Taihei Egashira

Giant Aneurysm of the Distal Portion of the Posterior Inferior Cerebellar Artery

The authors report a case of a giant aneurysm of the distal portion of the posterior inferior cerebellar artery presenting the classical picture of a tumor of the posterior fossa. CT scan of a giant aneurysm reveals the clear margin and high density area of aneurysm wall, and the homogeneous and high density area of the organized thrombus in a cavity of the aneurysm.

Use of Photoactivation by Argon Laser in Treatment of Brain Tumors (Part I)

An attempt was made to evaluate the biological effect on the central nervous system (CNS) and the in vivo and in vitro antitumor effect of argon laser photoirradiation with or without fluorescein pretreatment. Injury to the CNS was dose-dependently evaluated by exposing mouse brains to an activating argon laser of 514.5 nm wave length, and the photoactivating effect was evaluated by exposing spinal cords of cats after administration of fluorescein. Retardation or temporary arrest in growth of mouse fibrosarcoma (Fsa II) implanted subcutaneously in C3H mice, was accomplished by exposing the tumor to an activating argon laser of 514.5 nm wave length after administration of fluorescein. Photoirradiation by argon laser proved to be dose-dependently lethal to cultured glioma cells. This preliminary study suggests a new method of treatment of human gliomas. At the same time, an extensive thermal effect to the CNS was observed.

Use of evoked responses to measure laser photoradiation tissue effects.

The amount of argon laser irradiation necessary to first produce marked changes in somatosensory evoked potentials when applied to the dorsal columns of cats was used to measure the enhancement of tissue response by fluorescein previously injected intravenously. The mean radiant exposure was roughly 2700 J/cm2 in normal control animals compared to a mean radiant exposure of only about 560 J/cm2 in animals given fluorescein. Thus, the presence of fluorescein in these tissues enhanced the lasers effectiveness by a factor of 5. We suggest the use of evoked responses as a measure of laser photobiological effectiveness.