Patient radiation doses from adult and pediatric CT
Patient radiation doses from adult and pediatric CT
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DOI：
10.2214/ajr.06.0101
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发表时间：
2007-02-01
影响因子：
5
通讯作者：
Vance, Awais
中科院分区：
文献类型：
--
作者：
Huda, Walter;Vance, Awais
OBJECTIVE.我们研究的目的是确定典型的器官剂量，以及相应的有效剂量，成人和儿童患者接受一个单一的CT检查。将从新生儿到超大成人（120 kg）的患者的头部、胸部和胸部建模为均匀的水圆柱体。Monte Carlo剂量测定数据用于获得直接照射区域的平均剂量。使用剂量测定数据计算给予的总能量，并使用患者体型相关的每单位能量给予的有效剂量系数将其转换为相应的有效剂量。针对扫描协议获得了代表性患者剂量，该扫描协议考虑了典型MDCT扫描仪扫描的患者的尺寸。相对于20世纪90年代早期的CT扫描仪，目前的MDCT扫描仪在头部和身体体模中分别导致每单位mAs高出1.5和1.7的剂量。头部CT扫描中的器官吸收剂量从新生儿的30 mGy增加到成人的40 mGy。体重低于20公斤的患者接受的身体器官吸收剂量约为7毫戈瑞，比正常体重（70公斤）的成人低2倍。成人头部CT有效剂量约为0.9 mSv，比新生儿低4倍。新生儿接受体部CT的有效剂量与2.5 mSv相似，而正常体型成人的有效剂量与3.5 mSv相似。CT中的代表性器官吸收剂量大大低于诱导确定性效应的阈值剂量，有效剂量与天然本底辐射的年剂量相当。
OBJECTIVE. The purpose of our study was to determine typical organ doses, and the corresponding effective doses, to adult and pediatric patients undergoing a single CT examination.MATERIALS AND METHODS. Heads, chests, and abdomens of patients ranging from neonates to oversized adults (120 kg) were modeled as uniform cylinders of water. Monte Carlo dosimetry data were used to obtain average doses in the directly irradiated region. Dosimetry data were used to compute the total energy imparted, which was converted into the corresponding effective dose using patient-size-dependent effective-dose-per-unit-energy-imparted coefficients. Representative patient doses were obtained for scanning protocols that take into account the size of the patient being scanned by typical MDCT scanners.RESULTS. Relative to CT scanners from the early 1990s, present-day MDCT scanners result in doses that are similar to 1.5 and similar to 1.7 higher per unit mAs in head and body phantoms, respectively. Organ absorbed doses in head CT scans increase from similar to 30 mGy in newborns to similar to 40 mGy in adults. Patients weighing less than similar to 20 kg receive body organ absorbed doses of similar to 7 mGy, which is a factor of 2 less than for normal-sized (70-kg) adults. Adult head CT effective doses are similar to 0.9 mSv, four times less than those for the neonate. Effective doses for neonates undergoing body CT are similar to 2.5 mSv, whereas those for normal-sized adults are similar to 3.5 mSv.CONCLUSION. Representative organ absorbed doses in CT are substantially lower than threshold doses for the induction of deterministic effects, and effective doses are comparable to annual doses from natural background radiation.