Ultra-miniature photoacoustic microscope

Abstract

The present invention presents a novel photoacoustic or optoacoustic microscopy structure capable of solving the problem wherein accessing a target area when scanning various recessed areas of a human body is difficult due to the large physical size occupied by a scanning head, that is, the large footprint problem of the scanning head in conventional mechanical scanning-type photoacoustic or optoacoustic microscopy systems. A photoacoustic microscope presented by the present invention makes it possible to significantly reduce the footprint compared to the prior art when implementing a relevant device, and thus can be variously applied to not only a handle-type, that is, a handheld probe implemented so that a user can freely image any desired area by holding the device directly by hand, but also to a miniature probe used to visualize an area of interest in an invasive manner accompanying surgery or a non-invasive manner, and an endoscope device used to diagnose suspected disease areas such as the gastrointestinal tract or blood vessels.

Description

Ultra-miniature photoacoustic microscope

[0001] The present invention is an invention most closely related to photoacoustic microscopy (PAM) among photoacoustic computed tomography (PACT), photoacoustic microscopy (PAM), and photoacoustic endoscopy (PAE), which are known as the three core areas of photoacoustic imaging technology, which is attracting attention as a next-generation medical imaging technology.

[0002] The present invention belongs to the field of photoacoustic imaging, and in particular, relates to photoacoustic microscopy (PAM) using a single ultrasonic transducer-based mechanical scanning method.

[0003] First, a single ultrasonic transducer-based mechanical scanning photoacoustic imaging device does not necessarily mean that the number of transducers applied to the relevant system must be a single unit, but rather refers to devices that scan by physically directly moving the ultrasonic transducer applied to the relevant system or its surrounding elements for the purpose of obtaining a desired image over a certain range according to the photoacoustic imaging principle, that is, devices that operate in a manner that contrasts with the so-called array transducer-based scanning method that obtains an image by electrically scanning without any direct physical moving elements.

[0004] Photoacoustic microscopy systems that follow this mechanical scanning method have been considered a very important system implementation method in terms of commercialization because their implementation costs are relatively lower than those of photoacoustic microscopy systems that use array transducers, and in many cases, their image quality is also superior.

[0005] However, conventional photoacoustic microscopes developed according to this mechanical scanning method have a very large footprint, which has significant limitations in accessing and smoothly acquiring images of areas required in many real-world situations, such as sunken areas. Furthermore, many devices that follow this method have the problem of considerably slow scanning speeds because they apply a raster scanning method such as a round-trip scan.

[0006] The purpose of the present invention is to provide an ultra-miniature photoacoustic microscope device that has a structure that is much easier to image, such as a sunken area, by applying a mechanical scanning method and without the problem of excessive size of the scanning head that existing photoacoustic microscope systems have.

[0007] Through this, the ultra-miniature photoacoustic microscope according to one embodiment of the present invention can drastically reduce the footprint of the scanning head to 2 to 3 cm or less, and can even reach up to several mm.

[0008] The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0009] An ultra-miniature photoacoustic microscope according to one embodiment of the present invention may include a scanning tip that is rotatably installed in one direction inside an imaging window and detects a photoacoustic signal generated by emitting light received from a light source to a subject; a bearing module that is installed inside the imaging window and supports the scanning tip so that the scanning tip can rotate relative to the imaging window; and a probe base that transmits a rotational force generated from a driving unit to the scanning tip.

[0010] In addition, the optical fiber connected to the scanning tip is installed along the central axis, and further includes a conductive FC / PC connector ferrule; and an FC / PC connector nut connected to the FC / PC connector ferrule and relaying an electric signal of the driving unit, wherein the probe base can receive laser light from the driving unit through the optical fiber.

[0011] Additionally, it may further include an encoder module that detects phase information about the rotation angle of the scanning tip.

[0012] Additionally, the encoder module may include a disk coupled to the scanning tip and rotated together with the scanning tip; and an encoder sensor that forms an electric pulse signal according to a predetermined step rotation of the disk.

[0013] Additionally, the encoder module may further include an encoder base interposed between the imaging window and the scanning tip and to which the encoder sensor is coupled.

[0014] Additionally, the above disk may have a ring shape.

[0015] Additionally, the disk may be arranged in a structure in which the scanning tip penetrates its central axis.

[0016] Additionally, the bearing module may include a bearing housing coupled to the image window; and a plurality of bearings interposed with a gap between the bearing housing and the scanning tip.

[0017] Additionally, the bearing may be a ball bearing.

[0018] In addition, the device may further include a first imaging window fixing piece installed on one side of the image window and supporting one side of the image window; and a second imaging window fixing piece installed on the other side of the image window and supporting the other side of the image window.

[0019] Additionally, the probe head may further include a radial shaft seal interposed between the first imaging window fixing piece and the scanning tip.

[0020] In addition, it may further include a terminal sealing screw detachably coupled to the second imaging window fixing piece; and a terminal sealing screw O-ring interposed between the second imaging window fixing piece and the terminal sealing screw.

[0021] Additionally, the interior of the imaging window may be filled with a matching fluid.

[0022] Additionally, the probe base may have a fluid inlet for injecting a matching fluid.

[0023] In addition, the scanning tip may include a transducer base; a first ultrasonic transducer and a second ultrasonic transducer spaced apart from each other on the transducer base; an optical fiber connected to the bearing module and a torque coil to guide light received from a light source to the transducer base; and a prism installed on the transducer base to reflect light guided to the transducer base from the optical fiber between the first ultrasonic transducer and the second ultrasonic transducer.

[0024] In addition, the transducer base may have a first inclined surface and a second inclined surface that are arranged symmetrically to each other, and the first ultrasonic transducer may be arranged on the first inclined surface, and the second ultrasonic transducer may be arranged on the second inclined surface.

[0025] In one embodiment, the disk may be coupled to a scanning tip casing of the scanning tip.

[0026] In one embodiment, the encoder sensor has a cross-sectional shape in the form of an arc and may be arranged such that a portion of the circumference of the disk is inserted along the internal space of the encoder sensor.

[0027] In one embodiment, the encoder base may have a hollow hole formed therein through which the scanning tip passes. Here, the hollow hole may be formed on the central axis of the encoder base.

[0028] In one embodiment, the bearing module may include a first bearing and a second bearing interposed with a gap between the bearing housing and the scanning tip.

[0029] In one embodiment, the terminal seal screw may be screwed into the second imaging window fixing piece.

[0030] Other specific details of the present invention are included in the detailed description and drawings.

[0031] The photoacoustic microscope probe according to one embodiment of the present invention enables the implementation of a scanning head having a much smaller footprint than existing devices, thereby expanding the scope of application of related technologies to more diverse areas, such as sunken areas of the body. In addition, due to the effect of the cylindrical imaging window, which is one of the core features of the device, the tissue to be examined is always placed at the working distance of the focusing lens during the scanning process, thereby significantly increasing the spatial range within which a designer can obtain a valid image with the level of resolution expected at the time of the original design, i.e., the field of view.

[0032] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

[0033] FIG. 1a is a schematic diagram showing a probe head portion of an ultra-miniature photoacoustic microscope according to one embodiment of the present invention.

[0034] Figure 1b is a cross-sectional view taken along the xy plane at point AA' of Figure 1a.

[0035] Figure 1c is a cross-sectional view of the first imaging window fixing piece section of Figure 1a taken along the xz plane.

[0036] FIG. 2 is a schematic diagram showing the base side configuration of an ultra-miniature photoacoustic microscope device according to one embodiment.

[0037] FIG. 3 is a perspective view three-dimensionally depicting a probe base portion implemented according to the embodiment presented in FIG. 2.

[0038] Figure 4 is a schematic diagram showing a probe end according to another embodiment of the present invention.

[0039] FIG. 5 is a schematic diagram showing a preferred base-side structure of a probe when implementing an ultra-miniature photoacoustic microscope according to the embodiment presented in FIG. 4.

[0040] FIG. 6 is a perspective view three-dimensionally depicting a probe base portion implemented according to the embodiment presented in FIG. 5.

[0041] Figure 7 is a schematic diagram showing a probe head according to another embodiment of the present invention.

[0042] FIG. 8 is a schematic diagram showing the structure of an ultra-miniature probe applying a magnetic encoder module according to another embodiment of the present invention.

[0043] Figure 9 is a schematic diagram showing a method for performing a 3D scan based on the embodiment presented in Figure 1a.

[0044] Figure 10 is a drawing showing an application example of a device implemented according to the present invention.

[0045] The present invention is capable of various modifications and embodiments. Specific embodiments are illustrated in the drawings and described in detail. The effects and features of the present invention, as well as the methods for achieving them, will become clearer with reference to the embodiments described in detail below, along with the drawings. However, the present invention is not limited to the embodiments disclosed below and can be implemented in various forms.

[0046] 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.

[0047] In the following examples, the terms first, second, etc. are not used in a limiting sense, but are used for the purpose of distinguishing one component from another.

[0048] In the examples below, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0049] In the examples below, terms such as “include” or “have” mean that a feature or component described in the specification is present, and do not preclude the possibility that one or more other features or components may be added.

[0050] In the following examples, when a component is said to be “connected” to another component, this includes not only being directly connected to the other component, but also being indirectly connected by another component.

[0051] FIG. 1A is a perspective view three-dimensionally depicting a probe head portion of an ultra-miniature photoacoustic microscope according to one embodiment of the present invention.

[0052] Referring to FIG. 1A, an ultra-miniature photoacoustic microscope according to one embodiment of the present invention comprises an optical fiber (110) that transmits pulsed laser light (not shown) incident through a probe base (200) to be described in FIG. 2 while being placed inside a torque coil (160) to a probe head (100), a lens (121) that focuses the laser beam emitted through the optical fiber (110) at a predetermined working distance point, a prism (122) that bends the direction of light passing through the lens (121) by 90° with respect to the z-axis, which is the central axis of the probe head (100), and a scanning tip (120) that is configured with a first ultrasonic transducer (123) and a second ultrasonic transducer (124) that detect a photoacoustic signal ultimately generated from a tissue to be examined according to the photoacoustic principle and is equipped to rotate in only one direction, and a bearing module (130) that is equipped to provide conditions for more stable rotational movement to the scanning tip, and The mentioned scanning tip (120) may include an imaging window (170) having a cylindrical shape that allows the scanning tip (120) to always maintain a constant distance from the target area during the scanning process, thereby placing the tissue to be examined at the optimal working distance of the lens mentioned above. The photoacoustic signal detected by the first ultrasonic transducer (123) and the second ultrasonic transducer (124) mentioned above is transmitted to the probe base via the first micro coaxial cable (123-1) and the second micro coaxial cable (124-1), which are connected to each of the two transducers (123, 124) and are arranged along the inside of the scanning tip casing (126) and the torque coil (160) and serve as a kind of conductive wire, and the first micro coaxial cable (123-1) and the second micro coaxial cable (124-1) rotate together with the torque coil (160) and the optical fiber (110) arranged therein during the rotational scan mentioned above.

[0053] The torque coil (160) is a mechanical element configured to have a single or multiple layers of a metal material having a shape like a spring, and has the characteristic of being able to smoothly transmit physical rotation from one end to the other even in a situation where its body is bent in any shape, so that the first micro coaxial cable (123-1), the second micro coaxial cable (124-1), and the optical fiber (110) mentioned above are physically protected by the torque coil (160) even in a situation where the torque coil (160) rotates while being bent, and each performs its assigned role without any problem.

[0054] In other words, the torque coil (160) protects the elements arranged inside it by wrapping them and transmits physical rotational force from the probe base to the scanning tip (120). It is ultimately connected to the scanning tip casing (126) illustrated in Fig. 1a, and the above-mentioned bearing module (130) supports the scanning tip casing (126) arranged in a form that extends to its inside so that it is always placed on its central axis, thereby preventing physical shaking when the scanning tip (120) rotates. That is, in this case, the scanning tip casing (126) also functions as a kind of shaft that rotates inside the ball bearing.

[0055] According to one embodiment shown in Fig. 1a, the bearing module (130) may include a first bearing (131) and a second bearing (132) arranged in a bearing housing (133), in other words, a plurality of bearings.

[0056] The bearing housing (133) supports the first bearing (131) and the second bearing (132), and is connected to a braided catheter (180) that surrounds and protects the aforementioned torque coil (160) through a probe head-body connecting piece (150).

[0057] With respect to the bearing module (130), an imaging window (170) is placed at the probe end (i.e., in the +z-axis direction) so as to maintain a cylindrical shape with the support of the first imaging window fixing piece (171) and the second imaging window fixing piece (172), and is placed in contact with the tissue to be examined while remaining stationary during actual image scanning. Through its thin wall, a laser beam is emitted toward the tissue to be examined according to the principle described above, and a practical photoacoustic signal acquisition procedure of detecting the photoacoustic wave induced thereby is performed. In order for this process to be carried out smoothly, the imaging window (170) must be optically transparent and also made of a material that allows ultrasound to pass through well acoustically. Of course, due to these requirements, the thinner the thickness, the better. The first imaging window fixing piece (171) and the second imaging window fixing piece (172) play a role in maintaining the shape as a cylinder, and in order to prevent distortion of the shape of the imaging window (170), the smaller the gap between the first imaging window fixing piece (171) and the second imaging window fixing piece (172) the better.

[0058] In the miniature photoacoustic microscope according to the present invention, the working distance and contact area (i.e., image range) when actually imaging a tissue to be examined are determined by the diameter (D) of the imaging window (170), the cylindrical shape of which is maintained by the first imaging window fixing piece (171) and the second imaging window fixing piece (172). That is, as the diameter (D) of the imaging window (170) increases, the working distance increases, and the area through which a valid image signal enters by direct physical contact with the tissue to be examined also increases.

[0059] When applying the miniature photoacoustic microscope according to the present invention to an actual subject, ultrasound gel may be applied to the surface of the imaging window (170) as needed for smooth propagation of ultrasound induced by the photoacoustic effect. In order for the ultrasound to effectively propagate to the first ultrasound transducer (123) and the second ultrasound transducer (124) located inside the imaging window (170), the inside of the imaging window (170) must be filled with a matching fluid (173) that is as optically transparent as possible and has low ultrasound attenuation characteristics.

[0060] Due to these acoustic requirements, the first imaging window fixing piece (171) and the second imaging window fixing piece (172) not only maintain the shape of the imaging window (170), but also seal the matching fluid (173) filled inside the imaging window (170) to prevent it from leaking out. In this case, there is a concern that the matching fluid (173) may leak between the first imaging window fixing piece (171), which must always remain stationary, even while the scanning tip (120) rotates. In order to prevent this, in the probe head (100) of the miniature photoacoustic microscope probe according to one embodiment shown in FIG. 1A, a probe head radial shaft seal (174) may be arranged between the inside of the first imaging window fixing piece (171) and the scanning tip casing (126), as shown in FIG. 1C, which is a cross-sectional view taken along the xz plane of the first imaging window fixing piece section of FIG. 1A. That is, the probe head radial shaft seal (174) has a main role of preventing the matching fluid (173) from leaking between the first imaging window fixing piece (171) that remains stationary and the scanning tip casing (126) that rotates relative to it. However, even if such a role is key, the material must be very soft and have almost no tightening force due to its own elasticity so as not to impede the rotational movement of the scanning tip casing (126).

[0061] A miniature photoacoustic microscope according to one embodiment may further include an encoder module (140) between the bearing module (130) and the first imaging window fixing piece (171), as illustrated in FIG. 1A.

[0062] The encoder module (140) is largely composed of a disk (142) that is attached to the scanning tip casing (126) and can rotate therewith, an encoder sensor (141), and an encoder base (143). It generates an electric pulse signal whenever the scanning tip (120) rotates by a predetermined angle. Of course, this electric pulse signal can be used as a reference signal necessary for synchronizing the linked devices, in other words, triggering peripheral devices such as a light source (not shown) that provides the aforementioned laser light and a data acquisition device (not shown). In this case, even if there is an irregular delay in the rotational power transmitted from the base to the probe head (100) through the torque coil (160) or fluctuation in the rotational angle, it is possible to obtain accurate phase information on how much the scanning tip (120) has moved.

[0063] An electric pulse signal generated from the encoder sensor (141) is transmitted to the base of the probe along the sensor signal line (141-1) connected thereto, and is arranged to pass along the outer surface of the braided catheter (180), as shown in FIG. 1b, which is a cross-sectional view taken along the xy plane at point A-A' in FIG. 1a. Of course, in this case, in order to prevent the sensor signal line (141-1) from being damaged, a polymer sheath (190) having a very thin wall thickness that surrounds both the sensor signal line (141-1) and the braided catheter (180) from the outside may be added.

[0064] The probe head (100) portion of the miniature photoacoustic microscope device according to one embodiment of the present invention has been described above, and an implementation method of the probe base (200) corresponding to the opposite end of the device will be described based on FIG. 2.

[0065] At the probe base (200), an FC / PC connector (250) commonly used in the optical communication field is arranged so that a laser beam transmitted from a driving unit (not shown) of the present device, which can be implemented separately from the present invention, can smoothly enter through the entrance of an optical fiber (110) at the base end of the probe while being physically closely connected to the driving unit mentioned.

[0066] However, the FC / PC connector (250) according to the present invention can be understood as a kind of custom-designed part having somewhat different characteristics from a general FC / PC connector, and is largely composed of an FC / PC connector ceramic ferrule (250-1), an FC / PC connector housing (250-2), and an FC / PC connector nut (250-3), and has the characteristic of receiving a laser beam from the aforementioned driving unit (not shown) and also receiving mechanical rotational power and relaying an electrical signal.

[0067] To explain more specifically, the proximal end of the optical fiber (110) is terminated in the FC / PC connector ceramic ferrule (250-1), which is a part of the FC / PC connector (250), through which the laser beam is incident, and the mechanical rotational power is transmitted through the FC / PC connector housing (250-2) and then transmitted to the torque coil (160) through the hollow rotation shaft (210) that connects it with the torque coil (160). For this reason, the epoxy sealing portion (230) is an element that achieves a close physical coupling between the hollow rotation shaft (210) and the torque coil (160), and it is obvious that the optical fiber (110), the first micro coaxial cable (123-1), and the second micro coaxial cable (124-1), which are arranged along the internal space of the torque coil (160), must pass through it.

[0068] In one embodiment, the first micro coaxial cable (123-1) and the second micro coaxial cable (124-1) are combined into one inside the hollow rotary shaft (210), and the core-side wires of the two cables are connected to the surface of the FC / PC connector ceramic ferrule (250-1), and the shield-side wires are connected to the FC / PC connector nut (250-3), so that electricity can be transmitted through them when the FC / PC connector (250) is connected to a driving unit (not shown). In order to achieve such smooth electrical transmission, a conductive coating or a component having similar properties must be added to the surface of the FC / PC connector ceramic ferrule (250-1), and the FC / PC connector nut (250-3) must also be made of a material with excellent electrical conductivity. Of course, it is desirable to have an insulating member (not shown) installed on the FC / PC connector housing (250-2) for electrical insulation between the FC / PC connector ceramic ferrule (250-1) and the FC / PC connector nut (250-3).

[0069] That is, the FC / PC connector ferrule (250-1) can be installed along the central axis with an optical fiber (110) connected to the scanning tip (120) and can be conductively treated. In addition, the FC / PC connector nut (250-3) can be connected to the FC / PC connector ferrule and relay an electric signal from the driving unit. Here, the probe base (200) can receive laser light from the driving unit through the optical fiber (110).

[0070] According to the structure and characteristics of the FC / PC connector (250) and the hollow rotary shaft (210) described above, a laser beam, mechanical rotational force, and an electric signal are transmitted from a driving unit (not shown) toward a torque coil (160), and in the case of an electric signal, it can also be transmitted in the reverse direction if necessary.

[0071] Meanwhile, in order to ensure smooth rotational movement of the hollow rotary shaft (210) while ensuring clear spatial separation from the stationary surrounding environment and smooth physical coupling with the driving unit (not shown), it is preferable that a Teflon lining (220) and a base housing (240) are sequentially added to the outside of the hollow rotary shaft (210). In this case, the braided catheter (180) described above can be connected in a form that is closely coupled with the base housing (240). Of course, the Teflon lining (220) may also be formed as if it were included as a partial element on the inner surface of the base housing (240).

[0072] In addition to the structural features described above, FIG. 2 shows how the sensor signal line (141-1) comes out between the braided catheter (180) and the polymer sheath (190), and of course, unlike as shown in FIG. 2, this sensor signal line (141-1) can be implemented so that it can be connected to the relevant corresponding component on the driving unit (not shown) side along the surface of the base housing (240).

[0073] FIG. 3 is a three-dimensional perspective view to help better understand the probe base portion implemented according to one embodiment presented in FIG. 2.

[0074] In Fig. 1a, an embodiment of a miniature photoacoustic microscope is presented in which matching fluid (173) is filled in the probe head (100). However, in some cases, it may be necessary to implement a device that allows the matching fluid (173) to be filled in and removed from the probe head (100) only when desired.

[0075] FIG. 4 is another embodiment of a probe head (100) designed precisely according to this need, and can satisfy the need by implementing a different shape of the end point of the end portion so that a detachable / fastenable end sealing screw (175) can be applied to the end portion of the probe head (100). Of course, in this case, since a screw thread is formed on the central axis of the end sealing screw (175), a corresponding hole and screw thread must also be formed in the second imaging window fixing piece (172) that acts as a nut to be fastened thereto, and in addition, a end sealing screw O-ring (176) may be added to the bottom surface of the head of the end sealing screw (175) so that the matching fluid (173) filling the internal space of the imaging window (170) does not leak out.

[0076] Meanwhile, when implementing a miniature photoacoustic microscope device according to the embodiment presented in FIG. 4, in order to freely fill the internal space of the imaging window (170) with a matching fluid (173) at a desired time, it is preferable that the corresponding probe base (200) be implemented differently, as in FIG. 5, rather than the structure of FIG. 2 presented above.

[0077] The main difference of FIG. 5 based on FIG. 2 is that it additionally includes a fluid inlet (270) for injecting matching fluid (173) through a point on the surface of the base housing (240) and a base radial shaft seal (260) that prevents the matching fluid (173) injected therethrough from leaking into the gap between the base housing (240) and the hollow rotary shaft (210).

[0078] FIG. 6 is a perspective view to more clearly express the positional relationship of the two additional elements (270 & 260) mentioned above in three dimensions. If a miniature photoacoustic microscope device is implemented according to the embodiment of FIG. 5 or FIG. 6, the probe head radial shaft seal (174) as presented in FIG. 1A becomes unnecessary inside the probe head (100) of the device, and in this case, the matching fluid (173) injected through the fluid inlet (270) is filled from the base radial shaft seal (260) point to the end seal screw (175) located at the end of the probe head (100).

[0079] So far, a method for implementing a miniature photoacoustic microscope device with a somewhat limited number of usable times has been described through FIGS. 1A to 6. However, if the miniature photoacoustic microscope device according to the present invention is to be used semi-permanently, it may be necessary to implement a method in which the imaging window (170), which may experience surface wear over long periods of use, can be freely replaced at any desired time.

[0080] Fig. 7 is another embodiment designed to meet this need, and is an example of a miniature photoacoustic microscope device that is implemented so that the imaging window (170) portion can be freely separated in addition to the embodiment presented in Fig. 6.

[0081] In this embodiment, by adding a part having a thread that can be separated / combined with each other to the first imaging window fixing piece (171) and the encoder base (143) and adding an imaging window sealing O-ring (177) between them, it becomes possible to freely separate between the two points mentioned at any time, so that the entire imaging window (170) module connected to the first imaging window fixing piece (171) and the second imaging window fixing piece (172) can be replaced with a new one.

[0082] Since the main reason for designing this embodiment is to enable the imaging window (170) to be freely replaced at any time, in this case as well, it is preferable that the matching fluid (173) to be filled inside the probe head (100) is injected through the fluid inlet (270) shown in FIG. 5 before use and sealed with the end sealing screw (175) provided at the end of the probe head (100).

[0083] FIG. 8 is a schematic diagram showing the structure of an ultra-miniature probe that applies a magnetic encoder module (144) composed of a magnetic encoder sensor (145), a magnetic disk (146), and a magnetic encoder base (147), instead of the encoder module (140) presented in FIG. 1, according to another embodiment of the present invention. In this case, as in the embodiment applying the encoder module (140) presented in FIG. 1A, the magnetic encoder sensor (145) provides an electric pulse signal each time the magnetic disk (146) rotates each step together with the scanning tip (120), thereby providing accurate phase information on how much the scanning tip (120) has moved.

[0084] Through the above drawings 1a to 8, several embodiments capable of implementing an ultra-miniature photoacoustic microscope device are presented.

[0085] However, in another embodiment of the ultra-miniature photoacoustic microscope device according to the present invention, it is also possible to obtain a three-dimensional photoacoustic image by adding a simple one-dimensional pullback motion to the probe head (100) shown in the embodiment of FIG. 1a.

[0086] Fig. 9 shows exactly this embodiment, and by additionally connecting a pullback stage (300) to the probe head (100), the scanning tip (120) ultimately performs a helical movement due to the combined effect of the rotational movement of the scanning tip (120) itself and the one-dimensional linear movement provided by the pullback stage (300), thereby obtaining an accurate three-dimensional image. Of course, in this case, the movement speed of the pullback stage (300) must be set to be synchronized with the rotational speed of the scanning tip (120), and in that case, the pullback stage (300) moves a predetermined pitch for each rotation of the scanning tip (120), thereby obtaining an extremely accurate three-dimensional image.

[0087] Hereinafter, various embodiments have been presented that can realize a photoacoustic microscope with a significantly reduced footprint of the above-mentioned scanning head compared to the existing ones. It is clear that this innovative photoacoustic microscope concept provided by the present invention can open up a new way to freely image various depressed areas of the human body and local areas of small animals, which the existing inventions could not even imagine, as exemplified in Fig. 10. Therefore, the ultra-microscopic photoacoustic microscope concept provided by the present invention is expected to be applied in various ways, such as a handheld probe that allows the user to freely image any desired area by holding the device directly in their hand, as well as a miniature probe used to visualize an area of ​​interest in an invasive or non-invasive manner involving surgery, and an endoscopic device used to diagnose a suspected area of ​​disease such as the gastrointestinal tract or blood vessels.

Claims

1. A scanning tip that is installed so as to be rotatable in one direction inside the imaging window and detects a photoacoustic signal generated by emitting light received from a light source to a subject; A bearing module that supports the scanning tip so that it can rotate relative to the imaging window; and An ultra-miniature photoacoustic microscope comprising a probe base that transmits rotational force generated from a driving unit to the scanning tip.

2. In paragraph 1, An optical fiber connected to the scanning tip is installed along the central axis, and a conductive FC / PC connector ferrule; and Further comprising an FC / PC connector nut that is connected to the FC / PC connector ferrule and relays the electric signal of the driving unit, An ultra-miniature photoacoustic microscope, wherein the above probe base can receive laser light from the driving unit via the above optical fiber.

3. In paragraph 1, An ultra-miniature photoacoustic microscope further comprising an encoder module for detecting phase information on the rotation angle of the scanning tip.

4. In paragraph 3, The above encoder module, a disk coupled to the scanning tip and rotating together with the scanning tip; and An ultra-miniature photoacoustic microscope comprising an encoder sensor that forms an electric pulse signal according to a certain step rotation of the above disk.

5. In paragraph 4, The above encoder module, An ultra-miniature photoacoustic microscope further comprising an encoder base interposed between the imaging window and the scanning tip and to which the encoder sensor is coupled.

6. In paragraph 4, The above disk is an ultra-miniature photoacoustic microscope having a ring shape.

7. In paragraph 4, An ultra-miniature photoacoustic microscope, wherein the disk is arranged in a structure in which the scanning tip penetrates its central axis.

8. In paragraph 1, The above bearing module, a bearing housing coupled to the image window; and An ultra-miniature photoacoustic microscope comprising a single or multiple bearings interposed with a gap between the bearing housing and the scanning tip.

9. In paragraph 8, The above bearing is a ball bearing, ultra-miniature photoacoustic microscope.

10. In paragraph 1, A first imaging window fixing piece installed on one side of the image window and supporting one side of the image window; and An ultra-miniature photoacoustic microscope further comprising a second imaging window fixing piece installed on the other side of the image window and supporting the other side of the image window.

11. In paragraph 10, An ultra-miniature photoacoustic microscope further comprising a probe head radial shaft seal interposed between the first imaging window fixing piece and the scanning tip.

12. In paragraph 10, A terminal seal screw detachably connected to the second imaging window fixing piece; and An ultra-miniature photoacoustic microscope further comprising a terminal seal screw O-ring interposed between the second imaging window fixing piece and the terminal seal screw.

13. In paragraph 1, An ultra-miniature photoacoustic microscope, wherein the interior of the above imaging window is filled with a matching fluid.

14. In paragraph 1, The above probe base is an ultra-miniature photoacoustic microscope having a fluid inlet for injecting a matching fluid.

15. In paragraph 1, The above scanning tip is, transducer base; A first ultrasonic transducer and a second ultrasonic transducer arranged at intervals on the transducer base; An optical fiber connected through the bearing module and the torque coil to guide light received from the light source to the transducer base; and An ultra-miniature photoacoustic microscope, comprising a prism installed on the transducer base to reflect light guided from the optical fiber to the transducer base between the first ultrasonic transducer and the second ultrasonic transducer.

16. In paragraph 15, The above transducer base has a first inclined surface and a second inclined surface arranged symmetrically to each other, The above first ultrasonic transducer is arranged on the first inclined surface, An ultra-miniature photoacoustic microscope, wherein the second ultrasonic transducer is arranged on the second inclined surface.

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