Q: It’s been 10 years since I’ve smoked. Do I need a low-dose CT scan of my lungs?

A: It is no secret that smoking can have long-lasting, negative effects on your lungs. Cigarette tobacco contains thousands of chemicals that damage the lungs and can lead to cancer growth, so a history of smoking can put you at great risk for lung cancer — even after you quit. Therefore, it is crucial for those who are smokers or have smoked in the past to get screened for lung cancer.

One of the most effective ways to screen for cancer is with a computed tomography (CT) scan, which uses a combination of X-rays to produce high-resolution and detailed images of the body’s interior. To limit your body’s exposure to radiation, physicians use a low-dose CT scan, which involves a lower amount of radiation than a typical CT scan. These scans can be an incredibly beneficial tool for detecting lung cancer in the early stages and extending life expectancy.

The U.S. Preventive Services Task Force has guidelines in place to determine who is eligible to receive a CT scan. To qualify for a low-dose CT scan, you must meet the following requirements: be between ages 55 and 80; be an active smoker or have quit smoking within the last 15 years; and have a smoking history of 30 “pack years.” A pack year is defined as how many packs you smoke a day for a certain number of years. For example, if you smoke one pack a day for 10 years, you have a smoking history of 10 pack years. If you smoke half a pack a day for 10 years, you have a pack history of only five years.

Unfortunately, less than 10 percent of people who qualify for screenings receive them.

Often, people do not fully know or understand all the elements of a CT scan that need to be considered. The strongest argument in favor of low-dose CT screening is that it has been shown to decrease the risk of dying from lung cancer by 20 percent over a period of six to 10 years.

In rare cases, screenings can result in false positive results, causing unnecessary stress and worry. However, you can dramatically minimize the risks of a false positive and maximize the benefits of early screenings by visiting comprehensive multidisciplinary centers where radiology, pulmonology and oncology work together to decide when and how to act on test results.

For those who meet the criteria, screenings should be scheduled annually and continue for 15 years from your quit date.

Keep in mind that CT scans are not a substitute for quitting smoking altogether. Not smoking is the best way to prevent lung cancer.

If you are a smoker, or have smoked within the last 15 years, talk to your doctor about scheduling a low-dose CT scan and counseling methods to avoid smoking.

Rajan Singla, M.D., is a hematologist and medical oncologist at Nazareth Hospital and an assistant clinical professor of oncology at Thomas Jefferson University.