METHOD AND DEVICE FOR DIFFUSE EXCITATION IN IMAGING

• US 20110085721A1
• Filed: 10/05/2010
• Published: 04/14/2011
• Est. Priority Date: 10/08/2009
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (French Alternative Energies and Atomic Energy Commission)
• Original Assignee: Commissariat a L'Energie Atomique (French Alternative Energies and Atomic Energy Commission)
• Inventors: GUYON, Laurent, Debourdeau, Mathieu, Boutet, Jérôme
• Granted Patent: US 9,036,970 B2
• Time in Patent Office: Days
• US Class Current: 382/131
• CPC Class Codes: A61B 1/07 using light-conductive means, e.g. optical fibres
• CPC Class Codes: A61B 5/0073 by tomography, i.e. reconstruction of 3D images from 2D projections A61B5/0066 takes precedence
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure
• CPC Class Codes: G01N 21/645 Specially adapted constructive features of fluorimeters

Abstract

The invention concerns a coupling device for at least one optical fibre (10, 12) with a view to optical tomography-type examination of a medium (11) to be examined, comprising:

• • a mass (30) in diffusing material for a wavelength guided by the optical fibre, this mass comprising a bearing surface (22) to be applied against the surface (110) of the medium (11) to be examined,
  • at least one housing (27, 29) provided in the mass and capable of receiving the end of an optical fibre (10, 12).

Claims

1. Diffuse optical imaging device to image a medium, comprising:

a) a radiation source to form incident radiation on the medium, at least at a first wavelength,

b) a device to detect a diffused or fluorescence signal, emanating from the examined medium,

c) a coupling device comprising;

a mass comprising a bearing surface to be applied against the surface of the medium to be examined,

at least one collection optical fibre to collect a signal emanating from a medium, and to convey it towards detection device, and at least one excitation optical fibre to bring the incident radiation onto the medium to be examined, each optical fibre;

either having one end arranged permanently in the diffusing material,

or the coupling device comprising at least one housing capable of receiving said optical fibre, this housing being provided in the mass of diffusing material,

the end of the collection optical fibre or the bottom of the housing capable of receiving the collection optical fibre being located at a distance (h) from the bearing surface shorter than the distance (H) from the bearing surface at which the end of the excitation optical fibre or the bottom of the housing capable of receiving the excitation optical fibre is located,

said mass of the coupling device being in diffusing material for a wavelength guided by at least one of the optical fibres.

2. Device according to claim 1, the diffusing material having a reduced diffusion coefficient higher than 0.1 cm⁻

1 and less than 700 cm<sup>−

1</sup>.

3. Device according to claim 1, the diffusing material having an absorption coefficient higher than 0.01 cm⁻

1 and less than 1 cm<sup>−

1</sup>.

4. Device according to claim 1, further comprising an absorbent layer at least partly covering the mass in diffusing material.

5. Device according to claim 1, the spot of at least one incident beam, on the bearing surface intended to be in contact with the medium to be examined, having a surface area S_t of between 1 mm² and a few tens of cm².

6. Device according to claim 1, the bearing surface further comprising one or more convex protuberances with no sharp edges.

7. Device according to claim 1, comprising at least one housing whose bottom is located substantially in or at the protuberance, and/or comprising at least one fibre whose end is arranged in or at said protuberance.

8. Device according to claim 1, said radiation source being a pulsed, continuous-time or amplitude-modulated source.

9. Examination method of optical tomography type to examine part of a medium, wherein at least one device is used according to claim 1, and wherein:

the coupling device is applied against this medium,

the medium is illuminated or subjected to optical excitation using a radiation source to form incident radiation on the medium, then to cause this incident radiation to enter the medium,

an optical signal emanating from the medium is collected by at least one collection optical fibre.

10. Method according to claim 9, wherein a fluid is applied between the bearing surface of the diffusing medium of the coupling device and the surface of the medium to be examined.

11. Method according to claim 9, wherein a pressure is applied to the coupling device when it is in position against the medium, to cause the fluid contained in this medium to flow out of part of this medium towards a region located on the periphery of the coupling device.

12. Diffuse optical imaging device to image a medium, comprising:

a matrix or mass of material, this mass comprising a bearing surface with one or more convex protuberances and no sharp edges to be applied against the surface of the medium to be examined,

at least one optical fibre of which one end is arranged permanently in the diffusing material and/or at least one housing provided in the mass and capable of receiving the end of an optical fibre, said matrix or mass of material being in diffusing material for a wavelength guided by said optical fibre.

13. Device according to claim 12, comprising at least one housing whose bottom is located substantially in or at the protuberance, and/or comprising at least one fibre whose end is arranged in or at said protuberance.

14. Device according to claim 12, one of said protuberances having a substantially constant radius of curvature, said device further comprising an excitation fibre whose end is placed in the centre of said curvature.

15. Examination method of optical tomography type to examine part of a medium, wherein at least one device is used according to claim 12 and wherein:

the coupling device is applied against this medium,

the mass comprises an excitation fibre whose end is placed in the centre of the curvature of the protuberance to obtain homogeneous excitation over the entire surface of the tissue in contact with the protuberance forming a radiation source,

an optical signal emanating from the medium is collected by means of at least one collection optical fibre.

16. Examination method of optical tomography type to examine part of a medium, wherein at least one device is used according to claim 12 and wherein:

the coupling device is applied against this medium,

the medium is illuminated or subjected to optical excitation using a radiation source to form incident radiation on the medium,

the mass comprises a detection fibre whose end is placed in the centre of the curvature of the protuberance to collect homogeneous optical signal emanating from the medium.