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PET/CT
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What is CT?
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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How PET/CT Works?
 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.). Combining these two scanner technologies makes a PET/CT superior
to either technology 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 a
solution of glucose (sugar) that has been "tagged" with a radioactive chemical
isotope (generally fluorine 18, or FDG). 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.
1Zerhouni, E., M.D., Johns Hopkins Hospital (2001, June 21).
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What PET/CT Sees?
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:
Breast
Esophageal
Cervical
Melanoma
Lymphoma
Lung
Colorectal
Head and Neck
Ovarian
Thyroid
Other applications include:
Reducing biopsy sampling errors
Improvement of therapy planning
Assessment of response to treatments such as chemotherapy or radiation therapy1
PET/CT is also covered by Medicare for myocardial viability
and pre-surgery evaluation of refractory seizures, as well as in the
differential diagnosis of Alzheimer’s disease.
1Shreve, P., M.D., University of Michigan Health System, (2002, July
9).
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Preparation for Exams
For the entire day prior to your exam, do not eat or drink any sugars or
carbohydrates.
No vitamins for 24 hours prior to your exam.
For morning appointments, nothing to eat or drink (except water) after midnight
the night before.
For afternoon appointments, nothing to eat or drink (except water) after 6:00
am. If you have breakfast before 6:00 am, it must consist only of proteins – no
sugars or carbohydrates.
Drinking water prior to the study is encouraged. All necessary medication may
be taken with water. Do not drink any other kind of fluid.
Including preparation for the exam and time in the scanner,
please allow up to three hours for the entire visit. Upon your arrival, a
technologist will escort you to the imaging area and administer a very small
amount of radioactive glucose. Following the injection, you will rest in a
private room for 60 to 90 minutes while the glucose distributes through your
body. The scanning procedure is performed while you lie comfortably on the
scanner bed.
The PET exam itself causes no side effects and you will be
able to drive yourself home. However, some patients may request a mild sedative
be given to relieve anxiety. These patients must have someone drive them home.
If you have questions about the exam preparation please call
our scheduling department at (509 455-4455.
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| Tuesday, September 07, 2010 |
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© 2005 Inland Imaging
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