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.     

30例早期鼻咽癌调强放射治疗疗效分析

目的:探讨调强放射治疗(IMRT)对早期鼻咽癌的近期疗效和不良反应.方法:回顾分析30例早期鼻咽癌患者,鼻咽部和上颈部淋巴引流区采用IMRT技术照射,下颈部淋巴引流区采用颈前野常规照射.鼻咽大体肿瘤体积(GTVnx)处方剂量68Gy-74Gy,颈部淋巴结(GTVnd)处方剂量64Gy-70Gy,临床靶体积(CTV1)处方剂量 60Gy-64Gy,临床靶体积(CTV2)处方剂量 50Gy-54Gy,分30-34次进行照射.对于淋巴结分期为N1的患者,结合淋巴结的情况行诱导化疗和(或)同期化疗2-4周期,N0患者行单纯调强放射治疗.结果:鼻咽大体肿瘤体积(GTVnx)D95平均剂量为74.5Gy,GTVnx V95平均体积99.6%,脊髓D1cc平均剂量41.5Gy,脑干D3平均剂量50.3Gy,左腮腺D50平均剂量32.8Gy,右腮腺D50平均剂量31.4Gy,左颞叶D10平均剂量45.5Gy,右颞叶D10平均剂量45.2Gy,均低于限制剂量.中位随访时间33.5个月(4-45个月).1年、2年、3年的总生存率、无局部复发生存率和无远处转移生存率均为100%.最严重的急性反应是放射性黏膜炎,1-3级分别有 63.3%,30%,和6.7%,晚期不良反应主要表现为口干(Ⅰ度33.3%,Ⅱ度3.7%).结论:IMRT对初治早期鼻咽癌可获得理想的剂量分布,取得较好的近期疗效,正常组织得到很好的保护.     

30例早期鼻咽癌调强放射治疗疗效分析

目的：探讨调强放射治疗（IMRT）对早期鼻咽癌的近期疗效和不良反应。方法：回顾分析30例早期鼻咽癌患者,鼻咽部和上颈部淋巴引流区采用IMRT技术照射,下颈部淋巴引流区采用颈前野常规照射。鼻咽大体肿瘤体积（GTVnx）处方剂量68Gy-74Gy,颈部淋巴结（GTVnd）处方剂量64Gy-70Gy,临床靶体积（CTV1）处方剂量60Gy-64Gy,临床靶体积（CTV2）处方剂量50Gy-54Gy,分30-34次进行照射。对于淋巴结分期为N1的患者,结合淋巴结的情况行诱导化疗和（或）同期化疗2-4周期,N0患者行单纯调强放射治疗。结果：鼻咽大体肿瘤体积（GTVnx）D95平均剂量为74.5Gy,GTVnx V95平均体积99.6%,脊髓D1cc平均剂量41.5Gy,脑干D3平均剂量50.3Gy,左腮腺D50平均剂量32.8Gy,右腮腺D50平均剂量31.4Gy,左颞叶D10平均剂量45.5Gy,右颞叶D10平均剂量45.2Gy,均低于限制剂量。中位随访时间33.5个月（4-45个月）。1年、2年、3年的总生存率、无局部复发生存率和无远处转移生存率均为100%。最严重的急性反应是放射性黏膜炎,1-3级分别有63.3%,30%,和6.7%,晚期不良反应主要表现为口干（Ⅰ度33.3%,Ⅱ度3.7%）。结论：IMRT对初治早期鼻咽癌可获得理想的剂量分布,取得较好的近期疗效,正常组织得到很好的保护。     

Sparing the parotid glands and surgically transferred submandibular gland with helical tomotherapy in post-operative radiation of head and neck cancer: a planning study.

BACKGROUND AND PURPOSE: To evaluate the feasibility of sparing the parotid glands and surgically transferred submandibular gland (SMG) by intensity modulated radiotherapy (IMRT) in post-operative cases of head and neck cancer (HNC). MATERIALS AND METHODS: Ten patients (larynx-2, base of tongue-4, tonsil-3, and unknown primary-1; pathologic stages III-IV) who underwent SMG transfers on the side of N0 neck along with definitive surgery were selected for this study. IMRT planning was done retrospectively using helical tomotherapy approach. Planning objective was to deliver 60 Gy to PTV1 and 54 Gy to PTV2 while maintaining the mean dose to the total parotid volume (TPV) and SMG less than 26 Gy. RESULTS: The mean dose (+/-SD) to the TPV and SMG were 25+/-0.6 Gy and 23+/-1.9 Gy, respectively. The D(95) for PTV1 and PTV2 were 59.9+/-0.1 Gy and 54.9+/-0.3 Gy, respectively, satisfying our planning goal for PTV coverage. The D(99) for PTV1 and PTV2 were 58.2+/-0.7 Gy and 49.5+/-2.2 Gy, respectively, showing that sparing the salivary glands did not result in underdosing of the PTVs. CONCLUSIONS: By combining the gland transfer and IMRT, the mean dose to TPV and transferred SMG could be reduced to less than 26 Gy in post-operative patients of HNC.     

复发鼻咽癌调强放疗的剂量学探讨

目的：分析和评价复发鼻咽癌调强放疗（IMRT）的剂量学特点。方法：30例局部、区域复发的鼻咽癌患者使用IMRT的再程放疗,其中7例同时伴有颈淋巴结转移。根据1992年福州分期标准进行再分期,I、Ⅱ、Ⅲ、Ⅳ期分别为7、7、4、12例。鼻咽大体肿瘤体积（GTV）处方剂量为58．80—78．76Gy,分次剂量2．0—2．92Gy。结果：治疗计划GTV的中位体积为37．46cm。（14．30—227．52cm。）,覆盖鼻咽GTVD。;的平均剂量为62．56Gy,GTVV95的平均体积为98．69％;靶区内GTV、cTV,和CTV,的平均剂量分别为65．82Gy、54．02Gy和50．20Gy;GTV的平均分割剂量为2．28Gy（2．0—2．92Gy）。结论：IMRT能较好覆盖肿瘤靶区而降低邻近敏感器官剂量。     

A treatment planning analysis of inverse-planned and forward-planned intensity-modulated radiation therapy in nasopharyngeal carcinoma

PURPOSE: To compare dose-volume histograms of target volumes and organs at risk in 57 patients with nasopharyngeal carcinoma (NPC) with inverse- (IP) or forward-planned (FP) intensity-modulated radiation treatment (IMRT). METHODS AND MATERIALS: The DVHs of 57 patients with NPC with IMRT with or without chemotherapy were reviewed. Thirty-one patients underwent IP IMRT, and 26 patients underwent FP IMRT. Treatment goals were to prescribe a minimum dose of 66-70 Gy for gross tumor volume and 59.4 Gy for planning target volume to greater than 95% of the volume. Multiple selected end points were used to compare dose-volume histograms of the targets, including minimum, mean, and maximum doses; percentage of target volume receiving less than 90% (1-V90%), less than 95% (1-V95%), and greater than 105% (1-V105%). Dose-volume histograms of organs at risk were evaluated with characteristic end points. RESULTS: Both planning methods provided excellent target coverage with no statistically significant differences found, although a trend was suggested in favor of improved target coverage with IP IMRT in patients with T3/T4 NPC (p = 0.10). Overall, IP IMRT statistically decreased the dose to the parotid gland, temporomandibular joint, brain stem, and spinal cord overall, whereas IP led to a dose decrease to the middle/inner ear in only the T1/T2 subgroup. CONCLUSIONS: Use of IP and FP IMRT can lead to good target coverage while maintaining critical structures within tolerance. The IP IMRT selectively spared these critical organs to a greater degree and should be considered the standard of treatment in patients with NPC, particularly those with T3/T4. The FP IMRT is an effective second option in centers with limited IP IMRT capacity. As a modification of conformal techniques, the human/departmental resources to incorporate FP-IMRT should be nominal.     

Helical tomotherapy for parotid gland tumors

PURPOSE: To investigate helical tomotherapy (HT) intensity-modulated radiotherapy (IMRT) as a postoperative treatment for parotid gland tumors. METHODS AND MATERIALS: Helical tomotherapy plans were developed for 4 patients previously treated with segmental multileaf collimator (SMLC) IMRT. A primary planning target volume (PTV64) and two secondary PTVs (PTV60, PTV54) were defined. The clinical goals from the SMLC plans were applied as closely as possible to the HT planning. The SMLC plans included bolus, whereas HT plans did not. RESULTS: In general, the HT plans showed better target coverage and target dose homogeneity. The minimum doses to the desired coverage volume were greater, on average, in the HT plans for all the targets. Minimum PTV doses were larger, on average, in the HT plans by 4.6 Gy (p = 0.03), 4.8 Gy (p = 0.06), and 4.9 Gy (p = 0.06) for PTV64, PTV60, and PTV54, respectively. Maximum PTV doses were smaller, on average, by 2.9 Gy (p = 0.23), 3.2 Gy (p = 0.02), and 3.6 Gy (p = 0.03) for PTV64, PTV60, and PTV54, respectively. Average dose homogeneity index was statistically smaller in the HT plans, and conformity index was larger for PTV64 in 3 patients. Tumor control probabilities were higher for 3 of the 4 patients. Sparing of normal structures was comparable for the two techniques. There were no significant differences between the normal tissue complication probabilities for the HT and SMLC plans. CONCLUSIONS: Helical tomotherapy treatment plans were comparable to or slightly better than SMLC plans. Helical tomotherapy is an effective alternative to SMLC IMRT for treatment of parotid tumors.     

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。     

鼻咽癌调强放疗后近期腮腺功能影响因素分析

[目的]总结鼻咽癌调强放疗后腮腺功能影响因素。[方法]收集2008年7月至2009年8月初治的20例鼻咽癌调强放疗靶区及腮腺剂量学参数,随访其放疗后3个月口干情况,分析腮腺受照剂量与口干分级之间的关系。[结果]20例接受调强放疗鼻咽癌腮腺平均剂量41.25Gy,患侧腮腺V20：96.77%,V30：80.56%,V40：52.43%,健侧腮腺V20：971.47%,V30：69.95%,V40：40.85%。放疗后3个月轻度、中度、重度口干发生率分别为15%、55%、30%,口干分级与腮腺平均剂量、患侧及健侧腮腺V20、V30、V40呈正相关。[结论]鼻咽癌调强放疗后腮腺功能与腮腺受照体积、剂量显著相关。     

鼻咽癌调强放疗的剂量学研究

 【摘要】目的 分析鼻咽癌调强放疗各个靶区和周围正常组织器官的剂量学特点。方法 2005年1月-2006年6月住院的30例初治鼻咽癌进行调强放疗，将鼻咽和颈部的靶体积勾画为鼻咽大体肿瘤体积（GTVnx）、颈部大体肿瘤体积(GTVnd)、临床靶体积1（CTV1）和临床靶体积2(CTV2)，处方剂量分别为70、66、60、60Gy/30F，鼻咽和上颈部靶体积采用IMRT技术照射、下颈部靶体积采用下颈前野常规照射。研究GTV、CTV的最大、最小、平均剂量和颞叶、脑干、脊髓、视神经、晶体、眼球的最大受照剂量及腮腺、颞下颌关节的50%体积受照剂量。结果 GTVnx的最大、最小、平均剂量（均值）分别为79.2、59.5、71.9Gy, GTVnd的最大、最小、平均剂量分别为77.1、63.6、72.1Gy，CTV1、CTV2的最小剂量分别为47.6、49.7Gy，颞叶、脑干、脊髓、视神经、晶体、眼球的最大受照剂量及腮腺、颞下颌关节的50%体积受照剂量63.2、48.6、44.7、59.3、6.9、25.9Gy和34.0、36.3Gy。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，周围正常组织器官得到较好的保护，但是要注意CTV的低剂量区。鼻咽癌调强放疗剂量分布优于常规放疗。     

Compensator-based intensity-modulated radiotherapy in head and neck cancer: our experience in achieving dosimetric parameters and their clinical correlation

AimsTo review the Batra Hospital and Medical Research Centre experience of using compensator-based intensity-modulated radiotherapy (IMRT) to treat head and neck cancer.Materials and methodsBetween October 2003 and August 2004, 18 patients underwent IMRT for head and neck cancer at our institution. IMRT was delivered using partial transmission high-resolution compensator blocks.ResultsWith a median follow-up of 13.3 months, two patients had residual disease and two failed in the gross tumour volume (GTV). The complete response rate after surgical salvage was 94.5%. Both the locoregional relapse-free and disease-free survival rates were 81.8%. The target coverage in terms of average maximum, mean and minimum dose (in Gy) delivered was 78.6, 73.5 and 58.4 to the GTV–planning target volume, 82.3, 70.9 and 47.3 to clinical target volume 1 (CTV1) and 82.9, 66.2 and 29.6 to CTV2. The dose constraint of 30 Gy to less than 50% of the contralateral parotid volume was achieved in 12 (66.7%) patients. If the dose constraint was revised to 35 Gy, at least 50% of the parotid volume was spared in 17 (94.5%) patients. On average, 75% of the contralateral parotid volume received a dose less than 35 Gy in 13 (72.3%) patients with grade I xerostomia, whereas this was 49.3% in five (27.7%) patients with grade II xerostomia, and the difference was statistically significant (P = 0.001).ConclusionsIn our initial experience, compensator-based IMRT is feasible with regard to target coverage and parotid volume sparing. The parotid volume dose has significant clinical implications on the grade of xerostomia. Our results invoke rethinking into the issues of the parotid volume dose constraint in our subpopulation.     

49例复发鼻咽癌的调强适形放射治疗

目的 评价调强适形放射治疗(IMRT)对复发性鼻咽癌的疗效、放射反应以及对肿瘤的控制。方法 49例鼻咽局部复发的鼻咽癌患者(KPS≥80)均采用全程IMRT,其中伴有颈淋巴结转移的3例患者(N12例,N3l例)在IMRT后,给予PDD 5-Fu方案5～6个疗程化疗。结果 治疗计划结果显示,覆盖鼻咽GTV D95的平均剂量为68．09Gy,GTV V95的平均体积为98．46％,靶区内GTV、CTV1和CTV2的平均剂量分别为71．40Gy、63．63Gy和59．81Gy。49例患者的中位随访时间为9个月(3～16个月)。局部无进展生存率100％,IMRT结束时有3例(6．1％)出现局部残留,14例(28．6％)出现鼻咽腔黏膜坏死。结论 IMRT能有利覆盖肿瘤靶区而使邻近敏感器官获得有效分隔,对复发性鼻咽癌的再程放疗不失为一种有效方法。值得注意的是高剂量的鼻咽局部IMRT治疗对于复发性鼻咽癌容易导致鼻咽黏膜坏死,故应适当减少GTV的处方剂量以60～65Gv为宜。     

头颈部癌调强放疗过程中腮腺及靶区体积变化的临床分析

目的 研究头颈部癌患者在放疗过程中腮腺体积及GTV变化。方法 5例头颈部鳞癌（4例口咽鳞癌和1例喉鳞癌）患者均接受全程调强放疗。从第一次放疗开始至结束，1次／周三维锥形束CT（CBCT）检查。每次的CBCT图像与疗前CT图像进行融合，在每层图像上勾画出腮腺外轮廓，同时将GTV内放疗中出现的气腔勾画出来。经统计后分析放疗中腮腺体积、GTV内气腔大小的变化。结果 放疗结束时腮腺体积为疗初的90．1％，52．3％，即腮腺体积缩小了9．9％～47．7％；GTV内气腔由疗前的0体积逐渐增加，疗终时气腔体积占GTV的3．7％。16．8％。结论 放疗过程中腮腺体积及GTV内气腔体积存在着明显变化，利用CBCr可分析这种变化，为二次调强计划的实施奠定基础。     

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.