Monochromatic x-rays for low-dose digital mammography: preliminary results

Area of Science:

• Medical Imaging
• Materials Science
• Radiology

Background:

• Digital mammography is crucial for breast cancer screening.
• Current mammography techniques utilize polychromatic x-rays, which can lead to higher radiation doses and lower image contrast.
• Developing advanced imaging methods is essential for improving diagnostic accuracy and patient safety.

Purpose of the Study:

• To assess the feasibility of using monochromatic x-rays for digital mammography.
• To evaluate the potential of a multilayer reflector system for generating monochromatic x-rays at a low radiation dose.
• To determine if this technique can enhance image quality for breast examinations.

Main Methods:

• Designed and fabricated a multilayer mirror to select 21.5 keV monochromatic x-rays from a tungsten target x-ray tube.
• Utilized an experimental digital mammography setup with a scanning stage to acquire monochromatic x-ray images.
• Evaluated system performance using breast phantoms, spectrometers, and dosimeters, measuring contrast-to-noise ratio and spatial resolution.

Main Results:

• The multilayer mirror achieved 0.70 reflectivity at 21.5 keV with a narrow energy bandwidth (0.9 keV FWHM).
• Monochromatic x-rays resulted in a significantly lower radiation dose (0.0415 mGy) compared to polychromatic x-rays (0.497 mGy).
• Monochromatic images exhibited 1.85 times higher contrast, clearly visualizing fibers, calcifications, and masses, with a spatial resolution of 7 lp/mm.

Conclusions:

• Monochromatic x-rays generated via multilayer mirrors show promise for digital mammography.
• This technique offers high-contrast imaging capabilities with a substantially reduced radiation dose.
• It represents a potentially valuable diagnostic tool for enhanced breast examinations.