What is a PET scan?
Positron emission tomography (PET) is an imaging procedure used
for diagnosis. During a PET scan, pictures are taken of the
distribution of sugar, which is known as glucose.
For the PET scan, a small amount of radioactive glucose is
administered into a vein, and the administered material goes to
the same places in the body that use glucose. In this
procedure, your body is exposed to a very small amount of
radiation. The PET scanner that takes the pictures of the
glucose is similar in appearance to a CT scanner.
When is it used?
PET scanning is used when your doctor needs more information
than regular x-rays, CT, or MRI provide. PET scanning generally
is used to characterize as benign or malignant an abnormality
seen on another study or to determine the distribution of
tumors within the body.
How to I prepare for a PET scan?
You should not eat or drink anything for four hours prior to
the PET scan. You can take oral medications with water during
this time. If you are a diabetic, your blood sugar needs to be
in good control (less than 200) before having the PET scan. If
you need medication for pain or for anxiety during the scan and
you have these medications, bring them with you.
What happens during the procedure?
When you arrive for the PET scan, a brief history of your
illness will be obtained. You will then have an injection of
the radioactive glucose into a vein. Approximately 45 minutes
after the injection, you are placed in a reclining position on
a moving table that can change your position inside the
scanner. The table generally will be moved several times during
your examination.
The scanning machine is detecting the radiation given off by
the radioactive glucose that had been previously administered.
The pictures usually take 45 minutes to one hour 15 minutes to
obtain. The pictures are projected onto a TV screen and
prepared for the doctor to examine. You need to plan to be in
the PET area at least two hours.
What happens after the procedure?
Generally, there are no special measures to take after the
procedure. You will experience no side effects from the
procedure. You do not need to have someone with you for the
procedure.
What are the benefits of this
procedure?
The PET scan can provide your doctor with information that is
not available from the other imaging procedures. It will help
the doctor diagnose your problem.
What are the risks associated with this
procedure?
You are exposed to a small amount of radiation that is not
considered threatening to your health. Pregnant or lactating
women should not have a PET scan without discussing the risk
with their doctor.
When should I call the doctor?
The results of this examination will be available to your
referring physician on the day of the examination.
This article is intended as a resource for patients
receiving their cancer care at Duke University Hospital or Duke
Clinic. It is not intended to substitute for medical advice
from your healthcare team. If your doctor’s instructions differ
from the information in this article, please talk with your
doctor before making any changes.
Source: Duke Cancer Patient Education Program / Patient
& Family Education Committee 8/00
