Background

Radiation dose in computed tomography (CT) has become a topic of high interest due to the increasing numbers of CT examinations performed worldwide. Hence, dose tracking and organ dose calculation software are increasingly used. We evaluated the organ dose variability associated with the use of different software applications or calculation methods.

Methods

We tested four commercial software applications on CT protocols actually in use in our hospital: CT-Expo, NCICT, NCICTX, and Virtual Dose. We compared dose coefficients, estimated organ doses and effective doses obtained by the four software applications by varying exposure parameters. Our results were also compared with estimates reported by the software authors.

Results

All four software applications showed dependence on tube voltage and volume CT dose index, while only CT-Expo was also dependent on other exposure parameters, in particular scanner model and pitch caused a variability till 50%. We found a disagreement between our results and those reported by the software authors (up to 600%), mainly due to a different extent of examined body regions. The relative range of the comparison of the four software applications was within 35% for most organs inside the scan region, but increased over the 100% for organs partially irradiated and outside the scan region. For effective doses, this variability was less evident (ranging from 9 to 36%).

Conclusions

The two main sources of organ dose variability were the software application used and the scan region set. Dose estimate must be related to the process used for its calculation.

中文翻译：

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CT中的患者器官和有效剂量估算：四种软件应用程序的比较。

背景

由于全球范围内进行的CT检查数量不断增加，计算机断层扫描（CT）中的辐射剂量已成为人们高度关注的话题。因此，越来越多地使用剂量跟踪和器官剂量计算软件。我们评估了与使用不同软件应用程序或计算方法相关的器官剂量变异性。

方法

我们在医院实际使用的CT协议上测试了四种商业软件应用程序：CT-Expo，NCICT，NCICTX和Virtual Dose。我们比较了四种软件通过改变暴露参数获得的剂量系数，估计的器官剂量和有效剂量。我们的结果也与软件作者报告的估计值进行了比较。

结果

所有这四个软件应用程序都显示出对管电压和体积CT剂量指数的依赖，而只有CT-Expo也依赖于其他曝光参数，特别是扫描仪型号和间距导致直到50％的变化。我们发现我们的结果与软件作者报告的结果存在分歧（最多600％），这主要是由于检查身体部位的程度不同所致。对于扫描区域内的大多数器官，这四个软件应用程序的比较的相对范围在35％以内，但对于部分照射且在扫描区域之外的器官，其相对范围增加了100％。对于有效剂量，这种变化不太明显（9％到36％）。

结论

器官剂量变化的两个主要来源是所使用的软件应用程序和扫描区域设置。剂量估算必须与用于计算的过程有关。