Optimal photon energy comparison between digital breast tomosynthesis and mammography: a case study

Area of Science:

• Medical Imaging
• Radiology
• Biophysics

Background:

• Digital breast tomosynthesis (DBT) and digital mammography (DM) are crucial for breast cancer detection.
• Optimizing imaging parameters like energy (kV) is essential for balancing image quality and patient radiation dose.
• Understanding the optimal energy for each modality can improve diagnostic accuracy and patient safety.

Purpose of the Study:

• To compare the optimal energy levels that maximize image quality between DBT and DM.
• To evaluate the relationship between signal difference-to-noise ratio (SDNR) and mean glandular dose (MGD) for both imaging modes.
• To assess if the imaging system is quantum noise limited and how this affects optimal energy selection.

Main Methods:

• Utilized a MAMMOMAT Inspiration system with an amorphous selenium flat panel detector.
• Measured image quality using SDNR and patient risk using MGD.
• Employed a W/Rh anode filter combination and a 4.5 cm tissue-equivalent mammography phantom.
• Performed Monte Carlo simulations to validate experimental findings.

Main Results:

• Optimal voltage for maximal image quality in DBT was found to be 28 kV.
• Optimal voltage for maximal image quality in DM was found to be 30 kV.
• The system's automatic exposure control (AEC) selected 28 kV for both DBT and DM; Monte Carlo simulations supported this with an optimal energy of 20 keV.
• The system was not completely quantum noise limited, potentially explaining the slight experimental difference in optimal voltage.

Conclusions:

• Higher voltage settings are not necessary for improving image quality in DBT examinations.
• The optimal energy for DBT (28 kV) differs slightly from DM (30 kV), but AEC settings align with simulation findings.
• Understanding these optimal energy levels contributes to safer and more effective breast imaging practices.