Fetal radiation dose in three common CT examinations during pregnancy Monte Carlo study
Fetal radiation dose in three common CT examinations during pregnancy Monte Carlo study
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DOI：
10.1016/j.ejmp.2017.09.120
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发表时间：
2017-11-01
影响因子：
3.4
通讯作者：
Kortesniemi, M.
中科院分区：
文献类型：
--
作者：
Kelaranta, A.;Makela, T.;Kortesniemi, M.
目的：利用蒙特卡罗模拟技术确定三种常见的CT检查（肺CT血管造影、腹盆腔扫描和创伤扫描）在不同妊娠阶段的胎儿剂量。方法：对成年女性拟人幻肢进行64层CT扫描，采用肺血管造影、腹盆腔和创伤CT扫描方案。三种不同大小的凝胶丸放置在假人的腹部，模拟怀孕的不同阶段。宫内剂量被用来代替胎儿吸收的剂量。MC模拟估计子宫剂量。模拟剂量水平通过体积CT剂量指数（CTDIvol）测量和圆柱形CTDI体幻影中的MC模拟进行校准，并与金属氧化物半导体场效应晶体管剂量计测量的十点剂量进行比较。对宫内体积和子宫壁进行分割，计算各自的剂量体积直方图。结果：肺血管造影CT扫描、腹盆腔CT扫描和创伤CT扫描的子宫内平均剂量分别为0.04 ~ 1.04 mGy、4.8 ~ 5.8 mGy和9.8 ~ 12.6 mGy。MC模拟结果表明，在被测位置与MOSFET测量值具有良好的相关性。结论：三种研究检查提供了高度不同的胎儿剂量，从肺CT血管造影的亚毫戈瑞水平到腹盆腔和创伤扫描的显著较高水平，胎儿处于初级暴露范围。MC模拟在适当的拟人化幻影中提供的体积剂量分布在辅助点剂量测量时提供了全面的剂量评估。
Purpose: To determine fetal doses in different stages of pregnancy in three common computed tomography (CT) examinations: pulmonary CT angiography, abdomino-pelvic and trauma scan with Monte Carlo (MC) simulations.Methods: An adult female anthropomorphic phantom was scanned with a 64-slice CT using pulmonary angiography, abdomino-pelvic and trauma CT scan protocols. Three different sized gelatin boluses placed on the phantom's abdomen simulated different stages of pregnancy. Intrauterine dose was used as a surrogate to a dose absorbed to the fetus. MC simulations were performed to estimate uterine doses. The simulation dose levels were calibrated with volumetric CT dose index (CTDIvol) measurements and MC simulations in a cylindrical CTDI body phantom and compared with ten point doses measured with metal-oxide-semiconductor field-effect-transistor dosimeters. Intrauterine volumes and uterine walls were segmented and the respective dose volume histograms were calculated.Results: The mean intrauterine doses in different stages of pregnancy varied from 0.04 to 1.04 mGy, from 4.8 to 5.8 mGy, and from 9.8 to 12.6 mGy in the CT scans for pulmonary angiography, abdomino-pelvic and trauma CT scans, respectively. MC simulations showed good correlation with the MOSFET measurement at the measured locations.Conclusions: The three studied examinations provided highly varying fetal doses increasing from sub-mGy level in pulmonary CT angiography to notably higher levels in abdomino-pelvic and trauma scans where the fetus is in the primary exposure range. Volumetric dose distribution offered by MC simulations in an appropriate anthropomorphic phantom provides a comprehensive dose assessment when applied in adjunct to point-dose measurements.