胰腺癌患者立体定向体部放射治疗非共面锥形射束与共面扇形射束照射的剂量学差异

Dose difference of Non-Coplanar Cone Beam and Coplanar Fan Beam in Stereotactic Body Radiation Therapy for Pancreatic Cancer

目的评价胰腺癌患者射波刀(Cyberknife)与拓姆刀(Tomo)立体定向体部放射治疗(SBRT)计划设计的剂量学差异,为临床选择合适的SBRT照射技术提供参考。方法本研究选取13例局部晚期胰腺癌患者,根据同一CT图像分别制定Cyber计划和Tomo计划,对比分析剂量-体积直方图(DVH),并评价靶区和危及器官(OAR)的剂量分布差异。结果 Cyber计划和Tomo计划的V_(Dx)(100%处方剂量线的靶区覆盖率)参数比较,差异有统计学意义(P<0.05),Tomo计划的V_(Dx)明显高于Cyber计划,但两种计划的V_(Dx)均达到95%,且靶区以外均无D_(110%)(110%处方剂量)的热点出现。与Tomo计划相比,Cyber计划中脊髓的D_(max)、D_(<(0.25cc)、D_(<1.2cc)分别降低58.28%、59.70%、61.56%,小肠的D_(max)、D_(<5cc)分别降低28.92%、26.11%,胃的D_(max)、D<_(10cc)分别降低38.23%、33.52%,十二指肠的D_(max)、D_(mean)、D_(<5cc)、D_(<10cc)分别降低29.11%、19.28%、32.38%、33.19%,左右肾脏的Dmean也均有明显的下降(P<0.05)。结论综合分析胰腺癌的SBRT计划,本研究结果表明非共面射束计划明显优于扇形射束计划。因此,对于中晚期胰腺癌患者,射波刀立体定向放射治疗可作为一种更优的治疗方式供患者选择。

Objective To perform a dosimetry comparison of cyber-plan and tomo-plan in stereotactic body radiation therapy for pancreatic cancer.It can provide an appropriate clinical reference for selection of stereotactic body radiation therapy(SBRT)irradiation technology.Methods This research selected 13 locally advanced pancreatic cancer patients.The cyber-plan and tomo-plan were developed based on the same CT simulation image,respectively.The dose distribution was evaluated based on dose-volume histogram(DVH),including tumor or planning target volume(PTV),and organs at risk(OAR).Results The VDx of tumor or PTV(the target coverage with 100% prescription dose line)had significantly statistical difference between cyber-planning and tomo-plan(P<0.05).The tomo-plan markedly increased the VDx of target(tumor or PTV)compared with the cyber-plan.But the target coverage in both plans was over 95%,and there were no D110%(110% prescription dose line)hot dots beyond of the target volume.When compared with tomo-plan,Dmax,D<0.25cc and D<1.2cc of spinal cord in cyberplan had been reduced by 58.28%,59.70% and 61.56%,Dmax and D<5cc of bowel had been reduced by 28.92% and 26.11%,Dmax and D<10cc of stomach had been reduced by 38.23% and 33.52%,Dmax,Dmean,D<5cc and D<10cc of duodenum had been reduced by 29.11%,19.28%,32.38% and 33.19%,and the Dmean of kidney also had been reduced significantly(P<0.05),respectively.Conclusion By comprehensive analysis of the two plans,the results of this study indicated that non-coplanar beam planning was remarkably better than fan beam planning.So the SBRT of cyberknife can offer a better opportunity to select for patients with advanced pancreatic cancer.