Former public defender Denise Lee is spreading the word about a lung scan that saved her life — and she learned about it from a billboard Denise Lee, now 63, smoked for 40 years, starting when she was 14. A year after her last cigarette, she saw a public service announcement created by Hill Holliday for the American Lung Association’s Ad Council campaign, saying that former smokers were eligible for a special lung cancer screening. Lee got the scan, which led to a lung cancer diagnosis before she even had symptoms. Below, she shares her story with PEOPLE. I started  smoking  when I was 14. My  first cigarette  was one of my mom’s cigarettes. She never smoked in front of us — she always smoked in the bathroom, in our basement. One day, I just went in and got one of her cigarettes and smoked it. It was terrible. It was awful. But I viewed cigarette smoking as a weight-loss aid.…