用固体水进行加速器吸收剂量的日常QA校准

Dose calibration in daily quality assessment of linear accelerator with solid water

目的:探讨用固体水(IBA品牌)对加速器吸收剂量的日常质量保证(QA)校准的可行性。方法:通过对标准一维水箱内水和固体水在相同参数条件下进行吸收剂量对比测量,计算得到各个能量,固体水同水之间的吸收剂量等效系数,然后用该系数,对水的吸收剂量校正因子(CF_(water))进行重新校正,得到固体水的校正因子(CF_(solid water)),并将该校正因子输入剂量仪,重新测量相应能量射束的输出剂量。结果:用CF_(solid water)在固体水的吸收剂量测量结果同用CF_(water)在一维水箱水的测量结果相吻合(误差小于0.5%)。结论:可以用固体水对加速器吸收剂量进行日常QA校准。

Objective To study the feasibility of IBA solid water in the daily quality assessment（QA） calibration for the absorbed dose of linear accelerator.Methods With the same parameters,the absorbed doses of water and solid water in a standard onedimensional water tank were measured to calculate the energy and the absorbed dose equivalent coefficient between solid water and water.With the equivalent coefficient,the absorbed dose calibration factor of water（CF（water）） was recalibrated to obtain the calibration factor of solid water（CF（solid water））.The calibration coefficients were put into the dosimeter to recalculate the output dose of the beams with different energy.Results In the standard one-dimensional water tank,the absorbed dose in solid water measured with CFsolid watershowed good agreement with that in the water measured with CF（water）（error was less than 0.5%）.Conclusion IBA solid water is feasibility in the daily QA calibration for the absorbed dose of linear accelerator.