PET-CT indications

PET-CT is a combination of cross-sectional anatomic information provided by CT and the metabolic information provided by positron emission tomography (PET).

PET is most commonly performed with 2-[F-18]fluoro-2-deoxy-D-glucose (FDG). Fluorine-18 (F-18) is an unstable radioisotope and has a half-life of approximately 110 minutes.

The indications for F-18 fluorodeoxyglucose (FDG) PET-CT imaging include:

PET-CT can also be used as a problem-solving tool:

  • occult primary lesion (e.g. non-metastatic manifestation of neoplastic disease)
  • evaluation of suspected recurrence in patients with equivocal conventional imaging
  • evaluation of residual disease in patients with treated differentiated thyroid carcinoma and treated medullary thyroid carcinoma with negative/equivocal conventional imaging
  • prior to radical nodal resection in patients with metastatic melanoma
  • suspected malignant transformation in plexiform neurofibromata (neurofibromatosis type 1)
  • differentiate between radiation-induced necrosis and tumor recurrence (e.g. primary CNS malignancy)