What is a PET-CT scan?

PET-CT is a highly effective procedure for evaluating organs and tissues for the presence of disease or other conditions.

A PET-CT scan simultaneously utilizes two technologies to create a high-resolution image of the location and strength of disease in the body.

PET (positron emission tomography) evaluates the metabolism of a particular organ or tissue, providing information about the physiology (functionality), anatomy (structure), and biochemical properties, allowing early detection of disease onset.

CT (computed tomography) generates multiple cross-sectional images, allowing doctors to view a body from the inside, visualizing small nodules or tumors which otherwise would not be seen.

Coronal (front to back) view of PET, CT and fused PET-CT scan

During the scan, patients receive a very small amount of glucose injected into the vein of an arm. The glucose (with radioactive tracers) travels to the disease site where it is metabolized by active disease cells. When highlighted under the PET scanner, the tracers help your doctor see how well organs and tissues are working by measuring blood flow, metabolism, neurotransmitters, and radiolabelled drugs.

In oncology, a PET-CT scan provides information on the degree of tumor malignancy that no other imaging modality can deliver. It provides vital information for diagnosing cancer early and determining how cancer is responding to treatment.

How to Prepare for a PET-CT Scan

1-2 days prior to your scheduled test, someone from our center will contact you to go over specific instructions. Please inform us at that time if you are taking any medications. It is extremely important to inform us if you are diabetic.

  • Do not eat or drink anything except water for 5 hours prior to your exam. This includes gum and mints.
  • You may take your normal medications with water only, except diabetic medication.
  • It is very important that you arrive on time for your appointment.
  • Wear loose fitting, comfortable clothing.
  • Do not wear any jewelry.
  • Inform the technologist if you might be pregnant or if you are breast feeding.
  • Plan on being at our facility for 1 1/2 to 2 hours.

PET-CT in 3D representation with angled cut through

How a PET-CT Scan is Performed

Before the scan, you’ll get tracers through a vein in your arm. Your body needs time to absorb the tracers, so you’ll wait about an hour before the scan begins.

Next, you’ll undergo the scan. This involves lying on a narrow table attached to a PET-CT machine, which looks like a giant letter “O.” The table glides slowly into the machine so that the scan can be conducted.

You’ll need to lie still during the scan. The technician will let you know when it is that you need to remain still.

When all the necessary images have been recorded, you will slide out of the machine. The test is then complete.

After a PET-CT Scan

After the test, you can go about your day as normal unless your doctor gives you other instructions. Generally, all tracers leave your body after four hours.

Your physician will receive the results of your PET-CT scan within 48 to 72 hours.

What to Expect During Your PET-CT Scan

Check In: A small amount of paperwork needs to be completed. Please bring ID and insurance card.

History: Your medical history will be reviewed. Please bring any prior images and reports from other facilities.

Preparation: A small amount of radioactive glucose will be given through an IV injection.

Scan: You will be required to lie as still as possible for around 20 minutes.

After scan: The technologist will provide a CD containing your scanned images.

Results sent to your doctor: Your doctor will receive results once our radiologist has reviewed your scan.

Maximum Intensity Projection (MIP) of a PET scan

What is a PSMA PET-CT scan?

A PSMA Scan (Prostate-Specific Membrane Antigen) is a type of nuclear medicine imaging test used to detect prostate cancer and other diseases or abnormalities in the prostate gland. It works by using a radioactive tracer (Ga68-PSMA or F18-PSMA), which binds to receptors on the surface of cells, including those found in the prostate gland. The tracer helps create images of the prostate so doctors can look for any abnormal areas or growths.

Sagittal (side to side) view of PET, CT and fused PSMA PET-CT scan

Who should consider having a PSMA PET-CT scan?

Men who are at risk for prostate cancer may benefit from a PSMA Scan. This includes men over 40 years old with a family history of prostate cancer, as well as men with elevated PSA levels or evidence of tumor on biopsy. Additionally, men with recurrent prostate cancer after surgery or radiation therapy could also benefit from this kind of scan.

How is PSMA PET-CT scan different?

A PSMA PET-CT scan is different than other types of scans in that it uses a radioactive tracer to target and detect prostate-specific membrane antigens (PSMA). These antigens are more prevalent in prostate tissue compared to other organs, making them ideal for imaging purposes. The tracer (Ga68-PSMA or F18-PSMA) binds to these antigens which then light up when viewed under a scanner, allowing doctors to get detailed images of the patient’s prostate gland. As such, a PSMA scan can provide information about the size and shape of the prostate, any abnormalities, and help guide treatment decisions.

How to prepare for a PSMA PET-CT scan?

There are no special preparatory requirements for a PSMA PET-CT scan. Fasting is not required, nor are there any special dietary restrictions. Water consumption should be as per usual since there is no need to drink extra water. You should also inform your doctor if you have any allergies or medical conditions beforehand as this could affect how you should proceed with preparation.

What happens during a PSMA PET-CT scan?

During the appointment, you'll receive an injection of a radioactive tracer (Ga68-PSMA or F18-PSMA) which accumulates in high concentrations in the prostate tissue. You'll rest and wait one hour prior to scanning. The actual scan will last around 35 minutes where the scanning device takes images of the area of interest. Your appointment should last no more than 1 hour and 30 minutes.