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PET Scanning

Basic Information Regarding PET Scans

Your doctor has requested a PET (positron emission tomography) scan for you. This examination involves the administration of a radioactive molecule which is attached to glucose (sugar). Glucose is a major source of energy in the body, but certain disease processes make use of a much greater level of glucose than normal tissue. This will allow pictures to be taken revealing areas of abnormal glucose uptake. This procedure causes no side effects and provides only a small dose of radiation.

The PET Scan Procedure

Prior to the scan, information regarding the reason for the scan and your medical history must be known. Much of this will be provided by the doctor requesting the test, but questions may be asked upon your arrival. This may include certain facts concerning the history of your disease, allergies and medications. It is important for us to know if you have diabetes.

It is essential that we have your other studies for comparison. These may be x-rays, CT scans or MRIs. If they were performed at DHMC, they are available to us. If they were performed elsewhere and you have access to them, please bring them with you. We will use them as we read your PET scan and then return them by mail either to you or to the lending institution. If they are copies, we suggest that they be kept on file at DHMC. Please let us know if this is possible.

You should do no strenuous exercise for the 24 hours preceding the scan. You are to have nothing to eat for the six hours prior to the scan. Please take any prescribed medication (you may use water to take this medication). If you are to receive a CT scan with oral contrast administered within six hours prior to the PET scan, sugar-free contrast should be utilized.


If you have diabetes, your scan will be scheduled for the middle of the day and you may have a light breakfast with your normal morning diabetes medication and then nothing (including additional insulin) for 4 hours prior to the scan.

After checking in at the Nuclear Medicine reception desk, you will be taken to a preparation area where your blood glucose level will be checked with a fingerstick. In rare instances, usually in people with diabetes, it may be necessary to postpone or cancel a test if the blood glucose level is abnormal. An intravenous line will then be placed, usually in your arm. In some instances, when disease in the area of the bladder is a concern, a catheter may be placed into your bladder prior to the scan.

Following this, you will be taken to the PET scanning area. You will be placed on a stretcher and the radioactive glucose will be administered through the IV line. You will not feel this, nor any reactions or side effects. You will then lie quietly for 30-60 minutes. You may not get up, talk, read or chew gum. This is required because motion causes accumulation of glucose in the muscles, potentially degrading the quality of the scan.

Following this, you will be taken to a bathroom where you can empty your bladder and then brought to the scanner. The PET scanner is a ring shaped device, similar in appearance to a CT scanner. If you have or anticipate any problem with claustrophobia, please inform someone as soon as possible.

You will lie quietly and still on the PET scan table for an additional 30-60 minutes. Following this, the scan will be reviewed for quality. In few instances, additional pictures may be taken. Upon completion of the study, the IV and catheter (if present) will be removed. You will be asked to once again empty your bladder before leaving.

Following the Scan

After the study, we ask that you minimize close contact with children and pregnant women for eight hours. Please do not hold a child or have them sit on your lap for more than a couple of minutes. If you are breastfeeding, please stop for eight hours. We are extremely cautious in this regard; there are NO definite risks from this level of radiation.

Scan results will not be available while you are in the department. The interpretation of the study will be sent to your doctor who has requested the test. If you have brought any additional scans (CT, etc.) to the department, we request that you leave them with us with instructions as to where they should be returned.

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