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Diagnostic imaging has
changed the face of health care. With diagnostic imaging, your doctor
can see what is happening inside your body through images instead of
through surgery. Many times, these images are created using radiation.
Radiation: Waves of Energy
Radiation is a type of
energy and moves in the form of invisible waves, like lines curving up
and down. Radiation is not the only type of invisible energy. Wind,
light, and sound are also types of energy. To understand how radiation
is used to create diagnostic images, it helps to think of light.
Everything near an
uncovered light bulb is well lighted. The invisible waves of light
energy are not blocked, and an object nearby receives the full strength
of the waves. However, if a lampshade is placed over the light bulb,
things just outside the lampshade become less well lighted. This is
because some of those invisible waves are blocked by the lampshade. If a
thick object like a cardboard box covers the light bulb, nothing near
the cardboard box is lighted because the invisible light waves are
completely blocked.
Radiation: From Waves to Images
Just like light waves,
radiation waves are blocked by things that get in their way as they
travel. To create diagnostic images, your doctor sends radiation waves
through your body. Some parts of your body will act like the lampshade,
while others act like the cardboard box. Radiation waves move freely
through areas where there is nothing blocking them, less freely through
parts of the body where there is just a little something blocking them,
like your lungs or your heart, and they stop where there is something
completely blocking them, like bone.
During a diagnostic
imaging exam, radiation waves are pointed toward one side of your body
and a camera is placed on the other side. The camera collects the waves
that go through your body and creates an image from them. An x-ray image
looks like a black-and-white version of the photo negatives you get when
you have film from your camera developed. Where the beams move freely
and at full strength, the image appears black; where they are partially
blocked, the image appears grey; and where they are completely blocked,
the image appears white. In other types of diagnostic images, different
areas of the body appear in different colors.
Radiation’s Role
From x-rays to computed
tomography (CT or CAT scans), radiation plays a part in the health care
of millions of Americans every year. Without radiation, doctors would
often have to use surgery to determine what is happening inside a
patient’s body. By giving doctors an alternative to surgery, radiation
helps ensure safer, better quality patient care.
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