颈段食管癌固定野调强与旋转调强放疗计划比较研究

目的 通过比较颈段食管癌固定野调强放疗(IMRT)与旋转调强放疗(IMAT)计划,分析IMRT与IMAT在剂量学与实际应用方面特点和可行性.方法 选取10例在本院进行IMRT的颈段食管癌患者,针对相同CT图像与靶区制定单弧(IMAT1)、双弧(IMAT2)IMAT计划.使用Eclipse(R) ver 8.6计划系统,6 MV X线.模拟处方剂量为60 Gy分30次,计划要求97%计划靶体积(PTV)(V98)达98%处方剂量,超过110%处方剂量PTV(V110)<15%.脊髓最大剂量≤45 Gy.通过剂量体积直方图统计PTV相关剂量参数、适形指数(CI)、均匀指数(HI)、肺及心脏剂量体积参数,以及加速器总机器跳数、总治疗时间.用SPSS 13.0软件对3个组计划行单因素方差分析,LSD算法进行组内分析.结果 3个组PTV的D98、V98及CI,肺的V5、V10、V30、V40、V50及平均肺剂量差异均无统计学意义(P值均>0.05);PTV的D2、V110及HI,肺V20差异均有统计学意义(P值均<0.05).总机器跳数比较,IMRT组(1174.8 MU)比IMAT1(709.7 MU)、IMAT2(803.8 MU)组分别减少了39.6%、31.6%(F=39.25,P=0.000).总治疗时间比较,IMRT组(14.9 min)比IMAT1(1.9 min)、IMAT2(2.66 min)组分别减少了87.2%、82.1%(F=45.14,P=0.000).结论 IMAT可以达到与IMRT相似的剂量学要求,IMAT2计划优于IMAT1.IMAT具有较少总MU、总治疗时间优势,并减少了治疗中不确定性因素影响及患者不适感.     

鼻咽癌静态调强放疗计划中采用非分裂射野的研究

[目的]由于多叶准直器的限制,鼻咽癌静态调强放疗时宽度大于14cm的射野一般分裂为2个或2个以上的分射野,本研究探讨减少分裂射野的可行性。[方法]选取10例已经治疗的初治且计划靶区宽度大于14cm的鼻咽癌病例进行研究,每病例做两组调强放射治疗计划,一组是传统分裂射野,另一组不分裂射野。对比两种方法对靶区的剂量覆盖、危及器官和正常组织照射剂量的差异,以及射野数、治疗时间和机器跳数的差异。[结果]不分裂射野组与传统分裂射野组的靶区剂量偏差小于0.3%,危及器官剂量偏差小于0.7%。剂量验证结果,两组参考点剂量通过率（100%,100%）和射野通量图剂量通过率（100%,99%）基本相同。不分裂射野组射野数减少33.1%±6.1%,机器出线跳数减少11.8%±4.6%,治疗时间减少14.5%±4.6%。[结论]不分裂射野方法较传统分裂野方法剂量分布相同,但可以有效减少射野数、机器跳数和治疗时间。     

鼻咽癌旋转调强与固定野调强同步加量计划比较研究

目的 比较旋转调强技术与常规固定野调强技术在鼻咽癌计划中对靶区及危及器官剂量学差异.方法 选取10例同步加量放疗鼻咽癌患者,通过瓦里安Eclipse 8.6计划系统分别制定旋转调强放疗(IMAT)计划和固定野调强放疗(IMRT)计划,运用剂量体积直方图评价两种计划的靶区(PTV、PTV1、PTV2)及危及器官剂量参数、机器跳数(MU)和治疗时间(T).结果 IMAT和IMRT计划的PTV、PTV1、PTV2适形指数均不同,分别为0.71和0.75(Z=-2.32,P＜0.05)、0.54和0.59(Z=-2.56,P＜0.05)、0.71和0.78(Z=-2.52,P＜0.05);均匀指数均相似,分别为10.5和11.2(Z=-0.84,P＞0.05)、13.1和17.1(Z=-1.68,P＞0.05)、14.1和13.3(Z=-1.01,P＞0.05).IMAT和IMRT计划的脑干平均剂量相似,分别为(3512.8±406.2)cGy和(3384.3±361.3)cGy(Z=-1.82,P＞0.05),最大剂量也相似,分别为(5528.1±192.9)cGy和(5727.5±356.3)cGy(Z=-1.12,P＞0.05);脊髓最大剂量不同,分别为(4186.1±8 8.7)cGy和(4390.2±74.9)cGy(Z=-2.38,P＜0.05).两种计划中双侧腮腺平均剂量、腮腺33%体积受照剂量(D33)、D50、D60均相似(P值均＞0.05),正常组织[定义为全身(body)减去PTV,即B-P]受照500 cGy体积占总B-P体积百分比(V5)、V10均也相似(P值均＞0.05),但V15、V20、V25、V30、V35、V40、V45、V50均不同(P值均＜0.05).两种计划的MU不同,MUIMRT=1308±213,MUIMAT=606±96(Z=-2.52,P＜0.05).结论 IMAT计划靶区剂量覆盖与IMRT计划相当,适形度好于IMRT计划;危及器官受照剂量相当,B-P受照剂量明显降低;可减少机器跳数和治疗时间.     

Dosimetric Comparison between Single and Dual Arc-Volumetric Modulated Arc Radiotherapy and Intensity Modulated Radiotherapy for Nasopharyngeal Carcinoma Using a Simultaneous Integrated Boost Technique

Backround: Plan quality and performance of dual arc (DA) volumetric modulated arc therapy (VMAT) , single arc (SA) VMAT and nine field (9F) intensity modulated radiotherapy were compared using a simultaneous integrated boost (SIB) technique. Methods: Twelve patients treated in Elekta Synergy Platform (mlci2) by 9F-IMRT were replanned with SA/DA-VMAT using a CMS Monaco Treatment Planning System (TPS) with Monte Carlo simulation. Target delineation was conducted as per Radiation Therapy Oncology Protocols (RTOG0225 and 0615). A 70Gy dose prescribed to PTV70 and 61Gy to PTV61 in 33 fractions was applied for the SIB technique. The conformity index (CI) and homogeneity index (HI) for targets and the mean dose and maximum dose for OAR’s, treatment delivery time (min), monitor units (MUs) per fraction, normal tissue integral dose and patient specific quality assurance were analysed. Results: Acceptable target coverage was achieved for PTV70 and PTV61 with all the planning techniques. No significant differences were observed except for D98 (PTV61), CI(PTV70) and HI(PTV61). Maximum dose (Dmax) to the spinal cord was lower in DA-VMAT than 9F-IMRT (p=0.002) and SA-VMAT (p=0.001). D50 (%) of parotid glands was better controlled by 9F-IMRT (p=0.001) and DA-VMAT (p=0.001) than SA-VMAT. A lower mean dose to the larynx was achieved with 9F-IMRT (P=0.001) and DA-VMAT (p=0.001) than with SA-VMAT. DA-VMAT achieved higher CI of PTV70 (P= 0.005) than SA-VMAT. For PTV61, DA-VMAT (P=0.001) and 9F-IMRT (P=0.001) achieved better HI than SA-VMAT. The average treatment delivery times were 7.67mins, 3.35 mins, 4.65 mins for 9F- IMRT, SA-VMAT and DA-VMAT, respectively. No significant difference were observed in MU/fr (p=0.9) and NTID (P=0.90) and the patient quality assurance pass rates were >95% (gamma analysis Ґ3mm, 3%). Conclusion: DA-VMAT showed better conformity over target dose and spared the OARs better or equal to IMRT. SA-VMAT could not spare the OARs well. DA-VMAT offered shorter delivery time than IMRT without compromising the plan quality.     

鼻咽癌调强放射治疗的剂量学特点

[目的]分析鼻咽癌调强放疗各个靶区和周围正常器官的剂量学特点.[方法]2004年7月至10月入院的10例初治鼻咽癌调强放疗病人,用前7野方案,每野的照射范围从颅底到锁骨上淋巴预防区.剂量处方是:GTV1为2.18Gy/次,32次,GTV2为2.03Gy/次,32次,CTV1为1.88Gy/次,32次,CTV2为1.80Gy/次,28次.研究GTV的最大、最小和平均剂量,CTV的最小剂量,脊髓、脑干和晶状体的最大剂量,腮腺的50%体积受照剂量.[结果]10例病人GTV1的最大、最小和平均剂量(均值)分别是72.01Gy、68.65Gy、70.48Gy,GTV2的最大、最小和平均剂量(均值)分别是68.66y、65.50Gy、66.98Gy,CTV1的最小剂量为60.10Gy,CTV2的最小剂量为51.18Gy,脊髓、脑干和晶体状的最大剂量分别为44.7Gy、51.7Gy和6.8Gy,高剂量侧和低剂量侧,腮腺的50%体积的受照剂量分别为44.39Gy和39.36Gy.[结论]调强放疗可以使各个靶区得到足够的、均匀的剂量分布,周围的正常组织受到比较好的保护,腮腺50%体积受照剂量控制在40Gy～45Gy,显示已有较好的保护作用.     

Dose Planning Study of Target Volume Coverage with Intensity-Modulated Radiotherapy for Nasopharyngeal Carcinoma: Penang General Hospital Experience

Background: To compare the dosimetric coverage of target volumes and organs at risk in the radicaltreatment of nasopharyngeal carcinoma (NPC) between intensity-modulated radiotherapy (IMRT) and threedimensionalconformal radiotherapy (3DCRT). Materials and Methods: Data from 10 consecutive patientstreated with IMRT from June-October 2011 in Penang General Hospital were collected retrospectively foranalysis. For each patient, dose volume histograms were generated for both the IMRT and 3DCRT plans usinga total dose of 70Gy. Comparison of the plans was accomplished by comparing the target volume coverage (5measures) and sparing of organs at risk (17 organs) for each patient using both IMRT and 3DCRT. The meansof each comparison target volume coverage measures and organs at risk measures were obtained and testedfor statistical significance using the paired Student t-test. Results: All 5 measures for target volume coverageshowed marked dosimetric superiority of IMRT over 3DCRT. V70 and V66.5 for PTV70 showed an absoluteimprovement of 39.3% and 24.1% respectively. V59.4 and V56.4 for PTV59.4 showed advantages of 18.4% and16.4%. Moreover, the mean PTV70 dose revealed a 5.1 Gy higher dose with IMRT. Only 4 out of 17 organsat risk showed statistically significant difference in their means which were clinically meaningful between theIMRT and 3DCRT techniques. IMRT was superior in sparing the spinal cord (less 5.8Gy), V30 of right parotid(less 14.3%) and V30 of the left parotid (less 13.1%). The V55 of the left cochlea was lower with 3DCRT (less44.3%). Conclusions: IMRT is superior to 3DCRT due to its dosimetric advantage in target volume coveragewhile delivering acceptable doses to organs at risk. A total dose of 70Gy with IMRT should be considered as astandard of care for radical treatment of NPC.     

直肠癌术后调强放疗和三维适形放疗剂量学比较研究

目的比较研究直肠癌术后调强放疗（IMRT）和三维适形放疗（3DCRT）时靶区及其周围危及器官受照剂量的差异。方法随机选择6例直肠癌术后患者,进行CT扫描、靶区和危及器官的勾画,用三维治疗计划系统进行3DCRT和IMRT计划设计,并对结果进行比较分析。结果IMRT计划PTV的均匀性（1．09±0．02）和适形度（0．81±0．08）均优于3DCRT计划（1．17±0．01,0．66±0．05）,差异具有统计学意义（P〈0．05）。IMRT与3DCRT相比,在50Gy的高剂量区,膀胱的V50下降了10％,小肠的V50下降了4％,差异具有统计学意义（P〈0．05）,而左、右股骨头的差异无统计学意义。结论在直肠癌术后放疗中,IMRT技术较3DCRT技术有剂量学方面的优越性。     

T2期鼻咽癌旋转调强与固定野动态调强计划的剂量学比较研究

目的：比较旋转调强（ intensity-modulated arc radiotherapy,IMAT）与固定野动态调强（ dynamic intensity-modulated radiation therapy,dIMRT）在T2期鼻咽癌放射治疗计划中的剂量学差异。方法：随机选取10例已经接受固定野动态调强放射治疗的T2期鼻咽癌病例,将这10例放疗计划改为旋转调强方式,重新进行计划优化,比较两种计划的等剂量分布、靶区和危机器官的剂量参数、机器跳数以及治疗时间等。结果：两种计划的靶区剂量分布D98、D95以及D2等参数均无统计学差异（P〉0．05）,IMAT计划的脑干Dmax和D1cc、脊髓Dmax、右腮腺Dmean、右颞颌关节Dmax以及左中耳Dmean和Dmax均明显小于dIMRT计划的受量（P〈0．05）;同时IMAT计划的左右晶体Dmax、左右视神经Dmax和视交叉Dmax均明显大于dIMRT计划的受量（P〈0．05）。 IMAT计划正常组织受照剂量为5Gy的总体积明显大于dIMRT计划（P〈0．05）,而受照剂量在20Gy和30Gy的总体积明显小于dIMRT计划（P〈0．05）。 IMAT比dIMRT计划的单次照射总机器跳数平均减少了47．0%,单次照射时间平均减少48．2%。结论：对于T2期鼻咽癌,两种计划的剂量分布均满足临床要求,在靶区剂量分布没有统计学差异的情况下,IMAT技术能显著降低机器跳数,大大缩短治疗时间。     

简化调强技术在鼻咽癌外照射中应用的剂量学研究

背景与目的：放射治疗是治疗鼻咽癌的首选方法。该文旨在研究简化调强放射治疗(simplified intensity-modulated radiation therapy,sIMRT )与调强放疗(intensity-modulated radiation therapy,IMRT)技术在鼻咽癌(nasopharyngeal carcinoma,NPC)放射治疗中的剂量学差异。方法：对10例NPC患者以相同处方剂量和目标条件分别设计9野IMRT和sIMRT计划,比较两种计划靶区剂量分布和剂量适形指数(conformity index,CI)与均匀性指数(homogeneity index,HI),不同危及器官(organ at risk,OAR)剂量参数、机器总跳数(MU)和总子野数。结果：IMRT和sIMRT的CI、HI分别为0.647、0.057和0.633、0.071(t=2.14,P=0.062;t=-6.21,P=0.000),sIMRT计划的靶区均匀性略差于IMRT,但两种治疗计划均能满足临床剂量学的要求。两种计划中各OAR剂量参数差异无统计学意义(t=-0.51~2.22,P=0.053~0.621) 。sIMRT计划的机器总跳数和总子野数均少于IMRT计划。结论：鼻咽癌sIMRT计划的靶区剂量覆盖与IMRT计划相当,均匀性略差于IMRT;危及器官受照剂量相当,但sIMRT技术可显著减少机器总跳数和总子野数,对患者数量大的治疗中心提高治疗效率具有较高的优势。     

局部晚期非小细胞肺癌调强放疗与三维适形放疗的剂量学及临床疗效分析

[目的]分析比较局部晚期非小细胞肺癌（NSCLC）调强放疗（IMRT）与三维适形放疗（3D-CRT）的临床疗效及对靶区和危及器官的剂量学差异。[方法]回顾性分析局部晚期非小细胞肺癌102例,其中52例采用3D-CRT,50例采用IMRT治疗,处方剂量PTV：56~64Gy/28~33次,比较两组的临床疗效和不良反应。选择其中10例患者的CT定位图像,分别设计IMRT和3D-CRT计划,给予DT：64Gy/32f照射,用剂量体积直方图（DVH）评价2种治疗计划的靶区和危及器官的剂量参数。[结果]10例IMRT计划中肺的V20、V30及肺平均剂量低于3D-CRT,而V5高于3D-CRT计划（P〈0.05）,V10无差异（P〉0.05）。IMRT的靶区适形指数（CI）和靶区均匀指数（HI）均优于3D-CRT（P〈0.05）,IMRT计划中脊髓的最大剂量（Dmax）较3D-CRT低（P〈0.05）。IMRT组与3DCRT组的1、2、3年生存率分别为82.0%、46.0%、28.0%和76.9%、36.5%、19.2%,中位生存期分别为22个月和18个月（P〉0.05）,1、2、3年无进展生存率分别为70.0%、34.0%、16.0%和63.5%、25.0%、9.6%,中位PFS分别为18个月和16个月（P〉0.05）。同步放化疗患者1、2、3年总生存率、无进展生存率分别为90.5%、71.4%、47.6%和85.7%、52.3%、33.3%,与序贯化放疗相比有显著性差异（P〈0.05）。IMRT组与3D-CRT组的近期疗效分别为76.0%、55.8%（P〈0.05）,急性放疗反应发生率两组无显著性差异。[结论]调强放射治疗可提高非小细胞肺癌近期疗效,调强放射治疗的计划可以提高靶区的适形度和均匀性,同时降低危及器官的剂量。     

Intensity modulated radiotherapy (IMRT) with simultaneous integrated boost (SIB) in a patient with left breast cancer and pectus excavatum

Introduction

Pectus excavatum is a frequent anomaly. It represents a challenge for adjuvant radiotherapy in the conservative treatment of breast cancer. Primary objective of this study is to compare dosimetric outcomes, normal tissue complication probability (NTCP), and integral dose using four radiation techniques. Secondary objective is to describe acute toxicity and setup errors.

Methods and materials

A 57-year-old female patient with an inner quadrant, left breast, ductal carcinoma in situ, was identified. Whole breast was prescribed with 50?Gy in 25 fractions. Boost planning target volume (PTV) was prescribed with 60?Gy in 30 fractions for sequential boost (SB) plans or 57.5?Gy in 25 fractions in the simultaneous integrated boost (SIB) plan. All plans were normalized to deliver 47.5?Gy to 95?% of the breast PTV. Daily image-guided radiotherapy (IGRT) was performed. Setup deviations were described.

Results

Constraints were not accomplished for heart when using intensity modulated radiotherapy (IMRT)?+?SB or conformal radiotherapy with three photon fields and SB. Left lung constraint was not achieved by any of the techniques in comparison. IMRT?+?SIB and conformal photons and electrons?+?SB plan were closer to the objective. Integral doses were lower with IMRT for heart and ipsilateral lung; however, it were higher for contralateral breast and lung. Coverage and tumoral conformity indexes were similar for all techniques in comparison. Greater inhomogeneity was observed with the photons and electrons?+?SB. IMRT?+?SIB treatment was administered daily with grade I skin toxicity. The highest setup error was observed in Y direction.

Conclusion

Planning target volume coverage was similar with the four techniques. Homogeneity was superior with both IMRT plans. A good balance between dose constraints for organs at risk, PTV coverage, homogeneity, and NTCP was observed with IMRT?+?SIB. The documented daily setup error justifies the use of online IGRT.     

电子射野影像系统在测量调强放疗三维剂量上的应用

目的:采用三维γ分析与靶区平均剂量评估电子射野影像系统(electronic portal imaging device,EPID)在测量调强放疗三维剂量上的应用特点.方法:首先在固体水模体中测试规则野和调强野,分析点剂量、平面γ通过率及靶区三维γ通过率的模型重建精度;再采用EPID测量80例鼻咽癌患者调强放射治疗(i...     

局部晚期鼻咽癌新辅助化疗加同期调强放化疗的初步结果

[目的]评价局部晚期鼻咽癌新辅助化疔加同期调强放化疗的临床近期疗效和急性反应。[方法]初治局部晚期鼻咽癌患者127例,2003年UICC分期Ⅲ期71例,Ⅳ期56例。104例完成新辅助化疗＋同期化疗,23例完成同期增敏化疗（每周1次,共6—7次）。全组患者均采用全靶区调强放射治疗,处方剂量：GTVnx69．0—75．9Gy／30～33F、PGTVnx69．0～69．9Gy／30～33F、PTV160．OGy／30-33F、PTV250．9—54．0Gy／28～30F、GTVnd 67．5～69．9Gy／30～33F。急性反应评价标准参考RTOG评估标准。[结果]中位随访8个月,远处转移5例;1年局部控制率100％,1年总生存率（OS）99．2％．1年无远处转移生存率95.3％。[结论]局部晚期鼻咽癌新辅助化疗加同期调强放化疗是可行的,3～4级急性黏膜炎和3-4级血液学毒性是限制化疗进行的主要因素。     

Dosimetric Comparison and Feasibility of Simultaneous Integrated Boost (SIB) in Treatment of Malignant Gliomas Using Intensity Modulated Radiotherapy (IMRT) or Volumetric Modulated Arc Therapy (VMAT)

Objective: To evaluate the dosimetric parameters of Simultaneous Integrated Boost in the treatment of malignantgliomas and compare the SIB plans of VMAT and IMRT. Methodology: CT and MRI of 28 patients were used forgenerating SIB plans with VMAT and IMRT. A dose of 2Gy per fraction was prescribed to the CPTV and 2.4Gy tothe GPTV for a total of 25 fractions. The plans were accepted only if they met the set of planning objectives definedin the protocol. Results: We could achieve the planning objectives in all the SIB plans. Although GPTV coverage wasstatistically better in VMAT (98.67% vs 98.19% ;p=0.024) the difference is not clinically meaningful. The conformityindex for GPTV was higher in IMRT (0.83 vs 0.76; p=0.001). The coverage of CPTV was better in IMRT(97.88% vs 96.87%; p=0.021). But the conformity index of CPTVannulus was higher in VMAT (0.72 vs 0.67; p=0.01).There was no difference in homogeneity index of GPTV and CPTV annulus between the plans. The mean dose receivedby normal brain was higher in IMRT (28Gy vs 24.2Gy; p<0.001). Ipsilateral optic nerve has received lesser Dmax inIMRT (44.2Gy vs 46.95Gy; p=0.02). No difference was seen in Dmax of brainstem, optic chiasm, contralateral opticnerve. The treatment times and monitor units were significantly less in VMAT. Conclusion: SIB is dosimetricallyfeasible for hypofractionation in malignant gliomas using IMRT and VMAT. IMRT plans had better boost conformity,lower ipsilateral optic nerve and brainstem maximum doses compared to VMAT. Whereas, VMAT had better coverage,better overall PTV conformity, lower normal brain mean dose, lower monitor units and lesser treatment times. Althoughplanning of VMAT is cumbersome and time consuming, the advantage of reducing treatment time is beneficial tothe patients’ comfort and better managing of patient load in high volume centres.     

直线加速器二级准直器在全段食管癌术后调强计划中的应用

目的:探讨全段食管癌术后放疗患者调强计划中限制二级准直器位置对靶区和危及器官受照剂量的影响。方法:选择13例全段食管癌术后放疗患者,设计两种逆向调强放疗（IMRT）计划。第一种是二级准直器限制位置的IMRT（Jaw Fixed-IMRT,F-IMRT）:以心脏上下界为界,F-IMRT计划的靶区分为上、中、下三个分区,通过固定二级准直器来实现,三个分区分别设计射野数量及角度,两两分区之间二级准直器头脚方向重叠(overlap,OL)的距离定为0、1、2、3、4 cm,共生成5个F-IMRT计划（命名为F-IMRT-OL0.1.2.3.4）;第二种是常规IMRT(conventional-IMRT,C-IMRT):患者靶区为一个整体,不限制二级准直器,射野设置为9野共面均分。两种计划靶区及危及器官优化参数相同,对比分析两种计划的剂量学差异及加速器跳数（MU）。结果:F-IMRT计划中,二级准直器需要重叠以保证靶区足量,但随重叠距离增加危及器官受量呈递增趋势,本研究中F-IMRT-OL1为最优计划。F-IMRT-OL1与C-IMRT计划的适形指数（CI）和均匀性指数（HI）差异无统计学差异（P＞0.05）;F-IMRT-OL1肺的V5 Gy、V10 Gy、V20 Gy及Dmean低于C-IMRT,具有统计学差异（P＜0.05）,而对于肺的高剂量体积V30 Gy,无明显差异（P＞0.05）;F-IMRT-OL1计划心脏的V30 Gy和V40 Gy及Dmean均低于C-IMRT,具有统计学差异（P＜0.05）;F-IMRT-OL1肝脏、肾脏的Dmean低于C-IMRT（P＜0.05）;两种计划的脊髓和MU无明显差异（P＞0.05）。结论:对于全段食管癌术后患者的调强放疗计划设计, F-IMRT-OL1计划能在保持靶区剂量充分和剂量均匀性的同时,可以有效地减小肺和心脏剂量的照射体积及平均剂量。     

Organ-sparing Intensity-modulated Radiotherapy for Anal Cancer using the ACTII Schedule: A Comparison of Conventional and Intensity-modulated Radiotherapy Plans

AimsConventional external beam radiotherapy for anal cancer is associated with a high rate of treatment-related morbidity. The purpose of this retrospective study was to compare the dosimetric advantages of three intensity-modulated radiotherapy (IMRT) plans with the conventional plan with regards to organs at risk avoidance delivering the ACTII schedule of 50.4 Gy in 1.8 Gy/fraction: 17 fractions for phase 1 and 11 fractions for phase 2.Materials and methodsTen anal cancer patients (T1-3 N0-3) treated with the conventional plan using four fields and conformal boost were identified. The phase 1 planning target volume (PTV) included tumour, anal canal and inguinal, peri-rectal and internal/external iliac nodes. Phase 2 included identifiable disease only. Three step-and-shoot IMRT plans were generated: IMRT1: phase 1 inverse-planned IMRT with two- to four-field conformal phase 2; IMRT2: both phase 1 and phase 2 inverse-planned IMRT; IMRT3: phase 1 IMRT and phase 2 forward-planned IMRT. All IMRT plans were then compared against the conventional plan on PTV coverage, small bowel, genitalia, femoral heads, bladder and healthy tissue dose volume information.ResultsWhile achieving similar PTV coverage compared with the conventional plan, significant dose reductions were observed for IMRT plans in external genitalia, small bowel and healthy tissue. Reductions were also observed in the femoral heads and bladder.ConclusionsIMRT significantly reduces the dose to organs at risk while maintaining excellent PTV coverage in anal cancer radiotherapy.     

20例鼻咽癌调强放疗初步结果分析

目的:分析调强放疗（intensity modulated radiotherapy ,IMRT）在鼻咽癌应用的初步结果。方法:对天津医科大学附属肿瘤医院2007年1 月至2008年4 月20例经病理证实的鼻咽癌患者进行全程IMRT,其中Ⅱ期5 例,Ⅲ期13例,Ⅳa 期2 例。鼻咽肿瘤（PTV ）和颈部转移淋巴结（PTVnd ）处方剂量为69.96Gy,鼻咽区域及上颈部临床靶区（PTV 1）处方剂量为60.06Gy,下颈部锁骨上区域（PTV 2）处方剂量为50.96Gy。腮腺50% 体积≤35Gy,晶体、垂体、颞颌关节、下颌骨及颞叶的最高限量分别为9、54、60、70、60Gy,脑干、脊髓、视神经、视交叉的计划危及器官区（planning organ at risk volume,PRV ）1% 体积最高限量分别为54、40、54、54Gy。全组病例于IMRT 前均行1～2 个周期化疗。结果:中位随访时间为14个月,1 例因鼻咽癌骨转移、呼吸衰竭死亡。1 年总生存率为94.1% ,3 例发生远处转移,急性反应以1、2 级为主,其中口干多集中在1 级（17例）,1 级口腔黏膜急性反应3 例,2 级12例。PTV 、PTVnd 、PTV 1、PTV 2 的平均剂量均值分别为73.4、74.1、67.8、54.1Gy。左、右腮腺的平均剂量分别为43.9、41.9Gy。左、右晶体最高剂量平均值分别为8.06、8.12Gy,脑干、脊髓、左、右视神经、视交叉PRV 最大剂量平均值分别为60.6、46.6、50.0、55.0、56.0Gy。结论:IMRT 技术能对鼻咽癌的各靶区达到较好的剂量分布,可获得理想的局部区域控制,对正常组织器官有较好的保护作用。      

128例初治鼻咽癌调强适形放疗临床分析

目的分析调强适形放疗(intensity modulated radiation therapy,IMRT) 治疗初治鼻咽癌的临床疗效。方法鼻咽癌IMRT 初治患者128例,按1992年福州分期标准,Ⅰ期2例,Ⅱ期19例,Ⅲ期58例,Ⅳa期49例。鼻咽大体肿瘤体积（GTVnx）处方剂量为(70~74)Gy分30次,颈部淋巴结（GTVnd）处方剂量为(68~70)Gy分30次,临床靶体积1（CTV1）(60~64)Gy分30次,临床靶体积2（CTV2）(50~54)Gy分30次。采用Kaplan-Meier法进行生存分析和局部控制率计算,Log-rank检验组间差异。结果中位随访时间12月(6~24月),1、2 年总生存率分别为100%、96.9%,1、2 年无远处转移生存率分别为92.2%、88.3%,1、2 年局部控制率分别为96.1%和93.8%。N分期是影响有无远处转移生存率的最重要预后因素( P =0.04)。最严重的急性不良反应是放射性黏膜炎,Ⅰ~Ⅳ级分别为38.8%、48.4%、7.8%、0。晚期不良反应主要表现为口干,Ⅰ级67.2%, Ⅱ级19.5%。结论鼻咽癌IMRT 靶区剂量高,周围正常组织受量小,不良反应轻,是一种治疗鼻咽癌的有效方法。治疗失败最主要的原因是远处转移,其发生率与颈淋巴结转密切相关。     

初治鼻咽癌调强放疗布野及联合化疗的临床研究

[目的]研究鼻咽癌调强放射治疗(IMRT)的投照方式、近期临床疗效,以及单纯放疗和放、化疗结合的耐受性。[方法]2003年12月￣2005年12月157例初治鼻咽癌患者鼻咽和全颈及锁骨上全程实施前7野IMRT。鼻咽大体肿瘤体积(GTV1)、颈部大体肿瘤体积(GTV2)、临床靶体积1(CTV1)和临床靶体积2(CTV2)处方剂量分别为70Gy、66Gy、60Gy、50Gy,共32分次。88例患者行联合化疗。采用Kaplan-Meier法进行生存分析,RTOG标准评价急性反应和晚期损伤。[结果]治疗计划结果显示,靶区内GTV1、GTV2、CTV1和CTV2的平均剂量分别为70.5Gy、67.0Gy、60.1Gy和51.2Gy。中位随访时间16个月,1、2年局部区域无进展和无远处转移生存率及总生存率分别为97.4%、94.9%和93.6%、89.4%及96.4%、92.7%。放化综合治疗组的口咽、黏膜反应及血液系统毒性明显高于单纯放疗组。患者近期毒副反应均可以耐受,口干症状随着治疗后时间的延长逐渐减轻。[结论]IMRT使靶体积照射剂量提高,而周围器官受照剂量降低,对初治鼻咽癌可获得理想的局部区域控制,放化综合治疗对控制远处转移有一定价值。     

食管癌VMAT与IMRT剂量比较的Meta分析

目的 对食管癌VMAT与IMRT靶区和OAR剂量比较行Meta分析。方法 文献检索纳入相关研究,分析靶区和OAR剂量参数、机器跳数及治疗时间。结果 17项研究的323病例纳入Meta分析。VMAT计划中GTV的D_mean、在总剂量≤50.4 Gy时PTV的D_mean和在总剂量>50.4 Gy时PTV的D_max优于IMRT (P=0.009、0.043、0.039)。心脏D_mean、V₃₀、V₄₀,脊髓D_max,肺V₅、V₁₀、D_mean差异均无统计学意义(P>0.05);VMAT计划中肺的V₁₅、V₂₀、V₃₀优于IMRT计划(P=0.001、0.000、0.023)。VMAT计划中单次照射1.8、2.0 Gy的机器跳数较IMRT计划分别减少275.4、134.2 MU (P=0.000、0.022);VMAT计划中单次照射1.8、2.0 Gy的TT比IMRT计划分别缩短323.5、193.7 s (P=0.000、0.009)。结论 VMAT计划能显著减少TT和机器跳数、提高设备使用率,降低肺受照剂量和RP发生风险。VMAT与IMRT相比在照射总剂量≤50.4 Gy时除PTV的D_mean和GTV的D_mean、D_max外,靶区其他剂量参数均无明显优势。对脊髓和心脏保护VMAT也无明显优势。