Ⅱb~Ⅲb期宫颈癌腔内联合宫旁插植近距离治疗计划中的3种不同优化方法的剂量学比较

Comparison of three different optimization methods in the parametrial interstitial brachytherapy for stage IIb-IIIb cervical cancer

目的比较分析Ⅱb~Ⅲb期宫颈癌腔内联合宫旁插植近距离治疗计划中的3种优化方法的剂量学差异。方法选取Ⅱb~Ⅲb期宫颈癌患者33例,对每例患者制订3种计划,分别为手动优化组、模拟退火逆向计划优化算法(IPSA)组、混合逆向计划优化算法(HIPO)组。比较3组计划中高危临床靶区(HR-CTV)的体积剂量参数V_(150)、V_(100)、D_(100)、D_(90)、均匀性指数(HI),以及危及器官(直肠、膀胱、乙状结肠)的剂量参数D_(0.1 cm^(3))、D_(1 cm^(3))、D_(2 cm^(3))。结果 IPSA组和HIPO组的V_(150)、V_(100)均低于手动优化组,HI均高于手动优化组,HIPO组的V_(100)高于IPSA组,差异均有统计学意义(P﹤0.05)。IPSA组和HIPO组直肠、膀胱、乙状结肠的D_(0.1 cm^(3))、D_(1 cm^(3))和D_(2 cm^(3))均低于手动计划组,差异均有统计学意义(P﹤0.05);HIPO组直肠、膀胱的D_(0.1 cm^(3))、D_(1 cm^(3))和D_(2 cm^(3))均低于IPSA组,差异均有统计学意义(P﹤0.05)。结论对于局部晚期宫颈癌腔内联合宫旁插植技术,基于3组优化方法的计划均能满足临床需求。HIPO计划和IPSA计划能提高靶区剂量覆盖;HIPO计划较IPSA计划可以进一步提高靶区的V_(100)和HI指数,同时减少膀胱和直肠的受量。

Objective To compare and analyze the dosimetric discrepancies of the three optimization methods in the parametrial interstitial brachytherapy for stage IIb-IIIb cervical cancer.Method Thirty-three patients with stage IIb-IIIb cervical cancer were selected.Three plans were made for each patient,namely manual group,inverse planning simulated annealing(IPSA)group,and hybrid inverse treatment planning and optimization(HIPO)group.The volume does parameters V_(150),V_(100),D_(100),D_(90),homogeneity index(HI)of the high-risk clinical target volume(HR-CTV)in the three groups,and the dose parameters D_(0.1 cm^(3)),D_(1 cm^(3)),and D_(2 cm^(3)) of the organs at risk(rectum,bladder,sigmoid colon)were compared.Result V_(150 and V_(100) of the IPSA group and HIPO group were lower than the manual group,while HI was higher than the manual group,V_(100) of HIPO group was higher than IPSA group,the differences were statistically significant(P<0.05).The D_(0.1 cm^(3)),D_(1 cm^(3)),and D_(2 cm^(3)) of the rectum,bladder,and sigmoid colon in the IPSA group and the HIPO group were lower than those in the manual group,the D_(0.1 cm^(3)),D_(1 cm^(3)),and D_(2 cm^(3)) of the rectum and bladder in the HIPO group were lower than those in the IP-SA group,and the differences were statistically significant(P<0.05).Conclusion The plan based on the three groups of optimization methods could meet the clinical needs of the parametrial interstitial brachytherapy for locally advanced cervical cancer.The HIPO plan and IPSA plan could improve the dose coverage over the target.Attentionally,the HIPO plan would further increase the V_(100) and HI index of the target area compared with the IPSA plan,while narrowing the bladder and rectum affected volume.