Health Check-Up MRI/PET/CT Scans

PET Scans are often able to find cancers that have spread inside the body. A CT or MRI scan tells the doctor what an organ looks like, and where a tumour is. A PET scan shows how cells and organs in your body are working. A PET scan can measure how much energy a tumour is using. Scar tissue and tumours that have responded to chemotherapy or radiotherapy do not use much energy. Cells and tumours that are growing or active use a lot of energy. A PET scan can help tell the difference between these types of cells.

A PET scanner is a special camera that can take pictures of the inside of your body by sensing a radioactive tracer. For most studies this tracer is a radioactive glucose (sugar) called FDG. Before your PET scan you will be given an injection of a small amount of radioactive glucose. Cells in the body absorb glucose at different rates. The PET scan can measure how much radioactive glucose is being used. This reflects the cells’ metabolism. A PET scan may find disease before it shows up on other tests. It can tell doctors how a disease responds to treatment.

Epilepsy: to show seizure focus (where the seizures are coming from).
Alzheimer’s disease: to show areas of reduced glucose metabolism.
Parkinson’s disease: to show areas of reduced function.
Brain Tumours: to see if recurrent tumour is present.
Cancer: to show areas of increased glucose metabolism for staging.
Heart problems: to show blood flow and metabolism.

You will receive an injection of a radioactive tracer. The length of time between the injection and the scan depends on how long it takes the tracer to get to the part of your body being scanned.

Most often, this will be 45 minutes to an hour. If you are having a heart study you may not need to wait at all. During the waiting time you may notread, talk or listen to music. For some exams you may be asked to wait in a quiet dimly lit room so as not to stimulate your brain by reading or talking.

Do not eat or drink anything for 6 hours before your test (including gum).
If you take medicines every day, take them with a small sip of water.
If you have been told not to take your medicines on an empty stomach please do not eat more than 2 or 3 soda crackers within 4-6 hours of your exam.
If you have diabetes please let us know ahead of time so we can work with your doctor to find the safest way for you to get ready for your test.
If you have any problems with claustrophobia or pain, your doctor may prescribe medicine to help you relax and make you comfortable during your exam. If medicine is prescribed you must arrange for someone to drive you home.
If you are pregnant or breast feeding let us know.
Please bring your MRI or CT films with you if they were taken at a hospital or clinic other than UW Hospital.

You will lie on a table that moves slowly through the ring- like PET scanner. You must lie very still because movement can affect the test. You should feel normal during the test. It can last 30 minutes to 2 hours.

You may leave as soon as the scan is complete. You will be able to eat and drink right away unless you have been told not to. Drink a lot of fluids the day of the test to help clear the tracer from your system.

The radiation you receive is about the same as what you would receive from a bone scan; a test often done in Nuclear Medicine. The radioactive tracer does not remain in your body for very long. There is no reason to avoid being around other people once you have left. To be extra safe avoid being around infants or women who are pregnant for a couple of hours after the scan.