Multisection CT Protocols: Sex- and Age-specific Conversion Factors Used to Determine Effective Dose from Dose-Length Product
Multisection CT Protocols: Sex- and Age-specific Conversion Factors Used to Determine Effective Dose from Dose-Length Product
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DOI：
10.1148/radiol.10100047
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发表时间：
2010-10-01
期刊：
影响因子：
19.7
通讯作者：
Kalender, Willi A.
中科院分区：
文献类型：
--
作者：
Deak, Paul D.;Smal, Yulia;Kalender, Willi A.
用途：为确定国际放射防护委员会（ICRP）新出版的103号建议中针对成人和儿童患者的转换因子，并将Monte Carlo计算得出的有效剂量与不同身体区域和计算机断层扫描（CT）扫描协议的剂量长度乘积（DLP）得出的有效剂量进行比较。材料和方法：橡树岭国家实验室体模系列的有效剂量值，包括新生儿体模; 1岁，5岁和10岁的儿童;和成人，通过使用蒙特卡罗方法的64节多探测器CT扫描仪。对于每个体模，考虑五个解剖区域（头部、颈部、胸部、腹部和骨盆）。Monte Carlo模拟进行螺旋扫描协议与不同的电压。使用ICRP出版物60和出版物103建议计算有效剂量。计算出的有效剂量进行了比较，来自DLP通过使用以前公布的转换factors.Results：在一般情况下，转换因子的基础上确定的Monte Carlo计算导致较低的值与ICRP出版物的成人。ICRP出版物60和ICRP出版物103的数值分别比先前公布的数据低33%和32%。对于儿童个体，基于Monte Carlo计算的有效剂量高于从DLP和先前发表的转换因子获得的有效剂量（例如，对于5岁儿童的胸部CT扫描，预计增加约76%）。对于儿童，当管电压变化时，观察到转换因子的变化高达15%。对于成年人，没有依赖于电压observed.Conclusion：转换系数从DLP到有效剂量应分别指定为两种性别，并应反映新的ICRP的建议。对于儿科患者，应确定所用光谱的新转换因子。(C)RSNA，2010年
Purpose: To determine conversion factors for the new International Commission on Radiological Protection (ICRP) publication 103 recommendations for adult and pediatric patients and to compare the effective doses derived from Monte Carlo calculations with those derived from dose-length product (DLP) for different body regions and computed tomographic (CT) scanning protocols.Materials and Methods: Effective dose values for the Oak Ridge National Laboratory phantom series, including phantoms for newborns; 1-, 5-, and 10-year-old children; and adults were determined by using Monte Carlo methods for a 64-section multidetector CT scanner. For each phantom, five anatomic regions (head, neck, chest, abdomen, and pelvis) were considered. Monte Carlo simulations were performed for spiral scanning protocols with different voltages. Effective dose was computed by using ICRP publication 60 and publication 103 recommendations. The calculated effective doses were compared with those derived from the DLP by using previously published conversion factors.Results: In general, conversion factors determined on the basis of Monte Carlo calculations led to lower values for adults with both ICRP publications. Values up to 33% and 32% lower than previously published data were found for ICRP publication 60 and ICRP publication 103, respectively. For pediatric individuals, effective doses based on the Monte Carlo calculations were higher than those obtained from DLP and previously published conversion factors (eg, for chest CT scanning in 5-year-old children, an increase of about 76% would be expected). For children, a variation in conversion factors of up to 15% was observed when the tube voltage was varied. For adult individuals, no dependence on voltage was observed.Conclusion: Conversion factors from DLP to effective dose should be specified separately for both sexes and should reflect the new ICRP recommendations. For pediatric patients, new conversion factors specific for the spectrum used should be established. (C) RSNA, 2010