Material Decomposition in Contrast-enhanced Digital Mammography Based on Photon Counting: Monte Carlo Simulation Studies

Abstract

of the photons at 50-kVp. We simulated photons generated at 50 kVp and 11 mAs. We acquired two images, one below and one above the iodine K-edge using one exposure with energy selective windows. The calibration data were obtained for various combinations step wedge phantom of breast tissue equivalent materials and iodine. The images from the calibration phantom were used to produce the inverse mapping functions. Material decomposition was investigated in terms of a contrast-to-noise ratio (CNR). According to the results, the values of the CNR calculated the with dual energy technique were higher than that of a conventional X-ray system. The calculated values of the CNR with the cubic inverse mapping function were 50.082 times higher than those with the linear inverse mapping function for 0.2-mm iodine. The calculated values of the CNR with the quadratic inverse mapping function were 31.840 times higher than those with the linear inverse mapping function for 0.2-mm iodine. We demonstrated that the CdTe photon counting detector could reduce the radiation dose compared to two exposures with the dual energy technique. The calculated radiation dose of the one-exposure method had a 65% lower radiation dose than the dose of the two-exposure method. Our studies may be used as a basis for future studies on room-temperature semiconductor X-ray detectors. Eorts to reduce the errors in the inverse mapping functions and the scatter eects need to be investigated in the future.