Back x-rays (spine x-rays)

What is the test?

Doctors have used x-rays for over a century to see inside the body in order to diagnose a variety of problems, including cancer, fractures, and pneumonia. During this test, you usually stand in front of a photographic plate while a machine sends x-rays, a type of radiation, through your body. Originally, a photograph of internal structures was produced on film; nowadays, the image created by the x-rays goes directly into a computer. Dense structures, such as bone, appear white on the x-ray films because they absorb many of the x-ray beams and block them from reaching the plate. Hollow body parts, such as lungs, appear dark because x-rays pass through them.

Doctors use back x-rays to examine the vertebrae in the spine for fractures, arthritis, or spine deformities such as scoliosis, as well as for signs of infection or cancer. X-rays can be taken separately for the three areas of the spine: the cervical spine (neck), thoracic spine (middle back), and lumbar spine (lower back). Occasionally, doctors x-ray the pelvis to help diagnose the cause of back pain.

How do I prepare for the test?

You have to remove all clothing, undergarments, and jewelry from your upper body. You may be asked to wear a hospital gown.

What happens when the test is performed?

You either stand or lie down while a technician takes the x-rays. He or she positions you against the photographic plate (which looks like a large board) to get the clearest pictures. A front view and a side view are usually taken.

For cervical spine x-rays, the technician tells you to open your mouth as wide as you can before taking some of the pictures; this is done to avoid having your teeth block the view of the bones at the top of your spine.

The technician leaves the room or stands behind a screen while controlling the x-ray camera. To avoid a blurred image, he or she tells you to remain as still as possible, including holding your breath, before taking each picture.

What risks are there from the test?

The amount of radiation from x-ray tests is too small to be likely to cause any harm. However, if you're pregnant, talk to your doctor. Radiation may be harmful to a developing fetus.

Must I do anything special after the test is over?

No.

How long is it before the result of the test is known?

Although digital images are often available immediately, it may take additional time for a doctor to examine them. You'll probably get the results later in the day.