[Optimization of exposure conditions for amorphous selenium direct conversion DR-based mammography system]

Area of Science:

• Medical Imaging
• Radiologic Technology
• Diagnostic Radiology

Background:

• Digital radiography (DR) mammography offers improved visualization of breast lesions.
• Optimizing exposure parameters is crucial for enhancing image quality and diagnostic accuracy in mammography.

Purpose of the Study:

• To determine optimal exposure conditions (target/filter, tube voltage) for DR mammography.
• To compare phantom-based physical evaluations with visual assessments of breast specimens for optimizing image quality.
• To improve the detectability of microcalcifications and masses in mammographic images.

Main Methods:

• Evaluated contrast-to-noise ratios (CNRs) in polymethyl methacrylate (PMMA) phantoms of varying thicknesses under consistent average glandular doses (AGDs).
• Compared physical measurements with visual evaluations of 50 breast specimens irradiated under diverse exposure conditions.
• Controlled image histograms for consistency during visual assessment.

Main Results:

• Tungsten/rhodium targets/filters yielded the highest CNRs in phantoms ≥20 mm thick.
• Molybdenum/molybdenum was optimal for visualizing microcalcifications and masses in specimens ≤35 mm thick.
• Molybdenum/rhodium and tungsten/rhodium provided superior image quality for specimens >35 mm and >55 mm, respectively, at consistent AGDs.

Conclusions:

• Optimal exposure conditions for maximizing phantom CNR differ from those yielding the best diagnostic image quality for breast specimens.
• Visual evaluation of breast specimens is essential for optimizing DR mammography exposure settings for accurate and efficient clinical diagnosis.
• The findings enable more precise and effective mammographic examinations.