Scanning tip for PAE-EUS mini-probe device

Abstract

In the present invention, a unique probe design was derived that enables the acquisition of optically high resolution photoacoustic endoscope images, in addition to an arrangement structure of optical and ultrasonic elements that allows ultrasonic beams to overlap (i.e. collinearly) with respect to the laser beam axis from which the laser beam is emitted, using only one combination each of an optical fiber, a green lens, and a prism commonly used in the field, in a situation where one or two transducers having acoustic focusing capabilities are arranged symmetrically with respect to the laser beam axis to have synthetic acoustic focusing capabilities.

Description

Technology Field

[0001] The present invention relates to a scanning tip for a photoacoustic-ultrasound mini-probe that can be used in a medical tomography endoscope device, which is implemented in the form of a thin, long probe similar to an ultrasound endoscope currently used in clinical practice, inserted into a specimen, and capable of providing tomographic images of the surrounding area. Background Technology

[0002] The present invention relates to so-called integrated photoacoustic and ultrasonic endoscopy (PAE-EUS) mini-probe technology capable of simultaneously providing photoacoustic imaging information while maintaining the functions of conventional endoscopic ultrasound. The problem to be solved

[0003] In the case of conventional photoacoustic-ultrasonic probes, there was a problem in that the photoacoustic axis and the ultrasonic axis did not overlap or the overlapping range was very narrow. means of solving the problem

[0004] In the present invention, a unique probe design was derived that enables the acquisition of optical resolution photoacoustic endoscope images, and an arrangement structure of optical and ultrasonic elements that allows ultrasonic beams to overlap (i.e. collinearly) with respect to the laser beam axis from which the laser beam is emitted within the aforementioned probe space limit, in a situation where one or two transducers having acoustic focusing capabilities are arranged in a structure symmetrical to each other with respect to the laser beam axis to be described later to have synthetic acoustic focusing capabilities, using only one combination each of an optical fiber, a green lens, and a prism. Effects of the invention

[0005] By following the original structure and manufacturing method presented in the present invention, the optical axis and the acoustic axis are perfectly aligned (i.e., collinear) in a space of 0.7-1.5 mm in diameter and 10 mm or less in length of a rigid end scanning tip, and it is possible to simultaneously obtain optically resolved photoacoustic images and conventional ultrasound images without any damage to the optical element caused by a pulsed laser beam passing through the relevant area. In addition, since the ultrasound transducer is positioned on the surface of the probe and comes into more direct contact with the surrounding acoustic matching medium, the probability of bubbles or the like adhering to the surface of the ultrasound transducer during actual use and interfering with the related imaging procedure is significantly reduced.

[0006] The unique probe structure presented in this invention is primarily targeted at endoscopes for diagnosing digestive diseases, but it can be applied to cardiovascular disease diagnostic applications requiring much greater probe miniaturization, as well as to various other fields of endoscopy. Brief explanation of the drawing

[0007] FIG. 1a is a schematic diagram showing the end structure of a photoacoustic-ultrasonic mini probe according to one embodiment. FIG. 1b is a cross-sectional view of the probe shown in FIG. 1a cut along the xz plane including the central axis of the probe. FIG. 1c is a cross-sectional view of the probe shown in FIG. 1b cut along the xy plane at point A-A'. FIG. 2a to 2n are drawings showing the process of manufacturing the end structure of the photoacoustic-ultrasonic mini probe presented in FIG. 1 according to one embodiment. FIG. 3a is a drawing showing only the transducer base and two ultrasonic transducers among the elements shown in FIG. 1b. FIG. 3b is a side view of an ultrasonic transducer implemented to have acoustic focusing capability according to one embodiment. FIG. 3c is a top view of FIG. 3b. FIG. 4 is a drawing showing the photoacoustic-ultrasonic mini probe implemented from the scanning tip to the probe base according to one embodiment. FIG. 5 is a wire of an ultrasonic transducer according to one embodiment This is a schematic diagram showing the arrangement method. Specific details for implementing the invention

[0008] The present invention is capable of various modifications and may have various embodiments; therefore, specific embodiments are illustrated in the drawings and described in detail. The effects and features of the present invention, and the methods for achieving them, will become clear by referring to the embodiments described below in detail together with the drawings. However, the present invention is not limited to the embodiments disclosed below but can be implemented in various forms.

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. When describing with reference to the drawings, identical or corresponding components are given the same reference numerals, and redundant descriptions thereof will be omitted.

[0010] In the following embodiments, terms such as first, second, etc. are used not in a limiting sense, but for the purpose of distinguishing one component from another component.

[0011] In the following examples, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0012] In the following embodiments, terms such as "include" or "have" mean that the features or components described in the specification are present, and do not preclude the possibility that one or more other features or components may be added.

[0013] In the following embodiments, when a component is described as being "connected" to another component, this includes not only being directly connected to the other component but also being indirectly connected by another component.

[0014] FIG. 1a is a schematic diagram showing the end structure of a photoacoustic-ultrasonic mini probe having both optical resolution photoacoustic imaging and ultrasonic imaging functions while the optical axis and acoustic axis are collinear according to one embodiment, i.e., a schematic diagram showing the overall configuration and related operational concept of a scanning tip (100). FIG. 1b is a cross-sectional view of the probe shown in FIG. 1a cut along the xz plane including the central axis of the probe, and FIG. 1c is a cross-sectional view of the probe shown in FIG. 1b cut along the xy plane at point A-A'.

[0015] Referring to FIGS. 1a to 1c, the scanning tip (100) of the optical resolution photoacoustic-ultrasonic mini probe derived in the present invention may comprise a transducer base (120), a first ultrasonic transducer (111), a second ultrasonic transducer (112), an optical fiber (130), a green lens (140), and a prism (150). The first ultrasonic transducer (111) and the second ultrasonic transducer (112) are positioned on two inclined surfaces formed to have a predetermined angle of inclination (θ) with respect to the axis (z) of the endoscope probe. At this time, the first ultrasonic transducer (111) and the second ultrasonic transducer (112) may be positioned symmetrically with respect to the central axis of the through hole of the transducer base (120) from which a laser beam is emitted. The optical fiber (130) can receive a laser pulse emitted from a laser light source (not shown) separately provided externally from a device to which the probe is attached, and guide it to the scanning tip (100). The position of this optical fiber (130) can be fixed by an optical fiber housing (131). The tip of the optical fiber (130) can be located in the opposite direction to the direction in which the first ultrasonic transducer (111) and the second ultrasonic transducer (112) of the transducer base (120) are positioned. A green lens (140) can cause the laser beam emitted from the tip of the optical fiber (130) to be focused at a predetermined working distance. The position of this green lens (140) can be fixed by a green lens housing (141). A prism (150) can cause the laser beam refracted in a form gathered by the green lens (140) to be turned 90° with respect to the central axis of the probe.

[0016] The aforementioned elements are enclosed in a scanning tip casing (101), and a torque coil (200) having a predetermined length is connected to one end of the scanning tip casing (101). A first micro-coaxial cable (111-1) connected to a first ultrasonic transducer (111), a second micro-coaxial cable (112-1) connected to a second ultrasonic transducer (112), and an optical fiber (130) pass through the inside of the torque coil (200). An epoxy finish (160) is formed at the other end of the scanning tip casing (101) to prevent an acoustic matching medium in the form of a fluid, such as water or oil, from entering the inside of the scanning tip (100).

[0017] The optical fiber (130) placed inside the torque coil (200) formed up to the base of the probe can guide the laser pulse received from the device to which the probe is attached to the scanning tip (100). When the laser pulse reaches the end of the optical fiber (130), it is radiated at an angle determined by the optical numerical aperture of the optical fiber (130). Subsequently, the laser pulse travels from the internal space of the air-filled green lens housing (141) to the incident surface of the green lens (140), is refracted by the lens effect within the green lens (140), and finally travels into the prism (150), changes direction by 90° by the principle of total internal reflection, and is radiated in a form that focuses into the acoustic matching medium in which the probe is immersed. That is, since the laser beam is reflected from the four sides of the prism (150) by the principle of total internal reflection, the space bordering the four sides of the prism (150) must be filled with air. That is, the epoxy finish (160) serves to trap air inside the scanning tip (100). However, if a reflective coating is formed on the four sides of the prism (150), the principle of total internal reflection does not need to be applied, so it is not necessary to come into contact with air. For reference, the prism (150) shown in FIGS. 1a and 1b is depicted with a part of one leg removed to provide a path for the second micro coaxial cable (112-1) connected to the second ultrasonic transducer (112), but the present invention is not limited thereto.

[0018] When using a scanning tip (100) as illustrated in FIGS. 1a and 1b, optical focusing capability is provided so that optical resolution photoacoustic imaging can be performed, and since the first ultrasonic transducer (111) and the second ultrasonic transducer (112) are arranged in a symmetrical form, the effect of achieving acoustic focusing to some extent during the ultrasonic imaging process is achieved. Of course, in order to maximize the signal-to-noise ratio in the optical resolution photoacoustic imaging mode, it is desirable to form a focus of the laser beam at the point where the ultrasonic beam emitted by the first ultrasonic transducer (111) and the ultrasonic beam emitted by the second ultrasonic transducer (112) intersect. In this case, the working distance of the endoscope probe is controlled by the inclination angle (θ) to which the first ultrasonic transducer (111) and the second ultrasonic transducer (112) are attached, the pitch of the green lens (140), and the distance between the optical fiber (130) tip and the green lens (140), and can be optimized through appropriate adjustments according to each application. Of course, if high-resolution photoacoustic imaging at the optical resolution level is not required, the aforementioned green lens (140) may be excluded.

[0019] Hereinafter, with reference to FIGS. 2a to 2n, a method for actually assembling and manufacturing a scanning tip (100) is described in a total of 11 steps.

[0020] As shown in the plan view in FIG. 2a, in step 1, a transducer base (120) is prepared by machining the shape to have inclined surfaces that are symmetrical with respect to the laser beam exit (i.e., through hole) according to the shape shown in FIG. 1a. Here, the diameter of the laser beam exit must be equal to or smaller than the width of the prism to be described later.

[0021] In step 2, as illustrated in the plan view in Fig. 2b, an adhesive is applied to one inclined surface to attach the first ultrasonic transducer (111) and the first micro coaxial cable (111-1) connected thereto.

[0022] In each of FIGS. 2c to 2h, the assembly process is explained in detail through drawings illustrating views from two different directions.

[0023] In step 3, as illustrated in FIG. 2c showing a top view and a side view, an adhesive is applied to the opposite inclined surface facing the inclined surface to which the first ultrasonic transducer (111) is attached, thereby attaching the second ultrasonic transducer (112) and the second micro coaxial cable (112-1) connected thereto.

[0024] In step 4, as illustrated in FIG. 2d showing side and bottom views, a prism (150) is attached by applying adhesive to the opposite side (bottom) of the transducer base (120) to which the first ultrasonic transducer (111) and the second ultrasonic transducer (112) are attached. At this time, the position of the prism (150) must be accurately set so that one of the two vertical sides of the prism (150) includes the laser beam exit, and additionally, the edges of the laser beam exit (i.e., the through hole) must be sealed with adhesive so as not to allow the acoustic matching medium to seep into the optical system inside the scanning tip (100).

[0025] Meanwhile, a green lens module composed of a green lens (140) and a green lens housing (141), which are prepared in a separate step as shown in FIG. 2e showing a top view and a side view, is placed in close contact with one of the two vertical surfaces of the prism (150) in step 5 as shown in FIG. 2f showing a side view and a bottom view. At this time, it is preferable to apply the adhesive to the flat bonding surface between the green lens housing (141) and the transducer base (120) rather than to the contact surface between the green lens (140) and the prism (150).

[0026] As shown in the plan view on the left side of FIG. 2e, the length of the green lens housing (141) in the green lens module may be much longer than the length of the green lens (140) by length L, so as to set the desired working distance by appropriately adjusting the parameter L. In the right side view of FIG. 2e, the parameter D of the green lens module represents the diameter of the green lens module, and the parameter d represents the diameter of the green lens (140). As shown in FIG. 2e, the green lens housing (141) may not completely enclose the green lens (140) but partially enclose it. This can be understood as one side of the green lens module being removed by a thickness of (Dd) / 2. In this way, the part of the green lens module removed can be positioned on the transducer base (120). Through this design, the green lens is positioned precisely on the central axis of the scanning tip (100).

[0027] In step 6, as illustrated in FIG. 2g showing side and bottom views, the prism (150) is covered with a prism cover (151) having a cross-section in the shape of a "C" so that foreign matter does not adhere to the four sides of the prism (150) during the subsequent assembly process. Of course, this step is not mandatory and can be omitted.

[0028] Meanwhile, a fiber optic module consisting of a fiber optic cable (130) and a fiber optic housing (131), which are prepared in a separate step as shown in FIG. 2h showing a side view and a front view, is attached to the remaining flat surface on the transducer base (120) in step 7, as shown in FIG. 2i showing a side view, so as to be in close contact with the green lens module. The fiber optic housing (131) of the fiber optic module may be partially removed by a thickness of (Dd) / 2, as in the case of the green lens module described above. This is to ensure that the end of the fiber optic cable (130) is aligned with the central axis of the green lens (140). In a situation where the previously mentioned parameter L value is predetermined, the end of the fiber optic cable (130) must be placed precisely on the end surface of the fiber optic housing (131) (i.e., the surface in the drawing labeled as the front view in FIG. 2h).

[0029] In step 8, as illustrated in the side view FIG. 2j, the second micro coaxial cable (112-1) is bent so as to pass in the opposite direction to the direction in which the first ultrasonic transducer (111) and the second ultrasonic transducer (112) of the transducer base (120) are positioned, and is fixed along a pre-formed groove along one surface of the green lens housing (141) and the optical fiber housing (131). Thus, a groove may be formed on the surface of the green lens housing (141) and the optical fiber housing (131) so that the wire can pass through in a manner embedded within the groove, but the present invention is not limited thereto and may not form such a groove.

[0030] Subsequently, a scanning tip casing (101) in the shape of a tube of a predetermined length having an open area on a part of the side, as shown in the plan view in FIG. 2k, is prepared in advance in a separate step, and in step 9, as shown in FIG. 2l, the elements assembled in the previous step are moved in the direction of the arrow so that the elements assembled in the previous step are inserted into the scanning tip casing (101) and fixed with adhesive. The scanning tip casing (101) has an open area on the side, so that the through hole of the transducer base (120), the first ultrasonic transducer (111), and the second ultrasonic transducer (112) are positioned corresponding to the open area. When inserting the elements assembled in the previous step into the scanning tip casing (101), an optical fiber (130) having a predetermined length, a first micro coaxial cable (111-1), and a second micro coaxial cable (112-1) must be passed into the scanning tip casing (101).

[0031] The scanning tip casing (101) may have an opening (W) formed in an open shape at one end, which is a pre-formed part to allow the second ultrasonic transducer (112) to pass through smoothly when the elements assembled in the previous step are inserted. Of course, depending on the case, for example, if the inner diameter of the scanning tip casing (101) is sufficiently large, the shaping of the relevant opening (W) may be omitted.

[0032] When the elements assembled in the previous step are inserted into the scanning tip casing (101) and fixed by adhesive, the adhesive is sealed not only for the purpose of simple fixation but also to prevent the acoustic matching medium into which the probe will be immersed from flowing into the probe; therefore, it is sealed meticulously as if filling every gap. The epoxy finish (160) performs this sealing function at the end point of the probe. The epoxy finish (160) can seal not only one end of the scanning tip casing (101) but also the entire open portion (W). For reference, the scanning tip casing (101) has an epoxy injection hole (101a). This will be described later.

[0033] In step 10, as illustrated in plan view Fig. 2m, the torque coil (200) is inserted into the scanning tip casing (101) and fitted into the scanning tip casing (101). Of course, just before fitting, a suitable amount of epoxy can be applied to the end of the torque coil (200) for adhesion with the scanning tip casing (101).

[0034] In step 11, as illustrated in the plan view in FIG. 2n, additional epoxy is applied through an epoxy injection hole (101a) formed near the other end of the scanning tip casing (101) so that the epoxy is injected into at least some space within the scanning tip casing (101), thereby preventing the acoustic matching medium, into which the probe will be immersed, from flowing into the internal space of the scanning tip (100) through the internal channel of the torque coil (200). Of course, this epoxy injection hole may be omitted.

[0035] So far, a method for manufacturing a terminal structure of a photoacoustic-ultrasonic mini probe according to one embodiment of the present invention has been described. Since the method described above is merely one embodiment, the order described may be partially changed, and in some cases, some steps may be omitted or other steps may be added.

[0036] Although a scanning tip according to one embodiment has been presented having synthetic acoustic focusing capability in a direction aligned with the axis of laser beam emission using two ultrasonic transducers, the scanning tip of the photoacoustic-ultrasonic mini probe according to the present invention may also be implemented based on a single focused ultrasonic transducer. This will be explained below with reference to FIGS. 3a to 3c.

[0037] First, FIG. 3a is a drawing showing only the transducer base (120), the first ultrasonic transducer (111), and the second ultrasonic transducer (112) among the elements shown in FIG. 1b, and FIG. 3b and FIG. 3c are drawings schematically illustrating a case where, unlike this, an ultrasonic transducer is implemented with one piezoelectric element to have acoustic focusing ability. FIG. 3b can be understood as a side view and FIG. 3c as a top view. As shown in FIG. 3b and FIG. 3c, a scanning tip having acoustic focusing ability can be implemented by positioning a planar piezoelectric element (113) on a planar transducer base (121) having a flat shape and attaching an acoustic lens (113-2) thereon. In this case, the electrical signal entering and exiting the planar piezoelectric element (113) flows through the planar piezoelectric element cable (113-1), and the hole at the center of the acoustic lens (113-2) shown in FIG. 3c is the exit from which the laser beam comes out. An embodiment based on this single piezoelectric element can also be combined with other optical elements as shown in FIG. 1.

[0038] FIG. 4 is a figure showing a photoacoustic-ultrasonic mini probe implemented from a scanning tip to a probe base according to one embodiment.

[0039] The main purpose of the present invention is to provide a structure for a scanning tip that can be used in a photoacoustic-ultrasonic mini probe capable of solving the previously raised problem, but various embodiments of the scanning tip presented above may additionally include several base elements as shown in FIG. 4. FIG. 4 illustrates the aforementioned torque coil (200) being terminated in a form that includes a shaft (300) having a predetermined length to suit the application, an FC / PC connector (400), and a ceramic ferrule (500). In some cases, the length of the shaft (300) may determine the scan length of a three-dimensional pullback scan, and in other cases, a ball bearing module may be added around it. Furthermore, in another embodiment, it may be implemented in a form that includes only the ceramic ferrule (500) without the FC / PC connector (400). In an embodiment that includes both the FC / PC connector (400) and the ceramic ferrule (500), an electrical path may be simultaneously added to both elements through methods such as conductive plating.

[0040] FIG. 5 is a schematic diagram showing a different arrangement of wires of an ultrasonic transducer according to one embodiment.

[0041] In FIGS. 1a, 1b, 2j, 2l, 2m, and 2n, a second micro-coaxial cable (112-1) connected to a second ultrasonic transducer (112) is shown arranged to pass along the outer center of the green lens housing (141) and the optical fiber housing (131). However, if there is enough space, the second micro-coaxial cable (112-1) connected to the second ultrasonic transducer (112) may be allowed to pass through one side of the transducer base (120), as shown in FIG. 5. Additionally, the second micro coaxial cable (112-1) connected to the second ultrasonic transducer (112) may be allowed to pass along the path shown by the two-dot dashed line in FIG. 5, that is, through one side (+y direction) of the green lens housing (141) and the optical fiber housing (131).

[0042] Due to the dimensional limitations typically required in related applications (diameter: 0.7-1.5 mm, rigid end length: 10 mm or less), it is important to effectively position the optical and ultrasonic elements that must be provided within the end, the so-called scanning tip, of photoacoustic-ultrasonic mini-probes or catheters. If the laser beam radiated laterally from the end (i.e., the optical axis) and the acoustic axis formed by the ultrasonic beam are misaligned, and consequently the tissue under examination is not positioned at the distance where the laser beam axis and the acoustic axis intersect, the detected signal will be significantly reduced.

[0043] In addition, if the ultrasonic transducer is positioned deep inside rather than on the surface of the probe and the related sound waves are transmitted through one or more reflective surfaces, severe distortion occurs in the sound waves as they propagate along a narrow space, and problems such as bubbles adhering to the space inside the probe are likely to occur because the ultrasonic transducer is positioned too far inside. Furthermore, it is not easy to ensure that the related optical components are not damaged despite the pulsed laser having a very high instantaneous peak power within a limited space, and to achieve optical-resolution photoacoustic imaging capabilities that require high optical focusing.

[0044] Of course, regardless of the form of the endoscope probe structure, it is conceptually possible to reduce the related structure as much as possible, but in reality, actually implementing the endoscope probe within limited dimensions is by no means an easy task. For instance, even if we consider only the problem of designating the path for the wires connected to the ultrasonic transducer (i.e., the placement process), the related work may seem easy conceptually, but the actual implementation is by no means simple. This is because, since the ultrasonic transducer has a diameter of approximately 1 mm or less and a thickness of 0.3 mm or less, and the micro coaxial cable attached to the transducer for electrical signal input and output has a thickness of approximately 150 μm or more, and the total thickness of the endoscope probe is 0.7-1.5 mm, allocating space for a 150 μm thick cable is by no means a trivial matter.

[0045] However, by following the unique structure and manufacturing method presented in the present invention as described above, it becomes possible to simultaneously realize optically high-resolution photoacoustic imaging and conventional ultrasound imaging within a space of 0.7–1.5 mm in diameter and 10 mm or less in length of the distal scanning tip, while ensuring perfect alignment of the optical axis and acoustic axis without any damage to the optical element caused by the pulsed laser beam passing through the relevant area. Furthermore, since the ultrasound transducer is positioned on the surface of the probe, it comes into more direct contact with the surrounding acoustic matching medium; consequently, the probability of bubbles or the like adhering to the surface of the ultrasound transducer during actual use, which could interfere with the related imaging procedure, is significantly reduced.

[0046] The unique probe structure presented in this invention is primarily targeted at endoscopes for diagnosing digestive diseases, but it can be applied to cardiovascular disease diagnostic applications requiring much greater probe miniaturization, as well as to various other fields of endoscopy. Explanation of the symbols

[0047] 100: Scanning tip 101: Scanning tip casing 111: First ultrasonic transducer 111-1: First micro-coaxial cable 112: Second ultrasonic transducer 112-1: Second micro-coaxial cable 113: Planar piezoelectric element 113-1: Planar piezoelectric element cable 113-2: Acoustic lens 120: Transducer base 121: Planar transducer base 130: Optical fiber 131: Optical fiber housing 140: Green lens 141: Green lens housing 150: Prism 151: Prism cover 160: Epoxy finish 200: Torque coil 300: Shaft 400: FC / PC connector 500: Ceramic ferrule

Claims

Claim 1 A transducer base having a through hole and a first inclined surface located on one side of the through hole and a second inclined surface located on the other side of the through hole so as to be mutually symmetrical with respect to the central axis of the through hole; a first ultrasonic transducer disposed on the first inclined surface; a second ultrasonic transducer disposed on the second inclined surface; an optical fiber having a tip located in the opposite direction to the direction in which the first ultrasonic transducer and the second ultrasonic transducer are disposed on the transducer base; a prism that reflects a laser beam emitted from the tip of the optical fiber to pass through the through hole; and a first micro-coaxial cable connected to the first ultrasonic transducer. A scanning tip for a photoacoustic-ultrasonic mini probe, comprising: a second micro coaxial cable connected to the second ultrasonic transducer; wherein the first micro coaxial cable is positioned in the direction in which the first ultrasonic transducer and the second ultrasonic transducer of the transducer base are positioned, and the second micro coaxial cable is bent to pass in the opposite direction to the direction in which the first ultrasonic transducer and the second ultrasonic transducer of the transducer base are positioned. Claim 2 A scanning tip for a photoacoustic-ultrasonic mini probe according to claim 1, further comprising a green lens interposed between the tip of the optical fiber and the prism. Claim 3 delete Claim 4 A scanning tip for a photoacoustic-ultrasonic mini probe according to claim 1, further comprising: a green lens interposed between the tip of the optical fiber and the prism; and a green lens housing for fixing the green lens; wherein the second micro-coaxial cable is disposed in a groove formed in the green lens housing. Claim 5 A scanning tip for a photoacoustic-ultrasonic mini probe according to claim 1, further comprising an optical fiber housing for fixing the optical fiber, wherein the second micro-coaxial cable is disposed in a groove formed in the optical fiber housing. Claim 6 A scanning tip for a photoacoustic-ultrasonic mini probe according to claim 1, further comprising a scanning tip casing that accommodates the transducer base, the first ultrasonic transducer, the second ultrasonic transducer, the optical fiber, and the prism inside, and has an open area corresponding to the through hole, the first ultrasonic transducer, and the second ultrasonic transducer. Claim 7 A scanning tip for a photoacoustic-ultrasonic mini probe according to claim 6, wherein the scanning tip casing has a tube shape of a preset length and has an open area on the side corresponding to the through hole, the first ultrasonic transducer, and the second ultrasonic transducer. Claim 8 In claim 7, the scanning tip casing is a scanning tip for a photoacoustic-ultrasonic mini probe having an open portion at one end. Claim 9 A scanning tip for a photoacoustic-ultrasonic mini probe according to claim 8, further comprising an epoxy finish that seals one end of the scanning tip casing and the opening. Claim 10 In claim 8, the scanning tip casing has an epoxy injection hole located adjacent to the other end, for a scanning tip for a photoacoustic-ultrasonic mini probe. Claim 11 A scanning tip for a photoacoustic-ultrasonic mini probe according to claim 10, further comprising epoxy filling the inside of the scanning tip casing through the epoxy injection hole.

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