Questions to Ask at Scheduling

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Recent surgeries or biopsiesAfter surgery or biopsy, healing may increase 18F-FDG uptake. Negative or unknown biopsy result may prompt physician to postpone imaging of area of interest. Positive result may prompt physician to proceed with imaging to look for distant metastasis (4).
DiabetesDiabetic patients are best scheduled for earliest available appointment because they cannot eat or drink beforehand. Blood glucose should be <150–200 mg/dL, depending on facility’s protocol. Use of insulin degrades scans; insulin may need to be withheld or diabetes management temporarily changed (1,2).
ClaustrophobiaClaustrophobic patients may need anxiolytic medication and a driver.
Ability to lie supine for 30 minPatients need to know that scanning may take 30 min and that they will need to lie supine during it. To comply, many may require pain medication and a driver. In extreme cases, prone or on-the-side positioning may be needed.
ExerciseExercise tears down and rebuilds muscle, causing 18F-FDG uptake. Scheduling scan 24–48 h after strenuous exercise allows uptake in muscles to dissipate (2,4).
AntibioticsIf patient is taking antibiotics because of infection, physician may postpone scan to avoid uptake by infected tissue.
SteroidsLearning that patient is taking steroids may reveal a current medical condition that will affect scan (5). Also, physician needs to know of steroid use because it can elevate blood glucose and decrease tumor metabolism, reducing SUVs.
Pregnancy or breastfeedingScanning is usually contraindicated in pregnant or breastfeeding patients. Some facilities may require pregnancy test on day of scan or written informed consent to scanning. Breastfeeding is withheld for 18–24 h after scan; 18F-FDG secretion into breast milk is minimal, but close contact exposes child to radiation. Also, there may be increased uptake in erector spinae muscles of mother (6).
Travel to home after examIf patient lives far from exam site, traveling from exam with a pregnant woman or small child is not advisable because they will be exposed to radiation from patient.
Duration of scanPatients who do not know that scanning takes 2 h may make other appointments for same day and choose to reschedule without giving advanced notice.
Other scanning before PET scanIf patient is scheduled for scan requiring contrast agent before PET scan, the agent may attenuate the PET signal.
Nothing-by-mouth instructionsPatients must not eat or drink for 4–6 h before undergoing scan. Need for any special dietary or medication arrangements should be determined (2), as well as patient’s willingness to comply with instructions.