When should smokers get chest x-rays to screen for lung cancer?

Smokers with a greater than 30-pack-year history of smoking may benefit from CT lung scans, a type of x-ray screening, to detect early lung cancer. A recent study of a group of older smokers who had a greater than 30-pack-year smoking history (smoking a pack per day for 30 or greater years) showed that CT scans apparently allowed earlier detection of lung cancers, enough that they had a significant (20%) decrease in deaths.
Screening CT scans for all smokers, however, is not the answer. Some doctors will order an x-ray for smokers in the hopes that they might at least see some noncancerous damage from the smoking that might be enough to motivate them to quit.