摘要目的 研究用热释光剂量计(TLD)核查非参考条件下光子线束和电子线束剂量学参数方法.方法 用60Coγ线束,高能X射线束和电子线束,开展TLD分散性、非线性剂量响应、衰退、能量和有机玻璃支架(IAEA提供)等校正实验,建立估算TLD水中光子线束和电子线束吸收剂量方法.选择了60 Co,6、10、15和18 MV光子线束(离轴),剂量随着照射野和30°楔形角度变化研究;选择了6和10 MV光子线,剂量随着源皮距,照射野和楔形角度变化进行可靠性研究;选择了9和15 MeV电子线,剂量随着源皮距离变化进行可靠性研究.结果 用建立的TLD方法,估算非参考条件下光子线束(离轴)研究结果,相对偏差在-0.1％ ～7.2％(IAEA要求不大于±7.0％)范围内.非参考条件光子线束(轴上)验证研究结果,相对偏差在0.1％ ～7.0％范围内;参考和非参考条件电子线束验证研究结果,相对偏差为0 ～4.7％(IAEA要求不大于±5.0％)范围内.结论 用TLD核查放射治疗非参考条件临床的剂量学参数方便准确,经在医院做可靠性验证,对高能电子线束,用平行板电离室校准吸收剂量,用TLD验证,效果很好.

abstractsObjective To develop a methodology for auditing dosimetric parameters using TLD for photon and electron beams in non-reference conditions.Methods The correction experiments have been developed for non-linear dose response,PAAM holder,energy,fading and dispersion using TLD for 60Co γ-ray,high energy X-ray and electron beams.The measuring method was set up for absorbed dose estimation by TLDs in water.3 photon beams and 2 electron beams were selected for research purposes,and 5 photon beams and 4 electron beams for reliability research.Results The research results were evaluated for60Co source,6,10,15 and 18 MV photon beams in non-reference conditions at off-axis,with the relative deviation within-0.1％-7.2％ at-off axis (IAEA's acceptable deviation:± 7.0％).The verification results were evaluated for 5 photon beams in non-reference conditions at on-axis,with the relative deviation are within 0.1％-7.0％.The verification results were evaluated for 4 electron beams in non-reference conditions,with the relative deviation within 0-4.7％ (IAEA's acceptable deviation:±5.0％).Conclusions It is convenient and accurate to use TLD method for quality audits for clinic dosimetry parameters in radiotherapy.Two kinds of IAEA TLD holders are feasible for use in TLD audits.Absorbed doses for high energy electron beam were corrected using plane parallel chambers and verified using TLD,with good results obtained.