Introduction
Radiography, known to most people as x-ray, uses electromagnetic
radiation to make images of bones, teeth and internal organs.
X-rays allow doctors to take pictures of the inside of your body.
One of the oldest forms of medical imaging, x-ray
is a simple, painless medical test that can help your doctor provide
you with appropriate treatment. It's a fast, easy and safe way
for your doctor to view and assess conditions ranging from broken
bones to pneumonia to cancer. Many different types of x-rays,
such as bone or chest x-rays, exist. The type your doctor uses
depends on what part of your body needs examining and for what
purpose.
Uses of X-rays
- Determine whether a bone is chipped, dislocated or broken (fractured)
- Evaluate joint injuries and bone infections
- Diagnose and monitor the progression of degenerative conditions,
such as arthritis and the bone-thinning disease osteoporosis
- Screen for lung and heart diseases
- Find and treat artery blockages
- Diagnose the cause of persistent coughing or chest pain
- Check for broken ribs or a punctured lung
- Evaluate unexplained abdominal pain
- Help locate objects that may have been accidentally swallowed
by a child
- Determine whether you have injured a bone or disk in your spine
- Detect scoliosis, an abnormal curvature of the spine, and other
spinal defects
- Evaluate infection of the sinuses (sinusitis)
- Locate dental problems such as cavities, abscessed teeth and
other tooth and jaw abnormalities
- X-ray exams also play an important role in the detection and
diagnosis of cancer. In fact, one use of x-ray in diagnosing
cancer is to see whether you have lung cancer or whether cancer
from another part of the body has spread (metastasized) to the
lungs. Cancer may appear lighter in color on X-ray films than
does normal, healthy lung tissue. X-rays may also be used to
examine cancers of the intestines, stomach, liver, spleen, kidneys
and breasts.
Preparing for an X-ray
Different types of x-rays require different preparations.
In general, you undress the area of your body that needs examination.
You may wear a gown to cover yourself during the exam, depending
on what area is being x-rayed. You may also be asked to remove
jewelry, eyeglasses and any metal objects that could, like clothing,
obscure the x-ray image.
You may wear a lead apron to shield your sex
organs from exposure to x-rays. At very high doses, radiation
can damage a woman's eggs or a man's sperm. Since you're exposed
to a small amount of radiation during most x-rays, the lead apron
is used simply as a precaution.
At
high doses, radiation also can be harmful to a fetus. Always inform
the x-ray technologist if there's any possibility that you are
pregnant. Your doctor may suggest you either forgo the x-ray exam
or, if one is necessary at the time, take precautions to minimize
radiation exposure to the fetus.
Before some types of x-rays, such as a barium
enema, you're given a liquid called contrast medium, or a dye.
Contrast mediums help outline a specific area of your body on
x-ray film. You may swallow the contrast medium, insert it as
an enema or receive it as an injection into a vein. Contrast medium
appears opaque on x-ray film, providing a clear outline of structures
such as your digestive tract or blood vessels.
If you're to receive a contrast medium before
an x-ray, tell your doctor if you have a history of allergy to
x-ray dye.
How X-rays Work
X-rays are a form of energy or radiation. X-rays exist
in nature, emanating from outer space, rocks and even the soil.
You cannot see or feel x-rays. Because they're of higher energy
than visible light, x-rays can penetrate objects, including your
body.
An x-ray machine produces an x-ray beam using
an x-ray tube carefully aimed and focused on the body part being
examined. The machine produces a tiny burst of radiation, at a
safe level, that passes through your body and produces an image
on film or on a TV or computer screen.
As x-rays pass through your body, different tissues
absorb different amounts. For example, your bones are dense and
absorb x-rays well. But soft tissues, such as your skin, fat,
muscles and organs, allow more x-rays to pass through them. The
result is that bones appear white on the x-ray. Your other tissues
appear in varying shades of gray. Structures containing air, such
as your lungs, appear black.
What You Can Expect During an X-ray
X-rays are performed at most doctors' offices, dentists'
offices, emergency rooms and hospitals. You may lie on a table,
sit or stand between the x-ray machine and the x-ray film. The
technologist helps position your body to obtain the necessary
views. He or she may use pillows or sandbags to help you hold
the proper position. The technologist then aims the machine at
the area of your body that needs examination. Once you're in the
proper position, the technologist enters a control booth. During
the xX-ray exposure, you remain still and hold your breath to
avoid moving, which can cause blurring on the film.
The technologist may take x-rays from multiple
angles.
If your young child is having an x-ray, restraints
may be used to help keep him or her still. You may be allowed
to remain with your child during the test. If you remain in the
room during the x-ray exposure, you're typically given a lead
apron to wear to shield you from unnecessary exposure.
An x-ray procedure may last from several minutes,
for a bone x-ray, to about an hour, for more involved procedures
such as those using a contrast medium.
For most x-rays, you feel no discomfort other
than the hardness of the x-ray table or the temperature of the
room, which may be kept cool to keep the equipment from overheating.
It may be necessary to compress momentarily the body part being
examined. This compression may be uncomfortable, but the discomfort
lasts only briefly during the x-ray exposure. If you're having
a test that requires contrast medium, ask your doctor what to
expect.
After an x-ray, you generally dress and return
to your normal activities. Routine x-rays usually have no side
effects. However, if you receive an injection of contrast medium
before your x-rays, call your doctor if you experience pain, swelling
or redness at the injection site. Ask your doctor about other
signs and symptoms to watch for pertaining to your specific x-ray
procedure.
You may worry that x-rays are not safe because
it is known that high levels of radiation exposure can cause cell
mutations that may lead to cancer. But the amount of radiation
that you are exposed to during an x-ray is so small that the risk
of any damage to cells in your body is extremely low. Thus, for
most x-ray examinations, the benefits of any medically indicated
examination are thought to greatly outweigh the small risk. In
addition, great care is taken to use the lowest radiation dose
possible to produce the best image for the radiologist to evaluate.
No radiation remains after an x-ray examination.
However, if you're pregnant or suspect that you
may be pregnant, inform your doctor before having an x-ray. Though
the risk of most diagnostic x-rays to an unborn baby is small,
your doctor may consider whether it's better to wait or to use
another imaging test such as ultrasound.
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