Karen Lindsfor, a professor of radiology and chief of breast imaging at the University of California, Davis Medical Center, examines the mammogram of a patient with heterogeneously dense breast tissue. Lindfors is among those doctors who say there was insufficient evidence to support the idea that additional screenings would detect cancers earlier. Rich Pedroncelli/AP hide caption

itoggle caption Rich Pedroncelli/AP

Budding scientists, engineers and doctors lined up to try surgical robots from Intuitive Surgical at a science festival in Washington, D.C., over the weekend. Scott Hensley/NPR hide caption

itoggle caption Scott Hensley/NPR

People who are interested in and paying close attention to each other begin to speak more alike, a psychologist says. iStockphoto.com hide caption

itoggle caption iStockphoto.com

Noah Stewart shelters in the closet just 15 minutes before an April 2011 tornado demolished his house. Wearing the helmet may have saved his life, one doctor says. Courtesy of the Stewart family hide caption

itoggle caption Courtesy of the Stewart family

The Colorado Coalition for the Homeless runs the Stout Street Clinic in Denver, helped Dale Miller get a CT scan. Colorado Coalition for the Homeless hide caption

itoggle caption Colorado Coalition for the Homeless

Come summer, mailboxes of 1 in 3 buyers of individual health insurance buyers could get rebate checks. JS Callahan/tropicalpix/iStockphoto.com hide caption

itoggle caption JS Callahan/tropicalpix/iStockphoto.com