Abstract—

This work relates to the study of organ dose during a Chest computed tomography (CT). Organ dose has been simulated with the Monte Carlo Simulation code (GEANT4/GATE) using two computational phantoms Adam male and Eva female. Simulated scans were performed for helical mode, collimation of 10 mm and tube voltages of 80, 110 and 130 kV. The method “dose by region” used in GATE to calculate the organ doses was validated with maximal agreement of 7%. Organ doses for Adam and Eva were evaluated and contributions to effective dose were compared to those obtained from IMPACT CT and CT-EXPO. It was found that Eva lungs were more irradiated than Adam by averaged difference of 3 mGy. For breasts absorbed dose, the tube voltage increase effect (80–130 kV) was estimated to be around 71%, 74 and 86% for this study, CT-EXPO and IMPACT CT respectively. The largest contributions to effective dose were from remainder tissues (29%), lungs (27%) and breast (21%). Generally, the results show that organ doses obtained from software exceeded those from GATE simulations. This work attests the ability to assess organ dose by using a GATE “dose by region” actor, as well as, evaluates organ dose estimation errors inducted by commercial software.

中文翻译：

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使用 GATE Monte Carlo 模拟估计成人胸部 CT 检查的器官剂量

摘要-

这项工作涉及胸部计算机断层扫描 (CT) 期间器官剂量的研究。器官剂量已通过蒙特卡罗模拟代码 (GEANT4/GATE) 使用两个计算幻影 Adam 男性和 Eva 女性进行模拟。对螺旋模式、10 毫米准直和 80、110 和 130 kV 管电压进行了模拟扫描。GATE 中用于计算器官剂量的“按区域剂量”方法经过验证，最大一致性为 7%。评估了 Adam 和 Eva 的器官剂量，并将对有效剂量的贡献与从 IMPACT CT 和 CT-EXPO 获得的那些进行比较。发现 Eva 的肺比 Adam 的肺受到更多的辐照，平均差异为 3 mGy。对于乳房吸收剂量，本研究、CT-EXPO 和 IMPACT CT 的管电压增加效应（80-130 kV）估计分别约为 71%、74 和 86%。对有效剂量的最大贡献来自其余组织 (29%)、肺 (27%) 和乳房 (21%)。一般来说，结果表明从软件获得的器官剂量超过了 GATE 模拟的剂量。这项工作证明了通过使用 GATE“按区域剂量”参与者评估器官剂量的能力，以及评估由商业软件引起的器官剂量估计错误。