 This is a study to determine if having somo٠vTM U-Systems, Inc. Automated Breast Ultrasound ABUS done together with a routine screening mammogram, is more sensitive to detecting breast cancer in women with dense breast tissue than getting a routine screening mammogram without ABUS. Potential study volunteers will be recruited at participating breast centers from the cohort of asymptomatic women who are scheduled to undergo routine screening mammography. 