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目的核查放射治疗计划系统(TPS)计算病人治疗剂量的非均匀野剂量校正。方法将插有TLD的聚苯乙烯固体模体,聚苯乙烯/肺固体模体,聚苯乙烯/骨固体模体分别经CT扫描,影像分别传入TPS并计算高能X射线下监督单位数,使传递给中心束轴TLD剂量为2 Gy。在高能X射线下完成TLD照射,照射后的TLD经测量、剂量计算,D(TLD)与D(TPS)剂量比值在0.95~1.05范围为可接受范围。结果核查结果表明,光子线束均匀模体轴上(P)剂量和非均匀骨模体轴上(BP)剂量核查结果较好。非均匀肺模体轴上(LP)和离轴(LL)剂量核查结果误差很大。结论光子线束非均匀性剂量校正在放射治疗中是非常重要,尤其是肺组织。校正不当,对于肺组织剂量误差也可达到11.1%,离轴情况下更多达18.4%。对于骨组织剂量误差较小。
Objective To verify radiotherapy planning system (TPS) to calculate non-uniform dose correction of patient dose. Methods The polystyrene solid phantom, polystyrene / lung solid phantom and polystyrene / bone solid phantom inserted with TLD were respectively scanned by CT and the images were respectively transmitted to TPS and the number of supervised units under high energy X-ray was calculated. The dose delivered to the central beam axis TLD was 2 Gy. TLD irradiation was completed under high-energy X-ray irradiation. The TLD after irradiation was measured. The dose ratio of D (TLD) to D (TPS) was in the acceptable range of 0.95-1.05. The results of verification showed that the photon beam uniform axis of the body (P) dose and non-uniform phantom axis (BP) dose verification results are better. Non-uniform lung phantom axial (LP) and off-axis (LL) dose verification error is large. Conclusion Photon Harmonic Non-uniform Dosimetry is very important in radiation therapy, especially in lung tissue. Improperly calibrated, up to 11.1% dose error for lung tissue and up to 18.4% off-axis. For the bone tissue dose error smaller.