Patent ID: 7565249

Claim:
A method for selective determination of a light transport parameter which is characteristic for the light scattering in a biological matrix, for the purpose of the non-invasive determination of the glucose concentration in the biological matrix, the method comprising: performing a plurality of detection measurements, each of said detection measurements comprising: irradiating light at an irradiation site into the biological matrix; propagating light inside the biological matrix along a light path; determining an intensity measurement value of light emerging at a detection site wherein in at least two of the detection measurements the detection site is located at different measuring distances from the irradiation site; at least two detection measurements are performed at at least two different points of time for each of said different measuring distances; and the light transport parameter and the glucose concentration being derived from the intensity measurement values measured by the plurality of detection measurements by means of an evaluation algorithm, and an indication of the glucose concentration is output in a user readable format, said evaluation algorithm comprising: calculating from the intensity measurement values determined at at least two different points of time for the same measurement distance a time derivative value Δ t I(r) as an intermediate value describing the change of intensity versus time for said measurement distance; calculating at least two intermediate values Δ t I(r) for said at least two different measurement distances between irradiation site and detection site; and calculating a spatial derivative with respect to the measurement distance from said at least two intermediate time derivative values Δ t I(r).