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A PET/CT scan is a procedure that actually uses
two different imaging approaches to enable radiologists to look
for signs of disease or other problems within the body and to evaluate
how organs of the body are functioning: positron emission tomography
(PET) and CT (computed tomography).
In the PET scan, the patient is injected with
a small amount of radioactive material that circulates through the
bloodstream, making tissues and organs of the body, as they function,
visible to the imaging equipment.
The CT scan uses X-rays to image sections of the
body so that the radiologist can see organ structures or indicators
of disease.
Think of the PET scan as creating images that
show organs as they are functioning over time, whereas the CT scan
creates more of a snapshot of what a section of the body or an organ
looks like at a specific instant. PET/CT scans are used for a variety
of purposes, including:
- Cancer diagnosis or screening
- Preoperative planning before surgery
- Preparing for or guiding nuclear medicine
therapy for cancer
- Diagnosis or screening for heart disease
- Diagnosing neurological disorders such as
Alzheimer's or Parkinson's
Your physician may order a PET/CT scan for different
medical reasons, depending on your specific situation.
Your doctor has recommended a Positron Emission
Tomography (PET) scan. PET imaging uses a modified sugar that will
allow RMI radiologists to see areas of the body that have altered
metabolic function.
Preparations:
- You will need to fast from 10 pm the night
before your scan. You may not have any food, gum, or beverages
other than water. In addition, your last meal before fasting should
be a low carbohydrate meal.
- You are encouraged to stay well hydrated
by drinking lots of water before the scan.
- You may take your medications with water.
- If you are diabetic or have any problems
regulating your sugar levels, please alert our scheduling staff,
as you will need to follow special instructions to ensure a quality
scan.
- You may be given a small dose of Alprazolam
(Xanax) orally as prescribed by our doctor, which you should take
approximately 15-30 minutes before your appointment. If you take
this, please arrange to have someone else drive you to and from
your exam. This will help patients that are nervous/tense, or
have muscle spasms that could interfere with the scan. This also
suppresses muscle uptake that can mimic pathology. This is especially
important in patients with head and neck cancers, breast cancer,
and lymphoma. If needed, your ordering doctor should prescribe
this medication, as he/she will be most familiar with your allergies,
history, and potential reactions with other medications.
- You will need to bring any prior studies
(MRI, CT, Bone Scans, PET scans) that have been done outside of
RMI facilities so that we may compare them with your current exam.
- For patients scheduled for whole body scans,
feel free to bring any music CDs that you would like to listen
to during your exam.
- Do not exercise for at least 12 hours or
longer before your exam, as this can result in intense abnormal
muscle uptake of the labeled sugar and significantly hinder the
evaluation of your scan.
- The material used for your scan has a very
short "shelf life." It is ordered specifically for you
at the time you are scheduled for your examination. If you are
late for, or miss your appointment, the material will be wasted
and you will be charged for its cost.
The Positron Emission Tomography (PET) scan uses
a modified sugar to generate the images. If your body's sugar level
is too high, it could significantly impede the evaluation of the
scan.
Preparations:
- As each person may respond differently to
a given prep, you should perform a "practice run" of
the following protocol two days before the examination. Check
your sugar levels in the morning and notify our staff if your
sugar level is above 150, as we may need to modify the protocol
and tailor it to your specific needs. If your glucose level is
too high on the day you arrive for the test, we will cancel the
test and reschedule you at a later date.
- You will need to fast for 12 hours before
the scan. You should have a high protein/low carbohydrate meal
for dinner and then not eat after 7 pm. This fast should include
no food, no gum, and no beverages other than water. If you feel
that your blood sugar may drop too low with prolonged fast, please
check it more frequently during the practice run, as we may need
to adjust the length of your fast.
- You should take your routine sugar medications
(insulin or oral hypoglycemic) on the day before the exam. You
will not take your sugar medications on the morning of the exam
until after the test. Insulin can cause intense muscle uptake
of the labeled sugar and interfere with the PET scan.
- You may still take your other (non-sugar)
medications with water the day of the test.
- You are encouraged to stay well hydrated
by drinking lots of water before the scan. Do not drink anything
with sugar in it, such as soda or juice.
- You may be given a small dose of Alprazolam
(Xanax) orally as prescribed by your doctor, which you should
take approximately 15-30 minutes before your appointment. If you
take this, please arrange to have someone else drive you to and
from your exam. This will help patients that are nervous/tense,
or have muscle spasms that could interfere with the scan. This
also suppresses muscle uptake that can mimic pathology. This is
especially important in patients with head and neck cancers, breast
cancer, and lymphoma. If needed, your ordering doctor should prescribe
this medication, as he/she will be the most familiar with your
allergies, history, and potential reactions with other medications.
- You will need to bring any prior studies
(MRI, CT, Bone Scans, PET scans) that have been done outside of
RMI facilities so that we may compare them with your current exam.
- For patients scheduled for whole body scans,
feel free to bring any music CDs that you would like to listen
to during your exam.
- Do not exercise for at least 12 hours or
longer before your exam, as this can result in intense abnormal
muscle uptake of the labeled sugar and significantly hinder the
evaluation of your scan.
- The material used for your scan has a very
short "shelf life." It is ordered specifically for you
at the time you are scheduled for your examination. If you are
late for, or miss your appointment, the material will be wasted
and you will be charged for its cost.
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