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NORMAL BRAIN TISSUE RESPONSE TO PHOTODYNAMIC THERAPY USING ALUMINUM PHTHALOCYANINE TETRASULFONATE IN THE RAT
Author(s) -
Leach M. W.,
Khoshyomn S.,
Bringus J.,
Autry S. A.,
Boggan J. E.
Publication year - 1993
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1993.tb09221.x
Subject(s) - photodynamic therapy , phthalocyanine , chemistry , brain tissue , neuroscience , biophysics , medicine , biology , organic chemistry
— 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/cm 2 and energy doses ranging from 1.6 to 121.5 J/cm 2 . 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/cm 2 and an x intercept of 7.85 J/cm 2 . The slopes before and after the changepoint were 2.04 and 0.21 mm/In 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.