Volunteers search for needles and other drug paraphernalia along Church Street in Austin, Ind., in April. The region has recorded 142 new HIV cases since December, according to the state, in an outbreak tied to injected-opioid use. Seth Herald/Nurphoto/Corbis hide caption

itoggle caption Seth Herald/Nurphoto/Corbis

Science-based guidelines say there's no benefit to getting an EKG of heart activity before routine cataract surgery — even if the patient is old. But most doctors order such tests anyway. Bull's Eye/ImageZoo/Corbis hide caption

itoggle caption Bull's Eye/ImageZoo/Corbis

The U.S. Preventive Services Task Force recommends mammograms every other year, while the American Cancer Society endorses annual scans. Kari Lehr/Image Zoo/Corbis hide caption

itoggle caption Kari Lehr/Image Zoo/Corbis

Catharine Becker of Fullerton, Calif., was diagnosed with stage 3 breast cancer at 43 despite having a clean mammogram. The mother of three didn't know she had dense breast tissue until after she was diagnosed. Heidi de Marco/Kaiser Health News hide caption

itoggle caption Heidi de Marco/Kaiser Health News

Sequencing the genes of a cancer cell turns up lots of genetic mutations — but some of them are harmless. The goal is to figure out which mutations are the troublemakers. Kevin Curtis/Science Source hide caption

itoggle caption Kevin Curtis/Science Source

Anne Koller closes her eyes as an oncology nurse attaches a line for chemotherapy to a port in her chest. Koller typically spends three to six hours getting each treatment. Sarah Jane Tribble/WCPN hide caption

itoggle caption Sarah Jane Tribble/WCPN