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Introduction
Procedure
Technical Details
Risks
X-rays are invisible rays which which when passed through the body to a photographic film on the other side, they create a picture of internal body structures called a radiograph. This imaging modality is a good first-line imaging exam for many of the conditions that involve the spine. A radiograph of the low back (lumbar spine) is shown below.
To obtain the x-ray the patient either stands in front of a screen or lies on a table in an x-ray room similar to the one depicted below.
After appropriate positioning of the area to be imaged, x-rays are passed through the body and detected by the x-ray film which is then exposed and reviewed by the radiologist. The entire procedure taken only a few seconds to minutes for each x-ray.
X-rays are electromagnetic waves which when passed through the body are absorbed in different amounts by various body tissues. The less dense a structure of the body is, the more radiation passes through it and reaches the film. These x-rays then expose the film, changing its color similar to the way light would darken photographic film. Bones are more dense than soft tissues and they typically appear white or light on the x-ray film because they absorb much of the radiation, leaving the film only slightly exposed. Structures that are less solid than bone, such as skin, fat, muscles, blood vessels, and the internal organs appear darker on the film because they let more of the x-rays pass through and reach the film.
X-rays are ionizing radiations which while relatively harmless at low doses, can potentially increase the risk of certain types of cancers in chronic or repeated exposure. Furthermore, exposure to x-rays during pregnancy can increase the risk of birth defects. Therefore, all individuals, especially woman who are, or may be, pregnant, should carefully discuss this issue with their physician and radiologist before undergoing a scan in order to weigh the benefits of the study against its potential risks.
