Analyses and applications of single scan dose profiles in computed tomography

Area of Science:

• Medical Physics
• Radiological Sciences

Background:

• Computed tomography (CT) is a widely used imaging modality.
• Accurate dose assessment is crucial for patient safety in CT examinations.
• Existing methods for CT dose characterization require further validation and refinement.

Purpose of the Study:

• To comprehensively analyze and measure CT single-scan dose profiles across various scanners and conditions.
• To evaluate the contribution of primary and scattered radiation to CT dose index (CTDI).
• To develop and validate a method for estimating organ dose from CT scans.

Main Methods:

• Measurements of CT dose profiles using LiF:Mg,Cu,P and CaSO4:Dy thermoluminescent dosimeters.
• Utilized head and body CT dosimetry phantoms for measurements.
• Analyzed dose profiles using Gaussian and Lorentzian functions to model primary and scattered radiation.
• Correlated thermoluminescent dosimeter (TLD) CTDI measurements with ionization chamber measurements.
• Developed and compared an organ dose estimation method against Monte Carlo simulations.

Main Results:

• Characterized CT single-scan dose profiles, differentiating primary and scattered radiation contributions.
• Quantified the relative scatter to primary radiation contribution to CTDI at central and peripheral locations.
• Established a strong correlation between TLD-based CTDI measurements and ionization chamber measurements.
• Validated a novel method for estimating organ dose in CT, showing good agreement with Monte Carlo simulations.

Conclusions:

• The study provides a detailed understanding of CT dose profiles and the factors influencing them.
• The developed organ dose estimation method offers a practical approach for risk assessment in CT.
• Findings contribute to improved CT dosimetry accuracy and patient radiation protection strategies.