Originally published by Harvard Health.
What Is It?
Doctors have used x-rays for over a century to see inside the body. X-rays can diagnose a variety of problems, including bone fractures, arthritis, cancer, 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 a part of 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 absorb many of the x-rays and block them from reaching the plate. Calcium in bones is dense, so it absorbs lots of x-rays, making the image of the bone appear white. Fat and other soft tissues are less dense, so they allow more radiation to pass through them and appear in shades of gray. Hollow body parts, such as the lungs, appear dark or black because lots of x-rays pass through them. (In some other countries, like the United Kingdom, the colors are reversed, and dense structures are black.)
What It’s Used For
A foot x-ray can be used to diagnose broken bones, dislocated joints, arthritis or joint deformities such as bunions. A foot x-ray can help diagnose the cause of unexplained symptoms like general foot pain, swelling, and tenderness.
Foot x-rays are also used after a broken bone has been set, to ensure the bone was set properly and will heal correctly.
Usually you remove shoes, stockings, and any jewelry or other metal objects from the foot being x-rayed, as metal interferes with the x-ray imaging and will show up on the resulting image.
Women who are pregnant should generally avoid having x-rays taken, because there is a chance that x-ray radiation could harm the developing fetus. If x-rays are absolutely necessary, it is important to inform your doctor and the x-ray technician, as there are precautions which that can be taken to protect the developing baby.
How It’s Done
X-rays pass through most objects, including the body. An x-ray machine produces a small burst of radiation that passes through a part of the body, recording an image on photographic film or a special digital image recording plate.
An x-ray tech or radiologic technologist will position your leg on a table so that the foot can be x-rayed properly. To obtain different views, the technician may reposition your foot several times. For x-rays of the foot, three different images are usually taken to cover all views: one image is taken from the side, one from the front and one at a 45-degree angle between the front and side views.
The x-ray tech will leave the room or stand behind a screen while the x-rays are taken, in order to protect him or herself from repeated exposure to radiation.
Digital x-rays may be available immediately, but it will take additional time for a doctor to examine and interpret them. A radiologist will review the results of your x-rays and produce a report which will be sent to your primary care physician, who will go over the results with you.
Although there is a small amount of risk with any exposure to radiation, the amount of radiation generated during a foot x-ray is too small to cause harm. However, if you’re pregnant, talk to your doctor. Radiation may be harmful to a developing fetus.
When to Call a Professional
Because harmful side effects are not expected, people typically need to call their doctors only to discuss x-ray findings.
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