Doctors say while free lung cancer screenings are widely available, there is a high percentage of people who are at risk for the disease and eligible for a screening who are not making an appointment.

The American Lung Association's Saved by the Scan campaign has a short list of questions for people to answer to see if it makes sense for them to get a screening.

People are eligible for lung cancer screening if they are between 50 and 80, smoked or have quit within the past 15 years and have a 20 pack-year or more smoking history.

A screening is done with a low dose CAT scan to get a detailed look at lung tissue. Health insurance covers the screening and doctors say there should not be a co-pay.

The American Lung Association says the scan can reduce the lung cancer death rate by up to 20%. But data shows only about 16% of those who are eligible get tested.

"We'd all like to be screened and have it completely clean, but If you are going to develop lung cancer, you want to discover it at the earliest possible stage, when it's curable," says Michael Ebright, a surgeon at Stamford Health & NewYork-Presbyterian.

Enbright says CT scan imaging can spot potential issues people will not feel.

"There are no nerves in the lungs, you're not going to feel lung cancer. You're not going to necessarily have a cough, you're not going to be coughing up blood, you're not going to have chest pain. You're going to have no symptoms if you have early-stage lung cancer," he says