Screening ultrasound in dense tissue helps to find incidental tumors. In some studies in Asia, where dense breast tissue is more prevalent, whole breast ultrasound has picked up as many breast cancers as screening mammography, however, each study missed 33% of cancers picked up by the other modality (meaning both studies done together get the best results). Many of these cancers found incidentally are in addition to lesions detected on mammography. The cancers found on ultrasound tend to be invasive cancers. The gold standard of mammography however, picks up different types of cancers, many of which are missed on ultrasound alone, especially in it's early stages. Screening ultrasound in our facility is performed by a physician with expertise in breast ultrasound.