How It Is Done continued...
For this test,
you will lie on your back with your head tipped backward and your neck
extended. It is important to lie still during this test. A special camera
(called a gamma scintillation camera) takes pictures of your thyroid gland from
three different angles. The test takes
about 30 minutes.
For a whole-body thyroid cancer scan, the camera will scan your body from head to toes.
thyroid scan, you can do your regular activities. But you will be asked to take
special precautions when you urinate. This is because your body gets rid of the
radioactive tracer through your urine. This takes about 24 hours. During this time, it is important to flush the toilet twice each time you use it and wash
your hands thoroughly after each time you urinate.
How It Feels
You may find it uncomfortable to lie
still with your head tipped backward.
There is always a slight chance of damage to
cells or tissue from radiation, including the low levels of radiation used for
this test. But the chance of damage from the radiation is usually very low
compared with the benefits of the test.
This test is not done for
pregnant women because of the chance of exposing the baby (fetus) to radiation. This test is also not recommended
for breast-feeding women or young children.
A thyroid scan uses a
radioactive tracer and a special camera to make a
picture of the
thyroid gland. The radioactive tracer used in this test is usually iodine or
technetium. A thyroid scan is done to help find problems with the
A normal thyroid scan shows a small
butterfly-shaped thyroid gland about 2 in. (5 cm) long and
2 in. (5 cm) wide with an
even spread of radioactive tracer in the gland.
An abnormal thyroid scan shows a thyroid
gland that is smaller or larger than normal. It can also show areas in the
thyroid gland where the activity is less than normal (cold
nodules) or more than normal (hot nodules). Cold
nodules may be related to
A whole-body scan will show whether iodine
is in bone or other tissue (iodine uptake) after the thyroid gland has been
removed for cancer. The whole-body scan can check to see if cancer has spread
to other areas of the body.