Estimating Effective Dose for CT Using Dose-Length Product Compared With Using Organ Doses: Consequences of Adopting International Commission on Radiological Protection Publication 103 or Dual-Energy Scanning
Estimating Effective Dose for CT Using Dose-Length Product Compared With Using Organ Doses: Consequences of Adopting International Commission on Radiological Protection Publication 103 or Dual-Energy Scanning
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DOI：
10.2214/ajr.09.3462
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发表时间：
2010-04-01
影响因子：
5
通讯作者：
McCollough, Cynthia H.
中科院分区：
文献类型：
--
作者：
Christner, Jodie A.;Kofler, James M.;McCollough, Cynthia H.
OBJECTIVE.本研究的目的是比较基于剂量长度乘积（DLP）的有效剂量估计值与使用国际放射防护委员会（ICRP）103号出版物或双能CT协议中的组织加权因子进行的基于器官剂量的计算。使用扫描仪和能量依赖性器官剂量系数，我们计算了头部、胸部、冠状动脉、肝脏、腹部和骨盆CT检查的有效剂量，使用常规临床单能量或双能量协议和1991年ICRP出版物60和2007年ICRP出版物103中发表的组织加权因子。还使用仅取决于身体部位的已发表转换系数从相应DLP生成有效剂量。对于每种检查类型，相同的体积CT剂量指数用于单能量和双能量扫描。使用器官剂量估计值和ICRP 103组织加权因子计算的CT检查有效剂量相对于ICRP 60值的差异分别为-39%（-0.5 mSv，头部）、14%（1 mSv，胸部）、36%（4 mSv，冠状动脉）、4%（0.6 mSv，肝脏）和-7%（-1 mSv，腹部和骨盆）。基于DLP的有效剂量估计值（使用基于ICRP 60的转换系数得出）比基于器官剂量的ICRP 60估计值分别低4%（头部）、23%（胸部）、37%（胸部）和37%（胸部）。（冠状动脉），12%（肝脏）和19%对于ICRP 103，-34%（头部）、37%（胸部）、74%（冠状动脉）、16%（肝脏）和12%（腹部和骨盆）。所有结果均与能量无关。有效剂量估计值的这些差异表明，在采用ICRP 103时，需要重新评估DLP到E的转换系数，特别是对于乳房扫描。对于评价的扫描仪，DLP到E的转换系数与能量无关，但ICRP 60为基础的转换系数低估了有效剂量相对于器官剂量为基础的计算。
OBJECTIVE. The objective of our study was to compare dose-length product (DLP)-based estimates of effective dose with organ dose-based calculations using tissue-weighting factors from publication 103 of the International Commission on Radiological Protection (ICRP) or dual-energy CT protocols.MATERIALS AND METHODS. Using scanner-and energy-dependent organ dose coefficients, we calculated effective doses for CT examinations of the head, chest, coronary arteries, liver, and abdomen and pelvis using routine clinical single-or dual-energy protocols and tissue-weighting factors published in 1991 in ICRP publication 60 and in 2007 in ICRP publication 103. Effective doses were also generated from the respective DLPs using published conversion coefficients that depend only on body region. For each examination type, the same volume CT dose index was used for single-and dual-energy scans.RESULTS. Effective doses calculated for CT examinations using organ dose estimates and ICRP 103 tissue-weighting factors differed relative to ICRP 60 values by -39% (-0.5 mSv, head), 14% (1 mSv, chest), 36% (4 mSv, coronary artery), 4% (0.6 mSv, liver), and -7% (-1 mSv, abdomen and pelvis). DLP-based estimates of effective dose, which were derived using ICRP 60-based conversion coefficients, were less than organ dose-based estimates for ICRP 60 by 4% (head), 23% (chest), 37% (coronary artery), 12% (liver), and 19% (abdomen and pelvis) and for ICRP 103 by -34% (head), 37% (chest), 74% (coronary artery), 16% (liver), and 12% (abdomen and pelvis). All results were energy independent.CONCLUSION. These differences in estimates of effective dose suggest the need to reassess DLP to E conversion coefficients when adopting ICRP 103, particularly for scans over the breast. For the evaluated scanner, DLP to E conversion coefficients were energy independent, but ICRP 60-based conversion coefficients underestimated effective dose relative to organ dose-based calculations.