From the Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich.
Department of Radiology and Medical Informatics, University of Geneva, Geneva, Switzerland.
Invest Radiol. 2020 Dec;55(12):762-768. doi: 10.1097/RLI.0000000000000701.
Estimations of radiation dose absorbed by the fetus from computed tomography (CT) in pregnant patients is mandatory, but currently available methods are not feasible in clinical routine. The aims of this study were to develop and validate a tool for assessment of fetal dose from CT of pregnant patients and to develop a user-friendly web interface for fast fetal dose calculations.
In the first study part, 750 Monte Carlo (MC) simulations were performed on phantoms representing pregnant patients at various gestational stages. The MC code simulating vendor-independent dose distributions was validated against CT dose index (CTDI) measurements performed on CT scanners of 2 vendors. The volume CTDI-normalized fetal dose values from MC simulations were used for developing the computational algorithm enabling fetal dose assessments from CT of various body regions at different exposure settings. In the institutional review board-approved second part, the algorithm was validated against patient-specific MC simulations performed on CT data of 29 pregnant patients (gestational ages 8-35 weeks) who underwent CT. Furthermore, the tool was compared with a commercially available software. A user-friendly web-based interface for fetal dose calculations was created.
Weighted CTDI values obtained from MC simulations were in excellent agreement with measurements performed on the 2 CT systems (average error, 4%). The median fetal dose from abdominal CT in pregnant patients was 2.7 mGy, showing moderate correlation with maternal perimeter (r = 0.69). The algorithm provided accurate estimates of fetal doses (average error, 11%), being more accurate than the commercially available tool. The web-based interface (www.fetaldose.org) enabling vendor-independent calculations of fetal doses from CT requires the input of gestational age, volume CTDI, tube voltage, and scan region.
A tool for fetal dose assessments from CT of pregnant patients was developed and validated being freely available on a user-friendly web interface.
估算孕妇接受计算机断层扫描（CT）时胎儿所吸收的辐射剂量是强制性的，但目前可用的方法在临床常规中不可行。本研究的目的是开发和验证一种用于评估孕妇 CT 胎儿剂量的工具，并开发一个用户友好的网络界面，用于快速计算胎儿剂量。
在第一部分研究中，对代表不同妊娠阶段孕妇的体模进行了 750 次蒙特卡罗（MC）模拟。模拟供应商独立剂量分布的 MC 代码针对来自 2 家供应商的 CT 扫描仪进行的 CT 剂量指数（CTDI）测量进行了验证。使用 MC 模拟得到的体积 CTDI 归一化胎儿剂量值来开发计算算法，以便从不同暴露设置的各种身体区域的 CT 评估胎儿剂量。在机构审查委员会批准的第二部分中，该算法针对在 29 名接受 CT 检查的孕妇（妊娠 8-35 周）的 CT 数据进行的特定于患者的 MC 模拟进行了验证。此外，该工具与商业上可用的软件进行了比较。创建了一个用于胎儿剂量计算的用户友好型网络界面。
从 MC 模拟中获得的加权 CTDI 值与在 2 台 CT 系统上进行的测量非常吻合（平均误差为 4%）。孕妇腹部 CT 的胎儿剂量中位数为 2.7 mGy，与母体周长呈中度相关（r = 0.69）。该算法提供了胎儿剂量的准确估计值（平均误差为 11%），比商业上可用的工具更准确。允许从 CT 独立计算胎儿剂量的基于网络的界面（www.fetaldose.org）需要输入胎龄、体积 CTDI、管电压和扫描区域。
开发了一种用于评估孕妇 CT 胎儿剂量的工具，并在用户友好的网络界面上进行了验证，该工具可免费获得。
