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PET/CT Infection/Oncology Scan

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A PET scan is a shortened name for positron emission tomography. A PET scan views functioning tissues in the body. A CT or CAT scan is a shortened name for computerized tomography. A CT scan takes pictures of the inside of the body. The pictures are more detailed than a typical x-ray.

A PET scan combined with a CT scan shows detailed images and functioning tissues within the body. A PET/CT scan can help determine a diagnosis early. Your doctor will use this information to determine the best treatment for you.

Preparing for the Test

  • Avoid strenuous movement the day before and morning of the exam. This includes exercise, lifting, and strenuous housework. Please be fairly inactive on the day before and morning of your test.

  • Do not eat or drink anything other than water for 6 hours before the test is scheduled. Only water is allowed. Eating or drinking anything other than plain water within 6 hours may result in your test being delayed or rescheduled to another day. Prescription medications are permitted with water only.

  • Please contact the PET/CT department if you take insulin for diabetes (303.398.1683). No insulin is allowed within 4 hours of the scan.

  • It is best if your blood glucose levels are <200 mg/dl for the PET scan.

  • Let the technologist know if you are pregnant or nursing.

During the Test

The technologist will explain the PET/CT scan to you before you start. Ask questions if you do not understand. The technologist will place an IV into a vein in your arm. If you have a “port” that is accessed, we can inject through it. We generally do not access ports in the department. Please ask your doctor’s office to access your port prior to your test. Your doctor’s office will also need to remove the catheter from your port when your test is complete.

A small blood sample will be collected to test your blood glucose level. If your blood glucose is above 200 mg/dL, we may need to reschedule your test.

You will be given a small amount of a radiopharmaceutical through your IV. This will help view the functioning tissues during the scan. The radiopharmaceutical is not dye or contrast and does not produce reactions if you are allergic to these substances. You will wait 45-60 minutes after you are given the radiopharmaceutical. You will relax in a recliner. Reading, cell phone use, etc., is not permitted during this time.

After 45-60 minutes you will have the PET/CT scan. The PET/CT does not hurt. During the scan you will lie on a padded table. The technologist will give you instructions during the test. You will be asked to raise your arms above your head during the scan.

The scan will last 15-20 minutes for most patients.


After the Test

You can resume normal activities after the PET/CT scan.


Length of the Test

A PET/ CT scan takes about 2 hours.

Your appointment is in the Institute for Advanced Biomedical Imaging (Radiology). You will be directed where to go when you check in. If you have any questions you can contact Advanced Biomedical Imaging (Radiology) at 303.398.1611.


This information has been approved by Eric Yager, ARRT, BS (September 2023).