X-rays penetrate body structures and tissue in different ways. Bone is very dense and blocks much of the radiation, so the image of bone on the film appears white. Your heart also blocks some of the radiation and so appears as a lighter area on the film. Lungs are filled with air, so they block little of the radiation, creating a dark image.

A radiologist — a doctor trained in interpretation of X-rays and other imaging exams — analyzes the images, looking for clues that may suggest if you have heart failure, fluid around your heart, cancer, pneumonia or other lung problems, or other conditions.

Your doctor will discuss the results with you as well as what treatments or other tests or procedures may be necessary.

May. 21, 2011