Single-Exposure Contrast Enhanced Spectral Mammography

Contrast enhanced mammography exploits the K-edge, a sharp increase in the x-ray attenuation coefficient, of contrast agents for improved tumor detection. Conventionally, the process involves the subtraction of two separate exposures from a high and low energy spectra. We propose and demonstrate the use of electronic energy thresholds in a photon counting spectral detector in lieu of multiple exposures, thereby potentially allowing for single-exposure contrast enhanced mammography. A weighted logarithmic subtraction technique is applied to remove the soft tissue background and obtain the contrast enhanced image. We also studied the effects of aluminum filtration on the contrast enhanced image. We use the integral mode data and effective attenuations to estimate suitable weights in this contrast enhanced imaging. This idea is demonstrated using the Medipix3RX detector with CdTe sensor and an iodinated contrast phantom of up to 10 mg/ml with PMMA as the background material. Further studies will involve the use of an anthropomorphic breast phantom as well as the testing of lower iodine concentrations and dose benefit investigations.