Device and system for Doppler optical coherence tomography (OCT) of the human middle ear

Abstract

A device for Doppler optical coherence tomography (Doppler OCT), preferably of the human middle ear, is proposed. The device has an endoscope unit for at least partial insertion into the auditory canal. A sound source, a sound receiver, and OCT optics are integrated in the endoscope unit.

Claims

1) A device for Doppler optical coherence tomography (Doppler OCT), preferably of a human middle ear, comprising: an endoscope unit for at least partial insertion into an auditory canal, wherein a sound source, a sound receiver, and OCT optics are integrated in the endoscope unit.

2) The device according to claim 1, wherein the device comprises a main body and an exchangeable attachment, wherein the attachment has a base area, which can be secured releasably on the main body, and a mouth area, which is directed towards an eardrum during use of the device.

3) The device according to claim 2, wherein the OCT optics are designed such that an OCT sample beam coupled in at the base area is conveyed to the mouth area, and the sample beam reflected on the eardrum is transported back to the base area.

4) The device according to claim 1, wherein the OCT optics comprise an optical lens system, in particular one or more gradient index lenses or one or more rod lenses, and wherein the OCT optics are part of an attachment of the device.

5) The device according to claim 2, wherein the main body has a coupling area for coupling to an external OCT measurement head, wherein the coupling area is designed in such a way that, in a coupled state, an OCT sample beam from an OCT scanner is coupled into the OCT optics and a reflected OCT sample beam is transported back to the OCT scanner.

6) The device according to claim 1, wherein the endoscope unit has a light unit, and wherein the light unit comprises a light source and/or a connector for connection of an external light source and/or a light guide.

7) The device according to claim 6, wherein the light guide comprises a glass fibre or a glass fibre bundle and is integrated in an attachment of the device and/or in a main body of the device, and/or wherein the connector is integrated in the main body.

8) The device according to claim 2, wherein the attachment comprises an acoustic outgoing conductor for conveying sound from the sound source to the mouth area, and wherein the outgoing conductor comprises a small tube or a small metal tube.

9) The device according to claim 2, wherein the attachment comprises an acoustic return conductor for conveying sound from the mouth area to the sound receiver, and wherein the return conductor comprises a small metal tube.

10) The device according to claim 1, wherein the sound receiver is integrated in the main body and comprises a microphone.

11) The device according to claim 1, wherein the sound source is integrated in the main body.

12) The device according to claim 2, wherein the attachment is provided with an ear mould for sealing the auditory canal.

13) The device according to claim 1, wherein a main body of the device has an adjusting device, which is provided for adjusting a distance between a coupling area and an optical image transmission unit, wherein the adjusting device comprises an adjusting gear for longitudinal adjustment of the optical image transmission unit relative to the coupling area.

14) The device according to claim 1, wherein a main body of the device comprises an internal OCT measurement head.

15) The device according to claim 14, wherein the device has an evaluation unit for performing the Doppler optical coherence tomography (Doppler OCT) on a basis of image and sound information supplied by an OCT scanner and by a microphone.

16) A system for Doppler optical coherence tomography (Doppler OCT) of a human eardrum, the system having an OCT measurement head and a device according to claim 1 coupled to the OCT measurement head.

17) A device for Doppler optical coherence tomography (Doppler OCT), the device comprising: an endoscope unit for at least partial insertion into an auditory canal of a human middle ear, the endoscope unit including a sound source, a sound receiver, and OCT optics integrated in the endoscope unit, the endoscope unit has a light unit comprising a light source and/or a connector for connecting an external light source and/or a light guide; a main body, the main body comprises a coupling area for coupling to an external OCT measurement head, the coupling area is designed such that in a coupled state, an OCT sample beam from an OCT scanner is coupled into the OCT optics and a reflected OCT sample beam is transported back to the OCT scanner; and an exchangeable attachment, the attachment having a base area and a mouth area, the base area is releasably secured on the main body, and the mouth area is directed towards an eardrum during use of the device, the attachment also comprising an acoustic return for conveying sound from the mouth area to the sound receiver, and an ear mould for sealing the auditory canal; and an evaluation unit for performing the Doppler optical coherence tomography (Doppler OCT) on a basis of image and sound information supplied by the OCT scanner and by a microphone; wherein the OCT optics comprise an optical lens system having one or more gradient index lenses or one or more rod lenses, and wherein the main body has an adjusting device for adjusting a distance between the coupling area of the main body and an optical image transmission unit, the adjusting device comprises an adjusting gear for longitudinal adjustment of the optical image transmission unit relative to the coupling area.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIGS. 1 and 2 show schematic sectional views of a device for Doppler optical coherence tomography (Doppler OCT) of the human eardrum according to an illustrative embodiment of the present invention.

[0024] FIG. 3 shows a schematic view of a system for Doppler optical coherence tomography (Doppler OCT) of the human eardrum according to the illustrative embodiment of the present invention.

EMBODIMENTS OF THE INVENTION

[0025] In the various figures, identical parts are always provided with the same reference signs and are therefore generally also named or mentioned just once in each case.

[0026] FIGS. 1 and 2 show schematic sectional views of a device 1 for Doppler optical coherence tomography (Doppler OCT) of the human eardrum according to an illustrative embodiment of the present invention.

[0027] In the present example, the device 1 comprises an endoscope unit (also designated as an endoscope add-on) which can be fitted onto an OCT measurement head 5 (cf. FIG. 3) of an OCT system 21. The endoscope unit comprises a main body 2, and an attachment 3 which is plugged releasably onto the main body 2 and is secured with a union nut 24. The main body 2 comprises a coupling area 4, with which the main body 2 is coupled to the OCT measurement head 5. Moreover, a sound source 6 and a sound receiver 7 in the form of a microphone are integrated in the main body 2. The main body 2 finally has a connector 8 for an external light source (not shown) via which light from the external light source is coupled in. The external light source in particular provides light in the visible spectrum.

[0028] The attachment 3 comprises a base area, which faces towards the OCT measurement head 5, and a mouth area, which faces towards the eardrum during use. The attachment 3 is inserted at least slightly into the auditory canal of a patient. From the base area to the mouth area, the attachment 3 has a strongly tapering design in order to improve the ergonomics. Arranged in the interior of the attachment 3 there are several sound and light guides which are supported and held by the wall of the attachment 3. In the present example, the wall of the attachment 3 is for this purpose made of metal, as a result of which the necessary hygiene requirements can at the same time be ensured. Moreover, the attachment 3 is exchangeable and sterilizable, such that either a new attachment or a freshly sterilized attachment 3 can be fitted onto the main body 2 from patient to patient. The attachment 3 comprises a light unit 9 functioning as a light guide in the form of a glass fibre bundle, into which the light from the external light source is coupled and is conveyed to the mouth area. The light emerging from the light unit 9 in the mouth area serves to illuminate the eardrum. The reflected light serves for otoscopy by the treating physician or for optical video endoscopy by means of a camera, for example a CCD camera.

[0029] Moreover, the attachment 3 has OCT optics 10 which run parallel to the light guide between the mouth area and the base area. The OCT optics 10 comprise one or more lenses or rod lenses and preferably a gradient index lens or a combination of gradient index lenses and further optical elements. The end of the optical image transmission unit 10 towards the base area end protrudes into the coupling area 4, such that a sample beam provided by the OCT measurement head 5 can be coupled into the OCT optics 10 and is conveyed by means of the OCT optics 10 from the base area to the mouth area, where the sample beam emerges from the OCT optics 10 and impinges on the eardrum. The sample beam scattered and reflected on the eardrum enters the OCT optics 10 in the mouth area and is conveyed back to the base area and thus to the OCT measurement head 5. There, the sample beam impinges on further components of the OCT system 21 in which the sample beam is brought into interference with a reference beam by means of an interferometer, in order to generate an image of the structure of the eardrum. To ensure that a spatially resolved, three-dimensional image of the structure of the eardrum can be generated by the OCT system 21, the sample beam is moved systematically across the eardrum, and the eardrum is scanned with spatial resolution with the aid of an OCT scanner of the OCT system 21. A beam deviation for the systematic scanning of the eardrum could preferably take place in the OCT measurement head 5 or could alternatively be arranged in the main body 2 or in the mouth area.

[0030] A semi-transmitting mirror is provided within the OCT measurement head 5 or within the base body 2, which mirror filters light in the visible spectrum out of the reflected sample beam and leads it for otoscopy purposes onto an eyepiece or for purposes of optical video endoscopy onto a CCD camera. In this way, traditional optical otoscopy/endoscopy can be performed parallel to the OCT. The semi-transmitting mirror and the CCD camera are optionally integrated in the main body 2 of the endoscope unit. Alternatively, it would also be conceivable that, for otoscopy, an additional image transmission unit is provided in the attachment or a CCD camera is provided in the mouth area.

[0031] The attachment 3 moreover has an acoustic outgoing conductor 11 in the form of a small metal tube. Acoustic waves, which are emitted by the sound source 6, are conveyed through the acoustic outgoing conductor 11 to the mouth area in order to stimulate the eardrum in a defined manner. The vibrated eardrum can now be analyzed by means of the OCT scanner, and a frequency-resolved and spatially resolved measurement of the eardrum vibration can be performed by means of the Doppler OCT, additionally taking account of the Doppler shift in the sample beam, which is caused by the scattering of the sample beam on the vibrating or moved eardrum. The data processing can take place in a known manner in the context of time domain OCT (TD-OCT) or Fourier domain OCT (FD-OCT), in particular swept source OCT (SS-OCT). The endoscope unit thus permits Doppler OCT at the same time as the OCT and the otoscopy. Similarly, the data evaluation can conceivably be extended, e.g. in the sense of polarization-sensitive OCT or spectroscopic OCT (SD-OCT).

[0032] The OCT optics 10 function as optics for the OCT scanner. To set the optical parameters such as working distance and size of the viewing field, the endoscope unit has an adjusting device with which the distance between the OCT scanner or the coupling area 4 and the end of the optical image transmission unit 10 towards the base area end is adjustable. For this purpose, the main body 2 has a base part 13, and an adjustment part 14 movable with respect to the base part 13. The base part 13 comprises the coupling area 4, while the adjustment part 14 is connected to the attachment 3. A relative movement between base part 13 and adjustment part 14 in the longitudinal direction thus has the effect that the distance between the OCT scanner and the optical image transmission unit 10 changes. The base part 13 and the adjustment part 14 are coupled to each other via an adjusting gear. The adjusting gear comprises an outer hollow cylinder 25 in which guide grooves 16 are introduced. The hollow cylinder 25 has guide grooves 16A which have no pitch in the longitudinal direction, i.e. extend strictly in the circumferential direction. At least two guide pins 15 protruding radially outward from the base part 13 run in these guide grooves 16A, which guide pins 15 fix base part 13 and hollow cylinder 25 relative to each other in the longitudinal direction and nevertheless permit a rotational movement between base part 13 and hollow cylinder 25. Moreover, the hollow cylinder 25 also has guide grooves 16B which extend like a thread obliquely across the circumference of the hollow cylinder 25, i.e. not only have a directional component in the circumferential direction but also directional component in the longitudinal direction. Two guide pins (not seen in the figures for reasons of perspective) protruding radially outward from the adjustment part 14 run in these oblique guide grooves 16B, as a result of which a rotation of the adjustment part 14 relative to the hollow cylinder 25 leads to a longitudinal movement between adjustment part 14 and hollow cylinder 25 and thus also to a longitudinal movement between adjustment part 14 and base part 13. In this way, therefore, the distance of the OCT optics 10 from the OCT measurement head can be adjusted. To ensure that the guide pins of the adjustment part 14 protrude into the guide grooves 16B, the base part 13, which is arranged radially between the adjustment pan 14 and the hollow cylinder 25, has corresponding recesses designed as oblong holes for the guide pins of the adjustment part 14, which at the same time suppress a rotation of the adjustment part 14. To screen the adjusting gear, a housing 17 is provided in which the hollow cylinder 25 is encapsulated. Moreover, an adjustment ring 18 is provided which is connected to the hollow cylinder 25 in such a way that only the adjustment ring 18 has to be manually rotated relative to the housing 17 by the user in order to permit adjustment. The connector 8 for the light guide 9 is arranged in the area of the adjustment part 14 through the housing 17, such that the light connection is not interrupted during the adjustment.

[0033] In the present example, the attachment 3 additionally has an acoustic return conductor 12, which is preferably likewise designed as a small metal tube and conveys sound waves in the area of the ear drum to the sound receiver 7. By means of the sound receiver 7, conventional tympanometry can also be performed in addition to the OCT and Doppler OCT, in conjunction with a system which generates an underpressure/overpressure and which uses an additional pressure channel to generate a static pressure change in the auditory canal. The pressure channel can alternatively coincide completely or partially with the outgoing conductor or return conductor and can run externally or internally. In order to set the defined pressure in the auditory canal, the auditory canal has to be sealed off in a pressure-tight manner relative to the environment. For this purpose, the endoscope unit is preferably provided with a corresponding ear mould. Moreover, in Doppler OCT, it is possible to determine the phase relationship between the stimulation of the ear drum and the movement or vibration of the ear drum measured by the Doppler shift.

[0034] A system 21 for Doppler optical coherence tomography (Doppler OCT) of the human eardrum according to the illustrative embodiment of the present invention is shown in FIG. 3.

[0035] The OCT system 21 shown in FIG. 3 comprises the device 1 shown in FIGS. 1 and 2, and also an OCT measurement head 5. The OCT measurement head 5 is embedded here in a manual endoscope which is optionally provided with a handle 22 and is connected via a line 19 to an OCT central unit 20. The endoscope unit is connected to the OCT measurement head 5 via the above-described coupling area 4. An OCT scanner integrated in the OCT measurement head 5 can thus perform the OCT and Doppler OCT. The OCT measurement head 5 moreover has the light source, which is coupled into the light guide via the connector 8.

[0036] The recorded data of the OCT measurement head 5 are transferred digitally or optically to the central unit 20 and are evaluated there. It is conceivable that the central unit 20 has a corresponding evaluation unit for performing the Doppler optical coherence tomography on the basis of image and sound information supplied by the OCT scanner and by the microphone. Moreover, the central unit 20 has a screen 23 on which the results of the OCT and Doppler OCT and optionally additional image information are displayed for video endoscopy/otoscopy and tympanometry. The endoscope unit or the central unit 20 are preferably equipped with signal elements, such as acoustic signal transmitters or lights, in order to indicate to the treating physician the end of the measurement procedure, for example, or a defined operating state. It is also conceivable that the measurement head or the endoscope, or the handle of the endoscope, is provided with buttons by which measurement procedures can be started, stopped and the like.

LIST OF REFERENCE SIGNS

[0037] 1 device [0038] 2 main body [0039] 3 attachment [0040] 4 coupling area [0041] 5 OCT measurement head [0042] 6 sound source [0043] 7 sound receiver [0044] 8 connector for an external light source [0045] 9 light unit [0046] 10 OCT optics [0047] 11 outgoing conductor (acoustic) [0048] 12 return conductor (acoustic) [0049] 13 base part [0050] 14 adjustment part [0051] 15 guide pins [0052] 16 guide groove [0053] 17 housing [0054] 18 adjustment ring [0055] 19 line [0056] 20 central unit [0057] 21 OCT system [0058] 22 grip/handpiece [0059] 23 screen [0060] 24 union nut [0061] 25 hollow cylinder