自动IMRT计划在宫颈癌术后放疗中的可行性

Feasibility of automatic planning in intensity-modulated radiotherapy for postoperative cervical cancer patients

目的:通过比较自动IMRT计划与人工IMRT计划的剂量学差异,探讨自动计划在宫颈癌术后IMRT计划设计中的可行性。方法:使用飞利浦Pinnacle^3 9.10计划系统的自动IMRT和人工IMRT方法分别对25例宫颈癌术后患者进行计划设计,比较2种计划得到的靶区和危及器官的剂量学参数、机器跳数、调试次数及计划设计时间。结果:自动和人工IMRT计划靶区的D_(mean)、D_(95)、CI及HI等参数均无明显差异(P>0.05);自动IMRT计划得到的危及器官剂量学参数均优于人工IMRT计划,其中膀胱V_(40)减少2.5%(P<0.05),直肠V_(40)减少0.9%(P<0.05),骨V_(35)减少2.8%(P<0.05),小肠V_(30)减少4.2%(P<0.05),左侧股骨头V_(30)减少5.2%(P<0.05)以及右侧股骨头V_(30)减少5.5%(P<0.05);并且自动计划明显减少了计划调试次数,将人工IMRT计划的平均调试次数由3次减少到平均2次,计划设计时间由人工IMRT的69.5 min减少到42.7 min;但自动计划的平均跳数(1 042 MU)高于人工计划(931 MU)。结论:基于Pinnacle^3的自动IMRT计划质量可以达到人工IMRT计划水平的同时,明显提高了计划设计效率,在宫颈癌术后的IMRT计划设计中具有可行性。

Objective To investigate the feasibility of automatic intensity-modulated therapy （IMRT） planning for postoperative cervical cancer patients by comparing the dosimetric differences between automatic IMRT plan and manual IMRT plan. Methods The manual IMRT planning and automatic IMRT planning of Philips Pinnacle3 9.10 treatment planning system were used to design treatment plans for 25 cervical cancer patients. The dosimetric parameters of target areas and organs-at-risk, monitor unit, optimization times and planning time were compared between the two plans. Results No significant differences were found in the Dmean, D95, conformity index and homogeneity index of target areas between automatic and manual IMRT plans （P〉0.05）. Compared with manual IMRT plan, automatic IMRT plan showed better dosimetric parameters of organs-at-risk, having 2.5% reduction in bladder V40, 0.9% in rectum V40, 2.8% in bone V35, 4.2% in intestine V30, 5.2% in left femoral head V30 and 5.5% in right femoral head V30 （all P〈0.05）. Compared with manual IMRT plan, the automatic IMRT plan reduced the average optimization times from 3 times to 2 times and planning time from 69.5 min to 42.7 min. Moreover, the automatic IMRT plan had a higher monitor unit than manual IMRT plan （1 042 MU vs 931 MU）. Conclusion Pinnacle3-based automatic IMRT planning is feasible in the IMRT planning for postoperative cervical cancer patients for automatic IMRT plan can significantly enhance efficiency and simultaneously improve plan quality.