两台不同品牌医用直线加速器剂量输出长期稳定性分析

Analysis on the long-term stability of dosage output of two kinds of medical linear accelerators

目的:对两台不同品牌医用直线加速器6 MV光子束长期稳定性进行对照分析,以确保直线加速器运行的准确性和稳定性。方法:运用PTW QUICK CHECK webline晨检仪采集Varian(Clinac iX)型和Elekta(Synergy)型两台医用直线加速器为期2年的日检数据进行系统性对照分析,评价两台机器剂量输出偏差和长期稳定性。结果:两台直线加速器6 MV光子束中心轴输出剂量偏差分别为(-0.10±0.67)%和(0.09±0.82)%,其中Synergy加速器因检测电离室故障导致1次测量结果>2%,其余均在允许范围之内。平坦度和对称性(LR/GT)的测量偏差在±1%内的比例>93%,稳定性较好。两台直线加速器射线质稳定性测量偏差分别为(-0.32±0.69)%和(0.09±0.72)%,均在允许范围。结论:两种医用直线加速器6 MV光子束均具有较好的剂量输出长期稳定性,加速器输出剂量日常检测能够保证设备运行的准确性和稳定性,可在保证精确治疗的实施中发挥重要作用。

Objective:To compare and analyze the long-term stability of 6MV photon beams of two kinds of imported medical linear accelerators so as to ensure the accuracy and stability of the linear accelerator.Methods:The PTW QUICK CHECK webline morning detector was used to conduct the daily check data of two medical linear accelerators[Varian(Clinac iX)and Elekta(Synergy)]in 2 years for systematic contrast analysis.And then,the deviation and long-time stability of dosage output of two machines were evaluated.Results:The deviations of the output dosage in the central axis of the 6MV photon beam of the two linear accelerators were(-0.10%±0.67%)and(0.09%±0.82%)respectively.The one measured result of Synergy accelerator was larger than 2%due to the fault of test ionization chamber,and other results of that were within the allowance range.The ratio of measured deviation of flatness and symmetry(LR/GT)within±1%was larger than 93%,and the stability was favorable.The measured deviations of stability of actinogen of two linear accelerators were(-0.32%±0.69%)and(0.09%±0.72%),respectively,and all of them were within the allowance range.Conclusion:The 6 MV photon beams both of two medical linear accelerators have better long-term stability of dose output,and the routine test of output dosage of accelerator can ensure the accuracy and stability of equipment operation,and can ensure the accelerator to play important role in the implementation of precise treatment.