Clinical 18F-FET PET in paediatric brain tumors: Single institution experience

418 Objectives To determine the role of 18F-FET PET/CT (FET) in the management of paediatric brain tumours. Methods FET scans were performed on a Siemens Biograph mCT PET/CT. PET studies were co-registered with the most recent MRI. PET and MRI scans were reviewed retrospectively and correlated with clinical course and histopathology if available. SUVmax, SUVmean, TBR SUVmean/BG SUVmean and TBR SUVmax/BG SUVmean were compared in pts with malignant tumors or who had died and pts with low grade or benign tumors. Results There were 34 scans in 26 pts age 0.75-16.6yr (mean 9.4) and sex M16, 10F. Tumour types: pilocytic astrocytoma (3), diffuse intrinsic pontine tumour (3), medulloblastoma (2), ependymoma (2), anaplastic glioblastoma (3), high grade glioneuronal (1), PNET (1), NF type1 (7), choroid plexus papilloma (1), malignant tumour unclassified (1), malignant cerebellar tumour (1), mass L parietal lobe (1). Indications: to determine extent, residual / recurrent malignancy post treatment, grade of malignancy in NF1. FET performed alone in 16 pts and 10 also had FDG studies. Path correlation obtained in 5 pts: 4 surgery and 1 autopsy. True negative studies were found in 2 pts, 9 pts have died, 11 pts stable, 1 slowly progressing, 2 pts palliative care and 1 pt was lost to follow up. There was significantly higher SUVmax (p Conclusions 18FET PET/CT with co-registration to MRI was clinically useful in paediatric pts with brain tumours. FET correlated with the detection of residual and recurrent disease and negative studies were accurate in excluding disease. Combination of FDG and FET was useful in differentiating between benign, low grade and malignant tumours.