CN107411708A - A kind of optical coherence tomography and photoacoustic imaging bimodal endoscope - Google Patents

Abstract

The present invention provides an optical coherence tomography and photoacoustic imaging dual-mode endoscope, including a light source, a cavity, an optical coherence tomography unit and a photoacoustic imaging unit respectively arranged inside the cavity, the optical coherence tomography unit Including single-mode optical fiber, gradient index lens, reflective prism and imaging scanning module; the dual-mode endoscope of optical coherence tomography and photoacoustic imaging in the invention can perform dual-mode endoscope through the combination of optical coherence tomography and acousto-optic imaging. Modal endoscopic imaging, which realizes a smaller dual-mode endoscope and realizes simultaneous optical coherence tomography and photoacoustic imaging scanning, which is especially suitable for imaging in occasions with high size requirements, such as small diameter In the endoscopic imaging of blood vessels, the present invention combines the high resolution of optical coherence tomography and the large penetration depth of acousto-optic imaging, and can obtain high field of view and high resolution images at the same time, providing a good advantage for the development of medical diagnosis Application prospects.

Description

A dual-mode endoscope with optical coherence tomography and photoacoustic imaging

technical field

The invention relates to the field of optics, in particular to an optical coherence tomography and photoacoustic imaging dual-mode endoscope.

Background technique

Optical coherence tomography (Optical Coherence Tomography, OCT) is a technology developed in the past two decades that can perform high-resolution end-face imaging of biological tissue structures. Compared with the previous imaging technology, optical coherence tomography has the following outstanding advantages: using near-infrared light source, no damage to the human body; using low-coherence interference principle to make it have a high resolution (up to 10 microns or less); using optical fiber system, the cost is low and the equipment is portable. Due to these advantages, optical coherence tomography has been greatly developed in the past two decades, and it is currently an important tool in the clinical detection of glaucoma, fundus diseases and other ophthalmological fields. In addition to the eye, optical coherence tomography can also image various tissues of the human body, such as skin and teeth. In order to image the internal organs of the human body, a variety of optical 7 coherence tomography endoscopic probes have emerged, which can be extended into the body for detection, greatly expanding the scope of application. For example, the probe can be inserted into blood vessels to image the section of blood vessels to study the process and mechanism of vascular fat and vascular blockage, especially the imaging of easily ruptured plaques will be able to diagnose early atherosclerosis. After nearly ten years of development, endoscopic optical coherence tomography probes have shown good application prospects in blood vessels, respiratory tract, and digestive tract.

However, optical imaging technology usually has a contradiction between field of view and lateral resolution, and usually cannot achieve a wide field of view and small lateral resolution at the same time, and optical coherence tomography is no exception. Conventional optical endoscopic probes, including fiber optic bundle-based and camera-based probes, typically have a field of view on the order of a few centimeters, but their lateral resolution is only tens of micrometers. In optical coherence tomography endoscopic probes, both lateral and longitudinal resolutions can reach about 10 microns, but the field of view is usually on the order of several millimeters. In many applications, both a large field of view and high resolution are required, which cannot be achieved with existing technologies. On the other hand, due to the high scattering of near-infrared light by biological tissues, the effective detection depth of optical coherence tomography is also limited, which is generally 1-2 mm for epidermal tissues. This limits imaging of large areas extending into tissue. Therefore, there is an urgent need for a new technical means that can realize a dual-mode endoscope with a smaller size and realize simultaneous optical coherence tomography and photoacoustic imaging scanning, so that it can be used in occasions with high size requirements.

Contents of the invention

In view of the shortcomings of the prior art described above, the present invention provides a dual-mode endoscope for optical coherence tomography and photoacoustic imaging to solve the above technical problems.

The optical coherence tomography and photoacoustic imaging dual-mode endoscope provided by the present invention includes a light source, a cavity, an optical coherence tomography unit and a photoacoustic imaging unit respectively arranged inside the cavity, and the optical coherence tomography unit includes Double-clad optical fiber, gradient index lens, reflective prism, and imaging scanning module, the light source includes a first light source for optical coherence tomography and a second light source for acousto-optic imaging, and the first light source is coupled to A single-mode optical fiber is used for imaging through the imaging scanning module, the second light source passes through the gradient index lens to generate a focused beam, and the focused beam is reflected on the sample surface through a reflective prism, and the photoacoustic imaging unit receives the The photoacoustic signal generated after the sample absorbs the pulsed laser is used to complete the dual-mode endoscopic imaging.

Further, the first light source is an infrared light source for optical coherence tomography, the second light source is a pulsed laser for photoacoustic imaging, and the first light source is transmitted through the inner layer of the double-clad optical fiber. single mode transmission.

Further, it also includes an ultrasonic probe arranged in the cavity, the ultrasonic transducer is connected to the double-clad optical fiber, and the first light source passes through the ultrasonic probe through the double-clad optical fiber.

Further, the photoacoustic imaging unit includes an optical resolution subunit or an acoustic resolution subunit, the second light source is coupled to a double-clad optical fiber for transmission, and a focused beam is generated through the gradient index lens, and the focused beam The optical resolution subunit receives the photoacoustic signal generated after the sample absorbs the pulsed laser light after being reflected on the surface of the sample by the reflective prism.

Further, the second light source is coupled to the double-clad optical fiber for multi-mode transmission, the pulsed laser is transmitted through the multi-mode optical fiber, and a focused beam is generated through the gradient index lens, and the focused beam is reflected by a reflective prism to the surface of the sample. On the surface, the acoustic resolution subunit receives the photoacoustic signal generated after the sample absorbs the pulse laser.

Further, the imaging scanning module includes a scanning mirror, a micromotor and a magnet, the scanning mirror is fixed to the magnet, and the magnet rotates under the magnetic force of the micromotor.

Further, the inside of the cavity is filled with liquid for propagating acoustic signals and an isolating device for isolating the liquid, the ultrasonic probe and the micro-motor are respectively isolated from the liquid through the isolating device, and the scanning mirror is set inside the liquid.

Further, the ultrasonic probe is a hollow piezoelectric ultrasonic transducer.

Beneficial effects of the present invention: the optical coherence tomography and photoacoustic imaging dual-mode endoscope in the present invention can perform dual-mode endoscopic imaging through the combination of optical coherence tomography and acousto-optic imaging, and achieve smaller size The dual-mode endoscope realizes the simultaneous scanning of optical coherence tomography and photoacoustic imaging, which is especially suitable for imaging in occasions with high size requirements, such as endoscopic imaging of blood vessels with small diameters. The present invention combines Combining the high resolution of optical coherence tomography and the large penetration depth of acousto-optic imaging, high field of view and high resolution images can be obtained at the same time, which provides a good application prospect for the development of medical diagnosis.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

Fig. 2 is a schematic flow chart of the method of the present invention.

Fig. 3 is a schematic diagram of the system structure of the present invention.

Explanation of reference signs:

Micromotor-1, Magnet-2, Scanning Mirror-3, Isolation Device-4, Liquid-5, Acoustic Lens-6, GRIN Lens-6, Ultrasonic Detector-8, Double Clad Optical Fiber-9, Signal Line-10 , transparent film-11, first light source-21, second light source-22, dichroic filter-23, lens-24, core-25, inner package-26, outer package-27, signal line-31, Conductive glue-32, ground wire-33, insulating glue-34, double-layer gold-plated lithium niobate-35, matching layer-36, acoustic lens-37.

detailed description

Embodiments of the present invention are described below through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes, and various modifications or changes can be made to the details in this specification based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, in the case of no conflict, the following embodiments and features in the embodiments can be combined with each other.

It should be noted that the diagrams provided in the following embodiments are only schematically illustrating the basic ideas of the present invention, and only the components related to the present invention are shown in the diagrams rather than the number, shape and shape of the components in actual implementation. Dimensional drawing, the type, quantity and proportion of each component can be changed arbitrarily during actual implementation, and the component layout type may also be more complicated.

As shown in Figures 1 and 2, the optical coherence tomography and photoacoustic imaging dual-mode endoscope in this embodiment includes a light source, a cavity, an optical coherence tomography unit and a photoacoustic imaging unit respectively arranged inside the cavity , the optical coherence tomography unit includes a double-clad optical fiber, a gradient index lens 7 (GRIN lens), a reflective prism and an imaging scanning module, and the light source includes a first light source 21 for optical coherence tomography and a first light source for optical coherence tomography The second light source 22 for acousto-optic imaging, the first light source 21 is coupled to a single-mode optical fiber, imaging through the imaging scanning module, the second light source 22 generates a focused beam through the gradient index lens, and the focused beam Reflected on the surface of the sample by the reflective prism, the photoacoustic imaging unit receives the photoacoustic signal generated after the sample absorbs the pulsed laser, and completes the dual-mode endoscopic imaging. In this embodiment, the double-clad optical fiber can ensure the optical The two imaging modes of coherent tomography and photoacoustic imaging realize co-location imaging, which can simultaneously obtain high-field-of-view and high-resolution images, and the size of the probe is small, which is suitable for imaging in occasions with high size requirements.

In this embodiment, the optical coherence tomography optical path is located in the middle of the probe, and the optical coherence tomography unit includes a double-clad optical fiber, a gradient index lens 7 and a reflective prism, and its longitudinal resolution is determined by the spectral width of the near-infrared light source, while Its lateral resolution is determined by the parameters of the gradient index lens and the working distance of the probe. The optical coherence tomography unit directly collects the signal reflected by the sample through the optical fiber, and then detects it through the optical coherence tomography system end to complete the optical coherence tomography imaging.

In this embodiment, the first light source 21 is an infrared light source used in optical coherence tomography, the second light source 22 is a pulsed laser used in photoacoustic imaging, and the first light source 21 performs single-mode transmission through the double-clad optical fiber. At the input end, the light of optical coherence tomography is coupled to the inner layer of the double-clad fiber through the dichroic filter 23, while the pulsed light of photoacoustic imaging is coupled to the single-mode fiber in the inner layer of the double-clad fiber depending on the design. Optical fiber or outer layer of multimode optical fiber. as shown in picture 2. In addition, the input end of the single-mode fiber will be connected with the optical coherence tomography system. A gradient index lens is placed behind the fiber to generate a focused beam, which is then reflected by a mirror onto the sample surface.

In this embodiment, it includes an ultrasonic probe 8 disposed in the cavity, the ultrasonic probe 8 is connected to a double-clad optical fiber, and the first light source 21 passes through the ultrasonic transducer through the single-mode optical fiber, such as As shown in Fig. 3, the ultrasonic probe 8 in the present embodiment adopts a hollow piezoelectric ultrasonic transducer, and the structure of the hollow piezoelectric ultrasonic transducer in the present embodiment is as shown in Fig. 3, including signal Wire 31, conductive glue 32, ground wire 33, insulating glue 34, double-layer gold-plated lithium niobate 35, matching layer 36 and acoustic lens 37, the inside of which is a hollow structure, and the hollow part is connected to the double-clad optical fiber 9.

In this embodiment, the photoacoustic imaging unit includes an optical resolution subunit or an acoustic resolution subunit. The second light source 22 is coupled to the double-clad optical fiber for single-mode transmission, and a focused beam is generated through the gradient index lens. The focused light beam is reflected on the surface of the sample through a reflective prism, and the optical resolution subunit receives the photoacoustic signal generated after the sample absorbs the pulsed laser; the second light source 22 is coupled to the double-clad optical fiber for multiple mode transmission, the pulsed laser is transmitted through a multimode optical fiber, and a focused beam is generated through the gradient index lens 7, and the focused beam is reflected on the sample surface by a reflective prism, and the acoustic resolution subunit receives the sample absorption Photoacoustic signal generated after pulsed laser. The optical resolution method can obtain high-resolution images in shallow layers, while the acoustic resolution method can obtain imaging depths up to several centimeters with moderate resolution. In the optical resolution mode, the pulsed laser is transmitted through a single-mode fiber and focused on the sample through a graded-index lens. The optical coherent tomography light source can also be transmitted through the same single-mode fiber. The photoacoustic signal generated after the sample absorbs the pulsed laser will be received by the ultrasonic detector. Since the lateral resolution is determined by the focused spot size, ultrasound probes can be non-focused or weakly focused. In the acoustic resolution mode, since the laser is not focused, a multimode fiber is required to carry sufficient laser energy. In addition, since the laser light is not focused, the ultrasound probe 8 must be focused in order to provide the lateral resolution required for imaging. These two methods can be implemented in the same system. The structure of the double-clad optical fiber in this embodiment is shown in FIG. 2 , including a core 25, an inner wrapping 26 and an outer wrapping 27.

In this embodiment, the imaging scanning module includes a scanning mirror 3, a micromotor 1 and a magnet 2, the scanning mirror 3 is fixed to the magnet 2, and the magnet 2 rotates under the magnetic force of the micromotor 1, and the scanning of the imaging is performed by The small magnet 2 driven by the micro-motor 1 is realized by magnetically driving another small magnet, and the scanning mirror 3 is pasted on the small magnet to be driven to rotate. In this embodiment, the interior of the cavity is filled with a liquid 5 for propagating acoustic signals and an isolating device 4 for isolating the liquid. In this embodiment, the isolating device 4 is used for isolation. Its specific structure is shown in Figure 1. The ultrasonic detector 8 The micromotor 1 is isolated from the liquid 5 through the isolation device 4, the scanning mirror 3 is arranged inside the liquid, the liquid 5 in this embodiment is water, and the ultrasonic detector 8 part needs to be flushed with water to propagate the sound. Signal, this part needs to be isolated from micromotor 1 and other parts of the probe.

The above-mentioned embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the present invention should still be covered by the claims of the present invention.

Claims (8)

1. A dual-mode endoscope for optical coherence tomography and photoacoustic imaging, characterized in that: it comprises a light source, a cavity, an optical coherence tomography unit and a photoacoustic imaging unit respectively arranged inside the cavity, the optical coherence The tomography unit includes a double-clad optical fiber, a gradient index lens, a reflective prism, and an imaging scanning module. The light source includes a first light source for optical coherence tomography and a second light source for acousto-optic imaging. A light source is coupled to a single-mode optical fiber, and is imaged by the imaging scanning module. The second light source passes through the gradient index lens to generate a focused beam, and the focused beam is reflected on the sample surface through a reflective prism. The photoacoustic The imaging unit receives the photoacoustic signal generated after the sample absorbs the pulsed laser, and completes the dual-mode endoscopic imaging. 2. The optical coherence tomography and photoacoustic imaging dual-mode endoscope according to claim 1, characterized in that: the first light source is an infrared light source for optical coherence tomography, and the second light source It is a pulsed laser for photoacoustic imaging, and the first light source is transmitted in a single mode through the inner layer of the double-clad optical fiber. 3. The optical coherence tomography and photoacoustic imaging dual-mode endoscope according to claim 2, characterized in that: it also includes an ultrasonic probe arranged in the cavity, the ultrasonic transducer and the double-clad optical fiber connected, the first light source passes through the ultrasonic probe through the double-clad optical fiber. 4. The optical coherence tomography and photoacoustic imaging dual-mode endoscope according to claim 2, characterized in that: the photoacoustic imaging unit includes an optical resolution subunit or an acoustic resolution subunit, the second The two light sources are coupled to the double-clad optical fiber for transmission, the gradient index lens generates a focused beam, and the focused beam is reflected on the sample surface by a reflective prism, and the optical resolution subunit receives the sample absorption pulse Photoacoustic signal generated after laser. 5. The optical coherence tomography and photoacoustic imaging dual-mode endoscope according to claim 4, characterized in that: the second light source is coupled to the double-clad optical fiber for multi-mode transmission, and through the multi-mode optical fiber The pulsed laser is transmitted, and a focused beam is generated through the gradient index lens, and the focused beam is reflected on the surface of the sample by a reflective prism, and the acoustic resolution subunit receives the photoacoustic signal generated after the sample absorbs the pulsed laser . 6. The optical coherence tomography and photoacoustic imaging dual-mode endoscope according to claim 3, characterized in that: the imaging scanning module includes a scanning mirror, a micro-motor and a magnet, and the scanning mirror is fixed on the magnet, The magnet rotates under the magnetic force drive of the micro-motor. 7. The optical coherence tomography and photoacoustic imaging dual-mode endoscope according to claim 6, characterized in that: the cavity is filled with a liquid for propagating acoustic signals and an isolation device for isolating the liquid, The ultrasonic probe and the micro-motor are respectively isolated from the liquid through the isolation device, and the scanning mirror is arranged inside the liquid. 8 . The optical coherence tomography and photoacoustic imaging dual-mode endoscope according to claim 3 , wherein the ultrasonic probe is a hollow piezoelectric ultrasonic transducer.