18F-Fluoropivalate PET/MRI: imaging of treatment naïve patients and patients treated with radiosurgery

Background: Approximately 20–40% of patients with cancer will develop metastatic cancer to the brain during the course of their illness. The brain niche imposes metabolic constraints on tumour cells that metastasise to the organ involving utilisation of short chain fatty acids (SCFAs) in the presence of glucose (Mashimo et al Cell 2014). We developed 18 F-fluoropivalate (FPIA), for imaging SCFA transcellular flux and showed high uptake in orthotopic human brain tumours in mice. In humans, FPIA was found to have favourable dosimetry-0.0154 mSv/MBq. We hypothesised that FPIA uptake will be high in metastases regardless of primary tumour of origin and will decrease with treatment. In this interim analysis we ask a) whether FPIA uptake is higher over background in cerebral metastases, and b) whether Steareotactic Radiosurgery (SRS) impacts FPIA uptake at early time points (4–8 weeks) when changes in …