ON THE USEFULNESS OF BRAIN PET SCANNING TO THE PEDIATRIC NEURO-ONCOLOGIST

Positron emission tomography (PET) scanning adds a functional dimensio n to brain scanning; levels of metabolic activity are imaged and this information may complement the more ''anatomic'' imaging of CT and MRI . In a series of 10 young patients the usefulness of PET scanning tech nique was investigated. The major areas of usefulness were the distinc tion of posttreatment sequelae from active tumour (both postsurgical M RI changes from tumour and postradiation MRI changes from tumour) and the localization of persisting tumour amenable to radiosurgical treatm ent. The technique was beneficial in assessing continuing activity in pineal tumours (residual pineal teratoma mass and residual pineocytoma mass) and in assessing activity in brainstem/cerebellar peduncle glio mas (three cases). In one unusual case of widespread leptomeningeal me lanoma, the PET scan under-read the situation.