The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 17, 2001
Filed:
Jul. 13, 1999
Robert A. Weersink, Toronto, CA;
Michael S. Patterson, Ancaster, CA;
Photonics Research Ontario, Toronto, CA;
Abstract
The present invention provides a method for measurement of concentration of fluorophores in turbid media. The method uses a fluorescence plus reflectance technique to measure quantitatively the in vivo concentration of a fluorescent drug independent of the tissue optical properties. The method involves using the reflectance measurement as a means of correcting for tissue scattering and absorption in the fluorescence measurement. Light directed to the tissue by means of an optical fiber to excite the fluorophores. Fluorescence from the fluorophores is measured by another fiber at a distance (D,) from the source in the turbid medium, while the excitation light is simultaneously collected at a distance (D,) from the source. The ratio fluorescence/reflectance will be approximately constant for a fixed concentration of the fluorophore and a judicious choice of D,and D,, regardless of the optical properties of the tissue. The ratio of fluorescence to reflectance on a tissue sample is compared to a calibration curve for a range of fluorophore concentrations, in order to estimate the in vivo concentration in the turbid medium. The optimum distances D,and D,are obtained by constructing several sample turbid mediums with known optical properties mimicking the optical properties of the samples on which the measurements are to be made. Fluorescence and reflectance measurements are performed at several distances from the excitation point for all turbid samples and a best fit obtained for each pair of distances with pairs exhibiting the lowest values of sum of squares of residuals lower than a threshold being used.