Clinical Presentation

A 50-year-old woman with a history of metastatic colon cancer completed chemotherapy 1 year ago. During the last 3 months, she has started to experience fleeting abdominal pains and has lost about 6 to 8 lb. Furthermore, her carcinoembryonic antigen (CEA) level has risen from 1.1 to 2.7 ng/mL (the upper limit of normal is 2.5 ng/mL).

Fig. 76.1

Fig. 76.2

Technique

• The patient is instructed to avoid vigorous exercise for 24 hours prior to the scan, fast for at least 4 hours before the study, drink water during the fasting and uptake periods, and void prior to the scan

• A venous serum glucose sample is obtained prior to the injection of ¹⁸F-FDG (reference range is < 120 mg/dl for non-diabetic patients and < 200 mg/dl for diabetic patients), and the patient’s height and weight are recorded

• A 10–20 mCi dose of ¹⁸F-FDG is injected intravenously (in a dimly lit quiet room for brain PET scans), and the patient is asked to rest comfortably in a room that is kept warm

• Sixty minutes following the ¹⁸