As health providers shift to more preventive measures to control costs, hospitals such as Abbott Northwestern in Minneapolis are focusing more of their patient marketing on their ability to use technology to see inside the body in greater detail than ever. But the push for more scans has only heightened the debate over whether they are necessary for many of the people who get them. At Abbott's Minneapolis Heart Institute, officials are quick to point to the early warning benefits for people considered at low to intermediate risk of heart disease, highlighting their service, called HeartScan, which measures calcium deposits in arteries around the heart. Still, the practice of selling scans to patients who could otherwise be healthy sparks plenty of criticism from some within the medical community.