Abstract:
L'invention concerne un procédé d'acquisition d'imagerie de fluorescence, in vivo, d'un tissu au moyen d'un système d'acquisition comprenant au moins une fibre optique d'excitation du tissu par balayage d'un faisceau lumineux. Selon l'invention, on utilise le système pour la détection de signaux de fluorescence émis par du Bleu de Méthylène présent dans le tissu.
Abstract:
L’invention concerne une tête optique confocale miniature (4) pour un système d’imagerie confocale, notamment endoscopique, ladite tête comprenant une source ponctuelle (2b) pour produire un faisceau lumineux (13) ; une lentille boule (12) disposée à l’extrémité de la tête optique, partiellement à l’extérieur, pour faire converger ledit faisceau lumineux en un point d’excitation (19) situé dans un champ observé (14) subsurfacique d’un échantillon (15), l’ouverture numérique de cette lentille et les dimensions de la source ponctuelle étant adaptées pour assurer la confocalité de l’ensemble ; et des moyens de balayage (10, 21, 22) pour déplacer la source ponctuelle en rotation de façon à ce que le point d’excitation (19) balaye ledit champ observé. Le système selon l’invention permet d’obtenir une image confocale en temps réel (environ 10 images/s) de très bonne qualité optique et homogène dans tout le champ (les aberrations optiques sont constantes dans tout le champ du fait de la symétrie sphérique de la lentille boule), et ce au moyen d’une tête miniature.
Abstract:
Le procédé utilise un guide d'image fait de plusieurs milliers de fibres optiques, un signal d'excitation étant émis par une source, dévié et injecté tout à tour dans l'une des fibres dudit guide, chaque point d'excitation du tissu en sortie de fibre émettant en retour un signal de fluorescence collecté par ladite fibre, puis détecté et numérisé pour former un élément d'image. Selon un premier aspect, le procédé prévoit la focalisation du faisceau en sortie de fibre pour exciter un plant subsurfacique et réaliser une image confocale. Selon un second aspect le procédé prévoit de produire un faisceau divergent en sortie de fibre susceptible d'exciter un microvolume du tissu depuis la surface. Selon l'invention, le procédé est caractérisé en ce que l'on dévie le signal d'excitation à une vitesse correspondant à l'acquisition d'un nombre d'images par seconde suffisant pour une utilisation en temps réel et en ce que l'on détecte le signal de fluorescence à une fréquence de détection correspondant à une fréquence minimale d'échantillonnage des fibres une à une. Grâce à l'invention, on peut réaliser une image in vivo in situ et en temps réel.
Abstract:
The invention concerns an optical head for equipping the distal end of a flexible optical fiber bundle (2), designed to be urged into contact with an analyzing surface and comprising optical means (3) for focusing an excitation signal into a so-called excitation focal point located at a specific depth beneath the analyzing surface and for sampling a signal backscattered by the excitation focal point which is carried back by said fiber bundle. The invention is characterized in that it comprises an optics-holder tube (4) wherein are inserted on one side the distal end portion (1) of the fiber bundle (2) and on the other optical means, the latter including a plate (21) placed in contact with the end (14) of the fiber bundle whereof the index is close to that of the fiber core and a focusing optical block (3), an output window (30) being further provided adapted to provide index adaptation so as to eliminate parasitic reflection occurring on the analyzing surface.
Abstract:
The invention concerns an equipment comprising an image guide (1) consisting of flexible optical fibers with: on the proximal end side: a source (2), angular scanning means (3), injection means (4) in one of the fibers, means for splitting (5) the illuminating beam and the backscattered signal, means for spatial filtering (6), means for detecting (7) said signal, electronic means (8) for controlling, analyzing and digital processing of the detected signal and display; and on the distal end side: an optical head (9) for focusing the illuminating beam exiting from the illuminated fiber. The invention is characterized in that the means (3) comprise a resonant line mirror (M1) and a galvanometric field mirror (M2) with a variable frequency and two afocal optical systems adapted to conjugate the two mirrors (M1, M2) firstly in the field mirror (M2) and the injection means (4) in the image guide in a second step.
Abstract:
An imaging device includes an illumination module comprising at least one emitter for emitting at least one excitation beam; a scanning and injection module comprising an image guide, a proximal end and a distal end of which are linked by a plurality of optical fibers; a scanning and injection optical system configured to alternately inject the at least one excitation beam into an optical fiber of the image guide from the proximal end of the image guide; a detection module comprising a detector for detecting a luminous flux collected at the distal end of the image guide, wherein at least one of the illumination module and the detection module is optically conjugated with the scanning and injection module using a conjugating optical fiber.
Abstract:
The invention concerns a miniaturized optical head provided to equip the distal end of a beam of flexible optical fibres scanned by a laser beam, said optical head being designed to come in contact with a sample and to excite said sample confocally; this optical head consisting of means for correcting spherical aberrations and focusing means. According to the invention, the focusing means comprise: at least a first lens (L4) of high convergence associated with a spherical or hemispherical lens (L5) arranged at the distal end of the optical head, and means for correction of the axial and lateral chromatic aberration provided with a single divergent lens (3b) the curvature of which is substantially centred on the pupil of the optical fibre beam and arranged at the exact distance for this pupil for which the conditions of lateral achromatization coincide with the conditions of axial achromatization; this divergent lens being associated with a second convergent lens (L3a) in the form of a doublet (L3).
Abstract:
The invention concerns an optical head comprising: a point source (2b) producing an excitation beam, optical means (12, 13) adapted in particular to converge said optical beam into an excitation point S located in a subsurface plane P relative to the surface of a sample, said plane being perpendicular to the optical axis of the optical head; and means for scanning said excitation point so as to define an observation field in said subsurface plane along two perpendicular scanning directions, a rapid online scanning and a slow columnar scanning. The invention is characterized in that it comprises micro-electrical mechanical systems (MEMS) (14a, b) designed to move in translation along a selected displacement (Dc) at least one of the optical means (12, 13), which is mobile along a direction perpendicular to said optical axis so as to obtain at least one of the scanning directions. The invention provides the advantages of maintaining an axial illumination of the sample and of using a miniature head.
Abstract:
The invention concerns a miniature confocal optical head (4) for a confocal imaging system, in particular endoscopic, said head comprising a point source (2a) for producing a light beam (13); a ball lens (12) arranged at the tip of the optical head, partly outside, to cause said light beam to converge in an excitation point (19) located in a subsurface field under observation (14) of a sample (15), the digital aperture of said lens and the dimension of the point source being adapted to ensure confocality of the assembly; and scanning means (10, 211, 22) for rotating the point source so that the excitation point (19) scans said field under observation. The inventive system produces a real-time confocal image (about 10 images/sec.) of very high quality and homogeneous in the entire field (the optical aberrations are constant in the entire field due to the spherical symmetry of the ball lens), and this is achieved through a miniature head.