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
2013年
5期
540-543
,共4页
徐辉%王建超%尉可道%岳保荣
徐輝%王建超%尉可道%嶽保榮
서휘%왕건초%위가도%악보영
乳腺数字体层合成摄影%乳腺剂量仪%角响应%校正因子%乳腺平均剂量
乳腺數字體層閤成攝影%乳腺劑量儀%角響應%校正因子%乳腺平均劑量
유선수자체층합성섭영%유선제량의%각향응%교정인자%유선평균제량
Digital breast tomosynthesis%Mammographic dosimeters%Angular dependence%Correction factor%Average glandular dose
目的 研究不同乳腺剂量仪在单一能量X射线时的角响应性能,以及不同能量X射线时乳腺剂量仪角响应的变化趋势,对乳腺数字体层合成摄影(DBT)中受检者乳腺平均剂量的评价进行探讨.方法 分别用4种低能标准射线质对4种不同类型乳腺剂量仪进行照射,照射角度从0°至90°变化.每个角度重复曝光3次,记录4种剂量仪的测量值并计算该角度相对于垂直入射时的角响应值.结果 4种剂量仪的剂量响应均在射线垂直人射探测器表面时最大,随着射线入射角度的增大,其剂量响应逐渐降低.射线入射角为10°时,剂量仪A、B、C和D的角响应分别为0.99、0.99、0.96和0.96;入射角为25°时,分别为0.96、1.00、0.78和0.52.电离室剂量仪角响应曲线下降较为平缓,半导体探测器剂量仪的角响应曲线在角度较大明显下降,当射线入射角度大于45°时已检测不出剂量信号.对于电离室剂量仪,在角度不变时,射线能量较低时通常角响应值也较低.结论 在进行DBT系统中剂量测量时,现有的方法会低估乳房表面接受的实际剂量,进而低估了受检者的乳腺平均剂量.为使因球管旋转角度带来的误差降至最低,应该针对不同DBT设备对不同类型乳腺剂量仪进行相应角响应校正.
目的 研究不同乳腺劑量儀在單一能量X射線時的角響應性能,以及不同能量X射線時乳腺劑量儀角響應的變化趨勢,對乳腺數字體層閤成攝影(DBT)中受檢者乳腺平均劑量的評價進行探討.方法 分彆用4種低能標準射線質對4種不同類型乳腺劑量儀進行照射,照射角度從0°至90°變化.每箇角度重複曝光3次,記錄4種劑量儀的測量值併計算該角度相對于垂直入射時的角響應值.結果 4種劑量儀的劑量響應均在射線垂直人射探測器錶麵時最大,隨著射線入射角度的增大,其劑量響應逐漸降低.射線入射角為10°時,劑量儀A、B、C和D的角響應分彆為0.99、0.99、0.96和0.96;入射角為25°時,分彆為0.96、1.00、0.78和0.52.電離室劑量儀角響應麯線下降較為平緩,半導體探測器劑量儀的角響應麯線在角度較大明顯下降,噹射線入射角度大于45°時已檢測不齣劑量信號.對于電離室劑量儀,在角度不變時,射線能量較低時通常角響應值也較低.結論 在進行DBT繫統中劑量測量時,現有的方法會低估乳房錶麵接受的實際劑量,進而低估瞭受檢者的乳腺平均劑量.為使因毬管鏇轉角度帶來的誤差降至最低,應該針對不同DBT設備對不同類型乳腺劑量儀進行相應角響應校正.
목적 연구불동유선제량의재단일능량X사선시적각향응성능,이급불동능량X사선시유선제량의각향응적변화추세,대유선수자체층합성섭영(DBT)중수검자유선평균제량적평개진행탐토.방법 분별용4충저능표준사선질대4충불동류형유선제량의진행조사,조사각도종0°지90°변화.매개각도중복폭광3차,기록4충제량의적측량치병계산해각도상대우수직입사시적각향응치.결과 4충제량의적제량향응균재사선수직인사탐측기표면시최대,수착사선입사각도적증대,기제량향응축점강저.사선입사각위10°시,제량의A、B、C화D적각향응분별위0.99、0.99、0.96화0.96;입사각위25°시,분별위0.96、1.00、0.78화0.52.전리실제량의각향응곡선하강교위평완,반도체탐측기제량의적각향응곡선재각도교대명현하강,당사선입사각도대우45°시이검측불출제량신호.대우전리실제량의,재각도불변시,사선능량교저시통상각향응치야교저.결론 재진행DBT계통중제량측량시,현유적방법회저고유방표면접수적실제제량,진이저고료수검자적유선평균제량.위사인구관선전각도대래적오차강지최저,응해침대불동DBT설비대불동류형유선제량의진행상응각향응교정.
Objective To study the angular dependence of four different mammographic dosimeters to monoenergetic X-ray beams and observe the variation tendency in angular dependence to different energy X-rays and to discuss the evaluation of average glandular dose(AGD)in digital breast tomosynthesis(DBT)system.Methods One ionization chamber and three semiconductor dosimeters were exposed by four kinds of beam quality.The signal of each dosimeter was tested over an angular range of 0° to 90°.The dosimeters were exposed for three times at each selected angular position.The measurement at each angle was normalized to the appropriate measurement at perpendicular incidence.Results The responses from all the dosimeters had a maximum at 0° and decreased with increasing angles.When the radiation incidence angle was 10°,the angular dependence were 0.99,0.99,0.96 and 0.96 for dosimeters A,B,C and D,respectively.And the angular dependence decreased to 0.96,1.00,0.78 and 0.52 when the incidence angle was up to 25°.For semiconductor dosimeters,no signal was recorded when incidence angle was beyond 45°.For ionization chamber,the magnitude of the angular dependence generally decreased with increasing energy.Conclusions All of the dosimeters will underestimate the dose if used in DBT.In order to minimize the error due to the rotation angle of X-ray tube,correction factor of mammography dosimeter should be used for the measurement of AGD in DBT systems.
