Abstract:
Provided is a miniaturized photo-acoustic probe for a clinical image capable of effectively measuring a photo-acoustic signal by making an ultrasonic axis and an optical axis parallel. The photo-acoustic probe for a clinical image includes a laser generator configured to generate a laser beam, an ultrasound transducer disposed to be parallel to the laser generator and configured to analyze ultrasound output from an object, first and second reflectors configured to receive ultrasound generated in an axis identical to that of the laser beam generated by the laser generator, and a medium material configured to allow the laser to be transmitted from the first reflector to the object and increase ultrasound reflectivity of the first and the second reflector.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2013-0119893, filed on Oct. 08, 2013 and Korean Patent Application No. 10-2014-0052404, filed on Apr. 30, 2014, the disclosure of which is incorporated herein by reference in its entirety. 
       TECHNICAL FIELD 
       [0002]    The present invention relates to a photo-acoustic probe for a clinical image, and more particularly, to a miniaturized photo-acoustic probe for a clinical image capable of effectively measuring a photo-acoustic signal by coaxially aligning an ultrasonic axis and an optical axis. 
       BACKGROUND 
       [0003]    In general, photo-acoustic imaging techniques obtain information by generating a sound by light. General photo-acoustic imaging techniques will be described briefly with reference to  FIG. 1 . 
         [0004]      FIG. 1  is a view illustrating a structure of a related art photo-acoustic probe. 
         [0005]    As illustrated in  FIG. 1 , a related art photo-acoustic probe has a structure in which an ultrasound transducer  12  is disposed slopingly at a predetermined angle with respect to a pulse laser  11  to make an axis of a laser beam output from the pulse laser  11  and an axis of ultrasound incident to the ultrasound transducer  12  oblique to reduce a device between a path of a laser beam and a path of ultrasound as possible to minimize loss generated therebetween. 
         [0006]    However, when the two paths are sloped at a predetermined angle, a dark zone may appear in a region  4  of  FIG. 1 , where an image cannot be measured. Also, the oblique structure may increase a volume due to a structural limitation causing user inconvenience. 
         [0007]    Alternatively, an effective probe structure in which a glass plate is used to make a laser beam irradiated to a sample and an ultrasound beam placed coaxially to reduce a dark zone has been proposed. 
         [0008]    However, since a connector inputting light to a probe and an ultrasound transducer that receives ultrasound is at a right angle (90°), it is difficult to use the probe structure. 
       SUMMARY 
       [0009]    Accordingly, the present invention provides a photo-acoustic probe for a clinical image capable of effectively measuring a photo-acoustic signal and miniaturizing a probe structure by adjusting an ultrasonic axis and an optical axis such to be coaxially placed. 
         [0010]    In one general aspect, a photo-acoustic probe for a clinical image may include: a laser generator configured to generate a laser beam; an ultrasound transducer disposed to be parallel to the laser generator and configured to analyze ultrasound output from an object; first and second reflectors configured to receive ultrasound generated in an axis identical to that of the laser beam generated by the laser generator; and a medium material configured to allow the laser to be transmitted from the first reflector to the object and increase ultrasound reflectivity of the first and the second reflector. 
         [0011]    The medium material may include a frame having an inner space and a liquid accommodated in the inner space. The first and second reflectors may be formed of a glass plate (slide glass). 
         [0012]    The photo-acoustic probe may further include a lens and beam controller positioned between the laser generator and the medium material. 
         [0013]    In another general aspect, a photo-acoustic probe for a clinical image may include: a laser generator configured to generate a laser beam; an ultrasound transducer disposed to be parallel to the laser generator and configured to analyze ultrasound output from an object; a first reflector configured to reflect the laser beam so as to be incident to the object; a second reflector configured to allow the laser beam reflected from the first reflector to be transmitted therethrough and reflect the ultrasound so as to be incident to the ultrasound transducer; and a medium material configured to transmit the laser beam to the object and transmit the generated ultrasound to the ultrasound transducer. 
         [0014]    The medium material may include a frame having an inner space and a liquid accommodated in the inner space. 
         [0015]    The first reflector may include a mirror or a prism, and the second reflector may include a glass plate (slide glass). 
         [0016]    The second reflector may allow the laser beam to be transmitted therethrough and totally reflects the ultrasound. 
         [0017]    The photo-acoustic probe may further include a lens and beam controller positioned between the laser generator and the medium material. 
         [0018]    The laser generator and the ultrasound transducer may be disposed to be perpendicular to the laser beam incident to the object. 
         [0019]    The laser generator and the ultrasound transducer may be disposed at a predetermined angle with respect to the laser beam incident to the object, rather than being perpendicular to the laser beam. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  is a view illustrating the related art structure of a photo-acoustic probe; 
           [0021]      FIG. 2  is a view illustrating a structure of a photo-acoustic probe according to a first embodiment of the present invention; 
           [0022]      FIG. 3  is a view illustrating a structure of a photo-acoustic probe according to a second embodiment of the present invention; and 
           [0023]      FIG. 4  is a view illustrating a modified structure of the photo-acoustic probe illustrated in  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0024]    Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
         [0025]    The advantages, features and aspects of the present invention will become apparent from the following description of the embodiments with reference to the accompanying drawings, which is set forth hereinafter. The present invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. The terms used herein are for the purpose of describing particular embodiments only and are not intended to be limiting of example embodiments. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
         [0026]    Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In adding reference numerals for elements in each figure, it should be noted that like reference numerals already used to denote like elements in other figures are used for elements wherever possible. Moreover, detailed descriptions related to well-known functions or configurations will be ruled out in order not to unnecessarily obscure subject matters of the present invention. 
         [0027]    The present invention relates to a probe for effectively receiving ultrasound in a photo-acoustic imaging technology, a medical imaging technology. Specifically, the present invention provides a probe appropriate for effectively obtaining a photo-acoustic signal using a light source and an ultrasound transducer, which are used in the same manner as those of an existing method, but by aligning the light source and the ultrasound transducer such that axes thereof are parallel. 
         [0028]      FIG. 2  is a view illustrating a structure of a photo-acoustic probe according to a first embodiment of the present invention. 
         [0029]    Referring to  FIG. 2 , the photo-acoustic probe includes a laser generator  110 , an ultrasound transducer  120 , a medium material  130 , first and second reflectors  140  and  150 , a lens and beam controller  160 . 
         [0030]    A laser beam output from the laser generator  110  transmits through the first reflector  140  and is incident to an object  170 . 
         [0031]    The ultrasound transducer  120  is positioned in parallel on one side of the laser generator  110 . Ultrasound generated by the object  170  is reflected from the first and second reflectors  140  and  150 , and a reflected ultrasound beam is received by the ultrasound transducer  120  and the ultrasound transducer  120  analyzes the ultrasound information. 
         [0032]    In order to minimize loss during ultrasound reflection and laser transmission, the photo-acoustic probe is filled with the medium material  130 . Here, the medium material  140  may include a frame having an inner space and a liquid accommodated in the inner space of the frame. 
         [0033]    A liquid, the medium material  130 , may be a material having acoustic impedance similar to that of the object  170 . 
         [0034]    Also, the liquid, the medium material  130 , may be a material having a low absorption coefficient of ultrasound generated by the object  170 . 
         [0035]    In order to reduce optical loss, the first and second reflectors  140  and  150  may be formed of a thin glass plate (slide glass) as a material having a refractive index similar to that of the medium material  130  and having acoustic impedance significantly different from that of a sound wave from the object  170 . 
         [0036]    The first reflector  140  may allow a laser beam output from the laser generator  110  to be transmitted therethrough and incident to the object  170 . 
         [0037]    The first reflector  140  is positioned to face the object  170  and reflects ultrasound generated by the object  170  toward the second reflector  150 . 
         [0038]    The second reflector  150  is positioned to face the ultrasound transducer  120  and reflects ultrasound reflected by the first reflector  140  toward the ultrasound transducer  120 . 
         [0039]    The lens and beam controller  160  is positioned between the layer generator  110  and the medium material  130  and controls a laser beam to produce optimal conditions for generating a photo-acoustic signal. 
         [0040]    Thus, a laser beam output from the laser generator  110  passes through the lens and beam controller  160  and transmits through the medium material  130  so as to be irradiated to the object  170 . 
         [0041]    Ultrasound generated by the object  170  passes through the medium material  130  and is incident to the ultrasound transducer  120 , and the receiver  120  receives the incident ultrasound and analyzes ultrasound information. Here, the ultrasound generated by the object  170  is reflected by the first reflector  140 , passes through the medium material  130 , is reflected by the second reflector  150 , and is subsequently incident to the ultrasound transducer  120 . 
         [0042]    Any material other than the medium material  130  may be used as a transmission medium of ultrasound; however, since a liquid has a low sound wave transmission coefficient, loss of ultrasound may be reduced. 
         [0043]      FIG. 3  is a view illustrating a structure of a photo-acoustic probe according to a second embodiment of the present invention, and  FIG. 4  is a view illustrating a modified structure of the photo-acoustic probe illustrated in  FIG. 3 . 
         [0044]    Components and functions of the components illustrated in  FIGS. 3 and 4  are identical, and thus, the components illustrated in  FIG. 3  will be mainly described. 
         [0045]    Referring to  FIG. 3 , a photo-acoustic probe according to the second embodiment of the present invention includes a laser generator  210 , an ultrasound transducer  220 , a medium material  230 , third and fourth reflectors  240  and  250 , a lens and beam controller  260 . 
         [0046]    The laser generator  210  outputs a laser beam to an object  270 , and the laser beam output from the laser generator  210  is incident to the medium material  230  and incident to the object  270  by the third and fourth reflectors  240  and  250  within the medium material  230 . 
         [0047]    The ultrasound transducer  220  is positioned in parallel on one side of the laser generator  210 , receives ultrasound generated by the object  270 , and analyzes ultrasound information. 
         [0048]    The medium material  230  may be positioned on one side of the laser generator  210  and the ultrasound transducer  220  to form a movement path of the laser beam and ultrasound and provide a space in which the third and fourth reflectors  240  and  250  are disposed. In this case, the medium material  230  may include a frame having an inner space and a liquid accommodated in the inner space of the frame. 
         [0049]    A liquid, the medium material  230 , may be a material having acoustic impedance similar to that of ultrasound generated by the object  270 . 
         [0050]    Also, the liquid, the medium material  230 , may be a material having a low absorption coefficient of ultrasound generated by the object  270  and light generated by the laser generator  210 . 
         [0051]    The third and fourth reflectors  240  and  250  may be positioned within the medium material  230  and change a movement path of the laser beam and ultrasound. One reflector changes a movement path of the laser beam, and the other reflector changes a movement path of ultrasound. 
         [0052]    In the present embodiment, it is assumed that the third reflector  240  is disposed in parallel to the laser generator  210  to change a movement path of a laser beam and the fourth reflector  250  is disposed to face the ultrasound transducer  220  to change a movement path of ultrasound. 
         [0053]    The third reflector  240  reflects a laser beam to the object  270 , and the fourth reflector  250  allows the laser beam to be transmitted therethrough and reflects the ultrasound to the ultrasound transducer  220 . The third reflector  240  may be configured to totally reflect the laser beam and the fourth reflector  250  may be configured to totally reflect the ultrasound. 
         [0054]    The third reflector  240  may be formed of a material having high optical reflectivity, and may be formed of a mirror or a prism to increase optical reflectivity. 
         [0055]    The fourth reflector  250  may be formed of a material having acoustic impedance significantly different from that of a liquid as the medium material  230  and the object  270 . 
         [0056]    The fourth reflector  250  may be formed of slide glass to reduce optical loss. 
         [0057]    The lens and beam controller  260  may be positioned between the laser generator  210  and the medium material  230  to control a laser beam output from the laser generator  210 . 
         [0058]    In  FIG. 3 , the laser generator  210  and the ultrasound transducer  220  are disposed to be perpendicular to the laser beam incident to the object  270 . 
         [0059]    In comparison, as illustrated in  FIG. 4 , the laser generator  210  and the ultrasound transducer  220  may be disposed at a predetermined obtuse angle with respect to the laser beam incident to the object  270 . Here, the third and fourth reflectors  240  and  250  are appropriately disposed to allow the laser beam to be incident to the object  270  and the ultrasound to be incident to the ultrasound transducer  220  according to positions of the laser generator  210  and the ultrasound transducer  220 . 
         [0060]    According to embodiments of the present invention, in the structure of a photo-acoustic probe for a clinical image, since an ultrasound beam positioned to be coaxial with a laser beam output from the laser generator is measured by the ultrasound transducer, a dark zone may be reduced. 
         [0061]    Ultrasound transmission loss, which may be made in the structure of a photo-acoustic probe for a clinical image in which the axes of the laser generator and the ultrasound transducer are parallel, may be minimized 
         [0062]    The photo-acoustic probe for a clinical image has been described according to the embodiments, but the scope of the present invention is not limited to a specific embodiment. The present invention may be corrected and modified within the technical scope obvious to those skilled in the art. 
         [0063]    A number of exemplary embodiments have been described above. Nevertheless, it will be understood that various modifications may be made. For example, suitable results may be achieved if the described techniques are performed in a different order and/or if components in a described system, architecture, device, or circuit are combined in a different manner and/or replaced or supplemented by other components or their equivalents. Accordingly, other implementations are within the scope of the following claims.