Dosimetry in x-ray-based breast imaging.

Area of Science:

• Medical Physics
• Radiological Dosimetry
• Biomedical Imaging

Background:

• Accurate estimation of mean glandular dose (MGD) is vital for quality control, risk assessment, and optimization in X-ray breast imaging.
• Current methods often rely on conversion factors derived from Monte Carlo simulations to link incident air kerma to MGD.

Purpose of the Study:

• To review and analyze the evolution of MGD estimation methodologies for mammography, digital breast tomosynthesis (DBT), and dedicated breast CT (DBCT).
• To compare dose estimates derived from simple geometrical models versus complex patient-specific models.

Main Methods:

• Review of mathematical models for breast dosimetry, ranging from basic geometric shapes to advanced models utilizing patient DBCT data.
• Discussion of Monte Carlo calculations for conversion factors relating incident air kerma to MGD.
• Analysis of breast phantoms for incident air kerma measurement and comparison with patient-derived doses.

Main Results:

• Complex breast models, informed by patient DBCT data, indicate that simple models can overestimate MGD in mammography by up to 30%.
• Patient-specific dose estimations, special views, and the impact of breast implants were considered.
• Discrepancies exist between patient and phantom-based dose estimates.

Conclusions:

• Harmonization of international dosimetry protocols for mammography is needed, moving beyond simple geometrical models towards more sophisticated, patient-specific approaches.
• Advanced modeling is essential for accurate MGD assessment in modern breast imaging techniques.
• The findings highlight the need for updated dosimetry protocols to reflect current imaging technologies and anatomical variations.