How the Positron emission tomography procedure is performed

How to prepare for the PET-CT scan


  • Before the procedure a low-carbohydrate diet is recommended, considerably limiting the intake of carbohydrates. Food products rich in carbohydrates, mainly bread, noodles, potatoes, and grain products, should be replaced with products rich in fat or protein, such as meat, fish, eggs, and cheese. The low carbohydrate diet recommends the intake of vegetables and fruit with low levels of carbohydrates e.g. lettuce, broccoli, cucumber, spinach, raspberries, nuts.
  • On the day preceding the procedure the patient should avoid eating and drinking products containing large amounts of sugar, including fruit, fruit juices, sweets, desserts and flour products. For  24 hours before the scan, the patient should abstain from the consumption of alcohol and drinks containing caffeine (coffee, cola, tea, etc.) and should not chew gum.
  • The patient should avoid any physical activity (jogging, gymnastics, shopping etc.) as well as hypothermia.
  • 6 hours before the scheduled scan, the patient should not take in any food or drink. Drinking a large amount of mineral water is, however, permissible.
  • If the patient takes any medication as prescribed by a doctor, he/she is allowed to take it at the normal time and drink only water.
  • On the day preceding the procedure and on the day of the procedure, the patient should avoid intense physical strain, and also refrain from sporting activities and hard physical work.


  • Before the procedure the patient should inform the medical staff of which medicines are currently prescribed as well as the current blood glucose level. The procedure will be performed in the middle of the day. A light breakfast is recommended, as is the normal use of anti-diabetic medicines. For four hours before the procedure, the patient should not take in anything at all, including insulin. Only still water is allowed.  Before the procedure, the patient’s blood glucose level will be checked. It is of vital importance that the level of glycaemia should be stable. Abnormally high values of glycaemia can bring about the formation of artefacts, such that in many cases it may be impossible to carry out the procedure.  


  • The patient should wear warm, comfortable clothes, free of metal parts such as zips, bra underwires etc. or take them as a change of clothes only. The procedure does not require undressing; however jewellery and dentures must be removed.
  • Small children or pregnant women are not permitted to undergo such an examination.
  • The patient should notify staff if he or she is on antibiotics or steroids, has a cold, has had any medical procedures in the past month, is in the middle of chemo- or radiotherapy or his or her weight has considerably changed (more than 5kg)
  • The administered radiopharmaceutical agent does not influence the ability to operate machines and drive vehicles.


  • An ID document with a photo
  • The original referral letter completed legibly by the physician with his signature and stamp
  • Medical documentation including the results of investigations performed to date, CDs, photos, and hospital discharge summaries
  • Approximately 1.5 litres of still mineral water, which should only be drunk following the nurse’s instructions

The procedure


  • Please arrive 15 minutes before the scheduled start of the scan to fill in a medical questionnaire on chronic diseases, allergies, medicines taken or possible contraindications against the examination.
  • Before the scan the physician discusses the procedure with the patient.
  • Next the nurse inserts the cannula through which a radiopharmaceutical will be applied, and checks the blood glucose level by pricking the finger. The cannula will be removed after the procedure has been completed.
  • The nurse will put small portions of radioactive isotope of glucose (FDG) through the inserted cannula. This isotope has a very short half-life. The administration of the isotope is not painful and does not cause any side effects.
  • The patient is taken by the nurse to a room where he/she will be asked to lie down on a couch and relax. During approximately one hour of rest and relaxation, the administered isotope will be naturally bio-distributed in the body. Conversation and any unnecessary movements should be avoided at this time.


  • The patient enters the scanner room and lies down on a special motorised bed. He remains in a lying position throughout the procedure, most frequently on his back, side or front while the bed is moved in and out of the scanner.
  • The healthcare staff leave the CT scanner room, as the computer which processes the information is located in a separate room from the one in which the technician operates the scanner and monitors the examination.
  • Next, images of the distribution of the isotope in the body are performed. The examination is a pain-free procedure.
  • The patient is monitored by the technician, physician and nurse and instructions are given by microphone.
  • During the examination, the patient may be asked to hold his breath and not to move as any body movement may lead to mistakes in the images obtained, which may interfere with the diagnostic results. The scan usually lasts several minutes.


  • After the procedure the patient is led by the nurse to an appropriate exit.
  • The administration of radiotracers does not adversely affect well-being; therefore, after the procedure the patient should feel well and may leave the centre and return to his normal activities and diet.
  • By the end of the day, for 6-12 hours post-procedure, the patient should refrain from contact with children, young people and pregnant women.
  • Over the course of the day the patient should drink a large amount of fluid so that the part of the radioisotope which remains in the blood can be more quickly eliminated from the body through urination.
  • The patient should observe the rules of hygiene, particularly: flush the toilet twice; thoroughly remove all urinary soiling with a separate piece of toilet paper which should be thrown away into the toilet and flushed; after each visit to the toilet, wash hands in running water to remove the possibility of radioisotope contamination; do not share towels with other users.
  • Getting the results
  • The patient will receive information concerning the examination results at the reception desk. The results will be interpreted and analysed by our specialists. The results may be collected in person or by a third party upon signature of a special authorization form. The results contain a report as well as a CD with the relevant images and report.