[Development of a X-ray Exposure Dose Control Tool for CT Examination by Using Spreadsheet Software].

Purpose: We developed X-ray dose monitoring and optimization software for computed tomography (CT) by using a spreadsheet software.

Methods: The analysis was carried out on 1,212 patients using 2,128 CT examinations at our institution, in the period of April 2020 to April 2022. These cases were extracted in the limitation of patient's weight in the range of 50 to 70 kg. The individual radiation report, including CTDI and DLP, on the console displayed by a CT system was used and manually transferred to our software. The X-ray dose distribution was evaluated by using a boxplot chart and a scatter plot, and the data were referred to Japan DRLs 2020 (National Diagnostic Reference Levels in Japan 2020).

Results: Almost all patient's doses in our institution were distributed in the acceptable ranges in comparison with the Japan DRLs 2020. Neither extremely high nor low dose data were recorded. However, seven cases recorded outlier dose values. Three cases were caused by errors during manually inputting the data. Four from seven cases were explored the reason to record outlier dose values.

Conclusion: Our software on a spreadsheet software worked well to explore the CT dose data, such as CTDI and DLP. Our software was able to find cases that were recorded as outlier dose values, but their values were not extremely high/low values. The cautionary notice of either high or low dose, as a function of our software, will be able to keep our patient's CT dose in the universal-standard "justification and optimization" level.