Derreumaux S, Chavaudra J, Bridier A, Rossetti V, Dutreix A
Department of Physics, Institut Gustave-Roussy, Villejuif, France.
Phys Med Biol. 1995 Jul;40(7):1191-208. doi: 10.1088/0031-9155/40/7/004.
In the frame of the experimental implementation of a European quality assurance network for external radiotherapy, the methodology in the European Measuring Centre (MC) is presented. Mailed TL dosimeters are used for the check of the beam output and of the beam quality of photon beams. The thermoluminescent material is PTL 717 LiF powder. The readings were first performed on a manual, and then on an automatic reader, with standard deviations of the mean of 0.7% for one dosimeter. Corrections for supralinearity and for the energy dependence of the dosimeter response are applied. An original method has been developed to correct for the variation of the LiF response as a function of time. It is shown that the sensitivity of the powder changes during storage, leading to a kind of 'inverse fading'. The global uncertainty of the TL postal measurement procedure is estimated to be about 1.5% for the 60Co beams and 2% for the x-ray beams. Intercomparisons with the IAEA and with the EORTC have shown an agreement better than 2% for all energies. It can be concluded that the results of the MC are suitable for the requirements of a European quality assurance network.
在欧洲外照射放疗质量保证网络的实验实施框架内，介绍了欧洲测量中心（MC）的方法。邮寄式热释光剂量计用于检查光子束的输出剂量和束流质量。热释光材料为PTL 717 LiF粉末。读数首先在手动读数器上进行，然后在自动读数器上进行，单个剂量计平均值的标准偏差为0.7%。对剂量计响应的超线性和能量依赖性进行了校正。已开发出一种原始方法来校正LiF响应随时间的变化。结果表明，粉末的灵敏度在储存过程中会发生变化，导致一种“反向衰退”。热释光邮政测量程序的总体不确定度估计对于60Co束约为1.5%，对于X射线束约为2%。与国际原子能机构（IAEA）和欧洲癌症研究与治疗组织（EORTC）的比对表明，在所有能量下的一致性均优于2%。可以得出结论，测量中心的结果符合欧洲质量保证网络的要求。
