A radiologist compares an image from earlier, 2-D technology mammogram to the new 3-D Digital Breast Tomosynthesis mammography in Wichita Falls, Texas in this file photo. In guidelines published Tuesday, Oct. 20, 2015, the American Cancer Society revised its advice on who should get mammograms and when, recommending annual screenings for women at age 45 instead of 40 and switching to every other year at age 55. The advice is for women at average risk for breast cancer. Doctors generally recommend more intensive screening for higher-risk women.