Evaluation of the minimum iodine concentration for contrast enhanced subtraction mammography

The aim of this work is to investigate the use of iodine based contrast media in mammography with two different double exposure techniques: K-Edge Subtraction Mammography and Temporal Subtraction Mammography. Both techniques have been investigated by using monochromatic beams produced at a synchrotron radiation facility and conventional beams obtained with a clinical digital mammography system. A dedicated three-component phantom containing cavities filled with different iodine concentrations has been developed and used for measurements. For each technique, information about the minimum iodine concentration which provides a significant enhancement of the detectability of the pathology by minimizing the risk due to high dose and high concentration of contrast medium has been obtained. In particular for cavities of 5 and 8 min of diameter filled with iodine solutions (0, 2, 4, 8, 16, 32 mg/ml), the minimum concentrations needed to obtain a contrast-to-noise ratio of 5 with a mean glandular dose of 2 mGy have been obtained.