DPM蒙特卡罗剂量计算算法在均匀组织和非均匀组织剂量精确性的验证

Verification of the Accuracy of Monte Carlo-based Dose Calculation Algorithm,DPM,In Homogeneous and Inhomogeneous Tissues

验证DPM蒙特卡罗剂量计算算法预测均匀组织和非均匀组织剂量的精确性。DPM分别计算:①6 MeV单能光子3cm×3cm照射野和Varian 60℃加速器源水模体百分深度剂量曲线和10cm深度处离轴比;②6 MeV单能光子3cm×3cm、10cm×10cm照射野分别在水(6cm)/肺(6cm)/水(8cm)、水(6cm)/骨骼(2cm)/水(12cm)非均匀组织的百分深度剂量曲线;③6MeV单能光子6cm×6cm照射野人体头部和腹部组织在射野内和射野外的百分深度剂量曲线。比较DPM计算值与DOSXYZnrc/EGSnrc系统在相同条件下的计算值。结果显示二者计算值在水模中的误差在±3%以内,在非均匀组织中,除了个别点,误差都在±3%以内。DPM能够精确计算均匀组织和非均匀组织剂量。

The present paper is to verify the accuracy of DPM,a Monte Carlo-based dose calculation algorithm,in homogeneous and inhomogeneous tissues.DPM was applied to calculate ① depth dose curves and off-axis ratios at a depth of 10cm in water using a 6MeV photon beam with a 3cm×3cm field and phase space file simulated Varian 60℃ medical linear accelerator with a 10cm×10cm field at SSD=100（cm）;②depth dose curves using 6MeV photon beam in inhomogeneous tissues,such as water（6cm）/lung（6cm）/water（8cm） with a 3cm×3cm field and water（6 cm）/bone（2cm）/water（12cm）with a 10cm×10cm field;③depth dose curves using 6MeV photon beam based on the CT data of a patient＇s head and abdomen.The doses based on DPM are compared to the doses calculated by DOSXYZnrc under the same condition.The error was within 3% in water phantom while the error was within 3% in inhomogeneous tissues,except a few points.It has been concluded that the DPM can accurately predict the dose to homogeneous and inhomogeneous tissues.