Compass剂量验证系统在VMAT脑肿瘤瘤床同步追量中的应用  

Application of Compass dose verification system in tumor bed synchronous integrated boost radiation of VMAT for brain tumor

作　　者：宋婷婷 盛晓芳 汪洋 韩磊 胡小洋 

机构地区：[1]上海伽玛医院放疗中心,上海200235

出　　处：《中国医学物理学杂志》2016年第10期1012-1016,共5页Chinese Journal of Medical Physics

摘　　要：目的:应用Compass剂量验证系统评估容积弧形旋转调强放疗(VMAT)技术在实施脑肿瘤瘤床同步追量中的剂量精确性。方法:将50例脑瘤瘤床同步追量患者的治疗计划导入Compass剂量验证系统,生成治疗质量保证(DQA)计划,得到计算剂量。按照DQA计划出束照射体模,并重建实际出束剂量,将两者进行对比,比较肿瘤追量照射区域(PGTV)、肿瘤计划照射区域(PTV)、全脑组织、脑干等靶区和危及器官的γ分析结果和剂量体积直方图(DVH)分析结果。结果:50例瘤床同步追量VMAT计划以3%/3 mm为标准进行评估,PGTV、PTV的γ通过率分别为(97.92±1.69)%、(96.72±1.99)%,其他危及器官的γ通过率均在90.00%以上。追量的瘤床个数对γ通过率无影响(P>0.05)。DVH比较分析表明,视交叉、视神经、晶体的D1%剂量差异均大于3%,其他危及器官和PGTV、PTV的D_(mean)、D_(1%)剂量差异均小于3%。结论:VMAT技术实施脑肿瘤瘤床同步追量的剂量精确性较高。Compass剂量验证系统可作为VMAT瘤床同步追量的日常DQA工具,但对于小体积的正常组织进行DVH比较分析时有一定误差。Objective To investigate the dose accuracy of volumetric modulated arc therapy （VMAT） technique for the tumor bed synchronous integrated boost radiation in brain by using Compass dose verification system. Methods Totally, 50 patients with brain tumor were selected, whose treatment plans were transplant to the Compass dose verification system to generate delivery quality assurance （DQA） plan and acquire the compute dose. The phantom was radiated according to DQA plan and the delivery dose was reconstructed. The compute dose was compared with the reconstructed dose. The Gamma passing rate and dose volume histogram （DVH） of planning gross target volume （PGTV）, planning target volume （PTV）, whole brain tissue, brain stem and organs at risk （OARs） were compared. Results Based on the criteria 3%/3 mm, the Gamma passing rate of PGTV and PTV was respectively （97.92~ 1.69）% and （96.72~ 1.99）%. And the Gamma passing rates of OARs were all over 90.00%. The Gamma passing rate was not influenced by the number of tumor beds （P〉0.05）. The D~ difference of chiasmas, optic nerve and lens were over 3%, while the D~/o and Dm~ differences of PGTV, PTV and other OARs were less than 3%. Conclusion VMAT technique has the high dose deliver accuracy in the tumor bed synchronous integrated boost radiation. Compass dose verification system can be used as the daily DQA tool for VMAT, but some errors exist in the DVH analysis of the normal tissue of small volume.

关 键 词：脑肿瘤 瘤床同步追量 容积弧形旋转调强放疗 Compass剂量验证系统 

分 类 号：R815[医药卫生—放射医学]