Dennis Schmidt started smoking as a teenager, when that was so unexceptional that his Catholic high school designated outdoor “senior smoking quarters,” where students in their final year could take cigarette breaks. He smoked a pack of menthols daily for nearly 40 years.

As a registered nurse at the University of Cincinnati Medical Center and a former Air Force medic, he knew this was a bad idea. “I made a couple of attempts to quit and they failed miserably,” said Schmidt, now 75.

Not until 2007 was he able to stop, using a newly approved prescription drug that reduced cigarette cravings. “I put them down and never went back,” he said.

Despite his years as a healthcare professional, Schmidt was unaware that lung cancer screening had become available for current and past smokers. The influential U.S. Preventive Services Task Force, an independent expert panel, recommended it in 2013.

Besides, he said, “I thought I was in the clear after all these years of not smoking.”