How It Is Done continued...
For a PET scan of the
brain, you will lie on a bed. You may be asked to read, name letters, or tell a
story, depending on whether speech, reasoning, or memory is being tested.
During the scan, you may be given earplugs and a blindfold (if you do not need
to read during the test) to wear for your comfort.
If you are
having a PET scan of your heart, electrodes for an
electrocardiogram (EKG, ECG) will be put on your
During the test, you will be alone in the scanner room. The
technologist will watch you through a window and you will be able talk to him
or her through a two-way intercom at all times.
The test takes 1
to 3 hours.
After the test
After the test, drink lots of fluids for the next 24
hours to help flush the tracer out of your body.
How It Feels
You will not feel pain during the test.
The table you lie on may be hard and the room may be cool. It may be difficult
to lie still during the test.
You may feel a quick sting or pinch
when the IV is put in your arm. The tracer is unlikely to cause any side effects. If you don't feel well during or after the test, tell the person who is doing the test.
You may feel nervous inside the PET
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 is usually very low compared with the
benefits of the test.
Most of the tracer will be flushed from your
body within 6 to 24 hours.
Allergic reactions to the tracer are very rare.
In rare cases, some soreness or swelling may develop at the IV site where
the radioactive tracer was put in. Apply a moist, warm compress to your
Positron emission tomography (PET) is a
test that uses a special type of camera and a
tracer (radioactive chemical) to look at organs in the
radiologist may discuss preliminary results of the PET
scan with you right after the test. Complete results are usually available in 1
to 2 days.
Positron emission tomography (PET)
Blood flow is normal and organs are working
well. The flow and pattern of the tracer shows normal distribution in the
- Decreased blood flow and increased
metabolism may show that the blood vessels are
narrowed or blocked. This may mean
coronary artery disease (CAD) is
- Decreased blood flow and glucose metabolism may mean that
heart tissue is scarred and damaged, such as from a
- Areas of increased glucose metabolism or
lower oxygen use and blood flow may mean you have
- Decreased oxygen use and blood
flow may mean a
stroke has occurred.
- Decreased glucose
metabolism may mean a form of
dementia. Dementia may be caused by Parkinson's disease,
Huntington's disease, or mental illness, such as
- Patterns of blood flow and
oxygen use that are not normal may mean a brain tumor is present.
- A special test (called amyloid imaging) may show signs of Alzheimer's disease.
| Tumor detection:
Areas of increased glucose metabolism may mean
a tumor is present.