A chest tomogram is a picture of the chest area created by moving the x-ray machine in one direction while moving the recording film the other way. This method blurs structures in front of and behind the area of the chest being studied. This allows for a more detailed view of a specific level within the chest cavity.

The test is performed in a hospital radiology department by an x-ray technician. You will be asked to lie on your back on the x-ray table. You should not move during the test, as this will affect the image quality.

Tell the health care provider if you are pregnant. You must wear a hospital gown and remove all jewelry.

There is generally no discomfort associated with tomography.

A chest tomogram can show certain problems with the lungs, such as tumors or the breakdown of tissue.

Abnormal results may suggest:

• Lesions or tumors in the lungs
• Widening or narrowing of the bronchial (air) tubes

There is low radiation exposure. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most experts feel that the risk is low compared with the benefits. Pregnant women and children are more sensitive to the risks.

In most medical centers, computed tomography (CT) has replaced the use of this technique.