胰腺癌3DCRT计划设计中BAO和BAF两种优化的比较

To Comparison The Two Optimization Methods of Beam Angle Optimization and Beam Angle Fixed in Three-dimensional Conformal Radiation Therapy for Pancreatic

目的：探讨胰腺癌射野角度优化（Beam Angle OptimizationBAO）方法对三维适形治疗（3DCRT）的计划质量及计划设计效率的影响。方法：对8例胰腺癌患者以相同的处方剂量，但分别采用BAO和固定射野角度（Beam Angle Fixed BAF）方法设计4野的三维适形治疗（3DCRT）计划，BAO计划组初始角度为0°、90°、180°、270°，最终射野角度由系统自动优化得到：BAF计划组射野角度基于物理师临床经验，采用试错方法（Trial-and-erro）得到。比较两组计划在剂量分布、靶区适形指数（CI）与均匀性指数（HI），不同危及器官（OAR）的照射剂量以及计划设计效率的差异性。结果：两组计划均能满足临床剂量要求，与BAF相比，BAO计划组靶区PTv适形指数CI较优（p=0．037），靶区PTV中位剂量Dso＊略高（p=0．011）；BAO计划组危及器官照射剂量均比BAF组低（P=O．叭2～0．525），其中肝脏和双肾的平均剂量D-有显著性差异（p=0．030，0．012）；BAO和BAF计划组总计划时间和总机器跳数（Mu）分别为5．0（±0．5）min、360（±32）MU和10（±1．0）min、365（±38）MU（P=0．000、0．981），BAO组在计划设计效率方面提高了100％。结论：相比于固定射野角度方法，使用射野角度优化（BAO）可得到更优的胰腺癌三维适形计划，且可提高计划设计的效率，可以在临床上开展广泛应用。

Objective： To Investigate the plans dosimetric results and plan design efficiency using Beam Angle Optimization （BAO） in three-dimensional conformal radiation therapy （3DCRT） for the pancreatic carcinoma. Methods： Eight pancreatic carcinoma patients were enrolled in this study. For each patient, the BAO plans and BAF（Beam angle Fixed） plans were created with the same prescription using four beams 3DCRT technical,separately; The initial beam angles in BAO plans were 0° ,90° 180° ,270°,Final beam angles were decided by optimizing plan objective function in reverse method;The beam angles in BAF plans were got using trial and error method based on clinical experiences of medical physicist. The target dose conformity, ho- mogeneity, dosiemtric indexes and dose to organ at risks （OARs） were compared. Plan design efficiency were also evaluated. Results： All BAO and BAF plans met the clinical requirements. Compare with BAF,The dose conformity to PTV were better （p=0.037） and Higher median dose D50%（p=0.011） in BAO Plans. Compared with BAF Plans, BAO plans showed better OARs sparing （p=0.012- 0.525）. The mean doses of Live and Kidney show significant difference among all OARs. Furthermore, the BAO plans had fewer plan times （p=0.000）. Conclusions： BAO plan can achieve clinical needs with lower OARs dose and higher plan design efficiency.