KR20180077966A - Photoacoustic and ultrasonic endoscopic mini-probe - Google Patents

Abstract

According to the present invention, a photoacoustic-ultrasonic endoscope includes a probe and a probe driving unit. The probe includes: an optical-electromagnetic waveguide assembly which includes a conductive path and optical fiber including a cladding and a core; a scanning tip which is arranged at one end of the optical-electromagnetic wavelength assembly and detects a photoacoustic-ultrasonic signal generated from a subject by sending a laser beam to the subject; and a plastic catheter which surrounds the outside of the scanning tip and the optical-electromagnetic waveguide assembly. The scanning tip includes: an optical reflector included to reflect a laser beam transmitted through the optical fiber to a target point of a subject; and a piezoelectric element having a first window, through which the reflected laser beam passes, and configured to generate ultrasound or detect ultrasound generated from the subject. The photoacoustic-ultrasonic mini endoscope probe is provided to improve the reception sensitivity of a signal and the resolution of a photoacoustic image.

Description

[0001] The present invention relates to a photoacoustic-ultrasonic endoscopic mini-probe,

The present invention can be implemented in the form of an elongated probe such as an ultrasound endoscope (EUS) mini-probe or a catheter probe, which is currently used in clinical practice, and can be inserted into a subject to provide a tomographic image of the vicinity thereof To a medical tomography endoscope apparatus. This device can provide photoacoustic image information while retaining the general shape, size, and image capabilities of the aforementioned ultrasound endoscopic devices, and it can be applied to a variety of medical fields such as digestive or cardiovascular disease diagnosis It is expected to be widely used.

The present invention relates to an ultrasound-guided mini-probe (also referred to as an endoscopic ultrasound mini-probe, prior art 1, prior art 2) or a catheter probe for a blood vessel diagnosis (also called intravascular ultrasound catheter probe, prior art 3, prior art 4) The present invention relates to a tomographic endoscopic system in the field of photoacoustic endoscopy or optoacoustic endoscopy (Prior Art 5, Prior Art 6) developed for the purpose of applying to a medical field such as a digestive or cardiovascular diagnosis.

The photoacoustic endoscope is a technique of inserting a small-diameter probe into a subject and generating an ultrasonic signal by momentarily irradiating an electromagnetic wave having a pulse width of a very short (usually 1 占 퐏 or less) Refers to a tomographic endoscopy that acquires a tomographic image of the interior of the tissue by acquiring (i.e., scanning) across the region.

The general principle of how electromagnetic waves irradiated to biological tissues are converted into ultrasonic signals has been known as photoacoustic effect since the 1880s. However, based on this principle, a tomographic image is obtained from a subject such as a biotissue It was in the early 1990's, after pulsed light sources such as Q-switched lasers were commercialized, and since then, they have been implemented in many different types of systems, with more diverse medical applications. In a broader sense, techniques for obtaining tomographic images in tissue based on photoacoustic effects are collectively referred to as photoacoustic imaging techniques or photoacoustic tomography.

The reason why photoacoustic imaging technology is currently attracting a great deal of attention in the field of medical imaging is that it satisfies various technical conditions such as image depth, resolution, image speed, and safety problem, This is because it provides new and useful video information that can not be reproduced. The present invention relates to an endoscopic application of the photoacoustic imaging technique and provides a more advanced device configuration and operation principle and an implementation method thereof that can overcome the problems of the photoacousticoscopy systems proposed in the prior art.

In order to realize the photoacousticoscopy system, as in the case of a well-known general photoacoustic imaging system (i.e., not limited to an endoscope), a light source for generating a pulsed electromagnetic wave, Three device elements are required: an image scanner or probe to acquire the photoacoustic single-layer signal, and a data processor and displayer to process the obtained single-layer signal and present it to the user . However, in order to achieve the specific application purpose of endoscopy, image probes should be implemented in a very small or slender shape.

Various types of photoacousticoscopy probes have been proposed to satisfy these types and functional conditions. However, a commercialized photoacoustic endoscope system that can be applied to actual clinical situations due to various demanding system requirements has been developed yet There is no way. In order to establish a photoacoustic endoscope system, it is a key requirement to integrate an optical element and an ultrasonic element effectively in a small space called a probe, and to obtain a tomographic image by applying a series of scanning methods.

Although the endoscope has differentiated characteristics that the ultrasonic wave is generated by the pulsed electromagnetic wave to obtain the image, this technique is also applicable to the endoscopic ultrasound : EUS, Prior Art 1). In other words, the photoacoustic endoscope can be regarded as a system in which the optical or electromagnetic wave transmission and emission functions are added to the system elements of the existing ultrasound endoscopic technology, and due to the feature of the system configuration, Systems have the ability to provide both conventional photoacoustic images as well as conventional ultrasound images.

Therefore, in a photoacoustic endoscope probe, it is currently used in clinical ultrasound endoscopy (EUS) devices, considering only a configuration method for an ultrasound detection unit by excluding electromagnetic waves (generally laser pulses) A single-element ultrasonic transducer based mechanical scanning method and an array transducer based electronic scanning method can be applied (Prior Art 1). So let's look briefly to see what advantages and disadvantages to apply each scan method.

In the latter case, only one laser pulse is emitted based on a plurality of transducer elements to acquire data necessary for a two-dimensional or three-dimensional tomographic image configuration at the same time. That is, without moving the position of the sensor or the probe spatially, it is possible to acquire a tomographic image over a predetermined region very quickly through only one laser pulse emission. However, the miniaturization of the device is relatively difficult compared to the former, problems such as cross talk between the plural channels occur, and the cost for implementing the system may be high. Therefore, due to such a problem of the array type transducer, the ultrasonic endoscope (EUS) field currently used in clinical practice is mainly applied to an endoscope apparatus for digestion diagnosis which does not require a high degree of miniaturization (of course, in the ultrasonic endoscope apparatus, There is no need to fire.

On the other hand, in the case of applying electrons, since only one ultrasonic transducer capable of detecting only a signal propagating from a specific direction is installed in the endoscope probe, in order to obtain a two-dimensional or more tomographic image, (Generally rotating) the ultrasonic signal generated by the ultrasonic wave generated by the ultrasonic wave generated by the ultrasonic oscillator. However, since the space occupied by a single ultrasonic transducer is not so large, it can be implemented in a very small and thin shape, and the cost required for constituting the ultrasonic transducer is relatively low. Thus, in the field of ultrasound endoscopy (EUS), an intravascular ultrasound (IVUS) catheter probe is inserted into an instrument channel or an accessory channel of a video endoscope (prior art 3, prior art 4) Miniature probes (that is, an EUS mini-probe, a prior art 1, a prior art 2), and the like, which have a total diameter of 1 mm to 3 mm or less.

Because of the advantages and disadvantages described above, various systems employing the two ultrasonic detection methods have been proposed in the field of photoacoustic endoscopy, and a representative example of the prior art adopting a single ultrasonic transducer- For example, in the prior art 7 (Proc. SPIE 4256, 16 (2001)), Prior Document 8 (U.S. Patent Application No. 2011-0021924), Prior Document 9 (U.S. Patent Application No. 2011-0098572) (PloS One 9 (3), e92463 (2014)), Journal of the American College of Cardiology 64 (4), 385 (2014), Prior Art 12 (U.S. Published Patent Application No. 2011-0275890) Prior Art 13 (Journal of Biomedical Optics 19 (6), 066001 (2014)).

That is, all of the endoscope systems disclosed in these prior art documents have a light illuminating unit coupled to an optical fiber end for transmitting light and a single ultrasonic transducer for detecting the generated ultrasonic wave at a distal end of the probe, And a large number of these documents are inventions showing a possibility of a dual mode image capable of simultaneously acquiring a photoacoustic image as well as an existing ultrasonic image by a single device .

 However, the biggest problem commonly occurring in these prior arts is that the intensity of the photoacoustic signal that can actually be detected, that is, the efficiency of signal detection, is very low compared to the irradiated light energy. This is because the light illumination direction and the ultrasound detection direction formed by the two elements are spaced out from each other due to the fact that the light illumination unit and the ultrasonic detection unit provided at the end of the probe are disposed at spatially separated positions (see the prior art documents 7 to 11) Because the use of a mirror or the like that reflects a sound wave in the probe results in a distant section from the wall of the plastic tube in contact with the subject to an ultrasonic transducer that can detect real sound waves Literature 12 and 13), it is a very serious factor that deteriorates the main image performance such as image resolution as well as signal sensitivity in real biomedical image.

In addition to these problems, in the systems disclosed in the prior arts 7 to 11, the two elements, that is, the optical energy and the electric signal transmission cable disposed along the section from the probe base to the probe end (that is, the section called the catheter) It is difficult to uniformly transfer the mechanical rotational force from the probe base to the end point when the probe is subjected to the rotation scan in the bent state only by arranging each of the elements in a simple parallel arrangement instead of one organic assembly having symmetry It has technical limitations.

In short, a single transducer-based mini or catheter-type photoacoustic probe is a technology that can be successfully applied to real clinical situations if it meets both the uniformity of rotation scan and the superiority of signal sensitivity. have. However, the prior art does not satisfy all of these requirements, so the present invention aims to solve this problem.

Prior Art 2: United States Patent No. 5131393 (July 21, 1992) Prior Art 4: United States Patent No. 4354502 (October 19, 1982) Prior Art Document 8: U.S. Published Patent Application No. 2011-0021924 (Jan. 27, 2011) Prior Art 9: U.S. Published Patent Application No. 2011-0098572 (April 28, 2011) Prior Art 12: U.S. Published Patent Application No. 2011-0275890 (November 10, 2011) Prior Art 15: United States Patent No. 6134003 (Oct. 10, 2000)

Prior Art 1: C. Dietrich, Endoscopic Ultrasound: An Introductory Manual and Atlas, (Thieme, New York, 2006) (CRC Press, 2003), which is based on the results of the present study, Prior Art 5: JM Yang, et al., "Photoacoustic endoscopy", Optics Letters 34 (10), 1591 (2009) Prior Art 6: Oraevsky, et al., "Laser optoacoustic tomography of layered tissues: signal processing," SPIE, 2979, 59 (1997) Prior Art 7: Viator, et al., "Design and testing of an endoscopic photoacoustic probe for determination of treatment depth after photodynamic therapy ", Proc. SPIE 4256, 16-27 (2001) Prior art 10: X Bai, et al., "Intravascular optical-resolution photoacoustic tomography with a 1.1 mm diameter catheter", PloS One 9 (3), e92463 (2014) Prior Art 11: Da Xing, et al., "Characterization of lipid-rich aortic plaques by intravascular photoacoustic tomography", Journal of the American College of Cardiology 64 (4), 385-390 (2014) Prior Art 13: JM Yang, et al., "Catheter based photoacoustic endoscope", Journal of Biomedical Optics 19 (6), 066001 (2014) JM Yang, et al., "Simultaneous functional photoacoustic and ultrasonic endoscopy of internal organs in vivo," Nature Medicine 18 (8), 1297 (2012) Optics Letters 21 (7), 543-545 (1996), "Scanning single-mode fiber optic catheter-endoscope for optical coherence tomography ", G. J. Tearney,

As mentioned earlier, conventional photoacoustic endoscopes have a range from an inconsistency between the light illumination direction and the ultrasound detection direction, or an ultrasonic transducer, which detects a soundwave signal from a wall of a plastic tube called a catheter And deterioration of the signal sensitivity and the photoacoustic resolution caused by the distant formation.

Disclosure of Invention Technical Problem [7] The present invention has been made to solve the above-mentioned main technical problems including the above-mentioned core problems, and it is an object of the present invention to shorten the detection path of the ultrasonic signal and solve the inconsistency problem between the light illumination direction and the ultrasonic detection direction, And a photoacoustic-ultrasound mini-endoscope probe (hereinafter, photoacoustic-ultrasound endoscope) having improved resolution of a photoacoustic image. However, these problems are illustrative and do not limit the scope of the present invention.

The photoacoustic-ultrasonic endoscope according to the present invention includes a probe and a probe drive unit, wherein the probe includes an optical-electromagnetic waveguide assembly including an optical fiber and a conductive path including a core and a cladding; A scanning tip disposed at one end of the optical-electromagnetic waveguide assembly for detecting a photoacoustic-ultrasonic signal generated from the subject by sending a laser beam to the subject; And a plastic catheter surrounding the opto-electromagnetic waveguide assembly and the outside of the scanning tip, wherein the scanning tip comprises: a light reflector configured to reflect the laser beam transmitted through the optical fiber to a target point of the subject; And a piezoelectric element having a first window through which the reflected laser beam passes and generating ultrasonic waves or detecting ultrasonic waves generated from a subject.

The light reflector may be exposed through the first window.

The piezoelectric element has a first window at the center and may be formed symmetrically with respect to the first window.

The piezoelectric element may be concave in the direction of the light reflector.

The scanning tip includes a sound-absorbing layer capable of eliminating acoustic noise; And a casing surrounding the light reflector, the piezoelectric element, and the sound-absorbing layer.

The scanning tip may further include a transparent filler disposed on a light exit side of the light reflector to prevent fluid from entering the first window portion of the piezoelectric element.

The laser beam transmitted through the optical fiber may be reflected inside the optical reflector.

The scanning tip may further include an acoustic lens having a second window through which the reflected laser beam passes and disposed on the surface of the piezoelectric element.

The piezoelectric element may be formed flat, and the acoustic lens may be concave in the direction of the light reflector.

The photoacoustic-ultrasonic endoscope according to an embodiment may further include a GRIN (gradient index) lens disposed between the optical fiber and the light reflector and adapted to converge light.

Other aspects, features, and advantages will become apparent from the following drawings, claims, and detailed description of the invention.

According to an embodiment of the present invention as described above, since the scanning tip is configured such that a laser beam emitted from an optical fiber is reflected through a light reflector and irradiated to a subject through a first window of the piezoelectric element, The intensity of the photoacoustic signal actually detected relative to the light energy of the irradiated laser beam, that is, the efficiency of signal detection .

In addition, since the ultrasonic signal generated from the subject is directly detected by the piezoelectric element without being reflected by other components of the probe, the detection path of the ultrasonic signal is shortened and the reception sensitivity of the signal and the resolution of the photoacoustic image are improved .

Of course, the scope of the present invention is not limited by these effects.

1 is a schematic view schematically showing the configuration of a photoacoustic-ultrasound endoscope according to an embodiment.
Fig. 2 is a schematic view showing only the scanning tip portion of Fig. 1;
FIGS. 3 to 7 are schematic views schematically showing the configuration of a scanning tip according to another embodiment.
8 is a cross-sectional view taken along line VIII-VIII 'of FIG.
9 is a schematic view schematically showing the configuration of a photoacoustic-ultrasonic endoscope including a waveguide assembly according to another embodiment.
10 is a schematic diagram showing a specific configuration of a waveguide aggregate corresponding to A portion in FIG.
FIG. 11 is a photograph showing the actual implementation of the waveguide assembly of FIG.
12 is a schematic view showing a configuration of a waveguide aggregate according to an embodiment and a sectional view thereof.
13 is a schematic view showing a configuration of a waveguide aggregate according to another embodiment and a sectional view thereof.
14 is a schematic view showing an optical fiber according to an embodiment and a sectional view thereof.
15 is a schematic view showing a configuration of a plastic catheter according to an embodiment.
16 is a schematic view of a plastic catheter for use as an endoscopic endoscope according to an embodiment and a method of injecting fluid.
17 is a schematic diagram for performing a configuration of a plastic catheter for using a guiding wire according to an embodiment and performing a pullback scan.
18 is a schematic diagram showing the configuration of a probe base and a driving unit according to an embodiment.
19 is an overall system conceptual diagram showing a photoacoustic-ultrasound endoscope probe, a probe drive unit, and a system console for driving and controlling the two.
FIG. 20 is a diagram illustrating system elements for implementing a photoacoustic-ultrasound-optical coherence tomography (OCT) triplet imaging mode and their connection relationship in the photoacoustic-ultrasound imaging mode shown in FIG. It is a conceptual diagram.

The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in the detailed description. The effects and features of the present invention and methods of achieving them will be apparent with reference to the embodiments described in detail below with reference to the drawings. However, the present invention is not limited to the embodiments described below, but may be implemented in various forms.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals refer to like or corresponding components throughout the drawings, and a duplicate description thereof will be omitted .

In the following embodiments, the terms first, second, etc. are used for the purpose of distinguishing one element from another element, rather than limiting.

In the following examples, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

In the following embodiments, terms such as inclusive or possessive are intended to mean that a feature, or element, described in the specification is present, and does not preclude the possibility that one or more other features or elements may be added.

In the drawings, components may be exaggerated or reduced in size for convenience of explanation. For example, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and thus the present invention is not necessarily limited to those shown in the drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals refer to like or corresponding components throughout the drawings, and a duplicate description thereof will be omitted .

1 is a schematic view schematically showing the configuration of a photoacoustic-ultrasound endoscope according to an embodiment.

1, a photoacoustic-ultrasonic endoscope according to an exemplary embodiment includes a probe 200 and a probe driving unit 100. The probe 200 includes an optical fiber 241 including a core and a cladding, Electromagnetic wave waveguide assembly 240 (hereinafter referred to as 'waveguide assembly') including a conductive path CP and a waveguide assembly 240. The laser beam is transmitted to the object to be inspected, And a plastic catheter 220 that surrounds the outside of the scanning tip 250 and the scanning tip 250 includes a scanning tip 250 that detects the photoacoustic-ultrasonic signal and the optical- And a first window 251W through which the reflected laser beam passes. The first window 251W is configured to generate an ultrasonic wave or to transmit the ultrasonic wave from the object to be inspected To detect the generated ultrasonic waves And a piezoelectric element (251).

1, the photoacoustic-ultrasound endoscope probe 200 includes a portion enclosed by a plastic catheter 220 and a portion encompassed by a probe base 210, that is, a portion where the base frame 216 is physically enclosed Section. The section where the plastic catheter 220 is wrapped is not only physically flexible but also configured as a very thin and long tube structure so that it can be effectively inserted into a subject that can only be accessed through a narrow and curved passage.

The plastic catheter 220 also blocks the waveguide assembly 240 and the scanning tip 250 disposed along the inner space of the plastic catheter 220 from the outer space and isolates the outer space from the outer space, . At the same time, the plastic catheter 220 can also serve as a trap to prevent the matching fluid 230 filled therein from leaking out. Since the material of the plastic catheter 220 passes through the wall surface of the plastic catheter 220 and the laser beam and the ultrasonic signal, it is preferable to use a polymer material which can pass both the light wave and the sound wave.

The matching fluid 230 filling the internal space of the plastic catheter 220 may be ultra-pure water such as deionized water, but may be biocompatible and semi-permanently used, such as silicone oil of low viscosity. It is preferable to use a material that can be used. If the matching fluid 230 is water, it is important to electrically insulate the two conductive passages (CP, discussed below) of the waveguide assembly 240, which are coextensive with the matching fluid 230.

The plastic catheter 220 is configured in the form of an elongated tubular structure that can be effectively inserted into a subject accessible only through a narrow, curved passage. Thus, the plastic catheter 220 may have a diameter of about 1 mm or more and about 3 mm or less, and an overall length of about 0.5 m or more to about 3 m or less.

A waveguide assembly 240 is disposed in the probe 210 covered with the plastic catheter 220 so as to extend from the probe base 210 to the scanning tip 250. The waveguide assembly 240 also has a physically flexible characteristic and transmits a photoacoustic-ultrasonic electric signal detected by the piezoelectric element 251.

At one end of the waveguide aggregate 240, a probe base 210 that surrounds the waveguide aggregate 240 and receives rotational force from the probe drive unit 100 is disposed. The probe base 210 includes a base gear 217, a rotary transformer 211, a ball bearing module 212, an O-ring type airtight portion 213, a penetrating shaft 214, an epoxy charging portion 215, 211, 212, 213, 214, 215, 217).

The base gear 217 receives rotational force from the probe drive unit 100 and transmits the rotational force to the waveguide assembly 240. The rotary transformer 211 receives the electric pulse generated from the ultrasonic pulser-receiver 101 and transmits the electric signal generated by the piezoelectric element 251 to the piezoelectric element 251 while being positioned in the probe base 210, To the receiver (101). Of course, all of the electrical signals mentioned in these two processes pass through the waveguide assembly 240.

The O-ring type airtight portion 213 serves to prevent the matching fluid 230 filling the inside of the plastic catheter 220 from leaking out. The ball bearing module 212 may serve to provide a mechanical condition in which the penetrating shaft 214 can rotate smoothly in a stable position.

The probe drive unit 100 is a physically independent unit that can be separated from the photoacoustic-ultrasonic probe 200. The probe driving unit 100 includes an ultrasonic pulser-receiver 101 capable of sending and receiving an electric signal to and receiving an electric signal from the rotary transformer 211, a laser pulse inputting unit A light input device 102 that forms a so-called optical rotary junction in cooperation with the optical fiber 241, a driving gear 103 that transmits a rotational force to the waveguide assembly 240, An actuator 104 fastened to the gear 103, and an actuator driver 105 for driving and controlling the actuator 104, and the like. This will be described later.

At the other end of the waveguide bundle 240, a scanning tip 250 is disposed. The scanning tip 250 includes a light reflector 252 that reflects the laser beam transmitted through the optical fiber 241 in the waveguide assembly 240 to a target point of the object, (251W), and includes a piezoelectric element (251) provided to generate ultrasonic waves or detect an ultrasonic signal generated from a subject. That is, the scanning tip 250 transmits the laser beam transmitted through the optical fiber 241 in the waveguide bundle 240 or the ultrasonic pulse generated by the piezoelectric element 251 to the subject and causes the ultrasonic pulse generated in the subject And plays a key role in detecting an ultrasound signal reflected from a photoacoustic signal or a subject.

Fig. 2 is a schematic view showing only the scanning tip portion of Fig. 1;

Referring to FIGS. 1 and 2, a laser beam from an optical fiber 241 of the waveguide assembly 240 is reflected through a light reflector 252. The light reflector 252 may be, for example, a prism-shaped mirror operated by total reflection principle. The laser beam emitted from the optical fiber 241 is reflected by the light reflector 252 so that the traveling path can be bent by 90 degrees. Although not shown, the incident angle of the laser beam with the light reflector 252 can be adjusted to adjust the direction in which the laser beam is reflected.

Referring to FIG. 2 (a), that is, a side view of the scanning tip 250, a piezoelectric element 251 is arranged on the upper side of the light reflector 252 (that is, . The piezoelectric element 251 has a first window 251W through which the laser beam reflected by the light reflector 252 passes. Although the first window 251W is shown as a hole in the drawing, the first window 251W may be a transparent layer transmitting light.

The piezoelectric element 251 functions as an ultrasonic transducer for generating ultrasonic waves or detecting ultrasonic signals generated from a subject. When the laser beam reflected by the light reflector 252 contacts the subject, a subject absorbing the light energy thermally expands, resulting in a photoacoustic effect that generates a sound wave (SW) or an ultrasonic signal . The generated sound wave (SW) or ultrasonic signal is detected through the piezoelectric element 251 and converted into an electric signal.

The piezoelectric element 251 can be arranged so as to face the side surface of the probe 200, that is, the signal detecting surface thereof is substantially parallel to the direction in which the optical fiber 241 is elongated. The direction of the laser beam reflected by the optical reflector 252 is the same as that of the surface on which the piezoelectric element 251 is disposed when the laser beam emitted from the optical fiber 241 is bent through the optical reflector 252 by 90 °, . At this time, the ultrasonic signal SW generated from the subject is propagated toward the piezoelectric element 251 in the shortest path without being reflected by another component in the probe 200 and detected. That is, unlike the detection method disclosed in the prior art document 12, the total path through which the ultrasonic signal SW propagates is shortened and the acoustic numerical aperture also increases, so that the reception sensitivity of the signal and the resolution of the photoacoustic image are significantly improved .

Further, the direction in which the laser beam reflected by the light reflector 252 is irradiated coincides with the detection direction of ultrasonic waves generated from the test object. Thus, it is possible to obtain the effect of increasing the intensity of the photoacoustic signal actually detected, that is, the efficiency of signal detection, with respect to the light energy of the irradiated laser beam.

Meanwhile, in the present invention, the piezoelectric element 251 is disposed inside the plastic catheter 220. If the piezoelectric element 251 is not wrapped with the plastic catheter 220 or the like in order to further shorten the detection path of the ultrasonic signal SW, the whole of the scanning tip 250 as well as the piezoelectric element 251 is damaged by the foreign substance A phenomenon occurs. Further, the piezoelectric element 251 may come into direct contact with the inspected object, thereby causing physical damage to the inspected object. For reference, in the prior arts 10 and 11, there is no definite discussion on the placement problem of the plastic catheter 220 or its specific role.

According to one embodiment, the light reflector 252 may be exposed through the first window 251W. Referring to FIG. 2 (b), that is, a three-dimensional schematic diagram of the entire scanning tip taken in the direction in which the surface of the piezoelectric element 251 is viewed from the front, the light reflector 252 is arranged in a All or a part thereof is exposed, and is visible to the outside of the scanning tip 250 with the naked eye. That is, the light reflector 252 is disposed below the first window 251W of the piezoelectric element 251 on the basis of FIG. 2 (a), so that the light reflector 252 disposed inside the scanning tip as viewed from above I can see it.

According to one embodiment, the piezoelectric element 251 has a first window 251W at the center and may be formed symmetrically with respect to the first window 251W. 2, the piezoelectric element 251 has a first window 251W at the center, and the left portion 251L and the right portion 251R of the piezoelectric element 251 are located at the center of the first window 251W For example, in a symmetrical manner. In this situation, when the light reflected through the light reflector 252 shoots the object perpendicularly to the first window 251W surface, the portion of the object to be illuminated is moved to the left portion 251L of the piezoelectric element 251 and to the right side The intensity of the received ultrasonic wave SW is substantially constant over the entire region of the piezoelectric element 251. [ Therefore, the problem of inconsistency between the light illumination direction and the ultrasonic signal detection direction of the prior arts 7 to 11 is solved, and consequently, the reception sensitivity of the signal and the resolution of the photoacoustic image are improved.

According to one embodiment, the piezoelectric element 251 may be recessed in the direction of the light reflector 252. Generally, an ultrasonic wave (SW) generated in a subject having the shape of a very small point propagates in the form of a spherical wave. At this time, the piezoelectric element 251 is concave in the direction of the light reflector 252 The ultrasonic waves SW generated in the subject can be detected with almost constant intensity throughout the piezoelectric element 251. [ Thus, the reception sensitivity of the signal and the resolution of the photoacoustic image are improved.

According to another embodiment, the left portion 251L and the right portion 251R of the piezoelectric element 251 are physically separated from each other, that is, two pieces of piezoelectric elements are symmetrical with respect to the first window 251W Or in a form in which they are arranged in a form. Of course, in this case also, the two piezoelectric elements may be connected to each other as if they are electrically connected in parallel.

3 to 7 are schematic views schematically showing the structure of the scanning tip 250 of the photoacoustic-ultrasonic endoscope according to another embodiment.

According to one embodiment, the scanning tip 250 includes a sound absorbing layer 253 that can eliminate acoustic noise and a casing 254 that surrounds the light reflector 252, the piezoelectric element 251, and the sound absorbing layer 253 . The casing 254 surrounds the elements constituting the scanning tip 250 so that they can be stably fixed. A sound-absorbing layer 253 is disposed inside the casing 254. The sound-absorbing layer 253 serves to eliminate acoustic noise caused by the irregular reflection of the sound waves generated from the body of the subject, as well as to create an appropriate acoustic impedance difference with the piezoelectric element 251, It can affect the value. The sound-absorbing layer 253 is disposed below the piezoelectric element 251, and the piezoelectric element 251 can be fixed. The casing 254 may be composed of one or a plurality of pieces made of a metal material.

According to one embodiment, the photoacoustic-ultrasound endoscope is disposed toward the light exit direction of the light reflector 252 and includes a transparent filler 255 that prevents fluid from entering the first window 251W portion of the piezoelectric element 251, As shown in FIG. Referring to FIG. 3, on the light reflector 252, a transparent filler 255 exposed by the first window 251W is disposed. When the fluid enters the path through which the light emitted from the optical fiber 241 is reflected, that is, toward the light outlet direction, there arises a problem that the path of light changes due to the difference in refractive index. Therefore, by using the transparent filler 255, penetration of the fluid can be completely blocked while passing the laser beam.

According to one embodiment, the laser beam transmitted through the optical fiber 241 may be reflected within the light reflector 252. 4, a light reflector 252 according to this embodiment is a kind of optical prism having an isosceles right triangle shape in cross section, as shown in the figure. In FIG. 3, Lt; / RTI > is located at the point where it was placed. That is, one surface of the light reflector 252 is positioned substantially in the same plane as the piezoelectric element 251 to cover the first window 251W, and the other surface is in contact with the optical fiber 241. [ As a result, the laser beam emitted from the optical fiber 241 enters the inside of the optical reflector 252, and is reflected on the oblique surface of the optical reflector 252, that is, inside the optical reflector 252,

Of course, the oblique surface of the prism-shaped light reflector 252 may be light-reflective coated, or it may be coated with an air chamber 256 at the point where the light reflector 252 is located relative to the outer surface of the oblique surface, It is desirable to provide an empty space. If the latter method is applied, the refractive index of the light reflector 252 itself becomes larger than the refractive index of the air chamber 256, so that the total reflection of the laser beam at the interface between the oblique surface of the light reflector 252 and the air chamber 256 total reflection) can occur.

According to one embodiment, an acoustic lens 257 may be disposed on the surface of the piezoelectric element 251. 5, the acoustic lens 257 has a second window 257W through which the laser beam reflected by the light reflector 252 passes. The acoustic lens 257 focuses the ultrasonic wave generated from the inspected object according to the principle of refraction and transmits the focused ultrasonic wave to the piezoelectric element 251 to improve the ultrasonic reception sensitivity and the resolution. In this embodiment, the piezoelectric element 251 may be formed flat.

The material of the acoustic lens 257 has such an acoustic impedance value that the sound waves propagating through the matching fluid 230 can be transmitted to the piezoelectric element 251 as efficiently as possible, It is possible to select those having different sound wave velocity characteristics. If the sonic velocity at the acoustic lens 257 is faster in the matching fluid 230, the acoustic lens 257 may be recessed in the direction of the light reflector as in FIG. Conversely, if the sonic velocity at the acoustic lens 257 is slower than the sonic velocity at the matching fluid 230, then the acoustic lens 257 may be convexly shaped from the scanning tip.

According to one embodiment, the photoacoustic-ultrasound endoscope may include a green (GRIN) gradient index lens 258 disposed between the optical fiber 241 and the light reflector 252 and adapted to focus the light . The green lens 258 is made of a material whose refractive index decreases with distance from the central axis. The light incident on the green lens 258 is focused toward the focus positioned at a predetermined distance along the center axis of the green lens 258. [ Referring to FIG. 6, the laser beam focused through the green lens 258 is reflected through the light reflector 252 and irradiated to the subject. In this case, when the focused laser beam is applied, the light irradiation area formed on the surface of the object is smaller and the intensity of the laser beam per unit area becomes larger as compared with the laser beam not focused. The intensity of the photoacoustic signal is also increased and the signal-to-noise ratio (SNR) and lateral resolution are increased. Of course, it is preferable to use the single mode optical fiber 241 when the green lens 258 is disposed.

On the other hand, in the case of a small diameter allowable for manufacturing the scanning tip 250, not only a spatial margin to place the green lens 258 and the sound-absorbing layer 253 at the same time may be insufficient, The change in the refractive index is insufficient on the total path of the light traveling in the inside of the optical path, so that the optical focusing may not be effectively performed. In such a case, as shown in FIG. 7, the light reflector may be formed so as to include the prism-shaped reflecting portion 252R and the columnar portion 252C of the elongated shape of (252). In this case, although the distance from the green lens 258 to the point where the light is reflected by the column 252C is sufficiently long, even if the focal point of the green lens 258 is far from the green lens 258, It is possible to focus the light at a desired precise point within the range. Of course, at this time, the piezoelectric element 251 may be disposed on the light reflector 252, and the sound-absorbing layer 253 may be disposed on the opposite side.

The laser beam emitted from the optical fiber 241 is reflected through the optical reflector 252 and is transmitted through the first window 251W formed at the center of the piezoelectric element 251 to the object to be scanned The light illumination direction in which the laser beam reflected by the light reflector 252 is irradiated and the ultrasonic detection direction in which the ultrasonic signal generated from the object are received coincide with each other, That is, the efficiency of signal detection is enhanced.

In addition, since the ultrasonic signal generated from the subject is detected by the piezoelectric element 251 without being reflected by the other components of the probe 200, the detection path of the ultrasonic signal is shortened and the reception sensitivity of the signal and the photoacoustic image Resolution is improved.

Hereinafter, the optical fiber 241 and the conductive path CP included in the waveguide assembly 240 will be described.

8 is a sectional view taken along the line VIII - VIII 'in FIG.

Referring to FIG. 8, the optical fiber 241 generally has a core and a cladding structure as a basis, and a protective coating layer 241PCL made of a polymer or the like may be included outside the optical fiber 241. A conductive path CP which is disposed coaxially with the optical fiber 241 and surrounds the optical fiber 241 and transmits an electric signal is disposed outside the optical fiber 241. The conductive path CP includes a first conductive path 242 including a portion disposed coaxially with the optical fiber 241 and a portion disposed coaxially with the optical fiber 241. The conductive path CP includes a first conductive path 242, And a second conductive path 243 formed therein.

All of the three elements 241, 242, and 243 are arranged in a coaxial structure with respect to one reference point, which is the rotation center axis of the waveguide assembly 240, and all of them are integrated and can rotate at the same angular velocity .

On the other hand, in order to electrically isolate the two conductive passages 242 and 243, the surfaces of the two conductive passages 242 and 243 may be coated with an insulating layer IL. The insulating layer IL may include a polymer. Alternatively, a tube-shaped structure made of an insulating material may be additionally disposed between the two conductive passages 242 and 243.

Referring again to FIGS. 1 and 8, an optical fiber 241 is disposed at the center of the waveguide aggregate 240, and a first conductive path 242 and a second conductive path 243 are disposed coaxially outside the waveguide aggregate 240. Due to such a unique structure, the optical fiber 241 located at the center of the optical fiber 241 serves as an optical waveguide for transmitting light, and the two conductive paths 242 and 243 can be formed as an electric cable having a coaxial structure, As a kind of electromagnetic wave waveguide of a radio frequency band which can transmit the electromagnetic waves efficiently. For reference, the electric signal covered by the present invention lies mainly in the 0.1-100 MHz band, and in the case of the optical fiber 241, the multi-mode, the single-mode, And can be selectively installed according to a desired application purpose.

In addition to the optical and electromagnetic waveguide roles described above, the waveguide assembly 240 provides a mechanical rotational force to the probe base 210 (as shown in FIG. 3), as if the elements 241, 242, To the scanning tip 250, as shown in FIG. For this reason, the first conductive path 242 and the second conductive path 243 must take a form or structure that can physically be made good. For example, the optical waveguide assembly 240 may be flexibly bent at a certain physical distance between the optical fiber 241 and the two conductive paths so that the waveguide assembly 240 can effectively transmit the rotational force at the same time.

9 is a schematic diagram illustrating a method of configuring a waveguide assembly 240 according to an embodiment, FIG. 10 is a schematic diagram showing a detailed configuration of a portion A in FIG. 9, and FIG. 11 is a diagram And the waveguide assembly 240 is actually implemented. In particular, FIG. 9 schematically shows how a waveguide assembly 240 implemented on the basis of the present embodiment is installed and electrically connected within the entire system of photoacoustic-ultrasonic endoscope probe 200.

The first conductive path 244 is provided to enclose the optical fiber 241 and the second conductive path 245 is provided with a first conductive path 244 coaxially with the first conductive path 244. [ As shown in FIG. That is, the cross section of the optical fiber 241, the first conductive path 244, and the second conductive path 245 may be concentric as shown in FIG. At this time, at least one of the first conductive path 244 and the second conductive path 245 may be formed in a tube shape. In this case, the tubular shape means that the first conductive path 244 and / or the second conductive path 245 in the form of a hollow tube surrounds the outer surface of the optical fiber 241 with a constant thickness. At this time, at least one of the first conductive path 244 and the second conductive path 245 may be formed by directly coating a conductive material on the surface of the optical fiber 241, for example, by vapor deposition or plating.

The first conductive path 244 is provided to enclose the optical fiber 241 and the second conductive path 245 is provided with a first conductive path 244 coaxially with the first conductive path 244. [ And at least one of the first conductive path 244 and the second conductive path 245 includes a set of torque coils disposed outside the optical fiber 241 in the form of a coil .

10, a first conductive path 244 and a second conductive path 245 surrounding the optical fiber 241 may include a set of torque coils 244 and 245. In the present invention, these two torque coil sets 244 and 245 are referred to as an inner torque coil set 244 and an outer torque coil set 245, respectively. The reason why each name is referred to as a set is that the torque coils are not simply formed as one layer (or layer) as shown in FIG. 10, but a plurality of layers of torque coils are superimposed, It may take a form that functions as one unit. For example, referring to FIG. 11, each torque coil set 244 and 245 may be configured in such a manner that a plurality of wires form a two-layer structure (see a sectional view). This structure has the advantage of more effectively delivering the mechanical rotational force over a very long section, generally over one meter. On the other hand, if the given space is limited and flexibility is more important, each set of torque coils 244 and 245 may consist of only one layer as depicted in FIG.

In order to increase the electrical conductivity of each of the two sets of torque coils 244 and 245, their surfaces may be coated or plated with a material having high electrical conductivity. It is also possible to coat the outermost surface of each torque coil set with a polymeric insulator for electrical isolation between the inner and outer torque coil sets 244 and 245 or to apply a different tube structure polymer between the two sets 244 and 245 The tube can be inserted (see 244PT in Fig. 11). Of course, both of these methods can be applied in one embodiment.

Although the method of implementing the waveguide assembly 240 using the torque coil set with reference to the embodiment of FIG. 11 has been described, in addition to the torque coil, two conductive tubes having a very thin and uniform wall thickness are interdigitated, The waveguide assembly 240 can be implemented.

9, the inner torque coil set 244 functioning as the first conductive path and the outer torque coil set 245 functioning as the second conductive path are connected to the two electrodes of the piezoelectric element 251, respectively, Providing a passage through which electricity flows from the tip 250 to the rotating transformer 211 in the probe base 210. Of course, the two sets of torque coils 244 and 245 included in the waveguide assembly 240 are electrically connected to the left coil part 211-1 of the rotary transformer 211 rotating together with them.

12 and 13 are schematic diagrams showing the structure of the waveguide aggregate 240 according to another embodiment.

According to one embodiment of FIG. 12, the first conductive path 248 and the second conductive path 249 may be provided to cover at least a part of the surface of the optical fiber 241. 12, the conductive path CP includes a first conductive path 248 formed in a U-shape and a second conductive path 249 formed in an inverted U-shape. . The first and second conductive passages 248 and 249, which are divided into two parts, respectively surround a portion of the optical fiber 241. In this case also, since the two conductive paths CP provide a passage through which electric signals flow while maintaining the basic property of being geometrically coaxial with the optical fibers 241, even if the waveguide aggregate is placed in a warped state, .

One of the other advantages of the embodiment shown in Fig. 12 is that the above-mentioned "conductive passage" is formed not only in two but also in a plurality of shapes along its surface to be. That is, the conductive paths of several channels may be formed in parallel.

The main object of the present invention is to provide a photoacousticoscope based on a single ultrasonic transducer which detects a photoacoustic ultrasonic signal by installing one piezoelectric element at a scanning tip portion. However, if two or more piezoelectric elements are provided on the scanning tip and the electric signals generated therefrom are independently transmitted along the waveguide aggregate, the number of channels of the conductive channel is determined according to the coating method shown in FIG. 12 It can be increased accordingly.

In any case, the outer layer of the conductive path CP is preferably provided with an insulating coating layer 246 to prevent electrical leakage due to contact with the matching fluid 230.

Referring to FIG. 13, the first conductive path (inner conductive layer) 242 of the waveguide assembly 240 according to one embodiment includes an insulating coating layer 246 interposed between the optical fiber 241 and the second conductive path 247, Or directly on the surface of the cladding 241Cd of the optical fiber 241 or the entire surface of the first buffer layer (not shown). That is, in this case, the waveguide aggregate 240 includes a first conductive path CP 242 formed in a tubular shape to surround the entire surface of the cladding 241Cd of the optical fiber 241 or the first buffer layer (not shown) An insulating coating layer 246 surrounding the outer circumference thereof, and a second conductive path CP (247) formed of a torque coil set. Of course, the insulating coating layer 246 also serves to electrically isolate the two conductive passages 242 and 247 at this time. Also in the formation of the second conductive path, instead of applying a mechanical element called the torque coil set shown in the drawing, a method of coating a highly conductive material thinly on the outer surface of the insulating coating layer 246 surrounding the optical fiber Can also be implemented.

In any case, the structure shown in Figures 12 and 13 may be more effective when applied to an intravascular catheter probe or the like where the overall diameter of the probe must be very small.

14 is a schematic diagram showing an optical fiber 241 according to an embodiment. According to this embodiment, the optical fiber used in the waveguide bundle 240 includes a core 241Co capable of transmitting light, and a first cladding 241Cd-1. In addition to the basic structure, a first cladding 241Cd- And a second cladding 241Cd-2.

In FIG. 1, a plurality of optical-electromagnetic waveguide assemblies 240 having only one of a multimode optical fiber and a single mode optical fiber are disclosed. In general, a multimode optical fiber has the advantage of transmitting a large amount of optical energy. In the case of a single mode optical fiber, although the total energy that can be transmitted is small, an advantage of being able to concentrate light by attaching a lens or the like to the exit have. However, if a large amount of optical energy transfer and optical concentration are required at the same time, the waveguide aggregate 240 may be formed using the double cladding optical fiber 241 as shown in FIG. The double-cladding optical fiber 241 has a core 241Co disposed at the center thereof with a core 241Co as shown in a sectional view taken along the line XIV-XIV 'of FIG. 14, A first cladding 241Cd-1, which is another light propagation layer capable of transmitting mode light, surrounds the core 241Co. At this time, the first cladding 241Cd-1 also has a second cladding 241Cd-2 disposed at an outermost periphery so as to serve as an optical fiber capable of propagating light.

When the optical fiber 241 and the two conductive paths CP are coaxially disposed as described above, the rotational force acting on the probe base 210 can be uniformly transmitted to the scanning tip 250 disposed at the end of the probe.

Hereinafter, a photoacoustic-ultrasound endoscope including the rotation transformer 211 and the rotation optical couplers 102 and 241 will be described. In the present invention, these are collectively referred to as rotating optical-electromagnetic couplers (211, 102, 241).

The photoacoustic-ultrasonic endoscope according to one embodiment includes a probe 200 and a probe driving unit 100. The probe 200 includes a core 241Co (FIG. 13) and a cladding 241Cd (FIG. 13) A waveguide assembly 240 including an optical fiber 241 and a conductive path CP disposed coaxially with the optical fiber 241 is disposed at one end of the waveguide aggregate 240. The laser beam is sent from the subject A scanning tip 250 for detecting a photoacoustic-ultrasonic signal generated and a waveguide assembly 240 and a plastic catheter 220 surrounding the outside of the scanning tip 250 and a rotary transformer 211 electrically connected to the conductive path CP, The probe driving unit 100 includes an optical input unit 102 for transmitting optical energy to a rotating optical fiber 241 and an ultrasonic pulser-receiver 101 electrically connected to a rotating transformer 211.

Referring again to FIG. 1, the rotary transformer 211 is wound around an inside or a side edge of a magnetic core formed in a donut shape, and an electric coil wound in a direction parallel to the direction (i.e., a donut shape) The first primary coil portion 211-1 having a group and the other secondary secondary coil portion 211-2 having the same structure are symmetrical with respect to the primary coil portion Lt; / RTI >

Here, the primary coil part 211-1 is connected to the two conductive paths CP of the waveguide assembly 240, the secondary coil part 211-2 is connected to the input part (not shown) of the ultrasonic pulser- And is electrically connected. Therefore, by the rotation of the base gear 217, the waveguide assembly 240, as well as the through-hole shaft 214 connected to the waveguide assembly 240 and the primary coil portion 211-1 formed in the shape of a ring along the periphery thereof, The base frame 216 and the secondary coil portion 211-2 are not rotated by the ball bearing module 212 at all. That is, unlike the primary coil portion 211-1 electrically connected to the two conductive paths CP of the waveguide assembly 240, the secondary coil portion 211-2 is fixed to the base frame 216, I will not. As a result, electric signals can be input and output from the rotating waveguide assembly 240 without the problem of electric wires being twisted by the electric element called the rotary transformer 211.

That is, the rotary transformer 211 is an electric device that can transmit and receive electric signals without direct physical contact between two relatively moving objects or through electric wires, etc., and is operated by electromagnetic induction principle. Of course, due to this operating principle, there is a key advantage that a rotating transformer can only transmit an alternating signal, but it can exchange electrical signals from the rotating body without physical contact. In addition to the advantages mentioned above, it is possible to change the voltage or convert the electrical impedance during the transmission of electric signals by appropriately combining the coil ratios of the respective groups.

The light input device 102 refers to something like a convex lens, an objective lens, or the like, and inputs light energy to a rotating optical fiber 241. In other words, when a laser pulse is generated in the light source unit 300 (shown in FIG. 19), the laser pulse first travels to the optical input unit 102 through a separate guiding optical fiber (not shown) 102 transmits the induced laser pulse to the optical fiber 241 provided on the central axis of the waveguide assembly 240. The important point here is that the optical fiber 241 of the waveguide assembly 240 rotates while the optical input device 102 transmits light energy in a stationary state without rotating. That is, the optical input unit 102 for inputting light and the optical fiber 241 for receiving light form a kind of optical rotary junction.

The guiding optical fiber (not shown) may be attached to the waveguide assembly (not shown) without using the optical input device 102 having the same shape as the convex lens or the objective lens shown in FIG. 240 may be directly engaged with the optical fibers 241 of the optical fibers 241, 240, respectively. Of course, in this case, the ends of the guiding optical fibers (not shown) should be disposed as close as possible to the optical fibers 241 of the waveguide assembly 240, and optical fibers having the same specs are used for more efficient optical energy transmission .

The ultrasonic pulser-receiver 101 is electrically connected to the rotary transformer 211 and receives the photo-acoustic signal detected by the piezoelectric element 251 and electrically converted. This will be described later.

15 to 17 are schematic diagrams showing the configuration of a probe of a photoacoustic-ultrasonic endoscope according to an embodiment.

According to one embodiment, the photoacoustic-ultrasound endoscope may further include a mesh-like reinforcement 260 disposed within the plastic catheter 220. Referring to FIG. 15, a braided or mesh reinforcing member 260 made of a metal material or the like may be inserted into the plastic catheter 220. Thereby extending the physical life of the plastic catheter 220.

According to one embodiment of FIG. 16, the base frame 216 may further include a fluid inlet 261. Unlike the case where the photoacoustic-ultrasound endoscope probe 200 proposed by the present invention is inserted into a device channel of a video endoscope currently used in clinical practice, when it is desired to use the photoacoustic- The distal end portion of the plastic catheter 220 is opened to form a fluid outlet 262 and a fluid injection port 261 is additionally provided in the base frame 216 so that blood vessels It can be used for disease diagnosis. In this case, a saline solution or the like may be used as a fluid to be injected through the fluid injection port 261, and the matching fluid 230 filling the space inside the probe is also replaced with the saline solution.

17, the photoacoustic-ultrasound endoscope encircles the plastic catheter 220 and includes a guiding catheter fluid inlet 280 and a guiding catheter fluid inlet 280 And may further include a guiding wire 270 inserted therein.

17, a guiding catheter 290 having a dual lumen structure is additionally used to inject the fluid through the guiding catheter fluid inlet 280, and the guiding wire 270 The plastic catheter 220 is smaller in thickness than the guiding catheter 290 and can be inserted and withdrawn physically so that the position of the scanning tip 250 can be adjusted The image can be obtained by changing from the subject.

18 is a block diagram of a probe drive unit 100 and a probe base 210 according to an embodiment that transmit power in a manner different from the power transmission and rotation transformer 211 principle shown in FIG. In the case of the present invention.

1, the probe driving unit 100 includes a driving gear 103 that rotates in conjunction with an actuator 104. The probe base 210 includes a base gear (not shown) that rotates in engagement with the driving gear 103 217) have been illustrated. The power required for the waveguide assembly 240 to rotate is transmitted by the base gear 217 fastened directly to the drive gear 103. [

18, the probe drive unit 100 includes a drive timing pulley 106 connected to and rotating with the actuator 104, and the probe base 210 of the photoacoustic- And a timing belt 107 that includes a base timing pulley 218 that rotates in engagement with the drive timing pulley 106 and that transmits power between the drive timing pulley 106 and the base timing pulley 218 . Thus, in this case, the power required for the waveguide assembly 240 to rotate is transmitted through the drive timing pulley 106 and the base timing pulley 218, and the timing belt 107 connecting the two.

1 and 9, a structure is shown in which a rotary transformer 211 is mounted on the probe base 210 to receive an electric signal generated from the piezoelectric element 251 from the waveguide aggregate 240. However, if the mechanical noise is not a problem, the rotary transformer 211 is divided into two slip rings 219-1 and two brushes 219-2, A configured electrical signal input / output system can be used. Of course, in this case, the two brushes 219-2 are electrically connected to the ultrasonic pulser-receiver 101 through the signal cable 219-3 or the like.

18 illustrates the case where the base timing pulley 218 and the slip ring 219-1 are used together, the base timing pulley 218 may be used as the rotary transformer 211, or the base gear 217, May be used in combination with the slip ring 219-1 or the like.

In order to perform the photoacoustic-ultrasound endoscopic imaging using the photoacoustic-ultrasound endoscope probe 200 and the probe drive unit 100 in practice, And additional systems such as a data acquisition system (DAQ system) are additionally needed.

19 is a conceptual diagram showing a photoacoustic-ultrasound endoscope probe 200, a probe drive unit 100, and a peripheral system for driving both of them. Typical peripheral systems include a light source 300 for generating laser pulses, and a system console 400 for controlling the entire system.

As a key element constituting the light source unit 300, a cue switch laser capable of providing a laser beam with a very short pulse width is preferable. In addition to these characteristics, sufficient pulse energy It should have a repetition rate. When multi-wavelength photoacoustic imaging is to be performed simultaneously for two or more wavelengths, a plurality of laser systems capable of providing the two wavelengths or a laser system having a variable wavelength capability can be used.

In the case of the system console 400, a data acquisition system 402 receives a photoacoustic-ultrasound signal amplified and optimized from the ultrasonic pulser-receiver 101 and converts the photoacoustic-ultrasound signal into a numeric signal recognizable by a computer, A data processing unit 401 for converting the image data into image data and converting the image data into image data, a video image presenting apparatus 403 for presenting the image data to the user for viewing, and a detailed system control unit 404 for controlling various subsystems do.

Hereinafter, the principle of operation of the photoacoustic-ultrasound endoscope probe 200 and the probe drive unit 100 shown in FIG. 1 will be described with reference to FIGS. 1 and 19. FIG.

The user first inserts the photoacoustic-ultrasonic endoscope probe 200 into the subject to place the scanning tip 250 in the region of interest and then actuates the actuator 104 to rotate the driving gear 103 and the base gear 217 starts rotating and accelerates to reach a predetermined speed. For example, if imaging of a typical video rate is desired, it can be accelerated to about 30 Hz.

When the base gear 217 starts to rotate, the through-hole 214 directly connected to the through-hole gear 217 also rotates together with the rotation transformer (not shown) The waveguide aggregate 240 and the scanning tip 250 located at the end portions of the waveguide aggregate 240 are immediately transmitted to rotate together at a predetermined speed. Of course, the ball bearing module 212 located at the base provides a dynamic condition for smoothly rotating the through-hole shaft 214 in a stable state, and the O-ring type airtight portion 213 is provided with a photo- The matching fluid 230 filling the internal space of the ultrasonic endoscope probe 200 is prevented from leaking out.

When the various mechanical elements interlocked with each other reach the predetermined speed, the actuator driver 105 triggers every time the actuator 104, which is an actual power source of physical rotation, rotates by an angular step, A series of imaging sequences to obtain photoacoustic and ultrasound one-dimensional image data (usually called A-line data) in a synchronized form to the trigger pulse signal in the whole system, (imaging sequences) occur sequentially in turn. That is, for each trigger pulse signal, photoacoustic and ultrasonic one-dimensional data containing depth direction decomposition information for a specific direction in which the scanning tip 250 is pointing at that time is obtained, and this series of processes is called a scanning tip 250 ) Are repeated continuously to obtain two-dimensional image data of photoacoustic and ultrasonic waves which are spatially overlapped (coregistered). In addition, when the probe is pushed or pulled out, the data necessary for the three-dimensional image can be obtained. It is preferred that the trigger pulse used to trigger the above-described imaging sequences is of the transistor-transistor logic (TTL) type.

In order to sequentially acquire photoacoustic and ultrasonic one-dimensional data in the manner described above, a sequence of trigger pulse trains provided by the actuator driver 105 is first sent to the detailed system control unit 404, It should be divided into two different pulse trains with time difference to be used for photoacoustic and ultrasound imaging initiation respectively. Generally, the time difference of several tens of microseconds (μs) is appropriate. The reason for triggering the acquisition of photoacoustic and ultrasound one-dimensional data with such a time difference is that the subject sufficiently relaxes the alternating alternating photoacoustic and ultrasonic modes to allow time for relaxation. For reference, the prior art 14 is an example in which such a video sequence is actually applied.

Hereinafter, how the one-dimensional photoacoustic and ultrasound image data are obtained for a single trigger pulse will be described below.

First, when a photoacoustic imaging mode for obtaining one-dimensional photoacoustic data at a specific time is started, a laser pulse is first generated from the light source unit 300. The laser pulse is transmitted through an optical fiber (not shown) And is transmitted from the probe base 210 to the scanning tip 250 along the optical fiber 241 installed on the central axis of the waveguide aggregate 240. [ The laser pulse from the optical fiber 241 is reflected by the light reflector 252 and passes through the first window 251W of the piezoelectric element 251 and the plastic catheter 220 which transmits the light and is then sent to the subject.

When a laser beam is transmitted into the subject, a photoacoustic signal is induced immediately. A part of the thus induced photoacoustic wave propagates to the piezoelectric element 251 and is converted into an electric signal. The electric signal is transmitted through the rotary transformer 211 in the probe base 210 along the electromagnetic waveguide formed by the first conductive channel 242 and the second conductive channel 243 of the waveguide assembly 240, Receiver 101 located in the ultrasonic pulser-receiver 100 of Fig. Of course, the ultrasonic pulser-receiver 101 also serves to receive the photoacoustic signal detected by the piezoelectric element 251 and electrically converted. In the ultrasonic imaging mode, however, the piezoelectric element 251 emits ultrasonic pulses, To the piezoelectric element 251 and receives an ultrasonic echo signal detected by the piezoelectric element 251. [

In addition, the ultrasonic pulser-receiver 101 may also include a signal conditioning function that amplifies the signal and filters only the appropriate frequency band, which is then sent to the data acquisition system 402, Is processed in the data processing unit 401 in the storage unit 400 and stored temporarily or in the long term.

When the series of processes for obtaining the one-dimensional photoacoustic data as described above is completed, the ultrasound imaging mode in which the one-dimensional ultrasound data can be obtained with the predetermined set time difference is started. Of course, during this time difference, the scanning tip 250 may already be slightly rotated.

When this process is started, very short electric pulses are generated in the aforementioned ultrasonic pulser-receiver 101. The generated electric pulses are transmitted through the rotation transformer 211 to the first conductive Is transferred to the piezoelectric element 251 mounted inside the scanning tip 250 along the passage 242 and the second conductive path 243 and ultimately converted into an ultrasonic pulse. Then, the ultrasonic pulse advances in the direction of the subject similarly to the conventional ultrasonic imaging method, and some of the energy is reflected and returned and detected by the same piezoelectric element 251 that originally emitted the ultrasonic pulse, and eventually converted into an electric signal form. Thereafter, the electric signal is transmitted to the rotating transformer 211 along the first conductive path 242 and the second conductive path 243 of the waveguide assembly 240 in the reverse order of the above-described process, and then the ultrasonic pulser- As shown in FIG. Then, the amplified ultrasound signal is sent to the data acquisition system 402 as in the case of the photoacoustic signal described above, and then processed by the data processing unit 401 in the entire system console 400 and stored temporarily or in the long term.

 After obtaining the photoacoustic and ultrasonic one-dimensional image data in a predetermined amount (while the scanning tip 250 is completely rotated once), the data processing unit 401 processes the related data, 403 to the user.

The present invention has been designed with the primary purpose of being used in photoacoustic-ultrasonic imaging mode. However, if a portion of the optical fiber 241 required for the waveguide assembly 240 is used as a double-cladding optical fiber or a single-mode optical fiber and peripheral systems are configured as shown in FIG. 14, optical-acoustic ultrasound imaging as well as optical coherence tomography (OCT) Preceding Literature 15, Preceding Literature 16) may also be enforced at the same time.

FIG. 20 is a conceptual diagram showing system components and their connection relationship for implementing the photoacoustic-ultrasound-OCT triplet mode in the photoacoustic-ultrasound imaging mode shown in FIG. 19. FIG.

Referring to FIG. 20, the photoacoustic-ultrasound endoscopic system according to an exemplary embodiment may include an OCT light source 302 for providing optical energy for optical coherence tomography to an optical fiber 241. 19 and 20 are the internal structures of the light source unit 300 and the probe drive unit 100. First, in the case of the light source unit 300, a swept source or the like is used to perform optical coherence tomography. And the same OCT light source 302 is added. Note that the additional meaning used herein is meant to be a functional addition, not necessarily a device having physically distinct units. For example, a single light source may simultaneously provide the light waves required for photoacoustic imaging and OCT imaging. 20, an optical interferometer and an optical signal detector 108, which are commonly used for OCT images, are provided inside the probe driving unit 100 in addition to the OCT light source 302, And the OCT image can be additionally performed by taking over the light. Of course, in order to transmit the light taken over from the photoacoustic light source 301 and the light taken over from the OCT light source 302 to the photoacoustic-ultrasound-OCT endoscope probe 200 effectively, a beam combiner it is preferable to install a beam combiner 109.

To obtain spatially superimposed photoacoustic-ultrasound-OCT images, photoacoustic, ultrasound, and OCT one-dimensional image modes may be sequentially initiated and accomplished during the rotation of the scanning tip 250 in a manner similar to that described above.

The method of obtaining both photoacoustic, ultrasound, and OCT image information using the endoscope system proposed by the present invention has been described above. However, in some cases, it may be implemented in a system format in which only some of the image information (i.e. photoacoustic or photoacoustic-ultrasound image) is obtained. In the configuration and arrangement of the various subsystem elements 100, 300, and 400 shown in FIGS. 19 and 20, some elements may be integrated into one physical unit, The spatial location can also be changed accordingly. For example, the light source unit 300, the probe driving unit 100, and the system console 400 may be integrally formed, and the position of the OCT light source 302 may be transferred into the probe driving unit 100.

If the scanning tip 250 is configured such that the laser beam emitted from the optical fiber 241 is reflected through the optical reflector 252 and irradiated to the subject through the first window 251W of the piezoelectric element 251 as described above, Since the ultrasonic signal generated from the subject is detected by the piezoelectric element 251 without being reflected by other components of the probe 200 or the like, the detection path of the ultrasonic signal is shortened and the reception sensitivity of the signal and the resolution of the photoacoustic image become .

In addition, using the structure of the waveguide assembly 240 and the rotatable optical-electromagnetic couplers 102, 241, and 211, in the single ultrasound transducer-based base-activated rotation scan type photoacousticoscopy probe, It is possible to solve both the problem of processing the optical fiber 241 and the electric signal line and the problem of inputting and outputting the opto-electric signal at the probe base 210.

In the case of a photoacousticoscope that performs base-based rotation scan, it is necessary to form an electrical path through which an electric signal can be transmitted and received with an optical fiber capable of transmitting light along a predetermined rotating body (i.e., a torque coil or the like) The prior art, which is represented by the prior art document 10, is implemented by simply arranging the two elements in parallel in the torque coil for transmitting the mechanical rotational force, thereby failing to transmit a uniform rotational force from the base to the probe tip .

In this context, the present invention is directed to the use of a conductive path (CP) comprising an optical fiber (241) and coaxial first and second conductive passages (242, 243) And to provide an economical implementation method.

Therefore, when the photoacoustic endoscope is implemented on the basis of the proposed invention, since the probe 200 has a completely rotationally symmetrical structure, the probe flexibility and the uniformity of the rotation scan are significantly improved compared with the conventional photoacoustic endoscopes, it can effectively solve the problem of uniform rotational distortion (NURD). Of course, it can be greatly influenced by the electromagnetic interference noise existing in the external environment and can greatly improve the signal-to-noise ratio (SNR). In fact, this improved performance reduces deep kinking of the probe in deep bending conditions (ie, long probing depths), which improves image quality and increases probe life Can greatly improve. For example, it can be inserted more easily into the equipment channel of the video endoscope currently in clinical use.

The present invention solves the problem of installing a plastic catheter 220 outside the rotating body and filling and sealing the inside of the rotating body with the matching fluid 230. In the related art, A method of constructing a rotatable optical-electromagnetic coupler 102, 241, 211 for exchanging an electric signal using a laser beam as well as a rotary transformer 211, and a method for constructing a photoacoustic- A method of performing ultrasonic imaging as well as OCT imaging is also presented.

While the present invention has been described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

100: probe drive unit 101: ultrasonic pulser-receiver
102: optical input device 103: drive gear
104: actuator 105: actuator driver
106: Driving timing pulley 107: Timing belt
108: Optical interferometer and optical signal detector for OCT
109: Beam combiner
200: probe 210: probe donor
211: Rotary transformer 212: Ball bearing module
213: O-ring type airtight portion 214: Through-shaft
215: epoxy-
216: base frame 217: base gear
218: donut timing pulley 219-1: slip ring
219-2: Brush 219-3: Signal cable
220: plastic catheter 230: matching fluid
240: waveguide assembly 241: optical fiber
241Co: Fiber Optic Core 241Cd: Fiber Optic Cladding
241PCL: Optical fiber protective coating layer
242, 244, 248: a first conductive path
243, 245, 247, 249: a second conductive path
244PT: polymer tube
246: Insulation coating layer
250: scanning tip 251: piezoelectric element
252: light reflector 253: sound-absorbing layer
254: casing
260: reinforcement member 261: fluid inlet
262: fluid outlet port 270: guiding wire
280: guiding catheter fluid inlet
290: guiding catheter 300: light source
301: photoacoustic light source 302: OCT light source
400: System console 401: Data processing unit
402: data acquisition system 403: video image presentation device
404: Detailed System Control Department

Claims (10)

A probe and a probe driving unit,
The probe
An optical-electromagnetic waveguide assembly including an optical fiber and a conductive path including a core and a cladding;
A scanning tip disposed at one end of the optical-electromagnetic waveguide assembly for detecting a photoacoustic-ultrasonic signal generated from the subject by sending a laser beam to the subject; And
And a plastic catheter surrounding the opto-electromagnetic waveguide assembly and the outside of the scanning tip,
The scanning tip,
A light reflector provided to reflect the laser beam transmitted through the optical fiber to a target point of the object; And
And a piezoelectric element having a first window through which the reflected laser beam passes, the piezoelectric element being adapted to generate an ultrasonic wave or to detect ultrasonic waves generated from the object to be inspected. The method according to claim 1,
Wherein the light reflector is exposed through the first window. The method according to claim 1,
Wherein the piezoelectric element has a first window at the center and is formed symmetrically with respect to the first window, the photoacoustic- The method according to claim 1,
Wherein the piezoelectric element is recessed in the direction of the light reflector. The scanning device according to claim 1,
A sound absorbing layer capable of eliminating acoustic noise; And
And a casing enclosing the light reflector, the piezoelectric element, and the sound-absorbing layer. The scanning device according to claim 1,
Further comprising a transparent filler disposed on a light exit side of the light reflector to prevent fluid from entering the first window portion of the piezoelectric element. The photoacoustic-ultrasonic endoscope according to claim 1, wherein the laser beam transmitted through the optical fiber is reflected inside the light reflector. The scanning device according to claim 1,
Further comprising an acoustic lens having a second window through which the reflected laser beam passes and disposed on the piezoelectric element surface. 9. The method of claim 8,
Wherein the piezoelectric element is formed flat and the acoustic lens is concave in the direction of the light reflector. The method according to claim 1,
Further comprising a green (GRIN) lens disposed between the optical fiber and the light reflector and adapted to converge light.

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