It is well known that the permeability of the blood brain barrier and blood cerebrospinal fluid barrier changes more or less in various diseases of the central nervous system. At present, thee is no clinically available index which reflects the alteration of the permeability of the blood brain barrier and blood cerebrospinal fluid barrier. The brain scintiraphy is an examination which detects a breakdown in the blood brain barrier, its clinical usefullness is limited only in a localized and extremely pathological proces of the brain. In this report, a cerebrospinala fluid isotope measurement comined with the brain scintigraphy was presented as a clinical examination for blood brain barrier function. Thirty minutes prior to brain scintigraphy, potassium perchlorate (4 mg/kg) was given orally to reduce the accumulation of 99mTc04-in the choroid plexus and to minimize iradiation for tr other organs. Spinal tap was performed two hours after injection of 99mTc04- according to Haines's method...