SIMPLE METHOD OF SIZE-SPECIFIC DOSE ESTIMATES CALCULATION FROM PATIENT WEIGHT ON COMPUTED TOMOGRAPHY

Area of Science:

• Medical Physics
• Radiological Sciences
• Imaging Technology

Background:

• Accurate patient dosimetry is crucial for optimizing CT radiation exposure.
• Current methods for calculating mean size-specific dose estimates (mSSDE) often require specialized software.
• Establishing diagnostic reference levels (DRLs) is essential for dose monitoring and optimization.

Purpose of the Study:

• To develop a simple, software-independent methodology for calculating mSSDE using patient weight and volume CT dose index (CTDIvol).
• To create conversion formulas for estimating mSSDE based on weight and CTDIvol for chest and abdomen-pelvis regions.

Main Methods:

• Retrospective analysis of data from a dose index registry.
• Division of scan areas into chest and abdomen-pelvis regions.
• Development and validation of conversion formulas comparing estimated SSDEweight with software-calculated mSSDE using Bland-Altman analysis.

Main Results:

• Conversion formulas were derived to estimate mSSDE from weight and CTDIvol (SSDEweight).
• Bland-Altman analysis showed low root mean square differences: 1.4 mGy for chest and 1.5 mGy for abdomen-pelvis.
• The developed formulae accurately estimate mSSDE without dedicated software.

Conclusions:

• A simple, weight- and CTDIvol-based method for calculating mSSDE has been successfully developed.
• This methodology enables mSSDE calculation without specialized software, facilitating DRL establishment.
• The findings support optimization of CT radiation doses and improved patient safety.