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.
How to prepare for the test
Tell the health care provider if you are pregnant. You must wear a hospital gown and remove all jewelry.
How the test will feel
There is generally no discomfort associated with tomography.
Why the test is performed
A chest tomogram can show certain problems with the airways or lungs, including tumors.
What abnormal results mean
Abnormal results may suggest:
Lesions or tumors in the lungs
Widening or narrowing of the bronchial (air) tubes
What the risks are
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 the U.S., computed tomography (CT) has mostly replaced the use of this technique.
Gotway MB, Elicker BM. Radiographic techniques. In: Mason RJ, Broaddus CV, Martin TR, et al. Murray & Nadel's Textbook of Respiratory Medicine. 5th ed. Philadelphia, Pa: Saunders Elsevier; 2010:chap 19.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.