应用Delta4三维探测器阵列进行螺旋断层治疗计划剂量验证

Delta three-dimensional semiconductor array verification for intensity modulated planning of helical tomotherapy

目的研究采用Deha4三维半导体探测器阵列对螺旋断层治疗（HT）计划实施剂量验证的可行性。方法采用ScandiDos公司Delta4三维半导体探测器阵列验证10例恶性肿瘤患者HT计划。通过该系统兆伏特CT成像和配准来确保实现Delta4探测器阵列的精确摆位。实施质量保证的治疗计划照射后，将Deha4探测器阵列测量获得的平面剂量分布与计划系统模体计划计算获得的进行比较。选择阈值水平分别为5％、10％、20％、70％、90％时3％／2him、3％／3mm、3％／4mm、3％／5mm标准分别进行γ通过率验证。结果测量所得剂量分布与计算结果在相应平面几何分布均呈良好一致性。γ平均通过率均〉94．89％。结论Delta4三维探测器阵列用于HT计划验证能获满意结果，一般情况下可有效替代传统胶片验证。

Objective To investigate the feasibility of dose verification of intensity modulated planning of helical tomotherapy （HT） using three-dimensional semiconductor array （Delta4） and find a more time-consuming and accurate method to validate the delivery dose. Methods Delta4 detector array was used to verify the HT plan dose distribution of 10 patients. The precise setup of detector array was guided and registered by MVCT imaging. After the implementation of delivery, the measured dose distributions on the corresponding planes were compared with those calculated by the treatment planning system （TPS）. According to the different acceptance criteria combination of dose difference or distance to agreement at different threshold level including 3%/2 mm, 3%/3 mm, 3%/4 mm, 3%/5 mm at THS, TH10, TH20, TH30, TH70, TH90, the γ analysis method was utilized to evaluate the dose verification. Results The dose distribution measured by the Deha4 was well consistent with that calculated by the TPS. The mean γ passing rates were all above 94. 89%. Conclusions Delta4 detector array can get satisfying results when used in HT plan dose verification and is a viable tool to replace traditional film dosimetry system in clinical quality assurance work.