Mammographic x-ray unit kilovoltage test tool based on k-edge absorption effect

Area of Science:

• Medical Physics
• Radiological Imaging
• Quality Control

Background:

• Accurate determination of peak kilovoltage (kVp) is crucial for mammographic quality control.
• Existing methods may require complex calibration or multiple exposures.
• A need exists for a simple, integrated tool for kVp assessment.

Purpose of the Study:

• To design and evaluate a novel tool for determining the kVp of mammographic x-ray units.
• To achieve compatibility with the mammography accreditation phantom (MAP) for single-film quality control.
• To provide a method for precise kVp measurement using k-edge filter analysis.

Main Methods:

• Designed a tool utilizing k-edge discontinuities of sequential element filters to analyze x-ray attenuation.
• Employed Monte Carlo photon transport analysis to estimate photon transmission probabilities.
• Calculated optimum filter thicknesses to maximize attenuation differences within acceptable optical density ranges.
• Constructed a phantom with 21 elements for experimental data acquisition and MAP image analysis.

Main Results:

• The tool demonstrated the ability to determine kVp within +/-1 kV based on calculated relative transmission data.
• Experimental results showed average kVp determination differences of 0.8 kV and 1.0 kV for two mammography units.
• The method eliminates the need for independent calibration or calibration curves due to known k-edge energies.

Conclusions:

• The designed tool provides a simple and accurate method for kVp determination in mammography.
• The tool's compatibility with the MAP facilitates efficient quality control procedures.
• This approach offers a reliable, calibration-free solution for mammographic x-ray equipment assessment.