I. Introduction
CAncer is one of the leading causes of mortality in the world. In 2012, there were about 14.0 million new cases worldwide [1]. In 2015, cancer caused 8.8 million deaths. Approximately, one out of every six deaths in the world is due to this disease. The number of new cases is expected to increase by approximately 70% over the next 20 years. At the same time, new cases of breast cancer has increased significantly, especially in developed countries. According to the International Agency for Research on Cancer of the World Health Organization [2], breast cancer is the second leading cause of death, and certainly, the most frequent form of malignancy in women worldwide with 1.67 million new cases diagnosed in 2012 (25% of all cancers) [3]. Mammography is the best population-based breast cancer screening imaging modality in current clinical practice. It is the most efficient and effective technique used for detecting breast cancer at early stages. Recent study evaluates the performance of various breast imaging modalities for early detection of breast cancer [4].