy technique according to the Danish Breast Cancer Group plan objectives.ResultsIn total, 35 treatment plans were collected. Half of the submitted plans, for both the left-sided and the right-sided case, used the field-in-field (FiF) technique (nine for each), a quarter used volumetric arc radiation therapy (VMAT; five for right-sided, four for left-sided) and the remaining quarter was a mix of inverse intensity-modulated radiation therapy (IMRT), helicoidal therapy and hybrid (combined open fields and VMAT) techniques. Mean clinical target volume doses were in the range 99–102% of the prescribed dose. The median FiF mean heart dose (MHD) for right-sided radiation therapy was 1 Gy (range 0.8–3.7) and 5.2 Gy for left-sided radiation therapy (range 2.2–6.5). For right-sided radiation therapy, the median VMAT MHD was 3.42 Gy, for IMRT was 2.3 Gy and for helicoidal therapy was 5.1 Gy. For left-sided radiation therapy, the median VMAT MHD was 6.3 Gy, for IMRT was 7.8 Gy and for helicoidal therapy was 7.3 Gy.ConclusionsDifferent radiation therapy techniques could be used to plan radiation therapy in the setting of IBR. FiF provided good coverage with acceptable organ at risk doses. The best dose distribution results as a trade-off between the objectives of target volume coverage and high-dose organ at risk inclusion. The radiation therapy technique affects the interplay between these objectives.     

左乳腺癌保乳术后不同放疗方式的剂量学比较

目的:评价左乳腺癌保乳术后三种放疗方式（3DCRT,IMRT,VMAT）的剂量学特点。方法:选取本院2015年5月至2016年2月期间20例早期左乳腺癌保乳术后放疗患者,所有靶区及危及器官均由同一高级放疗医师勾画,包括临床靶区（CTV）、计划靶区（PTV）及危及器官（OAR）,并由同一高级放疗物理师分别设计3DCRT、IMRT、VMAT 三种治疗计划,处方剂量为50 Gy。比较三种计划的计划靶区（PTV）的靶区均匀性指数（HI）及适形度指数（CI）,最大剂量（Dmax）、平均剂量（Dmean）、最小剂量（Dmin）;肺、心脏的V5,V10,V20,V30,V40,Dmax,Dmean及Dmin等。结果:3DCRT、IMRT、VMAT三种放疗计划适形度指数（CI）分别为 0.75±0.08、0.84±0.04和0.89±0.04(P＜0.05),均匀性指数(HI)分别为 0.11±0.12、0.11±0.08 和0.10±0.09。VMAT与IMRT计划降低了危及器官高剂量区体积,但相应增加了低剂量区体积,尤其VMAT计划的心脏、患侧肺V5、V10明显增加(P＜0.05)。结论:IMRT计划不仅提高了靶区的适形度,而且降低了心脏和肺的低剂量受照体积及平均剂量。因此,IMRT计划更适用于左乳腺癌保乳术后的放射治疗。     

乳腺癌根治术后 VMAT技术对心脏受照剂量风险评估

目的：分析乳腺癌根治术后VMAT技术对心脏的物理剂量学和生物学的指标,评估心脏的受照风险。方法随机选取10例左侧乳腺癌根治术后患者,设计4种常用计划：①改良野中野调强计划FIF（8～10个子野）;②四野调强计划4F-IMRT;③五野（增加正对心脏射野）计划5F-IMRT;④包含心脏正对弧双弧VMAT计划。统计每个患者靶区、心脏和冠状动脉左前降支区LAD剂量体积参数,用NTCP-RSM模型计算放射性心脏病死亡率。统计分析VMAT技术的结果与其余技术之间的差异。结果患者心脏Dmean和V25在4种计划下平均值分别是：7．7 Gy,6．9 Gy,9．7 cGy,6．4 Gy;9．1％,7．9％,9．7％,4．9％;LAD的平均剂量分别是29．0 Gy,27．6 Gy,32．8 Gy,26．1 Gy;NTCP的平均值分别为2．7％,1．1％,1．3％,0．86％。靶区CI四套计划平均值为：0．44、0．56、0．61、0．71,HI为0．82、0．78、0．70、0．53,VMAT技术的CI和HI结果与另外3种的结果有统计学差异（ P＜0．05）。结论与常规调强技术相比,包含心脏正对弧的VMAT计划不会显著影响心脏的并发症概率（ NTCP）,同时VMAT计划靶区的CI、HI要优于静态IMRT计划,VMAT技术可以在提高靶区剂量的同时不明显增加心脏的受照风险。     

Target Volume Coverage and Organ at Risk Doses for Left-sided Whole-breast Irradiation With or Without Internal Mammary Chain Irradiation: A Comparison Between Three Techniques Representing the Past and the Present

AimsThe 15-year results of the EORTC 229922-10925 phase III trial showed a significant reduction in breast cancer mortality and breast cancer recurrences after internal mammary chain (IMC) and medio-supraclavicular irradiation. Unexpectedly, cardiac death was not increased, and the incidence of cardiac events did not differ between left- and right-sided cases, although target volume coverages and organ at risk doses were unknown. Therefore, a planning study was carried out comparing the past and the present, to eventually enable, thereafter, an increased therapeutic ratio of IMC irradiation.Materials and methodsA planning study was carried out on target volume coverage and organ at risk doses for whole-breast irradiation (WBI) ± IMC comparing the results between two-dimensional radiotherapy (free-breathing), hybrid intensity-modulated radiotherapy (IMRT; breath-hold) and robust intensity-modulated proton therapy (IMPT; free-breathing) for 10 left-sided breast cancer cases. Two-dimensional radiotherapy consisted of two tangential wedged photon breast fields and mixed electron/photon beams for the IMC. Hybrid IMRT included two tangential photon breast fields (70%) complemented with IMRT (30%). IMPT plans were created using multi-field robust optimisation (5 mm set-up and 3% range uncertainties) with two (WBI) or three (WBI + IMC) beams.ResultsTarget volume dose objectives were met for hybrid IMRT and IMPT. For two-dimensional radiotherapy, target coverage was 97% and 83% for breast and IMC, respectively. The mean heart dose for WBI only was <2 Gy for all techniques. For WBI + IMC, heart doses (mean heart dose, mean left anterior descending region, volume of the heart receiving 5 Gy (V5) were significantly higher for two-dimensional radiotherapy when compared with contemporary techniques. The V5 left anterior descending region reduced from 100% (two-dimensional radiotherapy) to 70% and 20% for hybrid IMRT and IMPT, respectively. Conclusion: Contemporary radiotherapy techniques result in improved target volume coverage and significantly decreased heart doses for WBI + IMC radiotherapy. Hence, nowadays an increased therapeutic ratio of elective IMC irradiation may be anticipated.     

Inversely planned intensity modulated radiotherapy of the breast including the internal mammary chain: a plan comparison study

The aim of this paper is to evaluate the benefit of inversely planned intensity modulated radiotherapy (IMRT) in the adjuvant irradiation of breast cancer when internal mammary lymph nodes are included in the treatment volume. 20 patients treated with 3D-planned conventional radiotherapy (CRT) following breast conserving surgery were included in the study. We chose 10 patients with left-sided and 10 patients with right-sided tumors. All treatment volumes included the internal mammary chain. For plan comparison to the applied CRT plan an inverse IMRT-plan in, step-and-shoot'-technique was calculated. For all patients IMRT resulted in an improved conformity of dose distribution to the target volume compared to CRT (mean COIN95: 0.798 vs. 0.514 with COIN95 = C1 * C2 (C1= fraction of CTV that is covered by > 95% of the prescribed dose and C2 = volume of CTV that is covered by > 95% of the prescribed dose/total volume that is covered by > 95% of the prescribed dose). In all cases with matching adjacent beams, the homogeneity in the target volume was improved. The volume of the ipsilateral lung irradiated with a dose higher than 20 Gy was reduced with IMRT from 24.6% to 13.1% compared to CRT. For left-sided target volume the heart volume with a dose higher than 30 Gy was reduced from 6.2% to 0.2%. The presented plan comparison study for irradiation of the breast and the parasternal lymph nodes showed a substantial improvement of the dose distribution by inversely planned IMRT compared to CRT. This is visible for the target volume, the ipsilateral lung and, in case of left-sided target volume, the heart. Despite an increase in integral dose to the entire normal tissue, the application of IMRT might be clinically advantageous in cases where no satisfying dose distribution can be obtained by CRT.