Epilepsy affects about 0.5 - 1% of the population. This disease is usually well controlled by modern antiepileptic drugs, but in some cases, the only solution to achieve seizure-free status is the surgical elimination of epileptogenic area. PET makes it possible to generate images of the brain showing areas with altered function. Thus in young epileptic patients PET helps to identify and locate the epileptic focus.
FDG PET makes it possible to differentiate dementia from mental deteriorations of other aethiologies, since changes viewed by PET are specific for Alzheimer's disease and for fronto-temporal dementia. This fact is important because, in case of early diagnosis, the progress of Alzheimerüs disease can substantially be prolonged by drug therapy.
PET examinations have a role in the diagnosis of brain tumours primarily by confirming the presence or absence of recurrence after radiotherapy, or as an objective verification of failure of the first treatment (using tracers other than FDG). Such indications are recommended mostly after a non-conclusive MR examination. In addition, PET can be used in neuro-oncology in for the non-invasive evaluation of tumour grade or in determining the optimal site of biopsy.
In modern radiotherapy of brain tumours, PET/CT constitutes the basis of precise dosimetry in determining the target volume of external-field radiation or brachytherapy (treatment by implanted radiotian sources) as well as of the gamma knife technique.