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Medically reviewed by Dr. Alex Tamm, BMSc, MD (STIR), FRCPC

What is an FDG PET CT scan?

An FDG PET CT scan is an advanced form of hybrid diagnostic imaging that uses fluorodeoxyglucose (FDG) to visualize sugar utilization in cells or tissues. FDG PET CT imaging is used in various applications, including cardiac, oncology and neurology, and is considered one of the most advanced forms of medical imaging available.

How does an FDG PET CT scan work?

Cells inside the body consume sugar (glucose) to function or grow. FDG PET CT imaging relies on fluorodeoxyglucose to mimic sugar from the food we consume, which fuels the cells in our body.

During this exam, we inject an FDG radiotracer and use PET CT cameras to monitor areas of normal, decreased, or increased cellular metabolism.

How does FDG PET CT imaging compare to traditional imaging exams?

FDG is the most common PET radiotracer used at MIC and has the power to change treatment plans and improve patient outcomes. By combining images from nuclear medicine (PET) and radiology (CT), we can target various cells throughout the body and distinguish minute details with increased sensitivity and specificity compared to traditional anatomical imaging.

The hybrid imaging exam saves our patients time since we can perform both scans (PET and CT) with the same machine during a single visit. Additionally, information gathered from FDG PET CT imaging can help avoid unnecessary tests, surgeries, and interventions, streamlining the patient’s journey through the healthcare system.

FDG PET CT Applications at MIC

FDG PET CT imaging is used in multiple applications, including cardiac viability and sarcoidosis imaging, oncologic applications targeting cancer or tumors, neurologic applications targeting degenerative diseases, movement disorders, neuroinflammatory conditions, neurosarcoidosis, and more.

FDG PET CT scans are also helpful in the setting of:

Early detection and diagnosis
Staging and prognosis
Assessing treatment response
Surveillance of recurrent disease and re-staging
Treatment planning

Cardiac FDG PET CT Applications

Cardiac Viability

FDG PET CT imaging is used in cardiac viability exams to assess how different parts of the heart process sugar (glucose). Cardiac viability exams involve two parts of the exam that use the radiotracers, Rubidium and FDG.

The first part of the exam assesses the resting blood flow (perfusion) to the heart with Rubidium, which is injected through an IV. The second part of the exam evaluates how various areas of the heart utilize glucose by injecting FDG through an IV. Damaged heart tissue will not process much glucose or FDG like healthy tissue.

Cardiac Sarcoidosis

FDG PET CT imaging also assesses cardiac sarcoidosis, a rare inflammatory condition affecting the heart. Inflammatory cells are usually very metabolically active and require more glucose to function. When we inject the FDG radiotracer through an IV, inflammatory cells are more likely to absorb the radiotracer. Our team will use the PET CT machine to capture images of your heart; the resulting images are important for a diagnosis, understanding the patient’s health, and may influence treatment decisions.

Learn more about cardiac PET CT imaging at MIC.

Oncologic FDG PET CT Applications

FDG is the most common radiotracer used in PET CT imaging for cancer, as the radiotracer helps visualize sugar utilization in tissues throughout the body. Since cancer cells become very metabolically active to fuel their rapid growth, there is an increase in sugar consumption, which results in FDG accumulating in hyperactive malignant cancer cells.

The average FDG PET scan has the potential to change the treatment plan for approximately 1 in 3 patients across all types of cancer and up to 2 in 3 patients for certain malignancies.

FDG PET CT Cancer Applications

FDG PET CT can help with staging, monitoring response to treatment, and tumor surveillance in various types of cancer, including but not limited to lung, breast, colorectal, head and neck, melanoma, and lymphoma (Hodgkin’s and non-Hodgkin’s).

Lung Cancer

Staging lung cancer correctly significantly impacts treatment options. Basic lung cancer treatment is often surgical, but not all patients who are diagnosed can be managed surgically. PET CT has changed management in 28-40% of cases (Greenspan, 2017; Marcus et al., 2015) and is the best test to stage disease and help patients avoid unnecessary surgery.

Breast Cancer

Precise staging is critical to selecting the best treatment options for breast cancer patients. PET CT imaging is more sensitive than conventional whole-body staging with a bone scan and CT for patients with higher-risk locally advanced cancers. PET CT imaging saves patients time by allowing a whole-body examination in one scan on one machine and can detect unsuspected distant metastases in bones or other organs.

Colorectal Cancer

PET CT is more accurate than CT for staging colorectal cancer and can identify secondary cancers in the liver or lung, providing valuable information that directly affects treatment options. PET CT scans prompt changes in the treatment of more than one-third of patients (Society of Nuclear Medicine and Molecular Imaging [SNMMI], 2023; Waxman et al., 2009). Furthermore, PET CT scans are currently the most effective means of detecting cancer recurrence and can distinguish between cancer recurrences and post-therapy scarring.

Head and Neck Cancer

Fewer than a third of patients present with local disease, necessitating FDG PET CT evaluation for local spread and distant disease for accurate staging (Goel et al., 2017). Accurate staging (highly dependent on imaging) is critical to determine prognosis and develop an appropriate treatment plan.CT and MRI look at the primary tumor, whereas PET CT plays a vital role in characterizing additional sites of local, regional, and distant disease at initial staging; assessing response to therapy and detecting recurrence and metastases at follow-up when suspected by clinical symptoms. At MIC, the PET can also be combined with a fully diagnostic CT, allowing for optimal functional and metabolic evaluation.

Melanoma (Skin Cancer)

PET CT can play a key role in the staging and surveillance of high-risk melanoma patients. Whole body scanning in one visit from the top of the head to the toes can be quickly obtained. Unlike other tumors, melanoma mostly affects young and middle-aged people. PET CT has been proven to be very sensitive for the detection of soft tissue, lymph node and organ metastases at initial staging or during follow-up.

Hodgkin’s and non-Hodgkin’s Lymphoma

PET CT can play a central role in imaging for lymphoproliferative disorders characterized by the uncontrolled production of white blood cells (lymphocytes) and differ in tissue behaviour, imaging, and treatment options.

For example, PET CT is a more accurate initial staging exam for Hodgkin’s lymphoma than conventional CT imaging since there is a larger FDG uptake with hyperactive cells associated with the disease. PET CT can also help avoid unnecessary biopsies by localizing sites of lymphoma that are both accessible and metabolically active when compared to CT imaging.

Learn more about oncologic PET CT imaging at MIC.

Neurologic FDG PET CT Applications

FDG PET CT imaging is very helpful in distinguishing between age-related cognitive decline and progressive neurodegenerative disorders. Information from FDG PET CT imaging can help guide therapy choices by identifying unique markers from otherwise similar disorder features (Alzheimer’s vs. Lewy body dementia, etc.).

Alzheimer’s

FDG PET CT imaging can help identify abnormalities in rare variants of Alzheimer’s disease. With the emergence of disease-modifying therapies for Alzheimer’s, identifying certain variants can help establish a probable diagnosis and determine if a patient is eligible for therapy to streamline the process.

Movement Disorders

FDG PET CT imaging can help doctors identify atypical Parkinson’s from typical Parkinson’s by evaluating changes in brain activity. While movement disorders like Parkinson’s can be very difficult to diagnose, FDG PET CT imaging can highlight distinct metabolic abnormalities like reduced striatal uptake, which are related to atypical Parkinson’s (typical Parkinson’s will reveal no change or increased uptake).

Neuroinflammatory Conditions

Neuroinflammatory conditions like encephalitis or neurosarcoidosis can be very challenging to detect on MRI but often show significant changes in brain activity on FDG PET CT scans. These changes in brain activity may be seen as areas of increased glucose metabolism across the different lobes of the brain (mesial temporal, frontal, occipital, or striatum). Your doctor may also use FDG PET CT imaging to help with cases related to complex epilepsy, as PET CT can help locate the source of seizures by analyzing increased metabolism patterns.

Learn more about neurologic PET CT imaging at MIC.

What to Expect During an FDG PET CT Scan

You may be asked to change into a gown when you arrive for your exam.
One of our technologists starts an intravenous (IV) line to inject the medications and/or radiotracer.
- You will have to wait for a short time in a private uptake room to allow the radiotracer to circulate through your body.
- You may need to get an IV injection of contrast dye.
The PET CT scanner is a large machine shaped like a doughnut – like a CT or MRI machine. You will lie on an exam table that slides into the doughnut opening. During the scan, you must remain still, as movement can make the scan images blurry.
The time for a PET CT scan varies depending on the type of exam, ranging between approximately 15 to 45 minutes. On average, the entire PET CT appointment can last around 2-3 hours.

How Much Does an FDG PET CT Scan Cost?

MIC uses FDG PET CT imaging in several applications: heart (cardiac) imaging, cancer (oncology) imaging, and brain (neurology) imaging. Currently, the Alberta Health Care Insurance Plan (AHCIP) only covers the cost of FDG PET CT imaging in cardiac applications when performed in a community-based clinic outside the hospital.

The cost of an FDG PET CT scan at MIC depends on whether an accompanying diagnostic CT is acquired simultaneously. Our booking team will be able to review the breakdown of the cost for the scan with each patient at the time of booking.

In general, the cost of an FDG PET CT scan in neurologic or oncologic applications starts at $999.

Patients are encouraged to talk to their employer or a Benefits Specialist before booking their exam to see if they qualify for extended coverage. Some extended benefits programs or health spending accounts may cover a portion or possibly the entire exam fee.

FDG PET CT FAQs

How do I know that my scan will cover everything of concern?

MIC dual-trained nuclear physicians and radiologists will recommend a specific protocol for each patient/request they receive. The protocols range from a simple unenhanced PET CT scan to some of the most complex protocols, performing multiphase contrast-enhanced diagnostic CT studies combined with a PET scan, potentially saving the patient unnecessary radiation exposure.

The MIC PET requisition provides ordering physicians with a number of opportunities to specify what specific areas they would like scanned. If there is ongoing uncertainty, the radiologist will contact the ordering physician to ensure the scan is optimized to address the clinical question.

How do I know what is included in my PET CT scan?

Our physicians are trained in both radiology and nuclear medicine, and one will review each requisition as well as the imaging done to date and protocol the study accordingly. If ordering physicians have a specific scan range or requirements, these requests can easily be made on our very flexible requisition form.

How experienced are the technologists with PET scanning?

Multiple MIC technologists have more than 10 years of PET training/experience and continue to train future generations of nuclear medicine technologists on PET scanners.

Do I have to fast before my FDG PET CT scan?

FDG PET CT scans are used in various applications, which all have different preparation instructions. Our team will review any fasting details with you when you book your exam. Regardless of the application, you will have to fast for at least 6 hours before your FDG PET CT scan. Some applications, such as cardiac sarcoidosis, require patients to fast for 12 hours before the exam.

Why am I scheduled for two PET scans?

Occasionally, to help with treatment decision-making, your physician may request both FDG and DOTATATE PET CT scans to help characterize the tumours or metastases. The FDG PET scan shows how metabolically active the tumor cells are, while the DOTATATE PET scan shows how many receptors the tumours have.

Each of these PET scans provides complementary information to aid the clinician in making the optimal personalized treatment decision for each individual.

View References

Alevroudis, E., Spei, M., Chatziioannou, S., Tsoli, M., Wallan, G., Kaltsas, G., Daskalakis, K. (2021, April). Clinical Utility of FDG PET in Neuroendocrine Tumors Prior to Peptide Receptor Radionuclide Therapy: A Systematic Review and Meta-Analysis. https://pmc.ncbi.nlm.nih.gov/articles/PMC8069875/

Bois, J., Muser, D., Chareonthaitawee, P. (2019). PET/CT Evaluation of Cardiac Sarcoidosis. https://med.emory.edu/departments/radiology/clinical_divisions/nuclear-medicine/documents/2020/nuclear-cardiology/pet.ct-evaluation-of-cardiac-sarcoidosis.pdf

Berti, V., Pupi, A., Mosconi, L. (2011, June). PET/CT in diagnosis of movement disorders. https://pubmed.ncbi.nlm.nih.gov/21718327/

Fazio, P., Varrone, A. (2019, March). FDG-PET/CT in Movement Disorders. https://doi.org/10.1007/978-3-030-01523-7_6

Goel, R., Moore, W., Sumer, B., Khan, S., Sher, D., Subramaniam, R. (2017, July). Clinical Practice in PET/CT for the Management of Head and Neck Squamous Cell Cancer. https://www.ajronline.org/doi/10.2214/AJR.17.18301

Greenspan, B. (2017, December). Role of PET/CT for precision medicine in lung cancer: perspective of the Society of Nuclear Medicine and Molecular Imaging. https://pmc.ncbi.nlm.nih.gov/articles/PMC5709134/

Hofman, M., Hicks, R. (2016, October). How we read Oncologic FDG PET/CT. https://doi.org/10.1186/s40644-016-0091-3

Khalaf, S., Al-Mallah, M. (2020, April). Fluorodeoxyglucose Applications in Cardiac PET: Viability, Inflammation, Infection, and Beyond. https://pmc.ncbi.nlm.nih.gov/articles/PMC7350806/

Litt, H., Kwon, D., Velazquez, A. (2023, July). FDG PET Scans in Cancer Care. https://jamanetwork.com/journals/jamaoncology/fullarticle/2807033

Marcus, C., Paidpally, V., Antoniou, A., Zaheer, A., Wahl, R., Subramaniam, R. (2015, February). FDG PET/CT and Lung Cancer: Value of Fourth and Subsequent Posttherapy Follow-up Scans for Patient Management. https://jnm.snmjournals.org/content/56/2/204

Ng, S., Lau, H., Raynor, W., Werner T., Saboury, B., Revheim, M., Alavi, A. (2022, August). Diagnosis and evaluation of cardiac sarcoidosis with FDG PET/CT and PET/MR. https://jnm.snmjournals.org/content/63/supplement_2/2641

Skali, H., Schulman A., Dorbala, S. (2013, April). FDG PET/CT for the Assessment of Myocardial Sarcoidosis. https://pmc.ncbi.nlm.nih.gov/articles/PMC4009625/

Society of Nuclear Medicine and Molecular Imaging. (2023). Fact Sheet: Molecular Imaging and Colorectal Cancer. https://snmmi.org/Patients/Patients/Fact-Sheets/Molecular-Imaging-and-Colorectal-Cancer.aspx

Waxman, A., Herholz, K., Lewis, D., Herscovitch, P., Minoshima, S., Ichise, M., Drzezga, A., Devous, M., Mountz, J. (2009, February). Society of Nuclear Medicine Procedure Guideline for FDG PET Brain Imaging. https://snmmi.org/common/Uploaded%20files/Web/Centers/PET%20Center%20of%20Excellence/SNM%20Procedure%20Guideline%20for%20FDG%20PET%20Brain%20Imaging.pdf

Learn more about PET CT imaging at MIC:

PET CT Imaging

PSMA PET CT Imaging

DOTATATE PET CT Imaging

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