Method and device for characterizing biological tissue

A method for characterizing a sample of biological tissue (30) comprising a first chromophorous and fluorescent compound (33) and a second chromophorous compound (34), said method comprising the following steps:

• determination, by optical measurement of fluorescence of the chromophorous and fluorescent compound (33), of the content of the second chromophorous compound (34) in said sample (30), said determination comprising the following steps:
• emission, by first means of emission (11, 12) towards said sample (30), of a first (111) and of a second (121) optical radiation, of different wavelengths, each chosen so as to induce a radiation of fluorescence (112, 122) of said chromophorous and fluorescent compound (33), such that one of the first and second radiations is absorbed by the second chromophorous compound and the other is only slightly or not at all absorbed by the second chromophorous compound,
• measurement, by first measurement means, of said radiations of fluorescence (112, 122) induced by said first and second radiations (111, 121), and
• determination, from said first measurement, of the content of the second chromophorous compound (34) in said sample (30);
• determination, by optical measurement of the absorption characteristics of the chromophorous and fluorescent compound (33), of the content of the chromophorous and fluorescent compound (33) in said sample (30), said determination comprising the following operations:
• emission, by second means of emission (13, 14) towards said sample (30), of a third (131) and of a fourth (141) optical radiation, of different wavelengths, such that one of the third and fourth radiations is absorbed by the chromophorous and fluorescent compound and the other is only slightly or not at all absorbed by the chromophorous and fluorescent compound,
• measurement, by second measurement means, of at least one unabsorbed part of the third and fourth radiations (131, 141), and
• determination, from said second measurement, of the content of the chromophorous and fluorescent compound (33) in said sample (30),
• characterized in that said first measurement means and said second measurement means comprise shared detection means (21), said method also comprising at least one first filtering, between said sample (30) and the detection means, (21), said filtering being intended to:
• block said first and second radiations (111, 121) from passing through to said detection means, (21),
• allow, at least partly, the unabsorbed part of said third and fourth radiations (131, 141) to pass through to said detection means, (21), and
• allow, at least partly, said radiations of fluorescence (112, 122) induced by said first and second radiations (112, 121) to pass through.