title: Normal brain tissue response to photodynamic therapy using aluminum phthalocyanine tetrasulfonate in the rat.
abstract: The effects of photodynamic therapy (PDT) on normal brain tissue and depth of brain necrosis were evaluated in rats receiving 2.5 mg/kg aluminum phthalocyanine tetrasulfonate. Twenty-four hours later brains were irradiated with 675 nm light at a power density of 50 mW/cm2 and energy doses ranging from 1.6 to 121.5 J/cm2. Brains were removed 24 h after PDT and evaluated microscopically. When present, brain lesions consisted of well-demarcated areas of coagulation necrosis. When plotting the depth of necrosis against the natural log of energy dose, the data fit a piecewise linear model, with a changepoint at 54.6 J/cm2 and an x intercept of 7.85 J/cm2. The slopes before and after the changepoint were 2.04 and 0.21 mm/ln J cm-2, respectively. The x intercept suggests a minimum light dose below which necrosis of normal brain will not occur, whereas the changepoint indicates the energy density corresponding to an approximate maximum depth of necrosis.
authors.affiliation: School of Veterinary Medicine, University of California, Davis 95616.
authors.forename: M W
authors.initials: MW
authors.lastname: Leach
authors.forename: S
authors.initials: S
authors.lastname: Khoshyomn
authors.forename: J
authors.initials: J
authors.lastname: Bringus
authors.forename: S A
authors.initials: SA
authors.lastname: Autry
authors.forename: J E
authors.initials: JE
authors.lastname: Boggan
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000473:pathology* / Q000528:radiation effects; D004487:Edema; D007211:Indoles / Q000633:toxicity*; D008027:Light; D008297:Male; D009336:Necrosis; D009942:Organometallic Compounds / Q000633:toxicity*; D010778:Photochemotherapy; D011838:Radiation-Sensitizing Agents / Q000633:toxicity*; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D007211:Indoles; D009942:Organometallic Compounds; D011838:Radiation-Sensitizing Agents; C048577:aluminum tetrasulfophthalocyanine