PET Scan Information
PET
Positron Emission Tomography
 Tennessee
Oncology has just acquired one of the most advanced pieces of technology
available today. The GE Discovery LS PET/CT hybrid imaging scanner.
What
is PET?
PET is an acronym for Positron Emission Tomography. PET is an imaging
test to gain important and unique information to help measure and
manage your disease. In the last 15 years, PET has moved from the
research environment to clinical application and is quickly becoming
a leading diagnostic tool for all types of cancer.
 How
does PET work?
The patient is injected with a glucose (sugar) solution that contains
a radioactive tracer element that is easily detected by the PET
scanner. Glucose is used as food by cancer tissue to a greater extent
than normal tissue, so cancerous tissue that absorbs the radioactive
glucose can be seen on the PET scan. While PET Scanning is a very
reliable way to detect cancerous tissue, Tennessee Oncology's Discovery
LS scanner goes one step further by merging the PET scan image with
a CT scan image. The tests are performed at the same time. The CT
portion of the scan provides an accurate account of the patient's
anatomy, while the PET scan portion shows us where the cancer is
in relation to the patient's anatomy.
Why
a PET scan instead of another kind of test?
PET is an imaging technique that relies on changes in tissue biochemistry
and the body's metabolism. Most medical imaging techniques, such
as x-ray, ultrasound, CT, and MRI, depend on changes in the anatomy
or structure of organs. PET is able to show disturbance in molecular
biology often before there is any change in anatomy. PET may result
in the earlier diagnosis of cancer. Unnecessary procedures and surgery
may be avoided if the patient is found to have more extensive disease
than expected. Treatment that is more appropriate or even life saving
may be offered to the patient shown to have disease that is less
advanced than expected. A costly battery of tests ordinarily required
for staging can be reduced by a single PET /CT scan.
 How
accurate is PET?
PET is very accurate in showing the presence or spread of many malignant
tumors. For example, it is more accurate in detecting the spread
of lung cancer and colorectal cancer than any other imaging method
currently available.
What
are the risks associated with a PET scan?
Like Nuclear Medicine Bone Scans and other types of diagnostic scans
the patient is exposed to a small amount of radioactive material
that is not considered to be a threat to the patient's health. The
amount of radiation exposure one receives is about the same as three
X-rays. Pregnant and lactating women should discuss the procedure
with their physician.
What
can I expect if I need a PET scan?
The patient will be asked to fill out a brief medical history, which
includes current medications. The patient will need to show his/her
insurance card. A blood glucose (sugar) level will be taken. In
most cases, the patient will be injected in his/her arm with the
radioactive glucose. The patient will then be asked to rest quietly
for 45 - 60 minutes while the tracer circulates through the body.
The resting time depends on the procedure being done. Next, the
part of the body being scanned will be positioned within a large
ring (similar to a large donut) on a scanning bed. After the patient
is positioned properly the bed will begin to move the patient into
the scanner. As pictures are being taken, the patient will be asked
to breathe normally and remain very still so clear images can be
obtained. The imaging time depends on the procedure, but generally
it only takes about 45 minutes. If you would like to see an example
of what to expect please click on the "What to expect video"
link provided.
 How
do I prepare for a PET Scan?
Plan not to eat eight hours prior to your exam. If you need to take
medications, they can be taken with a small amount of water. Diabetic
patients need to regulate their blood glucose to as normal a level
as possible. Blood glucose levels will be checked before the injection
of radioactive glucose. The blood glucose level needs to be less
than 200 at the time of the scan. If you take insulin, it must be
taken at least four hours prior to your scan. If your glucose levels
are over 200, please contact our PET facility prior to your appointment
time. You should bring medications for pain, anxiety or claustrophobia
if you need them plus someone to drive you home. Remember that a
PET scan is just like a CT or CAT scan. If you do not need medication
for the CAT scan, then you will be fine for the PET scan. Talk with
your physician. Wear comfortable clothes. Expect the procedure to
last a total of two hours. Please arrive thirty minutes prior to
your scheduled time. If you need to reschedule, notification must
be given forty-eight hours in advance.
Click here for a copy
of the PET scan PREP LIST
 What
should I bring for a PET scan?
If you have previous x-rays, CT, MRI, or Nuclear Medicine scans,
you need to bring them with you or arrange with Tennessee Oncology
to have them picked up.
If you need medicine for pain, anxiety, or claustrophobia, please
bring them with you to take prior to the scan. If you take medication
for any of these reasons you will need to bring someone to drive
you home.
What
happens after the PET scan?
You should eat and drink plenty of fluids after your study is completed.
You will not experience any side effects from the study.
When
will I receive results of the PET scan?
The results of your scan will be sent to your referring physician.
Your physician will give you the PET scan report.
If you have additional questions, please consult your physician.
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