The chest X-ray is the most common radiologic procedure. The X-ray is projected toward the chest to show the heart and lungs, bones and soft tissues. The actual time of the average X-ray exposure is extremely short -- often less than one-half second. Some of the radiation penetrates the part of the body being examined and thus creates the X-ray image.

To understand what happens when an X-ray is taken, a comparison can be made with the use of a camera in taking a photograph.

The X-ray exposes the film to form an image just as the light exposes the film inside a camera. The film in a camera is developed and used to make a photographic print or it is used directly as a slide. The X-ray film is also developed and viewed with transmitted light on a light box or computer screen.

The chest X-ray technique in young children involves two views. The initial view is from the front, and the second is a side view.

In young children, the patient lies on the table and the hands are held above the head.

In an older patient, the child stands upright and then in a lateral view as the images are obtained. The technologist tries to "tightly cone" the radiation beam using a light on the patient's chest. This reduces the scatter radiation to other parts of the body.

After the film is obtained, it is interpreted by a radiologist. Comparison with prior films is important, particularly in evaluating heart size and blood flow to the lungs.

A report is made and becomes part of the patient's permanent record. Results are shared with both the cardiologist and the referring physician.