Theocharopoulos Nicholas, Perisinakis Kostas, Damilakis John, Varveris Haralambos, Gourtsoyiannis Nicholas
Department of Medical Physics, Faculty of Medicine, University of Crete, Iraklion, Greece.
Med Phys. 2002 Sep;29(9):2070-9. doi: 10.1118/1.1500769.
Three methods of indirect effective dose estimation were reviewed and compared to a direct effective dose determination method. An anthropomorphic phantom and thermoluminescence dosimetry were used to obtain dosimetric data associated with anterior-posterior (AP) abdominal radiography, posterior-anterior (PA) chest radiography, PA head radiography, and AP heart fluoroscopy. Effective dose was determined using: (i) organ specific dose values directly determined by thermoluminescence dosimeters, (ii) data published by National Radiological Protection Board (NRPB) and entrance surface dose (ESD), (iii) NRPB data and dose area product (DAP), (iv) energy imparted derived from DAP. The effective dose values estimated from the Rando phantom measurements were 161, 32.3, and 8.4 microSv/projection for the abdomen, chest, and head radiographs, respectively. Cardiac fluoroscopy yielded an effective dose value of 111 microSv/min. The effective dose values obtained indirectly using NRPB data and DAP were in good agreement with directly assessed values in all simulated exposures (difference <8%). The effective doses using NRPB data and ESD values differed from directly assessed values by less than 15% for the radiographic exposures and 60% for heart fluoroscopy. The energy imparted method yielded 136, 31, and 6.6 microSv/projection for the abdomen, chest, and head radiographs, respectively, and 111 microSv/min for heart fluoroscopy. Indirect patient effective dose determination using the NRPB dosimetric data and the measured value of incident radiation allows for reliable patient effective dose estimates. The use of DAP rather than ESD is recommended because it yields accurate results even for complex radiologic exposures involving fluoroscopy. The value of energy imparted may be used for the accurate determination of patient effective dose, especially when specific organ dose values are not of interest. The calculation of energy imparted with the use of EAP provides a reliable starting point for estimation of effective dose from radiologic examinations for which dosimetric data are not provided by NRPB.
回顾了三种间接有效剂量估算方法，并与直接有效剂量测定方法进行了比较。使用人体模型和热释光剂量测定法来获取与前后位（AP）腹部X线摄影、后前位（PA）胸部X线摄影、PA头部X线摄影以及AP心脏荧光透视检查相关的剂量学数据。有效剂量通过以下方法确定：（i）由热释光剂量计直接测定的器官特定剂量值；（ii）国家放射防护委员会（NRPB）公布的数据和体表入射剂量（ESD）；（iii）NRPB数据和剂量面积乘积（DAP）；（iv）从DAP得出的授予能量。从兰多人体模型测量中估算出的有效剂量值，腹部、胸部和头部X线摄影分别为161、32.3和8.4微希沃特/投照。心脏荧光透视检查得出的有效剂量值为111微希沃特/分钟。在所有模拟照射中，使用NRPB数据和DAP间接获得的有效剂量值与直接评估值高度一致（差异<8%）。对于X线摄影照射，使用NRPB数据和ESD值得出的有效剂量与直接评估值的差异小于15%，对于心脏荧光透视检查则为60%。授予能量法得出的腹部、胸部和头部X线摄影的有效剂量分别为136、31和6.6微希沃特/投照，心脏荧光透视检查为111微希沃特/分钟。使用NRPB剂量学数据和入射辐射测量值间接确定患者有效剂量可实现可靠的患者有效剂量估算。建议使用DAP而非ESD，因为即使对于涉及荧光透视的复杂放射学照射，它也能得出准确结果。授予能量值可用于准确确定患者有效剂量，特别是当特定器官剂量值无关紧要时。利用体表空气比释动能（EAP）计算授予能量为估算NRPB未提供剂量学数据的放射学检查的有效剂量提供了可靠的起点。
