The present invention proposes a noninvasive method to distinguish two types of (micro)-calcification by x-ray imaging in mammography. Two major types of (micro)- calcification are found and confirmed by histopathology and they are correlated to benign and malignant breast lesions. Distinguishing them noninvasively will significantly improve early breast cancer diagnosis. This invention is based on the fact that these two types of (micro)- calcifications show opposite absorption and small-angle scattering signals in x-ray imaging. The imaging system, which can record these two signals of the breast tissue simultaneously (for instance, an x-ray grating interferometer), can be used to uniquely determine the micro- calcification type. The suggested invention is expected to be used in mammography to improve early breast cancer diagnosis, increase diagnosis accuracy and decrease the biopsy rate.