Accurate and reliable staging of disease extent in patients with malignant melanoma is essential to ensure appropriate treatment planning. The detection of recurrent or residual malignancy after primary treatment allows for early intervention and optimises patient survival. FDG PET/CT is indicated for surveillance of malignant melanoma due to its high sensitivity and specificity for soft-tissue or nodal recurrences and metastases.

It has been claimed that routinely scanning lower extremities and skull in addition to 'eyes to thigh’ images in PET/CT evaluation of metastatic melanoma is warranted. Whole-body PET/CT scan reports in patients with melanoma scanned from April 2005 to December 2008 were retrospectively reviewed. PET abnormalities in the brain/scalp and lower extremities were tabulated by location and whether they were 'expected'. Findings were correlated with pathology, other imaging studies and clinical follow-up.

94 PET/CT examinations in 268 patients with melanoma were included. 9 of 294 (3.1%) scans showed brain/scalp abnormalities, with only 4 (1.3%) showing unexpected abnormalities. 24 of 294 (8.1%) scans showed lower extremity abnormalities, with only 5 (1.6%) showing unexpected abnormalities. In no case was an unexpected solitary malignant lesion identified in the brain/scalp or lower extremities.

In patients with no known or suspected primary or metastatic melanoma involving the head or lower extremities, inclusion of these regions on PET/CT is of low yield and appears to seldom offer significant additional benefit, as detection of additional metastases in these patients is unlikely to change clinical management. Routine ‘eyes to thighs’ images is adequate for this subset of patients.