In general, most people should prepare for a PET scan by avoiding strenuous exercise a few days before the exam and stop eating a few hours before the procedure, according to Mayo Clinic. People should also inform their doctor if they have recently been sick or are claustrophobic.
Patients should also inform the doctor if they have ever had a severe allergic reaction and of the medicines, herbal supplements and vitamins they are taking, states Mayo Clinic. Additionally, women should inform the doctor if they are pregnant or breastfeeding.
The process of having a PET scan is painless, states Mayo Clinic. The machine itself resembles a large donut, and the entire process usually takes around two hours. Right before the examination, nurses may instruct the patient to change into a hospital gown and to empty the bladder. Next, nurses give the patient a radioactive drug, which inhaled, swallowed or injected with a syringe. The next step is to wait until the drug has moved throughout the patient's body, which could take 30 to 60 minutes.
After the die has been absorbed, the patient lies on a padded table, which slides inside of the machine, according to Mayo Clinic. Patients have to remain very still while the test is performed. Most tests take only 30 minutes, after which, patients can usually resume normal activities.