摘要
目的:比较旋转容积调强(VMAT)与固定野动态调强(dIMRT)在直肠癌放疗计划中的剂量学差异。方法:8例直肠癌患者利用瓦里安计划系统(Eclipse 8.6)分别进行VMAT和dIMRT放射治疗计划设计。利用剂量体积直方图来比较两种计划中靶区和危及器官的剂量学差异。结果:与dIMRT相比,VMAT靶区适合度指数(CI)、靶区剂量均匀性指数(HI)均更接近1,Dmin为(43.403±0.486)Gy,更接近处方剂量,差异有统计学意义,P<0.05。在VMAT计划中小肠的D30%、D50%和Dmean分别为(25.918±1.216)、(22.340±3.784)和(23.547±2.863)Gy,低于dIMRT计划的(28.073±3.114)、(24.172±2.540)和(25.257±1.374)Gy,P值分别为0.00、0.01和0.00;膀胱的D30%为(35.380±2.734)Gy,较dIMRT的(30.123±2.209)Gy偏高,P=0.00,但仍远低于剂量限值;股骨头的D5%和Dmean分别为(31.344±3.556)和(20.179±3.017)Gy,显著高于dIMRT计划的(26.731±2.828)和(17.459±3.279)Gy,P值均为0.00。VMAT总MU减少52.7%,治疗时间仅为dIMRT的1/4。结论:VMAT计划可以达到或优于dIMRT计划的靶区剂量分布,能更好地降低部分危及器官的受照剂量,并且具有较少总MU、总治疗时间的优势,减少了治疗中不确定性因素的影响及患者不适感。
OBJECTIVE： To compare the dosimetric difference between volumetric modulated arc therapy（VMAT） and fixed-gantry dynamic intensity modulated radiation therapy（dIMRT） for rectal cancer. METHODS： VMAT and dIM- RT treatment plans of 8 rectal cancer cases were generated by Vrian Eclipse ver8.6 treatment planning systerm. Dose vol- ume histograms were used to compare the target volume and organs at risks. RESULTS： Compared to dIMRT,conformity index（CI） and homogeneity index（HI） of VMAT closer to one. Dmi, of VMAT was （43. 403±0. 486） Gy,closer to pre- scription dose. There were significant differences in CI, HI and Drain （P〈0.05）. The small intestinal＇ s D30% , D50% and D were larger in dIMRT than those in VAMT（P values were 0. 00, 0. 01 and 0. 00）. D30% , D50% , Dmean in VMAT were （25. 918±1. 216）,（22. 340±3. 784） and （23. 547±2. 863） Gy,in dIMRT were （28. 073±3. 114）,（24. 172±2. 540） and （25. 257±1. 374）. The bladder＇s D30% was （35. 380±2. 734） in VAMT,larger than that in dIMRT,which was （30. 123± 2. 209） Gy （P=0.00） ,but still lower than the dose equivalent limits. The femoral head＇s Dsn and D were （31. 344± 3. 556） and （20. 179±3. 017） Gy in VAMT higher than those in dIMRT,which were （26. 731±2. 828） and （17. 459±3. 279） Gy（Pvalues were 0.00 and 0.00）. The number of monitor units was reduced by 52.7% and the teratment time by 75% in VAMT. CONCLUSION： Compared to the dlMRT plans,VAMT plans show similar or better effects in the target dose distribution, reduction of irradiation doses on oragans at risk and, moreover, significant decrease of the monitor units and delivery time.
出处
《中华肿瘤防治杂志》
CAS
北大核心
2012年第24期1900-1903,共4页
Chinese Journal of Cancer Prevention and Treatment
