Called WN, had them drop the number and re-add (as others have said to do), but it still didn't work. Same deal for second existing reservation. Many here have said that you should get it if you add the number after the fact, but it didn't work for me. Tried every work around and spent time talking to the WN folks on the phone... to no avail. Only starting getting precheck for reservations booked after adding the KTN to my WN profile.
1 You may drink water, as much water as you can would be helpful, until arrival. 2  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.
Most PET scans today are performed with an imaging radiopharmaceutical -- most commonly FDG (Fluorodeoxyglucose), which is a tracer that goes into the heart to provide a picture of the organ's function on PET scans. If a person exercises before having a PET/CT scan, more FDG appears in the heart region, obscuring the view. The researchers found that the same thing happens with caffeine: The heart beats faster when you drink coffee, just as it does when you exercise.