Distribution of radioactive microspheres injected into the vertebral artery of the dog

The aim of the present study was to evaluate the use of the vertebral artery for cerebral blood flow studies. In eight dogs a small catheter was introduced into an unligated a. vertebralis sin. Radioactive microspheres (141Cerium) were injected and detected with a gamma camera. The microspheres were distributed to all parts of the brain. The concentrations were highest in the cerebellum, pons and medulla oblongata, while the total activity was greatest in the cerebrum because of its higher weight. The activity in the extracerebral tissues in the head was found to be less than 5% of the brain activity.