18F-DOPA PET Imaging: an Evaluation of Biodistribution and Safety

Inclusion Criteria: * 1\. Pediatric patients (less than 17 years old) with congenital hyperinsulinism * 2\. Pediatric patients (less than 17 years old) with neuroblastoma * 3\. Pediatric patients (less than 17 years old) or Adult patients (17 or older) with known or clinically suspected neuroendocrine tumor outside of the pancreas * 4\. Adult patients (17 or older) with a clinical suspicion of Parkinson's disease. * 5\. Pediatric (less than 17 years old) or Adult patients (17 or older) with primary brain tumors Exclusion Criteria: * Unable to obtain consent * Weight \> 250 kg (weight limitation of PET/CT scanner) * Adult patients unable to lie flat for 20-30 minutes to complete the PET/CT scan * Young pediatric patients (less than 10 years old) who are unable to lie flat for 20-30 minutes and for whom clinical sedation is contraindicated (as determined by a pediatric anaesthesiologist) * Pregnancy * Lack of intravenous access