X-ray spectrum optimization of full-field digital mammography: simulation and phantom study

Area of Science:

• Medical Imaging
• Radiological Physics

Background:

• Conventional analog screen-film mammography has limitations in dynamic range and characteristic curve.
• New flat panel detectors in digital mammography offer high dynamic range and linear response.
• This allows independent optimization of radiographic technique for image quality and patient dose reduction.

Purpose of the Study:

• To compare different digital mammography setups for optimizing image quality and reducing patient dose.
• To evaluate the impact of various parameters on the detection of microcalcifications and tumors.

Main Methods:

• Simulations and phantom studies were conducted using an amorphous selenium detector.
• Image quality was assessed using signal difference-to-noise ratio (SDNR).
• Patient risk was quantified by average glandular dose (AGD). Parameters studied included monochromatic vs. polychromatic radiation, anode/filter combinations (Mo/Mo, Mo/Rh, W/Rh), filter thicknesses, anti-scatter grids, and tube voltages.

Main Results:

• The tungsten/rhodium (W/Rh) anode/filter combination proved optimal for all tested detection tasks.
• Monochromatic radiation reduced average glandular dose (AGD) by up to 2.3 times without compromising image quality compared to polychromatic spectra.
• Anti-scatter grids were beneficial only for breast thicknesses exceeding approximately 5 cm.

Conclusions:

• The W/Rh combination and monochromatic radiation represent significant advancements for digital mammography systems.
• Optimized technique selection can enhance diagnostic accuracy while minimizing radiation exposure.
• Detector technology enables tailored imaging protocols based on patient anatomy and clinical needs.