LINAC-Based Radiosurgery of Arteriovenous Malformation involving Visual Pathway: A Report of Two Cases / 대한뇌혈관외과학회지

ABSTRACT

The authors present two cases of arteriovenous malformation (AVM) involving the visual pathway following linear accelerator (LINAC) stereotactic radiosurgery. Both patients were treated with 18 Gy (marginal dose, 70-80% isodose line, 3 isocenter) delivered to the malformed vascular mass involving the optic tract on the right side. For both patients, however, less than 8 Gy were irradiated onto the ipsilateral optic chiasm and optic nerve, and 4.5 Gy were irradiated onto the contralateral optic nerve (20% isodose line). On the five-year follow-up MRI scan and angiogram, the AVM was totally obliterated in one patient and the AVM was markedly decreased in size in the other patient. Their visual fields were well preserved and visual acuities were even improved for both patients. We report here with on two cases of AVM involving the visual pathway that were effectively and safely treated with 18 Gy using LINAC-based radiosurgery, and we also attempt to define the safe and effective radiation dosage for the patients with AVM involving visual apparatus.