颈段食管癌淋巴结预防照射三种同期加量调强放疗计划剂量学比较

目的 探讨颈段食管癌预防性淋巴结照射同期加量调强放疗(SIB-IMRT)的3种计划的优选方案.方法 对6例颈段食管癌在模拟CT扫描图像上勾画靶区GTV、CTV(包括双侧中下颈部、锁骨上区、上纵隔淋巴引流区),GTV、CTV分别外扩5 mm为PGTV、PTV],设计5、7、9野下3种SIB-IMRT计划.PGTV处方剂量66 Gy分30次,PTV处方剂量60 Gy分30次.对各计划靶区及危及器官受量进行剂量体积直方图参数比较.结果 5、7、9野SIB-IMRT计划PGTV的适形指数(CI)和V66及D95均明显不同,分别为0.56、0.62、0.69(F=6.22,P＜0.01)和88.24%、95.03%、94.91%(F=4.39,P＜0.05)及6539.67、6601.83、6602.00 cGy(F=4.46,P＜0.05);PTV的也明显不同,分别为0.80、0.85、0.87(F=11.29,P＜0.01)和91.64%、94.05%、95.06%(F=4.10,P＜0.05)及5934.00、5987.17、6006.33 cGy(F=4.01,P＜0.05);脊髓最大受量也不同,分别为4707.17、4497.83、4357.00 cGy(F=11.26,P＜0.01).7、9野间上述各参数比较也均相似(P均＞0.05).结论 7野SIB-IMRT计划是颈段食管癌预防性淋巴结照射SIB-IMRT的优选方案.

Abstract：

Objective To evaluate the optimized simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) plans in cervical esophageal carcinoma underwent prophylactic lymphatic irradiation.MethodsSix patients with cervical esophageal carcinoma were studied.The gross tumor volume (GTV) and clinical target volume (CTV) (including bilateral mid-lower neck and supraclavicular lymph drainage regions,upper mediastinal lymph drainage regions) were delineated on sim-CT images,GTV and CTV were uniformly expanded by 5 mm to create PGTV and PTV.Five fields(5F) ,7F and 9F SIB-IMRT plans were designed.The prescribed doses to PGTV and PTV were 66 Gy and 60 Gy in 30 fractions respectively.The parameters of dose-volume histograms in three groups planning were compared.Results The values of conformity index(CI) of PGTV were 0.56,0.62 and 0.69 (F =6.22,P ＜0.01 ),the V66 with 88.24% ,95.03% and 94.91% ( F = 4.39,P ＜ 0.05 ) and D95 with 6539.67,6601.83 and 6602.00 cGy (F=4.46,P ＜0.05) in 5F,7F and 9F SIB-IMRT plans.The values of CI,V66 and D95 of PTV were 0.80,0.85 and 0.87 (F=11.29,P＜0.01),with 91.64%,94.05% and 95.06% (F=4.10,P＜0.05) and with 5934.00,5987.17 and 6006.33 cGy (F =4.01,P ＜0.05).The values of maximal dose of spinal cord were 4707.17,4497.83 and 4357.00 cGy( F = 11.26 ,P ＜0.011 ) in 5F ,7F and 9F SIB-IMRT plans.The values of all dosimetic parameters about PGTV and PTV were same in 7F and 9F SIB-IMRT plans ( all P ＞ 0.05 ).Conclusion 7F-SIB-IMRT plan is best one scheme for cervical esophageal carcinoma underwent prophylactic lymphatic irradiation.

A dosimetric comparison of three plans in simultaneous integrated boost intensity-modulated radiotherapy in cervical esophageal carcinoma undergoing prophylactic lymphatic irradiation

Objective To evaluate the optimized simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) plans in cervical esophageal carcinoma underwent prophylactic lymphatic irradiation. Methods Six patients with cervical esophageal carcinoma were studied. The gross tumor volume (GTV) and clinical target volume (CTV) (including bilateral mid-lower neck and supraclavicular lymph drainage regions, upper mediastinal lymph drainage regions) were delineated on sim-CT images, GTV and CTV were uniformly expanded by 5 mm to create PGTV and PTV. Five fields(5F),7F and 9F SIB-IMRT plans were designed. The prescribed doses to PGTV and PTV were 66 Gy and 60 Gy in 30 fractions respectively. The parameters of dose-volume histograms in three groups planning were compared. Results The values of conformity index(CI) of PGTV were 0.56, 0.62 and 0.69 (F=6.22,P<0.01), the V₆₆ with 88.24%,95.03% and 94.91%(F=4.39,P<0.05)and D₉₅ with 6539.67,6601.83 and 6602.00 cGy (F=4.46,P<0.05) in 5F,7F and 9F SIB-IMRT plans. The values of CI, V₆₆ and D₉₅ of PTV were 0.80,0.85 and 0.87 (F=11.29,P<0.01), with 91.64%, 94.05% and 95.06% (F=4.10,P<0.05) and with 5934.00,5987.17 and 6006.33 cGy (F=4.01,P<0.05). The values of maximal dose of spinal cord were 4707.17,4497.83 and 4357.00 cGy(F=11.26,P<0.01)in 5F,7F and 9F SIB-IMRT plans. The values of all dosimetic parameters about PGTV and PTV were same in 7F and 9F SIB-IMRT plans(all P>0.05). Conclusion 7F-SIB-IMRT plan is best one scheme for cervical esophageal carcinoma underwent prophylactic lymphatic irradiation.