PET/CT Scan: How to Prepare, What to Expect & Safety Tips

Positron emission tomography, also called PET imaging or a PET scan, is a diagnostic examination that involves getting images of the body based on the detection of radiation from the emission of positrons. Positrons are tiny particles emitted from a radioactive substance administered to the patient.

Patient Safety Tips Prior to the Exam

  • Please let us know if you have any allergies or adverse reactions to medications.
  • If you are pregnant or may be pregnant, please tell your doctor or technologist.
  • Please leave your valuables at home or in your room in the hospital.
  • Please let us now if you need interpreting services, this can be arranged for you.
  • Bring a list of your current medications with you (out-patient).

Preparation for the Procedure

  • You will be asked to follow the Limited Carbohydrate diet for the previous 24 hours before the date of your appointment.
  • Do not eat or drink anything, except water, for 6 hours before the exam. You may drink water, as much water as you can would be helpful, until arrival.
  • Routine medications may be taken, unless you have been instructed otherwise. If you are diabetic, you may take your diabetes medication no less than 4 hours prior to the exam.
  • Arrive 15-30 minutes before your PET scan.
  • The technologist will verify your identification and exam requested.
  • You will be given a contrast screening form to complete.
  • In certain situations, the doctor may order lab tests prior to contrast being given.
  • Commonly, contrast is injected into a vein to better define the images throughout the body. If the radiologist believes this is helpful, a small intravenous (IV) line is placed in an arm vein. Through this line, the contrast and the isotope will be injected. The contrast will be excreted through your kidneys.

During the Exam

  • The duration of the exam will vary, but the average is about 2 hours.
  • The technologist will position you on the exam table, and give you instructions to remain still or to hold your breath.
  • You will have the opportunity to ask the technologists questions. 

After the Procedure

  • You should drink about 5 glasses of water.
  • Nursing mothers should wait for 24 hours before resuming breast-feeding.
  • If you feel any symptoms such as nasal congestion, itchy eyes, hives, rashes, sneezing, restlessness, tremors, pain, nausea, vomiting, dizziness, please notify the staff immediately. The staff is prepared to handle these situations. If you feel any of these symptoms after you have left the department, please contact your doctor or go to the nearest emergency room. If your symptoms are life threatening, call 911.