What is Positron Emission
Tomography (PET/CT)?
Positron Emission Tomography (PET/CT) produces
cross-sectional whole body images of metabolic function. A diseased organ
may use greater or lesser amounts of energy or glucose than normal organs, and
diagnoses can be made from the amount of metabolic activity measured by a PET/CT
scan. Because malignant tumors use more energy than normal tissues, PET/CT
is particularly useful for the diagnosis and staging of cancer, and to determine
the effectiveness of treatment.
The
PET
Center at
Georgetown
University
Hospital
The
PET/CT Center staff works closely with physicians at the
Lombardi
Comprehensive
Cancer
Center and with
Georgetown
Hospital ’s Department of
Radiation Oncology.
The camera at
Georgetown
University
Hospital is a dedicated
PET/CT scanner that meets all of Medicare’s current requirements and is ACR
accredited.
HOW TO SCHEDULE A PET
SCAN
A PET/CT scan requires a physician referral. To schedule a scan
at the PET
Center at
Georgetown University
Hospital call 202-444-3363.
PET/CT and CANCER
PET
is used approximately 90% of the time for tumor imaging. Because cancer cells
tend to have a higher metabolic rate than normal cells, a PET/CT scan can detect
a cancerous tumor even in the very early stages, when the tumor isn’t large
enough to be detected by other means, such as CT or MRI alone. It can tell
whether tissue is cancerous or benign, important in situations where there could
be scar tissue from surgery or radiation therapy
PET/CT can also be
used to determine whether a course of treatment is working, by determining, for
example, whether a surgical procedure or chemotherapy was successful in removing
all cancerous tissue
How a PET/CT Scan
Works
In a PET/CT scan, the patient is injected with a radioactive
chemical, or tracer, attached to glucose, which is a sugar that cells use for
energy. As the tracer spreads throughout the body, areas that have a high rate
of metabolic activity absorb more of the tracer than areas of lower activity. As
the tracer chemical decays, it releases positrons whose emissions are detected
by sensors in the scanner. The computer assembles the signals it receives into
an image that maps out the different levels of activity throughout the body. In
areas of higher-than-normal metabolic activity, the tracer is more concentrated
and shows up as a "hot" spot on the PET scan.
PET/CT and
Diagnostic
CT
At
the Georgetown PET/CT center our patients can have both a PET/CT and diagnostic
CT completed within one visit. The
radiology department and the nuclear medicine department are working together to
increase patient convenience and to ensure the most accurate information.
Diagnostic
Computed Tomography or CT scan creates very clear two-dimensional images of the
brain and other parts of your body that cannot be seen on regular X-rays. In
many cases a contrast is injected to highlight certain tissues for closer
examination. A diagnostic CT provides detailed information about the location,
size, and shape of lesions or growths in the body.
Other Uses of
PET/CT
PET is also used to image neurological disorders such as
Alzheimer’s disease and epilepsy. Because certain brain cells in Alzheimer's
patients have low metabolic rates, they show up as dark spots in a PET
scan. Similarly, in cardiac patients, PET can help determine whether an area of
the heart has died or whether cardiac surgery may improve heart
function.
