A practical slice averaged image method for precise CT size specific dose estimates

Area of Science:

• Medical Imaging
• Radiology
• Radiation Dosimetry

Background:

• Computed tomography (CT) is essential for diagnosis, but anatomical variations complicate radiation dose estimation.
• Conventional dose indices like CTDI_vol and DLP are less effective than size-specific dose estimates (SSDE).
• Calculating water-equivalent diameter (D_w) for each CT slice is laborious and impractical for routine use.

Purpose of the Study:

• To introduce a novel, simplified method for calculating size-specific dose estimates (SSDE) in CT scans.
• To evaluate the accuracy and practicality of the SSDE slice-averaged image (SSDE_SAI) method compared to existing approaches.
• To assess the SSDE_SAI method's performance across different anatomical regions.

Main Methods:

• Developed the SSDE slice-averaged image (SSDE_SAI) method, calculating D_w from a single averaged CT image.
• Retrospectively analyzed CT data from 282 adult patients across chest, abdomen-pelvis, and combined chest-abdomen-pelvis regions.
• Compared SSDE_SAI with SSDE_center and mean SSDE using regression analysis and RMSE.

Main Results:

• SSDE_SAI demonstrated stronger agreement with mean SSDE than SSDE_center across all scan regions.
• Achieved high R² values (up to 0.991) and lower root mean square error (RMSE) with SSDE_SAI.
• The SSDE_SAI method effectively captures anatomical variability while reducing calculation complexity.

Conclusions:

• SSDE_SAI offers a more advanced and practical approach for radiation dose prediction in CT.
• This method provides a viable alternative to complex calculations for routine clinical application.
• The findings support the clinical utility of SSDE_SAI for accurate and efficient dose assessment.