Table of ContentsView AllTable of ContentsWhat Is a PET Scan?PET Scan for CancerWhat to ExpectOther Tests for CancerResults
Table of ContentsView All
View All
Table of Contents
What Is a PET Scan?
PET Scan for Cancer
What to Expect
Other Tests for Cancer
Results
A PET scan is often used to help determine a cancer diagnosis. A positron emission tomography (PET) scan uses a tracer with low levels of radiation to find places in your body where cells are unusually active—which can mean they’re cancerous.A PET scan can also show whether cancer has spread and to where.
PET scans for cancer provide insight that can help your medical team diagnose your condition and determine treatment options. Learn the benefits and the risks, along with why these tests are recommended and what to expect.
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Who Should Not Have a PET Scan?Although PET scans are safe, there are some conditions where they are not recommended. Be sure to tell your healthcare provider if you are pregnant or breastfeeding, have diabetes, or if you’ve had an allergic response to radioactive tracers in the past.
Who Should Not Have a PET Scan?
Although PET scans are safe, there are some conditions where they are not recommended. Be sure to tell your healthcare provider if you are pregnant or breastfeeding, have diabetes, or if you’ve had an allergic response to radioactive tracers in the past.
What Is a PET Scan for Cancer?
A PET scan is a test that creates 3 dimensional (3D) pictures of the inside of your body. It uses a mildly radioactive drug to highlight areas of your body where cells are more active than normal, which can be a sign of cancer.
How Is a PET Scan Used for Cancer?
Your healthcare provider may recommend a PET scan if cancer is suspected through other imaging tests, including:
Before recommending a PET scan, your healthcare provider may do a physical exam and ask about your family’s medical history. Additionally, lab tests of your blood, urine, or other bodily fluids may be ordered.
Since these lab tests do not necessarily mean you have cancer, scans such as PET or other imaging techniques may be used.
However, PET scans reveal possible cancerous areas earlier than other forms of testing can, making them very valuable for early detection and treatment.
If a cancer diagnosis is given, PET scans may be recommended throughout treatment to see if treatment is working and to assess the likely outcome of the disease.
After cancer treatment, PET scans can be used to check for cancer recurrence.
Before a Diagnosis
PET scans can help diagnose new or recurrent cancer.
Cell growth can be detected with a PET scan, but not all cancer types can be seen. Further tests typically need to be performed to complete the diagnosis.
Additionally, other tests will be necessary to determine whether an area with a lot of radioactive activity is malignant (cancerous) or benign (noncancerous). If your results are inconclusive, your healthcare provider will order further tests and care options.
After a Diagnosis
PET scans can be used to determine how much cancer is in a person’s body and how far the cancer has spread, which is called staging.
Since PET scans can detect more cancerous sites than CT scans alone, they are often used in the initial staging and follow-up testing. They can help determine if and how the cancer is spreading and whether treatment is working. PET scan results may lead to changes in your treatment plan.
The benefits of PET scans for cancer outweigh the potential risks.
BenefitsEarly detectionAccurate diagnosisCustomized treatment planDetailed images not available with other testsLess invasive and expensive than exploratory surgeryRisksLow level of radiation exposure (not harmful unless pregnant or breastfeeding)Allergic reaction (extremely rare)
BenefitsEarly detectionAccurate diagnosisCustomized treatment planDetailed images not available with other testsLess invasive and expensive than exploratory surgery
Early detection
Accurate diagnosis
Customized treatment plan
Detailed images not available with other tests
Less invasive and expensive than exploratory surgery
RisksLow level of radiation exposure (not harmful unless pregnant or breastfeeding)Allergic reaction (extremely rare)
Low level of radiation exposure (not harmful unless pregnant or breastfeeding)
Allergic reaction (extremely rare)
Knowing what to expect before the PET scan can help you feel prepared.
Before the Scan
During the Scan
After the Scan
Other imaging tests, such as CT and MRI scans, are often done in combination with PET scans. CT scans and MRIs can provide more information on cancerous (malignant) tumors and lesions. Which test is used can depend on the organs the healthcare provider wants to examine.
Nuclear scans like PET cannot always reveal whether a tumor is cancerous.
If a nuclear test shows hot spots of potentially unhealthy tissue, other imaging tests can be used to gain more insight.
Computed Tomography (CT)
CT scans use an X-ray to take multi-angled pictures inside your body, which are then used to construct 3D images of your organs. Contrast liquid may be swallowed and/or injected before the test to show tumors more efficiently.
Combined PET/CT Scanners Perform Almost All PET Scans TodaySince PET and CT scans used together provide the best picture of cancerous tissue, they are used in almost all PET scans today. This way the areas where unhealthy tissue exists and the anatomical 3D pictures of these areas are able to be examined.
Combined PET/CT Scanners Perform Almost All PET Scans Today
Since PET and CT scans used together provide the best picture of cancerous tissue, they are used in almost all PET scans today. This way the areas where unhealthy tissue exists and the anatomical 3D pictures of these areas are able to be examined.
Magnetic Resonance Imaging (MRI)
MRIs use magnets and radio waves to show slices of soft tissue, creating images that show where unhealthy tissue is located. An injection of contrast liquid may be given to show the tumors as a different, bright color in the images. MRI helps healthcare providers locate and possibly determine whether a tumor is cancerous or noncancerous.
What Do the PET Scan Results Mean?
PET Scans Help Identify Recurrences of CancerSince PET scans can detect potential cancer sooner than other tests, they are often used during the follow-up stages after cancer has been treated to catch potential recurrences.
PET Scans Help Identify Recurrences of Cancer
Since PET scans can detect potential cancer sooner than other tests, they are often used during the follow-up stages after cancer has been treated to catch potential recurrences.
Summary
A PET scan for cancer uses a tracer with low levels of radiation to find places in your body where cells are unusually active. PET scans reveal possible cancerous areas earlier than other forms of testing can, making them very valuable for early detection and treatment. Other imaging tests can provide more information on cancerous (malignant) tumors and the best treatment options.
In general, nuclear imaging tests like PET scans are very safe and the benefits of getting the test outweigh the potential downsides. If you have any concerns, talk to your healthcare provider before having the procedure.
7 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Cancer Institute.Positron emission tomography scan.National Cancer Institute.How cancer is diagnosed.Canadian Cancer Society.Positron emission tomography (PET) scan.Cancer Research UK.PET scan.Centers for Disease Control and Prevention.Facts about nuclear medicine.Radiology Info.PET/CT.American Cancer Society.Nuclear medicine scans for cancer.
7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Cancer Institute.Positron emission tomography scan.National Cancer Institute.How cancer is diagnosed.Canadian Cancer Society.Positron emission tomography (PET) scan.Cancer Research UK.PET scan.Centers for Disease Control and Prevention.Facts about nuclear medicine.Radiology Info.PET/CT.American Cancer Society.Nuclear medicine scans for cancer.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
National Cancer Institute.Positron emission tomography scan.National Cancer Institute.How cancer is diagnosed.Canadian Cancer Society.Positron emission tomography (PET) scan.Cancer Research UK.PET scan.Centers for Disease Control and Prevention.Facts about nuclear medicine.Radiology Info.PET/CT.American Cancer Society.Nuclear medicine scans for cancer.
National Cancer Institute.Positron emission tomography scan.
National Cancer Institute.How cancer is diagnosed.
Canadian Cancer Society.Positron emission tomography (PET) scan.
Cancer Research UK.PET scan.
Centers for Disease Control and Prevention.Facts about nuclear medicine.
Radiology Info.PET/CT.
American Cancer Society.Nuclear medicine scans for cancer.
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