PET-imaging is a useful tool for management of certain glioma patients. The variable availability of adequate tracers, their short half-life, but also administrative obstacles and financial constraints are hampering the prospective evaluation of PET. Its impact in tumor localization and accurate diagnosis, in treatment response evaluation and ultimately patient outcome needs to be demonstrated. Systematic algorithms for optimal and economical use are needed. We summarize the limitations of the usual imaging techniques, and of the added value of PET-imaging in specific clinical situations. We call for prospective studies and registries rather than the current largely resource-driven use of this valuable technique.