Special PET Scan Instructions for People with Diabetes

Positron emission tomography (PET) is a nuclear medicine imaging test conducted to provide doctors with accurate basis for diagnosing a variety of diseases. It involves the injection of a special form of glucose, called 18-F fluorodeoxyglucose (18-F FDG) or simply FDG, to aid in imaging the condition of the tissues and organs. 

Because FDG is sugar, the test results are likely to be affected if the person undergoing it has diabetes, a condition characterized by high blood sugar levels. The blood will not take up FDG efficiently since it already contains too much sugar. This, however, doesn’t mean that diabetics can no longer have a PET scan. They only need to do the following preparations to make sure that the results of the test will be reliable. 

Do Not Engage in Any Strenuous Activity for 48 Hours

When you work out, lift heavy objects, or perform an exhausting task, your body consumes more glucose than normal. To make up for the deficit, your liver will begin to increase the amount of glucose it releases into your bloodstream. The problem is that your supply of insulin, which is necessary for the absorption and processing of glucose, doesn’t kick off as quickly. As a result, glucose backs up in your bloodstream, causing your blood sugar level to rise.

Do Not Eat or Drink for 12 Hours

Your body gets glucose mainly from the food and drink you consume. If you eat or drink before your appointment, there’s a chance your sugar level will be too high to have a negligible effect on your blood’s ability to take FDG. While some physicians will tell you that you can still have a low-carbohydrate diet 12 hours before your appointment, it would be best to do full fasting right then.

Maintain a Blood Sugar Level of 80 to 150 mg/dL

After fasting for 12 hours, make sure that your blood sugar is between 80 and 150 mg/dL on the morning of your test. It can be difficult to achieve and maintain the required blood sugar level prior to the test but it’s doable. You can do a practice run to see if the fasting worked. If your blood sugar stays above 150 mg/dL, the test has to be postponed. 

To increase your chance of having a successful PET scan, consult with your diabetes care provider at least a couple of weeks before the test. He or she can discuss with you the best way to prepare for your test. For more helpful information, turn to a reputable MRI and PET scan provider, such as Glendale MRI.

Sources:

What is Diabetes?, NIH.gov

How Diabetes Works, HowStuffWorks.com