Raystation 论文集-第3期

目 录

Mimicdose 算法在调强备用计划设计中的应用

梁志文1 ，杨志勇1，商海焦2，李勤1 (1)

多目标优化方法在鼻咽癌临床中的剂量学研究

商海焦1，罗汉文1，梁志文2，王佳舟3，胡伟刚3 (8)

Implement a novel beam angle and multicriteria optimization technique for fast IMRT radiotherapy: a preclinical investigation in the gastric cancer.

Weigang Hu, Jiazhou Wang, Guichao Li, Jiayuan Peng,Saiquan Lu,

Zhen Zhang, M.D., (17)

CBCT-based volumetric and dosimetric variation evaluation of volumetric modulated arc radiotherapy in the treatment of nasopharyngeal cancer patients. Xiance Jin1, Weigang Hu2, Haijiao Shang3, Ce Han1, Jinling Yi1, Yongqiang Zhou1

Congying Xie1* (31)

Mimicdose 算法在调强备用计划设计中的应用

梁志文1 ，杨志勇1， 商海焦2， 李勤1

（1.华中科技大学同济医学院附属协和医院，肿瘤中心，武汉430023；

2.上海交通大学，通信与电子信息系统，上海200240）

【摘要】目的用Mimicdose算法把动态调强和旋转容积调强计划转换为静态调强计划，评估该算法的临床可行性。方法在瓦里安Eclipse计划系统里设计鼻咽癌9野动态调强计划和宫颈癌双弧旋转容积调强计划作为初始计划。把初始计划传至RayStation计划系统中用Mimicdose算法生成备用计划，鼻咽癌备用计划为9野静态调强，宫颈癌备用计划分别为7野静态调强和9野静态调强。在剂量直方图中评估后备计划与初始计划差异。结果鼻咽癌备用计划的质量与初始计划相当，宫颈癌7野备用计划靶区覆盖率低于初始计划，宫颈癌9野备用计划质量与初始计划相当。备用计划花费时间均不超过10分钟。结论用Mimicdose算法生成的备用计划准确快速，能在临床上使用。

【关键词】调强放疗旋转容积调强备用计划

Application of Mimicdose algorithm in Intensity Modulated Radiation

fallback planning

Zhiwen Liang1, Zhiyong Yang1, Haijiao Shang2, Qin Li1

(1.Cancer Center, union hospital, Tongji Medical College, Huazhong University of Science and technology 2. Communication and electronic information system department of

Shanghai Jiao Tong University)

Abstract Objective To evaluate the plan quality between fallback plans generated by Mimicdose algorithm and the original plans generated by dMLC intensity modulated radiation therapy (IMRT) and /or volumetric intensity modulated arc therapy (VMA T). Methods Nine fields dMLC IMRT plan created by V arian Eclipse as original plan for Nasopharyngeal carcinoma (NPC) case, dual full arc VMA T plan created by V arian Eclipse as

original plan for pelvis case. Three different sMLC IMRT plans (one plan for head and neck case, two plans for pelvis case) generated by Mimicdose algorithm as fallback plan. Plan quality was compared by dose volume histogram (DVH) from original plans and fallback plans. Results Fallback plans are comparable to original plan for both the NPC case and pelvis case, although the planning targets volumes (PTVs) coverage are slightly lower than the original plan for 7 field pelvis fallback case . The evaluation of the pelvis case also showed that the fallback plans were improved when more beams were used. Planning time is no more than 10 minutes for all fallback plans. Conclusion Fallback plans generated by Mimicdose have proved to be effective and time saving.

Key words：IMRT V AMT Fallback Planning

放疗过程中，可能会出现因机器故障而无法正常运行的情况。为避免延误患者的正常治疗，常会把患者转移到另外的加速器上。当放疗部门没有同一厂家或同一型号加速器时，转换治疗比较麻烦，因此临床上需要一种简单快速的方法获得能在另一台加速器上执行的备用计划，剂量分布满足临床要求，且与原始计划大致相同。

Mimicdose是RayStation计划系统多目标优化（Multicriteria optimization，MCO）过程[1-3]中所用到的一种算法，其主要功能是把已有的剂量分布转换为多叶光栅序列，生成实际可执行计划。转换过程中的优化目标是使备用计划与原始计划的剂量直方图（Dose V olume Histogram, DVH）函数差异最小[4]。

考虑到患者在同一厂家加速器之间转换治疗容易实现，不同厂家加速器之间转换治疗较难，且更具临床意义，因此本文主要研究了Trilogy加速器（瓦里安公司，美国）上的患者转移到Synergy加速器（医科达公司，瑞典）上治疗的临床可行性。

一、材料与方法

1.影像获取：对头颈部和宫颈两个部位各随机选取一例，在飞利浦大孔径CT上模拟定位，扫描层厚为3mm。