中华放射医学与防护杂志
中華放射醫學與防護雜誌
중화방사의학여방호잡지
Chinese Journal of Radiological Medicine and Protection
2014年
6期
461-465
,共5页
马新兴%罗素明%何志坚%周文珊
馬新興%囉素明%何誌堅%週文珊
마신흥%라소명%하지견%주문산
非参考条件%指形电离室%光子线束%电子线束%吸收剂量
非參攷條件%指形電離室%光子線束%電子線束%吸收劑量
비삼고조건%지형전리실%광자선속%전자선속%흡수제량
Non-reference condition%Finger ionization chamber%Photon beams%Electron beams%Absorbed dose
目的 研究用TLD核查医用电子加速器在非参考条件下,光子线束剂量随照射野、楔形板变化,电子线束剂量随照射野、源皮距变化的剂量学参数方法的可靠性.方法 在非参考条件下,用指形电离室测量光子线束水下10 cm处吸收剂量和电子线束最大剂量点处吸收剂量,并在同一位置放置TLD进行照射,将照射后的TLD邮寄到中国疾病预防控制中心辐射防护与核安全医学所进行测量并估算剂量.结果 光子线束剂量点共70个,其中58个点的TLD测量结果与指形电离室测量结果相对偏差在±7.0％以内(IAEA允许偏差±7.0％),合格率为82.8％.经过Ps值修正后,合格点数达到62个,合格率上升为88.6％;电子线束剂量点为24个,其TLD测量结果与指形电离室测量结果相对偏差均在±5.0％以内(IAEA允许偏差±5.0％),合格率为100％.结论 用TLD核查非参考条件电子线束剂量学参数方便,与指形电离室相互验证,可提高剂量测量的准确性.电子线束能量在5 MeV＜E0＜10MeV的范围内,用指形电离室测量吸收剂量参数,并用TLD验证,其结果精确可靠.
目的 研究用TLD覈查醫用電子加速器在非參攷條件下,光子線束劑量隨照射野、楔形闆變化,電子線束劑量隨照射野、源皮距變化的劑量學參數方法的可靠性.方法 在非參攷條件下,用指形電離室測量光子線束水下10 cm處吸收劑量和電子線束最大劑量點處吸收劑量,併在同一位置放置TLD進行照射,將照射後的TLD郵寄到中國疾病預防控製中心輻射防護與覈安全醫學所進行測量併估算劑量.結果 光子線束劑量點共70箇,其中58箇點的TLD測量結果與指形電離室測量結果相對偏差在±7.0％以內(IAEA允許偏差±7.0％),閤格率為82.8％.經過Ps值脩正後,閤格點數達到62箇,閤格率上升為88.6％;電子線束劑量點為24箇,其TLD測量結果與指形電離室測量結果相對偏差均在±5.0％以內(IAEA允許偏差±5.0％),閤格率為100％.結論 用TLD覈查非參攷條件電子線束劑量學參數方便,與指形電離室相互驗證,可提高劑量測量的準確性.電子線束能量在5 MeV＜E0＜10MeV的範圍內,用指形電離室測量吸收劑量參數,併用TLD驗證,其結果精確可靠.
목적 연구용TLD핵사의용전자가속기재비삼고조건하,광자선속제량수조사야、설형판변화,전자선속제량수조사야、원피거변화적제량학삼수방법적가고성.방법 재비삼고조건하,용지형전리실측량광자선속수하10 cm처흡수제량화전자선속최대제량점처흡수제량,병재동일위치방치TLD진행조사,장조사후적TLD유기도중국질병예방공제중심복사방호여핵안전의학소진행측량병고산제량.결과 광자선속제량점공70개,기중58개점적TLD측량결과여지형전리실측량결과상대편차재±7.0％이내(IAEA윤허편차±7.0％),합격솔위82.8％.경과Ps치수정후,합격점수체도62개,합격솔상승위88.6％;전자선속제량점위24개,기TLD측량결과여지형전리실측량결과상대편차균재±5.0％이내(IAEA윤허편차±5.0％),합격솔위100％.결론 용TLD핵사비삼고조건전자선속제량학삼수방편,여지형전리실상호험증,가제고제량측량적준학성.전자선속능량재5 MeV＜E0＜10MeV적범위내,용지형전리실측량흡수제량삼수,병용TLD험증,기결과정학가고.
Objective To verify the reliability of TLD-based quality audit for radiotherapy dosimetry of medical electron accelerator in non-reference condition by monitoring the dose variations from electron beams with different field sizes and 45° wedge and the dose variations from photon beams with different field sizes and source-skin distance.Methods Both TLDs and finger ionization chambers were placed at a depth of 10 cm in water to measure the absorbed dose from photon beams,and also placed at the depth of maximum dose from electron beams under non-reference condition.TLDs were then mailed to National Institute for Radiological Protection,China CDC for further measurement.Results Among the 70 measuring points for photon beams,58 points showed the results with a relative error less than ± 7.0％ (IAEA's acceptable deviation:± 7.0％) between TLDs and finger ionization chambers measurements,and the percentage of qualified point numbers was 82.8％.After corrected by P,value,62 points were qualified and the percentage was up to 88.6％.All of the measuring points for electron beams,with the total number of 24,presented a relative error within ± 5.0％ (IAEA's acceptable deviation:± 5.0％) between TLDs and finger ioization cylindrical chambers measurements.Conclusions TLD-based quality audit is convenient for determining radiotherapy dosimetric parameters of electron beams in non-reference condition and can improve the accuracy of the measuring parameters in connection with finger chambers.For electron beams of 5 MeV ＜ E0 ＜ 10 MeV,the absorbed dose parameters measured by finger ionization chambers,combined with TLD audit,can help obtain the precise and reliable results.
