Clinical PET is now primarily used in oncological indications. Fluorine-18-
fluorodeoxy-glucose (FDG) shows a high uptake in a variety of malignancies
and accounts for approximately 95% of the oncological PET studies. The firs
t part of this review deals with theoretical and methodological aspects of
FDG-PET. Possible sources of errors for the method are discussed briefly On
cological indications for FDG-PET are highlighted according to the results
of consensus meetings of experts from nuclear medicine and oncology, organi
zed by the German Society of Nuclear Medicine. FDG-PET is mainly used in st
aging and restaging, demonstrating of tumour recurrence and therapy control
. Main benefits of the method are functional imaging, better spatial resolu
tion than conventional scintigraphy and the possibility to perform whole-bo
dy imaging easily. A brief outlook on future prospects for the application
of PET in oncology is given.