Patients with neurofibromatosis type 1 (NF-1) are at elevated risk to develop certain tumors, especially malignant peripheral nerve sheath tumors (MPNST) and optic pathway glioma (OPG). MPNST is associated with lower survival, while OPG may produce visual acuity (VA) impairment which, if detected at a later stage, may not be reversed. PET and MRI are established imaging methods for these tumors. The purpose of this study was to determine the usefulness of these imaging methods in pediatric patients with NF-1 with or without symptoms (screening), and to possibly justify or reject their systematic indications in these patients. Screening using PET and MRI imaging was done in patients with neurofibromatosis type 1 over a period of around 10 and 20 years respectively at the Department of Pediatrics and Adolescent Medicine at the Medical University of Vienna. Our study results were promising for screening for MPNST using PET. Systematic screening for OPG using MRI could not definitely be justified by our results, corresponding to recent findings of other groups.