Purpose: Estimate organs doses (ODs) of patients subjected to unenhanced (S1) and enhanced (S2) chest CT studies relying on image parameters such as Hounsfield Units (HUs). Materials and Methods: CT scans and images of a total of 16 patients who underwent two series of chest CT studies were obtained and retrospectively examined. OD increments of liver and pancreas for both series (S1 & S2) were estimated using two different independent methods, namely simulation approach using CT-EXPO and Amato’s phantom-based fitting model (APFM). HUs were quantified for each organ by manually drawing fixed area-sized regions of interest (ROIs). The mean HUs were collected to obtain the ODs increments following APFM. Regression analysis was applied to find and assess the relationship between the HUs and the OD increments estimated using APFM and that using CT-EXPO. Spearman Coefficient and Wilcoxon Matched Paired t-test were conducted to show statistical correlation and difference between ODs increments using the two methods. Results: A strong significant difference was depicted between S1 and S2 scan series of liver and pancreas using CT-EXPO simulation. Mean HU values for S1 were lower than S2, resulting in statistically significant (p < 0.0001) HU changes. CT-EXPO simulation yielded significantly higher difference in ODs compared to the APFM for liver (p = 0.0455) and pancreas (p = 0.0031). Regression analysis revealed a strong relationship between HU of S1 and S2 and ODs increments using APFM in both organs (R ² =0.99), dissimilar to CT-EXPO (R ²=0.39 in liver and R ²=0.05 in pancreas). Conclusions: Although CT-EXPO allows for estimating ODs accounting for major acquisition scan parameters, it is not a reliable tool to evaluate the impact of contrast enhancement on ODs. On the other hand, the APFM accounts for contrast enhancement accumulation yet only provides relative OD increments, an information of limited clinical use.

目的：根据图像参数（例如 Hounsfield 单位 (HU)）估算接受非增强 (S1) 和增强 (S2) 胸部 CT 研究的患者的器官剂量 (OD)。材料和方法：获得并回顾性检查了总共 16 名接受两个系列胸部 CT 研究的患者的 CT 扫描和图像。两个系列（S1 和 S2）的肝脏和胰腺的 OD 增量使用两种不同的独立方法进行估计，即使用 CT-EXPO 的模拟方法和 Amato 的基于体模的拟合模型 (APFM)。通过手动绘制固定区域大小的感兴趣区域 (ROI)，对每个器官的 HU 进行量化。收集平均 HU 以获得 APFM 后的 OD 增量。应用回归分析来发现和评估 HU 与使用 APFM 和使用 CT-EXPO 估计的 OD 增量之间的关系。Spearman 系数和 Wilcoxon 配对配对t 检验进行了使用两种方法来显示 OD 增量之间的统计相关性和差异。结果：使用 CT-EXPO 模拟在肝脏和胰腺的 S1 和 S2 扫描系列之间描绘出强烈的显着差异。S1 的平均 HU 值低于 S2，导致统计显着 (p < 0.0001) HU 变化。与肝脏 (p = 0.0455) 和胰腺 (p = 0.0031) 的 APFM 相比，CT-EXPO 模拟产生了显着更高的 OD 差异。回归分析揭示了 S1 和 S2 的 HU 与两个器官中使用 APFM 的 ODs 增量之间的强相关性（R ² =0.99），与 CT-EXPO 不同（肝脏中的R ² =0.39 和胰腺中的R ² =0.05）。 结论：尽管 CT-EXPO 允许估计占主要采集扫描参数的 OD，但它不是评估对比度增强对 OD 影响的可靠工具。另一方面，APFM 考虑了对比度增强累积，但仅提供相对 OD 增量，这是临床使用有限的信息。