Quantitative analysis of transcranial and intraparenchymal light penetration in human cadaver brain tissue
This study investigated the light penetration gradients in the human cadaver brain using a Transcranial Laser System with a 30 mm diameter beam of 808 nm wavelength light. In addition, the wavelength dependence of light scatter and absorbance in intraparenchymal brain tissue using 660, 808, and 940 nm wavelengths was investigated. Transcranial application of 808 nm wavelength light penetrated the scalp, skull, meninges, and brain to a depth of approximately 40 mm. No differences were observed in the results between the PW and CW laser light. Transcranial light measurements of unfixed human cadaver brains allowed for determinations of light penetration variables. Comparisons of light scatter and penetration and estimates of fluence levels can be used to establish further clinical dosing. The 808 nm wavelength light demonstrated superior CNS tissue penetration.
Published: Lasers in Surgery and Medicine. 2015; 47(4): 312-322. doi 10.1002/lsm.22343
Keywords: central nervous system; isotropic optical fibers; low level light therapy; photobiomodulation; transcranial light therapy; 808 nm wavelength