What Is a PET/CT Scan?
In one continuous full-body scan (usually about 30 minutes), PET captures
images of miniscule changes in the body's metabolism caused by the
growth of abnormal cells, while CT images simultaneously allow physicians
to pinpoint the exact location, size and shape of the diseased tissue or tumor.
Essentially, small lesions or tumors are detected with PET and then precisely
located with CT.
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PET/CT Video & Breast Cancer
Positron Emission Tomography (PET) and Computerized Tomography (CT) are
both standard imaging tools that allow physicians to pinpoint the location
of cancer within the body before making treatment recommendations.
The highly sensitive PET scan detects the metabolic signal of actively
growing cancer cells in the body and the CT scan provides a detailed picture
of the internal anatomy that reveals the location, size and shape of abnormal
Alone, each imaging test has particular benefits and limitations but when
the results of PET and CT scans are "fused" together, the combined
image provides complete information on cancer location and metabolism.
The bottom line is that you can have both scans - PET and CT - done at
the same time.
How Does the Procedure Work?
While a CT scan provides anatomical detail (size and location of the tumor,
mass, etc.), a PET scan provides metabolic detail (cellular activity of
the tumor, mass, etc.). Combined PET/CT is more accurate than PET and
CT alone! 1
Anatomical: CT scanners send x-rays through the body, which are then measured by detectors
in the CT scanner. A computer algorithm then processes those measurements
to produce pictures of the body's internal structures.
Metabolic: PET images begin with an injection of FDG, an analog of glucose that is
tagged to the radionuclide F18. Metabolically active organs or tumors
consume sugar at high rates, and as the tagged sugar starts to decay,
it emits positrons. These positrons then collide with electrons, giving
off gamma rays, and a computer converts the gamma rays into images. These
images indicate metabolic "hot spots," often indicating rapidly
growing tumors (because cancerous cells generally consume more sugar/energy
than other organs or tumors).
The entire examination usually takes less than 30 minutes, providing comprehensive
diagnostic information to your health care team very quickly. The PET/CT
system provides exceptional image quality and accuracy of diagnostic information.
1 Branstetter BF, 4th: Radiology, May 2005; 235 (2): 580-6.
What Does PET/CT See?
PET/CT scanning integrates PET and CT technologies into a single device,
making it possible to obtain both anatomical and biological data during
a single exam. This integrated approach permits accurate tumor detection
and localization for a variety of cancers, including:
- Head and Neck
- Determines extent of disease
- Determines location of disease for biopsy, surgery or treatment planning
- Assesses response to and effectiveness of treatments
- Detects residual or recurrent disease
- May assist in avoiding invasive diagnostic procedure
Benefits of PET/CT
There are tremendous benefits of having a combined PET/CT scan:
- Earlier diagnosis
- Accurate staging and localization
- Precise treatment and monitoring
With the high-tech images that the PET/CT scanner provides, patients are
given a better chance at a good outcome and avoid unnecessary procedures.
A PET/CT image also provides early detection of the recurrence of cancer,
revealing tumors that might otherwise be obscured by scar tissue that
results from surgery and radiation therapy, particularly in the head and neck.1
In the past, difficulties arose from trying to interpret the results of
a CT scan done at a different time and location than a PET scan, due to
the fact that the patient's body position had changed. The combination
PET/CT provides physicians a more complete picture of what is occurring
in the body - both anatomically and metabolically - at the same time.2
1 Shreve, P., M.D., University of Michigan Health System, (2002, July 9).
2 Hricak, H., M.D., Memorial Sloan Kettering Cancer Center, (2002, January 15).
The Story of PET/CT
Doctors, especially cancer surgeons, were often frustrated in trying to
match PET images with CT images to determine the precise location of a
tumor in relation to an organ or the spinal column. They had little choice
other than to "eyeball" the two separate images and make an
educated guess as to the tumor's exact location - until 1992, when
engineer Ron Nutt and physicist David Townsend came up with the idea of
combining a PET and CT into one machine.
After working on their combined PET and CT concept for three years, Nutt
and Townsend received a grant from the National Cancer Institute. This
enabled the completion of a prototype machine, which was installed at
the University of Pittsburgh medical center in 1998.
The pair designed the machine to be more patient-friendly by making the
diameter of the PET/CT tunnel 28 inches, far more spacious than the typical
Time Magazine honored PET/CT as the "Medical Science Invention of
the Year" in 2000, noting that the PET/CT scanner has "provided
medicine with a powerful new diagnostic tool."1
1 Jaroff, L. Time Magazine (2000, December 4).
What Should I Expect?
Difficult questions deserve answers, and taking a "wait and see"
approach is sometimes unacceptable. A PET scan helps answer those tough
Your PET scan will produce a "picture" of how your body's
cells are functioning, whereas an x-ray, CT scan, or MRI produce a picture
of bones, organs and tissues.
Your PET scan will help you and your physician make a more informed decision
about your diagnosis and treatment path.
Some hints to prepare you for your scan:
- Dress comfortably and warmly. Scanner rooms can sometimes be cool.
- Avoid eating anything for at least four-six hours before your scan (this
includes sugar-free gum, mints, candy and beverages other than water).
- No strenuous exercise the day of your exam (example: working out, jogging, etc.).
- Please bring a copy of your most recent CT, X-Ray, or MRI films with you
on the day of your PET scan.
- Be prepared to lie still for 30-75 minutes while the scan is performed.
A PET scan is completely painless and has no side effects. After fasting
for 6 hours, you will receive an injection of a trace amount of radioactive
glucose, which is distributed throughout the body.
About 30-75 minutes after the injection, you will empty your bladder, then
lie down on a scanner bed. Images will be taken of your body as you lie
still on the scanner bed.
How Long Will the Scan Take?
A scan takes approximately 1-2 hours, depending on the type of scan you
are having (i.e., whole body, brain, etc.) and the type of scanner being
used. The results are then interpreted by a trained nuclear medicine physician
or radiologist and sent to your referring physician.
If you are diabetic, please call the facility for special instructions
After My PET Scan
When the PET scan is done, make sure to drink plenty of water or other
fluids throughout the day.
Results of My PET Scan
Your PET scan results will be reported to your referring physician within
1-2 business days. Please contact your physician to discuss your PET scan results.
The average cost of a basic PET scan is between $2,000 - $4,000 and most
insurance companies pay for clinically indicated PET procedures. To be
clinically indicated, the PET scan must be potentially beneficial in providing
information supportive of a diagnosis or monitoring certain conditions,
and be considered medically necessary. Many insurance companies have coverage
policies for certain clinical situations where PET scans have been proven
to be useful. If there are any questions, your physician's office
will work with the PET coordinator to determine if the PET scan is covered
by your insurance company. Since PET is a growing field, the published
data sometimes lags behind coverage policies. The indication may be covered,
even if it is not on the standard coverage list. Therefore, it is important
that your insurance company is contacted to determine your eligibility.
Please contact us for additional information on payment.
PET scans are covered by the Centers for Medicare and Medicaid Services
(CMS), Medicare, for specific clinical conditions under a National Coverage
- Most private insurance companies cover the same indications that Medicare
covers, but may cover additional indications. In either case, it is prudent
to check with the insurance company prior to the PET scan.
- The cost for the PET scan is broken into three components: (1) the FDG
radiopharmaceutical, (2) the actual scan, and (3) the professional fee
for the physician who reads/interprets the scan.
- Most insurance companies require pre-authorization for a PET scan. Physicians
routinely provide clinical information to the insurance company to obtain
the pre-authorization. Many coverage policies are local, so it is important
to determine the coverage policies from your payers.
- If private insurance does not cover PET and Medicare is not an option,
the patient may want to self-fund the PET scan. Please call us for information
about payment arrangements.
- Patients are responsible for deductibles, co-payments and remaining balances.
Payment is expected when services are rendered and all patients are responsible
to supply an insurance card and a referral from their Primary Care Physician
Please contact our office with questions regarding insurance and coverage
for PET scans.
Patient Instructions for PET Imaging
Non-diabetic patients NO sweets (desserts/candy/sodas). Limit carbohydrates
(bread, pasta, potatoes, and tortillas) the day before your exam.
For morning appointments scheduled between 7:00 - 10:30 a.m. do not eat
anything after midnight. For afternoon appointments scheduled between
12:30 - 4:30 p.m., you may eat only proteins (EGGS/STEAK/CHICKEN: NO SKIN)
with vegetable/olive oil, salt and pepper 3 hours prior to your PET/CT
scan. No coffee, juice, fruit, bread items, sugar, vegetables, bacon/sausage,
cheese or caffeine are allowed.
You may take your prescription medications with water only. NO antacids
(Rolaids/Tums), multi-vitamins, cough drops or elixirs (cough syrup),
gum, mints, or candy the day of your exam.
If you are diabetic, please call the facility for special instructions
You should not perform any strenuous exercise the day before or the day
of the study. (example: cutting down trees/mopping floor, etc)
Prior Imaging Studies
We will arrange to have your prior imaging studies sent to us (e.g. CT
scans, bone scans, x-rays, MRI scans, etc.) so that we can compare these
to your PET/CT scan. Contact us if you have had any recent studies your
doctor is not aware of so that we may obtain these studies prior to your exam.
Please be on time for your appointment. The injection that we give you
has a very short shelf life and is very expensive. Please notify us once
you receive this letter so that we may order the appropriate dose for
your exam, ask for Alma. If you need to reschedule please call us 24 hours
in advanced so that we may cancel your dose. If you need transportation
for your appointment please notify us and we will arrange for a taxi to
pick you up and take you home at our expense.
If you have trouble lying still or if you think you may become anxious
we can give you oral sedation to relax you. Please arrange for a ride
home if you think you might need sedation or inform us so that we may
arrange transportation. Even if we arrange for transportation you will
still need to have someone to accompany you for the examination if sedation
Wear loose warm clothing and no jewelry. We recommend that women wear
a two-piece outfit.
Children are not allowed to accompany you on the day of your exam.
What to Expect
An IV will be placed in your vein so that we can administer an injection
of F-18 FDG (fluorodeoxyglucose) which is a sugar-based solution with
a short-lived radioactive isotope. Following this injection, you will
wait 45 to 60 minutes to allow the isotope to be distributed throughout
your body. FDG is taken up by all the cells in the body. However, more
abnormally active cells (e.g. tumors) take up a greater percentage of
the FDG than normally active cells. These cells present as "hot spots"
on the images. After the 45 to 60 minutes wait period you will be escorted
to the PET/CT scanner for imaging. You will be lying still on the scanner
table for 30-45 minutes. Melanoma patients will be lying still on the
scanner table for approximately 1 hour.
Post Procedure Instructions
Following the study you may eat and resume your normal activities/diet.
Fluid is encouraged to promote excretion of the FDG. Because there is
a minimal amount of radiation remaining in your body for 6-8 hours following
the exam it is recommended that you avoid close contact with children
and pregnant women.
Download Patient Instructions for PET/CT Scan
You can also learn more about a PET/CT Scan by visiting out PET/CT Scan