PET is a sensitive and specific technique for the detection of melanoma, but micrometastases and lesions smaller than 10 mm
may not be detected. PET is more sensitive than CT for detection of metastases in subcutaneous sites, lymph nodes, abdomen,
and skeleton, but CT is equivalent to, or more sensitive than, PET for detecting small pulmonary lesions. Contrast-enhanced
MRI remains the preferred method for detection of brain metastases. Falsepositive PET findings may be seen at surgical sites
and in inflammatory lesions and may also be seen in some benign tumors. Clinical correlation significantly improves the specificity
of PET.
PET is indicated for determining the extent of known metastatic disease, especially if patients are potentially operable.
Approximately 4% to 24% of patients who are thought to have resectable limited disease based on physical examination and conventional
diagnostic tests are found to have nonresectable disease by PET. Conversely, in patients who are erroneously considered to
have nonresectable disease by conventional diagnostics, PET may show limited disease that is potentially operable.