Due to the radiation sensitivity of fast-growing tissues of a foetus, generally PET/CT scanning should not be performed in pregnancy. Breast feeding represents no contraindication: if breast milk is drained, mothers can continue breast feeding 24 hours after the examination.
In cases of high serum glucose level (e. g. diabetes mellitus) efforts should be made to reduce glucose levels to about the normal range (at least below 8.3 mmol/l=150 mg/dl) at the beginning of PET/CT scanning. Kidney failure makes the analysis of images more difficult but this condition does not represent contraindication to the examination.
The quantity of the administered adiopharmaceutical (FDG) is very small if expressed in mol/ml and it does not have any pharmacodynamic effect.
PET/CT scanning should be performed following a 6 hour-long fasting, but appropriate hydration is necessary (drinking 1-1,5l of mineral water is recommended), since drinking facilitates the excretion of FDG by the urinary system. In rare cases 5 mg diazepam (Seduxen) might be needed to reduce muscle tones and anxiety. Patients should not drive during the first 12 hours after taking diazepam.
The infected activity of intravenous FDG is usually 6-10 mCi (222-370 MBq) in adults, and proportionately smaller in
children as function of the body weight. Patients should rest in a stress-free environment from the time of injection of FDG. Recording of images typically starts 60-90 minutes after the injection of the radiopharmaceutical and the procedure takes about 15-20 minutes. After examination, the patient can leave to resume normal activities.