Background and Purpose--The treatment of large brain arteriovenous malformations (BAVMs) is challenging, and embolization alone is seldom curative. The study goal is to enhance the efficacy of arteriovenous malformation embolization by adding a -emitting isotope to the embolic agent.

Methods--The pig rete mirabile was used as a BAVM model. The body distribution of radioactivity was evaluated after selective rete injection of N-butyl,2-cyanoacrylate mixed with ¹³¹I-lipiodol in 8 animals using immediate whole body -scintigraphy. Activities within the whole rete mirabile and selected tissue samples were quantified with a gamma counter immediately after sacrifice. Two pigs were submitted to serial -scintigraphies for 6 weeks to detect delayed isotope leaching. Long-term effects of in situ irradiation were evaluated using a mixture of ¹⁸⁸Re/N-butyl,2-cyanoacrylate in 8 pigs. In 1 animal, autoradiography was performed to evaluate local rete mirabile distribution of the radioactivity. Seven pigs were injected with ¹⁸⁸Re/glue in 1 rete mirabile and with glue only on the opposite side, and the degree of vascular occlusion of both sides was compared on histology at 2 (n=2) or 6 months (n=5).

Results--There was negligible activity outside the target. Radiation caused occlusion of vessels unreached by the glue itself but in the vicinity of the radioactive source in 5 of 7 rete mirabile.

Conclusions--Selective deposition of a -emitter inside a BAVM model may be achieved by current embolization techniques. The adjunct use of an isotope may increase the efficacy of embolization.