Optimization of radiation protection in head computed tomography: A study of SSDE based on Deff, Dw and organ dose

Abstract

The aims of this study is to compare water-equivalent diameter (Dw) and effective diameter (Deff) for automated estimation of eye lens dose in head CT, with the goal of determining which metric provides greater accuracy for protocol optimization. A total of 109 patients (women: 38 %; men: 62 %) with a mean age of 59 ± 9 years were included in the study. These parameters were assessed on DICOM images using Indose CT software with an automatic method. Size-specific dose estimates (SSDE) were calculated, and mean effective doses (ED) were estimated for both diameters. Additionally, the radiation dose received by sensitive organs, such as the eyes, was measured. The results show that Dw is slightly higher than Deff, with mean values of 15.24 ± 1.23 cm for Dw compared to 14.24 ± 1.08 cm for Deff (r = 0.901, p < 0.0001). SSDE reveals that the uncertainty obtained with Deff is 7.03 %, whereas it is reduced to 4.58 % when using Dw, indicating better accuracy (r = 0.969, p < 0.001). Regarding the mean effective dose, the values were 1.75 ± 0.37 mSv for Deff and 1.71 ± 0.36 mSv for Dw. Sensitive organs, such as the eyes, received a mean radiation dose of 42.43 ± 4.99 mGy. Overall, the use of Dw improves the accuracy of dosimetric estimates compared to Deff, enabling better dose assessments for radiosensitive organs like the eyes. This highlights the importance of integrating Dw into CT imaging protocols to minimize radiation exposure while maintaining optimal diagnostic quality.