Lung cancer is the most common cause of cancer deaths among American men and women—more common than colon, breast and prostate cancer combined, with over 160,000 new cases discovered each year.

 
Low-dose spiral CT scans are emerging as one of the most promising tools in the early detection of lung cancer. Currently, when lung cancer is detected, the disease has already spread outside the lung in 15 percent to 30 percent of cases. Conventional lung X-rays are currently the gold standard in detecting lung cancers. Spiral CT, a technology introduced in the 1990s, can detect tumors well under 1 centimeter (cm) in size, while conventional chest X-rays detect tumors about 1 to 2 cm in size.

 
Spiral CT, also called helical CT, uses X-rays to scan the entire chest in about 15 to 25 seconds. The CT scanner rotates around the body, taking over 100 slices, or images, in sequence. A computer is reconstructs these images into a three-dimensional model of the lungs. The exposure to radiation is the same as a standard chest X-ray.

Most abnormalities detected on a lung spiral CT-scan are not cancer. They can be scars from smoking, areas of inflammation, or other non-cancerous conditions that can mimic lung cancer and may require additional testing. Studies are currently underway at several centers to further evaluate this technology.