Proposed DRLs for mammography in Switzerland

Area of Science:

• Medical Imaging
• Radiology
• Public Health

Background:

• Mammography is a vital screening tool for breast cancer detection.
• Establishing diagnostic reference levels (DRLs) is essential for optimizing radiation dose in medical imaging.
• Current DRLs for mammography in Switzerland needed updating to reflect current clinical practices.

Purpose of the Study:

• To propose updated diagnostic reference levels (DRLs) for mammography examinations in Switzerland.
• To establish DRLs based on a representative dataset reflecting current clinical practice across all Swiss linguistic regions.
• To provide benchmarks for mean glandular dose (MGD) across different mammography techniques and patient anatomies.

Main Methods:

• A nationwide survey was conducted across 31 centers in Switzerland, collecting data from 24,762 mammography acquisitions.
• Data included mean glandular dose (MGD), compressed breast thickness (CBT), mammography model, and examination parameters.
• Acquisitions were categorized by imaging type (2D vs. digital breast tomosynthesis - DBT), projection (craniocaudal - CC vs. mediolateral oblique - MLO), and CBT intervals (20-100 mm).

Main Results:

• The analysis confirmed the collected data accurately reflects Swiss clinical practice.
• Mean glandular dose (MGD) was found to be higher for digital breast tomosynthesis (DBT) compared to 2D mammography for similar compressed breast thicknesses (CBT).
• The 75th percentile of MGD values increased with CBT, with specific ranges provided for 2D and DBT acquisitions in CC and MLO projections.

Conclusions:

• The study successfully proposed new Swiss DRLs for mammography, stratified by examination type, projection, and CBT.
• The proposed DRLs are considered satisfactory when compared to international benchmarks.
• These DRLs will aid in optimizing radiation protection and ensuring quality standards in Swiss mammography services.