Simulation Study of a Monochromatic X-ray Beam with K-edge Filter for Low Dose Mammography

Abstract

X-ray mammography can be used to acquire images useful for early breast cancer detection in medical applications. There have been a number of approaches to diagnostic low-dose mammography. The purpose of this study was to design a concept for use of monochromatic X-ray beams by using K-edge filters for low dose mammography. The SRS-78 X-ray simulation code and Monte Carlo simulation GATE code were used to model the X-ray tube, target material, filter material, breast phantom, and detector. To achieve a monochromatic X-ray beam, molybdenum (Mo) and rhodium (Rh) were used as filter materials in various thicknesses. The direct conversion detector (FDXD 1417, Drtech, Seongnam, Korea) composed of thin-film transistor (TFT)-amorphous selenium (a-Se) was modelled through Monte Carlo simulation. According to the CVR and EER results, the filter thickness for optimal mammographic imaging is set to 6 and 3 HVL for Mo and Rh, respectively. SNR values with the Rh filter improved by 1.01, 6.28, 5.60, 5.60, 5.60, 5.60 % over the range from 0.1 to 0.6 μGy compared to analogous SNR values without filter. The present work demonstrates that monochromatic X-ray beams can be generated for low dose mammography. According to the results, Rh filter could be useful for enhancing calcification while absorbed dose is reduced.