Abstract
Marginal dose to the nidus is the decisive factor in order to attain complete AVM obliteration in radio-surgery. For large AVM's, the volume of irradiated surrounding normal brain increases and a sufficient dose for complete obliteration cannot be given while still avoiding radiation induced complications. Historically, conventional fractionated radiation has been tried but the results were disappointing, maybe due to the very slight difference, if any, in α/β ratio between the nidus and the brain. Hypo-fractionated radiation has also been tried but results that surpass that of single fraction treatment have not been reported at present. Repeat treatment for residual nidus after low dose treatment and volume-staged treatment for larger nidus have been performed and are reported to have some value. In both strategies, bleeding during the long latent period is a problem. Using the recent state-of-the-art technology including radiation devices and planning computers with ever advancing embolization technique, better results may be accomplished in the future.
