title: Thermal damage threshold of brain tissue--histological study of heated normal monkey brains.
abstract: The thermal damage threshold of normal brain tissue was evaluated from immediate and delayed histological changes caused by hyperthermia treatment of normal monkey (Macaca fuscata) brains. A 2450 MHz microwave antenna and an antenna cooling system devised by our group were used for interstitial hyperthermia treatment. The antenna within the cooling system was inserted through a small craniectomy under general anesthesia. The temperature at a reference point, 4 mm radially away from the surface of the cooling system, was maintained at 42, 43, 44, 45, or 46 degrees C for 60 minutes. Eighteen animals were treated and sacrificed immediately after the treatment, while nine animals were treated and sacrificed 7 days after the treatment. The histological changes were studied microscopically on sections stained with HE or Kluver-Barrera's method. The non-survival experiment demonstrated that areas heated at 44 degrees C or below showed no obvious irreversible changes. The survival experiment showed areas heated at 44 degrees C or above developed coagulative necrosis. These histological findings indicate that thermal damage occurs in normal brain tissue after heating at 44 degrees C or above for 60 minutes, suggesting that the safety limit for brain hyperthermia is 43 degrees C for 60 minutes.
authors.affiliation: Department of Neurological Surgery, Okayama University Medical School.
authors.forename: N
authors.initials: N
authors.lastname: Matsumi
authors.forename: K
authors.initials: K
authors.lastname: Matsumoto
authors.forename: N
authors.initials: N
authors.lastname: Mishima
authors.forename: E
authors.initials: E
authors.lastname: Moriyama
authors.forename: T
authors.initials: T
authors.lastname: Furuta
authors.forename: A
authors.initials: A
authors.lastname: Nishimoto
authors.forename: K
authors.initials: K
authors.lastname: Taguchi
mesh_terms: D000818:Animals; D001833:Body Temperature Regulation / Q000502:physiology*; D001921:Brain / Q000473:pathology; D001925:Brain Damage, Chronic / Q000473:pathology*; D004292:Dominance, Cerebral / Q000502:physiology; D006979:Hyperthermia, Induced / Q000295:instrumentation; D008251:Macaca; D008872:Microwaves; D009336:Necrosis