Abstract:
Disclosed herein is a digital mammography device. The digital mammography device comprises a pressure pad configured to be movably installed between an X-ray generator for irradiating X-rays and a detector for receiving X-rays that have passed through an object to be imaged, in such a way as to apply pressure to the object to be imaged; a pressure pad driving part configured to include a motor and a power transferring part for moving the pressure pad by means of the power of the motor, and an applied pressure transferring part configured to include a coupling block to which the pressure pad is fixed to the power transferring part and relatively and movably connected to the coupling block, and provides an electrical signal depending on a relative movement displacement between the coupling block and the mobile block.

Description:
[0001]    Embodiments of the present invention relates to a digital mammography device photographing a breast using X-ray, and more particularly, to a digital mammography device capable of monitoring and adjusting strength of force applied to the breast of the patient from a pressure pad. 
       BACKGROUND 
       [0002]    X-ray is generally defined as an electromagnetic wave having a short wavelength corresponding to wavelengths of 0.01 nm to 10 nm, and an X-ray photographing is referred to as a radiography that transparently displays an inside of a photographing target by the high penetrable X-rays. 
         [0003]    As well known, the X-ray involves an attenuation phenomenon depending on a material, a density, and a thickness of an object such as Compton scattering, a photoelectric effect, or the like during a process in which the X-ray penetrates through the object. Therefore, the X-ray photographing projects and displays the inside of the photographing target on a plane based on an amount of attenuation of the X-ray accumulated during the process in which the X-ray penetrates through the photographing target, and to this end, a dedicated X-ray system is used. 
         [0004]    Recently, an X-ray imaging technology has rapidly evolved to a digital X-ray imaging technology having various advantages such as relatively high resolution, a wide dynamic region, an easy generation of an electrical signal, simple data process and storage, and the like, instead of a conventional analog scheme using a film while being grafted to a semiconductor field. A digital based imaging technology meets the clinical and environmental requirements of an early diagnosis of diseases based on excellent diagnostic ability of a digital image. 
         [0005]    Therefore, “digital mammography”, which is a breast dedicated X-ray photographing technology capable of detecting a lesion and a micro-calcification for detection and early diagnosis of a breast cancer by expressing an internal structure of the breast in a high resolution image utilizing unique contrast ability of biological tissues of the X-ray has been proposed. The above-mentioned digital mammography has rapidly propagated due to unique characteristics such as an image expansion, a reduction in the number of photographs, an increase in resolution, and minimization of exposure through an adjustment of brightness and contrast ratio, together with various advantages of the digital X-ray imaging technology. 
         [0006]    A general mammography device includes a column of a column shape which is perpendicular to a bottom; a C-arm that generally shows a C letter or a shape similar to the C letter at both end portions which are bent in arc shapes facing each other in a state in which a middle portion is connected so as to be elevatable and rotatable along the column; an X-ray generator mounted in one end portion of the C-arm to irradiate X-ray toward the other end portion facing one end portion; a detector mounted in the other end portion of the C-arm to face the X-ray generator; and a pressure pad performing a straight-line reciprocating motion between the X-ray generator and the detector along an internal surface of the C-arm. 
         [0007]    In the mammography device as described above, when a patient enters a photographing position, the C-arm is elevated and rotated along the column to adjust a height and an angle so that the breast of the patient is placed at a target position on the detector, and when the pressure pad is moved in a direction of the detector to pressurize the breast, the X-ray is irradiated from the X-ray generator and is received at the detector. The detector generates an electrical signal for each position which is proportional to an incident amount of X-ray, and when the electrical signal and position information are read and are processed by an image processing algorithm, an X-ray image of the breast for the corresponding angle may be obtained. If necessary, the above-mentioned process may be repeated while the X-ray generator and the detector are rotated to face each other while having the breast therebetween, and as a result, the mammography device may obtain high resolution images for the breast of the patient at various angles. 
         [0008]    In the general mammography device showing the above-mentioned photographing principle, a key driving mechanism for minimizing inconvenience of the patient and obtaining a high quality X-ray image is a pressure operation of the pressure pad. That is, since the pressure pad directly applies pressure to the breast during the X-ray photographing, it is directly related to pain or inconvenience which is felt by the patient. According to the related art, when the pressure pad pressurizes the breast placed on an inspection plate, more pressure than necessary may be applied, and as a result, there is a possibility that the patient undergoes more pain than necessary. Particularly, since sizes, densities, and the like of the breast of the patients are different from each other, suitable pressure should be applied accordingly, but there is a problem that the suitable pressure is not accurately and reliably controlled. An improvement method capable of increasing reliability for the pressure operation of the pressure pad and precisely and accurately controlling the pressure operation is required. 
       BRIEF SUMMARY OF THE INVENTION 
       [0009]    An embodiment of the present invention is relates to a digital mammography device capable of performing a control so that suitable pressure is applied using a monitored electrical signal while monitoring pressure applied to a patient through a pressure pad in real time, and protecting the patient by interrupting driving force of the pressure pad in the case in which excessive pressure is applied. 
         [0010]    In another embodiment of the present invention, the digital mammography device is configured to transfer force using a mechanical mechanism including a spring between the pressure pad and a pressure pad driving part. In this manner, the device may reduce a risk that the excessive pressure is suddenly applied to a body of the patient even in the case in which a malfunction due to error of an electronic control device occurs. 
         [0011]    According to an exemplary embodiment of the present invention, there is provided a digital mammography device including: a pressure pad configured to be movably installed between an X-ray generator irradiating X-ray and a detector receiving the X-ray penetrating through a subject and compress the subject; a pressure pad driving part configured to include a motor and a power transferring part moving the pressure pad using power of the motor; and an applied pressure transferring part configured to include a coupling block to which the pressure pad is fixed and a moving block fixed to the power transferring part and relatively and movably connected to the coupling block, and provide an electrical signal depending on a relative movement displacement between the coupling block and the moving block. 
         [0012]    The applied pressure transferring part may include: a spring disposed between the coupling block and the moving block and deformed depending on the relative movement displacement; and a load cell disposed at one end portion of the spring to provide the electrical signal according to a deformation of the spring. The digital mammography device may further include: a piston member configured to be installed between one end portion of the spring and the load cell. 
         [0013]    The digital mammography device may further include: a controller configured to control the motor with the electrical signal and may further include: a safety switch configured to control the motor when the relative movement displacement exceeds a preset range regardless of whether or not the controller is functional. 
         [0014]    The digital mammography device according to an embodiment of the present invention may perform the control so that suitable pressure is applied using the monitored electrical signal while monitoring the pressure applied to the patient through the pressure pad in real time, and may protect the patient by interrupting the driving force of the pressure pad in the case in which excessive pressure is applied. 
         [0015]    In addition, the digital mammography device according to an embodiment of the present invention may prevent the risk that excessive pressure is suddenly applied to the body of the patient even in the case in which the malfunction due to the error of the electronic control device occurs, by transferring the force using the mechanical mechanism including the spring between the pressure pad and the pressure pad driving part. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a perspective view showing a mammography device according to an exemplary embodiment of the present invention. 
           [0017]      FIG. 2  is a partial exploded perspective view showing configurations of a pressure pad driving part and an applied pressure transferring part in the digital mammography device according to an exemplary embodiment of the present invention. 
           [0018]      FIG. 3  is a front perspective view showing the applied pressure transferring part of the digital mammography device according to an exemplary embodiment of the present invention. 
           [0019]      FIG. 4  is an exploded perspective view showing a configuration of the applied pressure transferring part in the digital mammography device according to an exemplary embodiment of the present invention. 
           [0020]      FIG. 5  is a schematic diagram showing the configuration of the applied pressure transferring part in the digital mammography device according to an exemplary embodiment of the present invention. 
           [0021]      FIG. 6  is a schematic diagram showing a configuration of an applied pressure transferring part in a digital mammography device according to another exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. A scope of the present invention may be clearly understood through the exemplary embodiments. However, the present invention is not limited to the exemplary embodiments described below and may be modified in various forms within the scope to which the present invention pertains. Meanwhile, like reference numerals used in several drawings denote a component having the same characteristics, and a description of the component having the same reference numeral as the component described with reference to any one drawing may be omitted from the description of another drawing. 
         [0023]      FIG. 1  is a perspective view showing a mammography device according to an exemplary embodiment of the present invention and  FIG. 2  is a partial exploded perspective view showing configurations of a pressure pad driving part and an applied pressure transferring part in the digital mammography device according to an exemplary embodiment of the present invention. 
         [0024]    The digital mammography device according to an embodiment of the present invention includes a column  10  which stands to be perpendicular to a ground and supports a load of the device; a C type arm  20  that generally shows a C letter or a shape similar to the C letter by both end portions which are bent in arc shapes facing each other in a state in which a middle portion is connected so as to be elevatable and rotatable along the column  10 ; an X-ray generator  30  mounted in one end portion of the C type arm  20  to irradiate X-ray toward the other end portion facing one end portion; a detector  40  mounted in the other end portion of the C type arm  20  to face the X-ray generator  30 ; a pressure pad  60  performing a straight-line reciprocating motion between the X-ray generator  30  and the detector  40 ; a pressure pad driving part  70  driving the pressure pad  60 ; and an applied pressure transferring part  100  installed between the pressure pad  60  and the pressure pad driving part  70 , transferring applied pressure from the power transferring part of the pressure pad driving part  70  to the pressure pad  60 , and measuring the transferred applied pressure to provide an electrical signal. 
         [0025]    The column  10  has a column shape which is perpendicular to a bottom, and an extension part  21  extended from the middle portion of the C type arm  20  is elevatably coupled to the column  10 . A vertical connection part  22  connecting one end portion and the other end portion facing each other of the C type arm  20  is rotatably coupled to the extension part  21 . 
         [0026]    The X-ray generator  30  collides electrons having high kinetic energy with a metal target to generate X-ray, and more particularly includes a collimator that controls an irradiation direction and an irradiation area of the X-ray, or the like. 
         [0027]    The detector  40  is a device that receives the X-ray penetrating through a subject, that is, penetrating through a breast of a patient to generate an electrical signal accordingly, and according to an exemplary embodiment of the present invention, a general technique such as a direct transforming scheme that directly obtains the electrical signal from the X-ray without a separate intermediate operation according to an X-ray transforming scheme, an indirect transforming scheme that transforms the X-ray into visible ray and indirectly obtains the electrical signal by the visual ray, or the like may be widely used. 
         [0028]    The pressure pad  60  pressurizes the breast on a support fixture which is separately installed at a front side of the detector  40  or the support fixture including the detector  40  to the support fixture side, and the breast in the pressurized state is photographed using the X-ray generator  30  and the detector  40 . The pressure pad driving part  70  is configured to vertically move the pressure pad  60  and provide applied pressure, and may be installed at the vertical connection part  22  of the C type arm  20 . 
         [0029]    The applied pressure transferring part  100  transfers a motion and force generated by the pressure pad driving part  70  to the pressure pad  60 , measures applied pressure applied to the breast of the patient, that is, a strength of repulsive force transferred to the pressure pad  60  from the breast of the patient, and generates the electrical signal using the measured strength of repulsive force, such that a controller may control an operation of the pressure pad driving part  70  based on the electrical signal. For example, the strength of the applied pressure itself or a change trench thereof may be detected in order to be used to generate a control signal driving a motor of the pressure pad driving part  70 . If the strength of the applied pressure exceeds a preset value, it is also possible to interrupt power of the pressure pad driving part  70 , drive the pressure pad driving part  70  in an opposite direction, or the like. 
         [0030]    The pressure pad driving part  70  includes a motor which is electrically controlled, and a power transferring part transforming power of the motor into a vertical reciprocal movement form. The power transferring part may include a gear box and a pulley which are connected to the motor, a belt wound around the pulley to be rotated, and the like. 
         [0031]    The exemplary embodiment shown in  FIG. 2  will be described in more detail. The pressure pad driving part  70  includes a pair of horizontal brackets  71 ; a pair of guide shafts  72  which are perpendicular to the horizontal brackets  71  and installed so as to be in parallel to each other; a guide block  73  of which a movement is guided by the pair of guide shafts  72  and to which a component of the applied pressure transferring part  100  is coupled; a belt  74  moving the guide block  73  and the applied pressure transferring part  100 ; and a driving motor and a gear box  75  driving the belt  74 . 
         [0032]      FIG. 3  is a front perspective view showing the applied pressure transferring part of the digital mammography device according to an exemplary embodiment of the present invention and  FIG. 4  is an exploded perspective view showing a configuration of the applied pressure transferring part in the digital mammography device according to an exemplary embodiment of the present invention. 
         [0033]    The applied pressure transferring part  100  includes a moving block  120  fixed to the belt  74 , which is a member substantially performing a vertical reciprocal motion as a part of the power transferring part; and a coupling block  110  having the moving block  120  which is coupled to one side thereof to be relatively movable and the pressure pad  60  fixed to the other side thereof. The coupling block  110  is installed with guide rails  152  and guide protrusions  151  are formed on sides of the moving block  120  corresponding to the guide rails  152 , such that a relative movement of the coupling block  110  and the moving block  120  may be guided. In addition, the coupling block  110  is provided with pressure pad coupling parts  112 , to which the pressure pad  60  is fastened. 
         [0034]    A spring  140  deformed depending on a relative movement displacement between the coupling block  110  and the moving block  120  and transferring force; and a load cell  170  disposed at one end portion of the spring  140  and measuring a strength of force transferred through the spring  140  to provide the electrical signal may be included between the coupling block  110  and the moving block  120 . In addition, a piston member  160  transferring all of the force across the spring  140  to a measuring part of the load cell  170  may be further included between the spring  140  and the load cell  170 . 
         [0035]    The piston member  160  may include a piston body  162  which is directly in contact with the spring  140  and the load cell  170 , and a piston rod  161  extended from the piston body  162  into the spring  140  to hold a position of the spring  140 . 
         [0036]      FIG. 5  is a schematic diagram showing the configuration of the applied pressure transferring part in the digital mammography device according to an exemplary embodiment of the present invention. 
         [0037]    The spring  140  may be installed in a spring housing part  124  provided in the moving block  120 , for example. An operation range of the spring  140  may be limited by the piston member  160  described above. For example, an initial state of the spring  140  may be adjusted by allowing the piston rod  161  to penetrate through an upper end portion of the spring housing part  124  and coupling an adjustment nut  163  to an upper end portion of the piston rod  161 . Minimum applied pressure at which a relative movement starts to be generated between the moving block  120  and the coupling block  110  depending on the initial state of the spring  140  is mechanically set. 
         [0038]    The load cell  170  has a bottom surface supported by the coupling block  110  and a measuring part which is directly in contact with the piston body  162 , and receives the applied pressure from the spring  140 . When the breast of the patient is photographed, a deformation no longer occurs after the deformation in which the breast of the patient is compressed to a predetermined degree occurs by the pressure pad  60  which is vertically moved. In this case, when the pressure pad driving part  70  continues to operate and the belt  74  presses down the moving block  120  in an arrow direction, a relative displacement occurs between the coupling block  110  and the moving block  120  while the spring  140  receiving repulsive force from the pressure pad  60  which is no longer descended by receiving the repulsive force from the breast of the patient is compressed. In other words, the spring  140  receiving the applied pressure from the pressure pad driving part  70  stores energy through an elastic deformation and transfers the applied pressure to the coupling block  110 , and the load cell  170  provides the electrical signal by measuring the applied pressure in real time. 
         [0039]    In addition, strong safety measures for protecting the patient may also be taken such as a relative movement range of the moving block  120  in a housing of the coupling block  110  being limited or the initial state of the spring  140  being adjusted by installing a support bolt  165  between the coupling block  110  and the moving block  120  as well as power supplied to the pressure pad driving part  70  being shut-down in the case in which the relative movement displacement exceeds a predetermined value by installing a safety switch  180  at a predetermined position, and the like. The reason that the safety switch  180  is operated depending on the relative movement displacement is that a strength of applied pressure applied to the breast of the patient becomes strong in proportion to the relative movement displacement between the coupling block  110  and the moving block  120  due to the existence of the spring  140  between the coupling block  110  and the moving block  120 . The safety switch  180  may be installed at a position at which the moving block  120  arrives when the spring  140  is deformed as much as maximum applied pressure which may be applied to the patient is transferred. In addition, as the safety switch  180 , a mechanical switch may be employed so that the patient may be protected under any situation. 
         [0040]      FIG. 6  is a schematic diagram showing a configuration of an applied pressure transferring part in a digital mammography device according to another exemplary embodiment of the present invention. 
         [0041]    The configuration of the digital mammography device shown in  FIG. 6  is substantially equal to that shown in  FIG. 5 , and only a difference therebetween will be described. 
         [0042]    A tensile load cell  190  is installed between the coupling block  110  and the moving block  120  so as to be tensioned as the moving block  120  is relatively moved in the housing of the coupling block  110 . Therefore, the piston body  162  is installed so that the bottom surface thereof is supported by the coupling block  110 . 
         [0043]    Similar to the load cell  170 , the tensile load cell  190  provides an electrical signal by measuring tensile force generated according to the movement of the moving block  120  in real time. 
         [0044]    This written description uses examples to disclose the invention, including the preferred embodiments, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.