应用一维、二维、三维探测器阵列进行螺旋断层调强放疗计划剂量验证

目的：比较Tomotherapy标配Cheese模体联合EBT3免冲洗胶片（一维探测器阵列）、Octavius八角模体配合PTW Seven29二维探测器阵列（二维探测器阵列）、Delta4三维探测器阵列用于螺旋断层放疗系统（Tomo Therapy,TOMO）的调强计划实施剂量验证的差异。方法：分别采用一维、二维、三维探测器对10例患者TOMO的调强计划实施验证。通过TOMO系统MVCT成像和配准消除床面沉降的影响,确保实现体模和探测器阵列的精确摆位。实施治疗质量保证（Delivery Quality Assurance,DQA）计划照射后将测量获得的平面剂量分布与TOMO计划系统模体计划计算获得的平面剂量分布进行比较。采用Gamma分析方法,选择多个不同的剂量标准分析评估验证情况。结果：采用3%/2mm、3%/3 mm、3%/4 mm、3%/5 mm四种不同剂量偏差/吻合距离剂量标准,γ≤1的平均通过率均超过95.2%,测量所得剂量分布与计算结果在相应平面的几何分布均呈现出良好的一致性。结论：胶片空间分辨率高于二维、三维探测器阵列,是调强计划验证的＂金标准＂。而二维和三维探测器阵列凭借其操作简便、数据处理快捷的特点可作为一维验证方法的有效补充。

Evaluation of EBT3,PTW Seven29 Combining Octavius Phantom,Delta4 for Tomotherapy Patient-specific Quality Assurance

Objective：To compare the difference of dose verification of intensity modulated planning of tomoTherapy （TO- MO） using the EBT3 no rinse film combining cheese phantom, PTW Seven29 2D-ARRAY inserted in a dedicated octagonal phantom, called Octavius and Delta4 three dimensional detector array. Methods：The EBT3 no rinse film, PTW Seven29 2D-ARRAY combining Octavius phantom and Delta4 detector array was used to verify the TOMO treatment plan dose distribution of 10 patients. The precise setup of detector array was guided and registered by MVCT imaging. After the implementa- tion of delivery quality assurance （DQA） plan, the measured dose distributions on the corresponding planes were compared with those calculated by the treatment planning system （TPS）. Based on several different Gamma criteria, the Gamma analysis method was utilized to evaluate the dose verification. Results：According to the different acceptance criteria combination of dose difference （DD） / distance to agreement （DTA） at different threshold level including 3.%/2 ram, 3%/3 mm, 3%/4 mm, 3% /5 mm, the mean passing rates with 7parameter ≤ 1 were all above 95.2%. the dose distribution measured by the EBT3 no rinse film, 2D-ARRAY combining Octavius phantom and Delta4 detector array was well Consistent with that calculated by the TPS. Conclusions： Film detector has the highest spatial resolution and is the golden standard in radiation therapy delivery ver- ification including TOMO. Two dimensional and three dimensional detector arrays are the complementary tools to film with their simple operation and easy data processing.in clinical quality assurance （QA） work.