Measurements of optical properties of pig brain tissue in vitro using a novel compact device

In numerous medical and scientific fields, knowledge of the optical properties of tissues can be applied. Among many different ways of determining the optical properties of turbid media; integrating sphere measurements are widely used. However, this technique is associated with bulky equipment, complicated measuring techniques, interference compensation techniques, and inconvenient sample handling. This paper describes measurements of the optical properties of porcine brain tissue using novel instrumentation for simultaneous absorption and scattering characterization of small turbid samples. The system used measures both angularly and spatially resolved transmission and reflection and is called Combined Angular and Spatially-resolved Head (CASH) sensor. The results compare very well with data obtained with an integrating sphere for well-defined samples. The instrument was shown to be accurate to within 12 % for μ_a. and 1 % for μ_s' in measurements of intralipid-ink samples. The corresponding variations of data were 17 %, and 2 %, respectively. The reduced scattering coefficient for porcine white matter was measured to be 100 cm^-1, while the value for coagulated brain tissue was 65 cm^-1. The corresponding absorption coefficients were 2 and 3 cm^-1, respectively.