Target volumes in radiotherapy for high-grade malignant glioma of the brain

Delineation of the clinical target volume (CTV) in radiation treatment plan ning of high-grade glioma is a controversial issue. The use of computerized tomography (CT) and magnetic resonance imaging (MRI) has greatly improved the accuracy of tumor localization in three-dimensional planning. This revi ew aims at critically analyzing available literature data in which tumor ex tent of high-grade glioma has been assessed using CT and/or MRI and relatin g this to postmortem observations. Attention is given to the pattern of tum or spread at initial presentation and to tumor recurrence pattern after ext ernal beam irradiation. Special emphasis is given to the site of tumor regr owth after radiation treatment in relation to the boundaries of the CTV. Gu idelines for delineating CTV will be inferred from this information, taking data on radiation effects on the normal brain into account. (C) 2000 Elsev ier Science Ireland Ltd. All rights reserved.