Lung Cancer Screening: What is a Chest CT?

A CT or CAT scan stands for a Computed Tomography scan that uses X-Rays to see inside a person’s body. A Chest CT provides a detailed look at a person from their throat to the top of the stomach including their lungs. They give the doctor valuable information that helps them make diagnoses from pneumonia to fibrosis (lung scarring) to cancer. In lung cancer screening, the Chest CT finds the lung nodules that could be lung cancer. 

In this picture, the hardness of the structures hit by the radiation creates the shades of gray pictured in the Chest CT. Bones (ribs) are hard and appear white. The heart is filled with blood and tissue and is of an intermediate hardness thus showing up gray. The blood vessels are of a similar gray color and appear either as dots or branches like the branches of a tree. Bronchi (airways) have a gray edge but are filled with air and thus have black centers. Finally, the lungs are full of air and if they are normal appear fairly black in color.