Patent Publication Number: US-2023157651-A1

Title: Proximity operation-type x-ray fluoroscopic imaging apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application relates to, and but does not claim priority from, Ser. No.: JP 2019-114042 filed Jun. 19, 2019, published as JP 2021-154A on Jan. 7, 2021, the entire contents of which are incorporated herein by reference. 
     FIGURE SELECTED FOR PUBLICATION 
       FIG.  6   . 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a proximity operation-type (operative) X-ray imaging apparatus, and particularly, relates to an X-ray fluoroscopic imaging apparatus having an X-ray shielding mechanism to reduce an X-ray exposed dose for an operator. 
     Background 
     Conventionally, the proximity operative X-ray fluoroscopic imaging apparatus is applied to a contrast radiography for a digestive tract using barium. Relative to the proximity operative X-ray fluoroscopic imaging apparatus, the operator stands by the X-ray fluoroscopic imaging apparatus, instructs a subject, conducts an operation of an X-ray imaging system and a tilting operation of a table. The X-ray imaging system comprises an X-ray tube that irradiates X-ray and an X-ray detector that detects such X-rays. With regard to the proximity operative X-ray fluoroscopic imaging apparatus, in general, an under-table tube type X-ray fluoroscopic imaging platform in which the X-ray tube positions beneath the table on which the subject is loaded and the X-ray detector positions above the table is applied (e.g., refer to Patent Document 1). 
     The proximity operative X-ray fluoroscopic imaging apparatus enables to reduce the anxiety of the subject and provide promptly and adequately the subject with an instruction, so that it can be more advantageous than the remote operation model with regard to such points. On the other hand, with regard to the proximity operative X-ray fluoroscopic imaging apparatus, the configuration thereof having an X-ray shielding mechanism to lower the X-ray exposed dose for the operator who positions in the proximity of the X-ray apparatus is proposed (e.g., referring to Patent Document 2). The traditional X-ray shielding mechanism has a sheet-like shielding material made of such as lead. Such a sheet-like shielding material shields the space between the operator, who is in the proximity of the table, and the X-ray imaging apparatus, so that the exposed dose against the operator can be lowered. 
     RELATED PRIOR ART 
     Patent Documents 
     
         
         Patent Document 1-JP 2010-240010 A1 
         Patent Document 2-JP 2008-061765 A1 
       
    
     ASPECTS AND SUMMARY OF THE INVENTION 
     Objects to be Solved 
     Nevertheless, in the case of a conventional example having such structure, following problems are remained to be solved. 
     For example, one shielding material for the X-ray shielding mechanism has a weight in between 5 kg and 10 kg, so that in some case, the shielding material may be deformed due to the own weight when installing vertically. Accordingly, the X-ray shielding mechanism is installed so as to connect with the X-ray detector installed above the table, and the shielding material hangs downwardly from the X-ray detector over the table to prevent the deformation of the shielding material due to the own weight. 
     Here, such a shielding mechanism to block the operator view depending on a kind of operation may not be required, so that the X-ray shielding mechanism of the conventional X-ray fluoroscopic imaging apparatus is configured to be arbitrary removable. However, when such a heavy X-ray shielding mechanism is removed, the weight balance of the X-ray imaging system with the counterweight is changed. It is problematic that the operability of the X-ray imaging apparatus worsens when the weight balance of the X-ray imaging system is changed. 
     One measures to avoid such an effect can be the method wherein a dummy weight replacing the X-ray shielding mechanism is connected with the X-ray detector when the X-ray shielding mechanism is removed. However, the measures for the X-ray shielding mechanism using the dummy weight needs an action to change the X-ray shielding mechanism to the dummy weight, so that a workload on the operator becomes larger and the time needed for the X-ray fluoroscopic imaging becomes longer. In addition, it can be problematic to find the storage space for the X-ray shielding mechanism or the dummy weight not in use must be ensured. 
     Considering such circumstances, the object of the present invention is to provide an X-ray fluoroscopic imaging apparatus capable of reducing the workload on the operator and lowering the radiation exposed dose for the operator. 
     According to one alternative aspect of the present invention, there is provided an X-ray proximity operative fluoroscopic imaging apparatus capable of reducing the workload on the operator and lowering the radiation dose for the operator. The X-ray shielding unit comprises a plurality of shielding slats. Each pedestal end of the shielding slats is supported so as to be freely movable with the imaging system that is in place above the table, and each free end of the shielding slats is extending toward a loading surface of the table. A plurality of the shielding slats are arrayed in parallel along the long side direction to table. The shielding switching element switches the X-ray shielding unit between the shielding state in which the X-ray exposure to the operator S is blocked and the releasing state in which the shielding state is released. The shielding switching element comprises the slat rotation mechanism that rotates the respective shielding slats around the short side direction axis of the table, and the slat rotation mechanism rotates the shielding slats so that the shielding state and the releasing state can be switched. 
     Means for Solving the Problem 
     The present invention constitutes the following structure to solve such problems. 
     Specifically, a proximity operative X-ray fluoroscopy and imaging apparatus of the present invention comprises: a table on which a subject is held; an imaging system in which an X-ray tube that irradiates X-ray and an X-ray detector that detects the X-ray irradiated therefrom and transmitting the subject are facing each other while sandwiching the table; a table driving element that tilts the table relative to the horizontal plane; an X-ray shielding mechanism having a plurality of X-ray shielding slats, wherein each pedestal end of said shielding slats is supported so as to be freely movable with said imaging system that is in place above said table, each free end of said shielding slats is extending toward a loading surface of said table, and said plurality of said shielding slats are arrayed in parallel along a long side of said table; and a shielding switching element that switches a shielding state, in which said X-ray shielding mechanism is in place between said subject and an operator to shield an X-ray exposed dose for said operator, and a releasing state, in which said shielding is being released; a release state in which the shielding is released; wherein the shielding switching element further comprises: a slat rotation element that rotates the respective shielding slats around the short side axis of the table, wherein the shielding state and the release state are switched by that the slat rotation element rotates respective X-ray shielding slats. 
     According to such a configuration, the X-ray shielding mechanism can be switched from the shielding state to the releasing state without taking the X-ray shielding mechanism having the X-ray shielding slats off the proximity operative X-ray fluoroscopic imaging apparatus. Accordingly, the weight balance of the imaging system would not change even when the X-ray shielding mechanism is switched to the releasing state, so that the incident of lowering the operability of the proximity operative X-ray fluoroscopic imaging apparatus can be prevented. In addition, the action to connect the dummy weight with the imaging system when the shielding state and the releasing state are switched is not needed, so that the workload on the operator lowers and the convenience of the proximity operative X-ray fluoroscopic imaging apparatus can be improved. 
     According to the present invention set forth above, it is preferable that 
     the slat rotation element changes the rotation angle of the X-ray shielding slats corresponding to the angle generated when the table driving element tilts the table. 
     Action and Effect 
     The proximity operative X-ray fluoroscopic imaging apparatus according to the present invention enables to rotate arbitrary the X-ray shielding slats corresponding to the tilt angle of the table when the table driving element tilts the table relative to the horizontal plane. Accordingly, an incident of deformation of the X-ray shielding slats due to the own weight of the X-ray shielding mechanism can be avoided. 
     According to the present invention set forth above, it is preferable that the slat rotation element switches between the shielding state to the releasing state by rotating respective X-ray shielding slats so that the traveling direction of the free end of the X-ray shielding slats becomes in parallel to the long side direction of the table. 
     Action and Effect 
     The proximity operative X-ray fluoroscopic imaging apparatus according to the present invention makes the X-ray shielding plane of the X-ray shielding mechanism further narrow when changed to the releasing state. Accordingly, the operator sight for such as the loading plane of the table can be ensured more adequately when the X-ray shielding mechanism is switched to the releasing state. 
     Effects of the Present Invention 
     The proximity operative X-ray fluoroscopic imaging apparatus according to the present invention can switch the X-ray shielding mechanism from the shielding state to the releasing state without taking the X-ray shielding mechanism having the X-ray shielding slats off the proximity operative X-ray fluoroscopic imaging apparatus. Accordingly, the weight balance of the imaging system would not change even when the X-ray shielding mechanism is switched to the releasing state, so that the incident of lowering the operability of the proximity operative X-ray fluoroscopic imaging apparatus can be avoided. In addition, the action to connect the dummy weight with the imaging system when the shielding state and the releasing state are switched is not needed, so that the workload on the operator lowers and the convenience of the proximity operative X-ray fluoroscopic imaging apparatus can be improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a front view illustrating the schematic structure of a proximity operative X-ray fluoroscopic imaging apparatus according to the Embodiment. 
         FIG.  2    is a right-side view illustrating the schematic structure of a proximity operative X-ray fluoroscopic imaging apparatus according to the Embodiment. 
         FIG.  3    is a back view illustrating a unit structure of the X-ray shielding unit according to the Embodiment. 
         FIG.  4    is a plan view illustrating the unit structure of the X-ray shielding unit according to the Embodiment. 
         FIG.  5    is a functional block diagram illustrating the proximity operative X-ray fluoroscopic imaging apparatus according to the Embodiment. 
         FIG.  6    is a front view illustrating the releasing state relative to the proximity operative X-ray fluoroscopic imaging apparatus according to the Embodiment. 
         FIG.  7    is a plan view illustrating the structure of the X-ray shielding unit in the releasing state according relative to proximity operative X-ray fluoroscopic imaging apparatus according to the Embodiment. 
         FIG.  8    is a front view illustrating the structure when the table of the proximity operative X-ray fluoroscopic imaging apparatus according to the aspect of the Embodiment is being tilted. 
         FIG.  9    is a front view illustrating the structure when the table of the proximity operative X-ray fluoroscopic imaging apparatus according to the Embodiment is tilted and the angle of the shielding slats is corrected. 
         FIG.  10    is a front view illustrating the structure of the proximity operative X-ray fluoroscopic imaging apparatus of the Embodiment of which the table is tilted, and the shielding unit is switched from the X-ray shielding state to the releasing state. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference will now be made in detail to embodiments of the invention. Wherever possible, same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps. The drawings are in simplified form and are not to precise scale. The word ‘couple’ and similar terms do not necessarily denote direct and immediate connections, but also include connections through intermediate elements, modules or devices. For purposes of convenience and clarity only, directional (up/down, etc.) or motional (forward/back, etc.) terms may be used with respect to the drawings. These and similar directional terms should not be construed to limit the scope in any manner. It will also be understood that other embodiments may be utilized without departing from the scope of the present invention, and that the detailed description is not to be taken in a limiting sense, and that elements may be differently positioned, or otherwise noted as in the appended claims without requirements of the written description being required thereto. 
     Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding embodiments of the present invention; however, the order of description should not be construed to imply that these operations are order dependent. 
     It will be further understood by those of skill in the art that the apparatus and devices and the elements herein, without limitation, and including the sub components such as operational structures, circuits, communication pathways, and related elements, control elements of all kinds, display circuits and display systems and elements, any necessary driving elements, inputs, sensors, detectors, memory elements, processors, resistors, capacitors, switches, and any other electronic-circuit-related elements, and any combinations of these structures etc. as will be understood by those of skill in the art as also being identified as or capable of operating the systems and devices and subcomponents noted herein and structures that accomplish the functions without restrictive language or label requirements since those of skill in the art are well versed in related devices, computer and operational controls and technologies of radiographic devices and all their sub components, elements, modules, and programs, including various circuits, elements, and modules, and combinations thereof without departing from the scope and spirit of the present invention. 
     Referring to FIGs, the inventors set forth the Embodiment of the present invention. 
     Illustration of the Entire Structure 
     Referring to  FIG.  1   , the proximity operative X-ray fluoroscopic imaging apparatus  1  according to the Embodiment comprises a table 3 on which a subject M is loaded. The table 3 is supported with a base  4  installed to a floor surface and is configured to be rotatable around a y-direction (the short side direction of the table 3). 
     An X-ray tube  5  that irradiates the subject M with X-ray is in place beneath the table 3. An X-ray detection unit  7  is in place above the table 3 to face the X-ray tube  5 . The X-ray detection unit  7  embeds an X-ray detector  8  that detects the X-ray irradiated from the X-ray tube  5  and outputs an X-ray detection signal. The X-ray detector  8  are in-place facing the X-ray tube  5  while sandwiching the table 3. Examples of the X-ray detector  8  are such as a flat panel detector (FPD) and an image intensifier. 
     An X-ray fluoroscopic imaging apparatus  1  comprises a support column  9 . Referring to  FIG.  2   , a pedestal portion of the support column  9  is connected with the table 3 through a connection element  10  and the support column  9  is extending in the intersecting direction with the table 3. The support column  9  is guided by a guide rail, which is not shown in Fig. and installed to the table 3 and configured to be movable in the long side direction of the table 3. In addition, the support column  9  can be directly connected with the table 3 or indirectly connected therewith through a member different from the connection element  10 . 
     One end of a brunch element  11  extending in the short side direction of the table 3 is fixed on the support column  9 . The brunch element  11  is movable up and down along the support column  9  and the other end of the brunch element  11  is connected with the X-ray detection unit  7 . The X-ray detection unit  7  is guided by a guide rail, which is not shown in FIG and installed to the brunch element  11 , and movable in the short side direction of the table 3. 
     In addition, the connection element  10  is connected with the support column  9  and also connected with the X-ray tube  5 . And the connection element  10  is guided by the guide rail embedded in the table 3 and the support column  9  and movable in the short direction of the table 3 in synchronism with the X-ray detection unit  7 . 
     Specifically, the imaging system comprises the X-ray tube  5  and the X-ray detector  8  which are connected to each other through the table 3, the support column  9 , the connection element  10  and the brunch element  11  and movable in synchronism with each other in both long side and short side of the table 3. In addition, when the table 3 rotates, the X-ray tube and the X-ray detection unit  7  rotates along with the table 3 in a unified manner. 
     The X-ray tube  5  comprises a collimator  13 . The collimator  13  limits X-rays irradiated from the X-ray tube  5  to a predetermined shape. An example of the predetermined shape is a cone shape like a pyramid. 
     Referring to  FIG.  1    and  FIG.  2   , an operation panel  15  and an operation grip  17  are installed to the tip portion of the X-ray detection unit  7 . The operation panel  15  comprises an operation device to set up an X-ray irradiation condition or an operation device for X-ray imaging and so forth, and the operator can input an instruction as to the X-ray fluoroscopic imaging by operating the operation panel  15 . The operation panel  15  is such as a touch panel, a switch for switching over, and a switch using a push button. 
     The operation grip  17  comprises a power assist unit (not shown in FIG.). The operator holds the operation grip  17  to move e.g., the X-ray detection unit  7  in the long side direction and short side direction of table 3 and an orthogonal direction thereto. The operation panel  15  and the operation grip  17  can be in place anywhere the operator can easily operate and accordingly, the installation position is not limited to the tip portion of the X-ray detection unit  7 . 
     An X-ray shielding unit  19  is in place to the tip portion of the X-ray detection unit  7 . The X-ray shielding unit  19  cuts the exposed dose for the operator with X-ray irradiated from the X-ray tube  5  and is in place between the operator S, who works on a variety of jobs in the proximity of the X-ray fluoroscopic imaging apparatus  1 , and the table 3. 
     Referring to  FIG.  2   , a pulley  21 , a wire  23  and a counterweight  25  are embedded in the support column  9 . The pulley  21 , which is embedded in the top end of the support column  9 , is hung with the wire  23 . One end of the wire  23  is fixed on the branch element  11  and the other end of the wire  23  is fixed on the counterweight  25 . The weight of the counterweight  25  is designed to balance with the total weight of the branch element  11 , the X-ray detection unit  7  and the X-ray shielding unit  19 . 
     The pulley  21  is rotatable in both clockwise (forward) and counterclockwise (reverse) directions and the wire  23  is movable in both direction while interlocked with rotation of the pulley  21 . And the branch element  11  connected with the wire  23  is movable up and down along the support column  9  while interlocked with the wire  23 . For example, given the pulley  21  rotates in the clockwise direction as shown in  FIG.  2   , the branch element  11  moves upward along the support column  9 . 
     Structure of the X-Ray Shielding Unit 
     The inventors set forth the configuration of the X-ray shielding unit  19 .  FIG.  3    is the back view of the X-ray shielding unit  19  and  FIG.  4    is the plane view of the X-ray shielding unit  19 . In addition, the X-ray shielding unit  19  is illustrated in  FIG.  1    and  FIG.  4    is in the shielding state described later. 
     The X-ray shielding unit  19  comprises a plurality of pieces of shielding slat  27 , a rotation gear  29 , an occlusion gear  31  and a motor  33 . According to the present Embodiment, the X-ray shielding unit  19  comprises five pieces of shielding slat  27 . 
     The pedestal portion of the respective shielding slats  27  is connected with the end of the X-ray detection unit  7 . Specifically, the X-ray detector  8  is indirectly connected with the pedestal portion of the shielding slats  27  through the X-ray detection unit  7 . And respective free ends of the shielding slats  27  are extending toward the load surface of the table 3. The plurality of the shielding slats  27  are arrayed in parallel along the long side direction of the table 3. The shielding slats  27  are made of an X-ray shielding (blocking) material and an example of such a component material is lead. 
     The rotation gears  29  are arrayed and connected with the back plane of the shielding slats  27 . The respective shielding slats  27  are connected with the X-ray detection unit  7  through the rotation axis  30  of the rotation gear  29 . The respective rotation gears  29  enable to rotate around the axis intersecting to the plane of the shielding slats  27  (X-ray shielding plane). According to the present Embodiment, referring to  FIG.  1    and so forth, the respective shielding slats  27  are arrayed in parallel so as to allow the X-ray shielding plane to be orthogonal to the short side direction of the table 3. Specifically, the shielding slats  27  can rotate in synchronism with the rotation of the rotation gear  29  around the axis which is in parallel to the short side direction of the table 3. 
     The occlusion gears  31  are in place between the respective rotation gears  29  and meshing with each rotation gear  29 . Specifically, the X-ray shielding unit  19  of the present Embodiment comprises five rotation gears  29  and four occlusion gears  31 . The occlusion gears  31  rotate in the opposite direction to the rotation direction of the rotation gears  29 , so that all rotation gears  29  rotates in the same direction. 
     A motor  33  is directly connected with a rotation axis  30  of at least one rotation gear  29  of a plurality of rotation gears  29 . The respective rotation gears  29  rotate in synchronism with one another in the same direction and with the same angle following rotation of the motor  33 . And the respective shielding slats  27  rotate in the same direction and with the same angle around the axis intersecting with the X-ray shielding plane. The respective shielding slats  27  rotate, so that the X-ray shielding unit  19  can be switched between the shielding state and the releasing state. The respective shielding slats  27  are arrayed so that the plane of the shielding slat  27  is orthogonal to the short side direction of the table 3. Accordingly, the respective shielding slats  27  rotate around the short side axis of the table 3 following the rotation of the rotation gears  29 . 
     &lt;Control of X-Ray Fluoroscopic Imaging Apparatus&gt; 
     The X-ray fluoroscopy imaging apparatus  1  further comprises: an image processing element  35 ; a display element  36 ; an input element  37 ; a control element  38 ; an imaging system driving element  39 ; a table driving element  40 ; a shielding switching element  41 ; a table angle detection element  43 ; and a slat angle correction element  45 . 
     The image processing element  35  that is installed to the latter part of the X-ray detection unit  7  generates an X-ray image based on the X-ray detection signal output from the X-ray detector  8  of the X-ray detection unit  7 . The display element  36  displays the X-ray image and one example thereof is a liquid crystal monitor. 
     The input element  37  for inputting a variety of instructions by the operator as to an action of the X-ray fluoroscopic imaging apparatus  1  comprises such as the operation panel  15  and the operation grip  17 . The control element  38  comprises e.g., a central processing unit (CPU) and so forth, and comprehensively controls the respective components of the X-ray fluoroscopic imaging apparatus  1  in accordance with such as the instruction input into the input element  37  by the operator. 
     The imaging system driving element  39  moves the X-ray tube  5  and the X-ray detection unit  7  according to the control signal of the control element  38 . The imaging system driving element  39  of the present embodiment is configured to allow the X-ray tube  5  and the X-ray detection unit  7  to move in synchronism with each other in the long side and short side direction of the table 3. In addition, the imaging system driving element  39  is configured to allow the X-ray detection unit  7  to move independently from the X-ray tube  5  in the extending direction (z-direction in  FIG.  1   ) of the support column  9 . 
     The table driving element  40  moves the table 3 according to the control signal of the control element  38 . Specifically, the table 3 rotates around the parallel axis to the short side direction of the table 3, and the titling angle of the subject M to the horizontal plane can be arbitrary changed. In addition, the table driving element  40  can change the relative position of the table 3 to the imaging system by shifting the table 3 to either x-direction or y-direction. 
     The shielding switching element  41  switches the X-ray shielding unit  19  between the shielding state and the releasing state according to the control signal of the control element  38 . The shielding switching element  41  comprises a slat rotation mechanism  42  having the rotation gears  29 , the occlusion gear  31  and the motor  33  rotates the respective shielding slats  27  around the axis parallel to the short side direction of the table 3. 
     A table angle detection element  43  comprise e.g., a potentiometer or an encoder and detects the tilt angle R1 of the table 3 to the horizontal plane thereby as needed. A slat angle correction element  45  is in place in the latter part of the table angle detection element  43 . The slat angle correction element  45  calculates a correction angle R2, with which the respective shielding slats  27  rotate, based on the information as to the tilt angle R1 detected by the table angle detection element  43 . The slat angle correction element  45  has also a function to control a slat rotation mechanism  42 , so that the rotation angle of the shielding slats  27  becomes the correction angle R2. 
     &lt;Operation of X-Ray Fluoroscopic Imaging Device&gt; 
     Now, the inventors illustrate the action of the X-ray fluoroscopic imaging apparatus  1  while describing particularly the operation of the X-ray shielding unit  19 . 
     First, the inventors illustrate the case in which the subject M is being laid in a horizontal state for the X-ray fluoroscopic imaging. First, the operator S rotates the table 3 to be horizontal by operating the input element  37  and loads the subject M on the table 3 in the dorsal position. And the rotation angle of the motor  33  is arbitrary adjusted by operating the input element  37  so that the X-ray shielding unit  19  is in the shielding state. 
     The shielding state is a state where the X-ray radiation exposure dose to the operator S is reduced in a relatively high efficiency by shielding the space between the operator S and the subject M using the shielding slats  27 . When the table in horizontal, the X-ray shielding unit  19  is switched to provide with the shielding state by rotating the respective shielding slats  27  so that the long side direction of the shielding slat  27  is orthogonal to the loading plane of the table 3. 
     The configuration of the X-ray fluoroscopic imaging apparatus  1  wherein the table 3 is in the horizontal state and the X-ray shielding unit  19  is in the shielding state is shown as-is in  FIG.  1    and  FIG.  2   . The long side of the shielding slats  27  turns to be orthogonal to the loading plane of the table 3, so that an overlapping area of the shielding slats  27  with one another becomes minimum in the front view of the X-ray fluoroscopic imaging apparatus  1 . Accordingly, the area of the X-ray shielding plane of the X-ray shielding unit  19  becomes maximum (referring to the sign P 1 ). 
     Following switching the shielding unit  19  into the shielding state, the operator S adjusts the position of the imaging system using the operation panel  15  and the operation grip  17  and so forth and also sets up an X-ray irradiation condition such as a tube voltage and a tube electric current. And then, the operator generates the X-ray image by irradiating X-rays from the X-ray tube  5  while providing the instruction with the subject M. At this time, referring to  FIG.  2   , the X-ray shielding unit  19  is in the shielding state, so that the respective shielding slats  27  shield adequately the space between the X-ray fluoroscopic imaging apparatus  1  and the operator S. Accordingly, the X-ray dose irradiated from the X-ray tube  5  and exposed to the operator S can be efficiently reduced. 
     Second, the inventors illustrate the case in which the X-ray shielding unit  19  is switched to the releasing state while the subject M is being laid in a horizontal position. Once the X-ray shielding unit  19  is turned into the shielding state, the sight of the operator S is blocked by the shielding slats  27 , so that it becomes difficult to recognize visually the subject M, particularly. Therefore, for example, when the operator S would not be exposed to the radiation and the necessity to recognize visually the table 3 or the subject M and so forth is high, the action can be performed more smoothly by releasing the shielding state of the X-ray shielding unit  19 . 
     When switching the X-ray shielding unit  19  into the releasing state, the operator S adjusts arbitrary the rotation angle of the motor  33  by operating the input element  37 . The releasing state is the state in which the shielding state of the X-ray shielding is released, and it is the state in which the space between the operator S and the subject M is not shielded by the shielding slats  27 . In other words, it is the state in which the sight of the operator S is not blocked by the shielding slats  27 . 
     According to the present Embodiment, the X-ray shielding unit  19  is switched from the shielding state to the releasing state by adjusting the rotation angle of the motor  33  so that the respective shielding slats  27  rotates to the 90° left (i.e., counterclockwise rotation). The motor  33  rotates, so that the rotation gears  29  directly connected with the motor  33  rotes counterclockwise. A rotation force of such a rotation gear  29  is transferred to another rotation gear  29  through the occlusion gear  31  and the rotation gears  29  rotate respectively counterclockwise in synchronism with one another. 
     The rotation gears  29  rotate respectively, so that the respective shielding slats  27  rotate 90° counterclockwise. Referring to  FIG.  6    and  FIG.  7   , the long side direction of the respective shielding slats  27  become parallel to the loading plane of the table 3 along with the rotation of such shielding slats  27 . And the short side direction of shielding slats  27  are orthogonal to the loading plane of the table 3. As a result, the respective shielding slats  27  are overlapped with one another in the front view of the X-ray fluoroscopic imaging apparatus  1 . Therefore, the area of the X-ray shielding plane of the X-ray shielding unit  19  becomes minimum (referring to the sign P 2 ). The switching operation into the releasing state is completed by narrowing the X-ray shielding plane of the X-ray shielding unit  19 . In addition, referring to  FIG.  6   , for convenience&#39;s sake to illustrate, the right end position of the shielding slats  27  in the shielding state is denoted by the dotted line. 
     When the X-ray shielding unit  19  is switched from the shielding state to the releasing state, the X-ray shielding area is minimum and also the shielding slats  27  are overlapped with the X-ray detection unit  7  in the front view of the X-ray fluoroscopic imaging apparatus  1 . Accordingly, the operator S sight relative to the loading plane of the table 3 cannot be blocked with the X-ray shielding unit  19  by switching the units  19  into the releasing state. The operator S puts the X-ray shielding unit  19  into the releasing state, so that the subject M on the table 3 can be easily and visually recognized and as a result, the posture of the subject M can be more adequately adjusted. 
     In such a way, the X-ray shielding unit  19  of the present invention rotates the respective shielding slats  27  connected with X-ray detection unit  7  around the short side direction of the table 3, so that the shielding state can be switched to the releasing state. Specifically, the state of the X-ray shielding unit  19  can be switched while keeping the connected condition in which the X-ray shielding slats  27  is being connected with the X-ray detection unit  7 , so that the X-ray shielding unit  19  can be switched from the shielding state to the releasing state without taking the X-ray shielding unit  19 , having the X-ray shielding slats  27 , off the X-ray fluoroscopic imaging apparatus  1 . 
     In addition, the respective shielding slats  27  rotate and shift around the pedestal end supported by the X-ray detection unit  7  as the center thereof, so that the shielding state can be switched from the shielding sate to the releasing state. Specifically, when switching to the releasing state, the positional relationship between the X-ray detection unit  7  and the shielding slats  27  does not change, so that the weight balance of the X-ray shielding unit  19  acting on the X-ray detection unit  7  can be kept always constant. Accordingly, an incident of dislocation or angle distortion of the X-ray detector  8  due to the change of the weight balance relative to the X-ray detection unit  7  when switching between the shielding state and the releasing state can be prevented. 
     Once preparation for irradiating X-ray while adjusting the posture of the subject M is completed, the operator S adjusts the rotation angle of the motor  33  to rotate the shielding slats  27  90° to the right (clockwise) by operating the input element  37 . According to such a rotation, the X-ray shielding unit  19  is switched from the releasing state, in which the area of the X-ray shielding plane is minimum, to the shielding state, in which the area of the X-ray shielding plane is maximum. The X-ray exposed dose against the operator S when the X-ray is irradiated can be reduced by switching to the shielding state. 
     Third, the inventors illustrate the case in which the subject M is being in a tilting position for the X-ray fluoroscopic imaging. In the medical diagnosis of the digestive tract e.g., stomach, the X-ray image, in some case, imaging the subject M in the tilting position may be needed in addition to the image imaging the subject M in the horizontal position Then, the operator S puts the X-ray shielding unit  19  into the shielding state following completion of preparation for the X-ray irradiation. And the input element  37  is operated to rotate the table 3 around the axis parallel to the y-direction (referring to the sign F). 
     The horizontal state of the table 3 referring to  FIG.  1    shifts to the tilting state referring to  FIG.  8    and  FIG.  10   , i.e., tilting to the horizontal plane by rotating the table 3. Now, according to the rotation of the table 3, the components connected with the table 3, i.e., such as the support column  9 , the X-ray tube  5  and the X-ray detection unit  7 , shift into the tilting state together with the table 3. In addition,  FIG.  8    and  FIG.  9    show the structure of which the X-ray shielding unit  19  is switched into the shielding state. 
     Referring to such as  FIG.  1   , the shielding slats  27  are connected with the X-ray detection unit  7 . Accordingly, unless the angle of the shielding slat  27  in the tilting state of the table 3 is corrected particularly, the respective shielding slats  27  tilt relative to the horizontal plane in synchronism with the rotation of the table 3, referring to  FIG.  8   . 
     Generally, the shielding slats  27  are made of the sheet material including e.g., lead to have a flexibility but relatively heavy. Accordingly, when the long side of the shielding slats  27  tilt largely relative to the horizontal plane, the shielding slats  27  may deform as distorted in the vertical direction due to the own weight denoted by the sign G. Such a distortion occurred in the shielding slats  27  remains even after the table 3 returns into the horizontal position and it can be a cause of functional deterioration of the X-ray shielding unit  19  in a long time. 
     Therefore, when titling the table 3 into the tilting state by rotating according to the present Embodiment, a further corrective action of the angle of the shielding slats  27  is preferably performed to avoid the deformation of the shielding slats  27  from a configuration standpoint. Specifically, the X-ray fluoroscopic imaging apparatus  1  comprises the table angle detection element  43  and the slat angle correction element  45 . And the tilt angle R1 between the loading plane of the table 3 and the horizontal plane is detected by the table angle detection element  43  as needed. The information relative to the tilt angle R1 is sent from the table angle detection element  43  to the slat angle correction element  45 . 
     The slat angle correction element  45  calculates a correction angle R2 of the shielding slats  27  using the information as to the tilt angle R1 of the table 3. The correction angle R2 is calculated as the rotation angles of the respective shielding slats  27  not to cause distortion on the shielding slats  27  even if the table 3 tilts. The slat angle correction element  45  controls the rotation angle of the motor  33  to provide the rotation angles of the respective shielding slats  27  having the correction angle R2 following the calculation of the correction angle R2. Referring to  FIG.  9   , according to the control result provided by the slat angle correction element  45 , the facing direction of the shielding slats  27  can be adjusted into the direction in which no distortion on the shielding slats  27  takes place. 
     Specifically, the slat angle correction element  45  of the present embodiment calculates the correction angle R2 of the shielding slats  27  as the angle equal to as the tilt angle R1 of the table 3. When the tilt angle R1 is equal to the correction angle R2, the long side direction of the shielding slats  27 , i.e., the direction in which the free ends of the shielding slats  27  are extending, is parallel to the perpendicular direction. Accordingly, not only the X-ray toward the operator S can be efficiently shielded, but also the incident in which the shielding slats  27  deform due to the own weight can be further absolutely prevented. 
     In addition, when the X-ray shielding unit  19  is switched from shielding state to the releasing state under the condition in which the tilt angle of the table 3 to relative to the horizontal plane is R1, the shielding switching element  41  adjusts the rotation angle of the motor  33  so that the rotation angle of the respective shielding slats  27  is R3. According to the present Embodiment, a value of the rotation angle R3 is obtained based on the tilt angle R1 using the following formula (A) as the preferred method for calculating the value of the rotation angle R3. 
         R 3=(90°− R 1)  (A)
 
     Referring to  FIG.  10   , the shielding slats  27  are rotated to provide the rotation angle of the shielding slat  27  having R3 obtained using the above formula (A), so that the long side direction of the respective shielding slats  27  become parallel to the loading plane of the table 3. And the respective shielding slats  27  are overlapped with one another in the front view of the X-ray fluoroscopic imaging apparatus  1 . Therefore, the area of the X-ray shielding plane of the X-ray shielding unit  19  can be minimized (referring to the sign P 2 ). Accordingly, the sight of the operator S becomes further wider relative to the table 3 and the subject M. 
     Effects of the Aspect of the Embodiment 
     According to the present Embodiment, a proximity operative X-ray fluoroscopic imaging apparatus  1  comprises: a table 3 on which a subject M is held; an imaging system in which an X-ray tube  5  that irradiates X-ray and an X-ray detector  8  that detects the X-ray irradiated from the X-ray tube  5  and transmitting a subject M are facing each other while sandwiching the table 3; a table driving element  40  that tilts the table relative to the horizontal plane; an X-ray shielding unit  19  that is supported so as to be freely rotatable by the imaging system having a plurality of X-ray shielding slats  27 , wherein each pedestal end of the X-ray shielding slats  27  is in place above the table 3 and each free end of the shielding slats  27  is extending toward the loading surface of the table and the plurality of the shielding slats  27  are arrayed in parallel along the long side of the table 3; and a switching element  41  that switches the shielding state, where the X-ray shielding unit  19  is placed in between the subject M and the operator S to block the X-ray exposure to the operator S, and the releasing state; wherein the shielding switching element  41  further comprises: the slat rotation mechanism  42  that rotates the respective shielding slats  27  around the short side direction axis of the table 3, wherein the slat rotation mechanism  42  rotates the shielding slats  27  to switch between the shielding state and the releasing state. 
     According to such a configuration, the X-ray shielding unit  19  can be switched between the shielding state and the releasing state without taking the X-ray shielding unit  19  having the shielding slats  27  off the X-ray fluoroscopic imaging apparatus  1 . Accordingly, the weight balance of the X-ray imaging system would not change even when the X-ray shielding unit  19  is switched to the releasing state, so that the incident of lowering the operability of the proximity X-ray fluoroscopic imaging apparatus can be avoided. In addition, the action to connect the dummy weight with the X-ray detection unit  7  when the shielding state and the releasing state are switched is not needed, so that the workload on the operator lowers and the convenience of the X-ray fluoroscopic imaging apparatus  1  is improved. 
     In addition, according to the present Embodiment, the slat rotation mechanism  42  changes the rotation angle of shielding slats  27  corresponding to the angle generated by the table driving element  40  to tilt the table 3. In such a configuration, the shielding slats  27  can be rotated arbitrary corresponding to the tilt angle R1 of the table 3 when the table driving element  40  tilts the table 3 relative to the horizontal plane. Accordingly, the incident of deformation of the X-ray shielding slats  27  due to the own weight of the X-ray shielding unit  19  can be avoided. 
     In addition, according to the present Embodiment, the slat rotation element  42  switches from the shielding state to the releasing state by rotating the respective shielding slats  27  so that the traveling direction of the free end of the shielding slats  27  becomes in parallel to the long side direction of the table 3. In such a configuration, the X-ray shielding plane of the X-ray shielding unit  19  that is changed to the releasing state becomes narrower. Accordingly, the operator sight for such as the loading plane of the table 3 can be ensured more adequately when the X-ray shielding unit  19  is switched to the releasing state. 
     Other Embodiments 
     Specifically, the aspects of the Embodiment disclosed at this time are examples and not limited thereto in any points. The scope of the present invention is specified in the claims and all alternatives are included in the scope of the claims and equivalents thereof. For example, the present invention can be implemented in the below alternative Embodiment. 
     (1) According to the present invention set forth above, the X-ray shielding unit  19  comprises the plurality of shielding slats  27  that are arrayed in parallel along the long side direction of the table 3, but the present invention is not limited thereto. Specifically, the direction in which the shielding slats  27  are arrayed in parallel and the position where the shielding slats  27  are in place may be arbitrary changed, corresponding to the positional relationship between the operator S and the X-ray fluoroscopic imaging apparatus  1  when the operator S operates the X-ray fluoroscopic imaging apparatus  1 . 
     (2) According to the present invention set forth above, the slat rotation mechanism  42  comprises one motor  33 , a plurality of the rotation gears  29  and the occlusion gear  31 , but the structure of the slat rotation mechanism  42  is not limited to the present embodiment as long as the structure in which the shielding slats  27  rotate. As the other embodiment of the slat rotation mechanism  42 , each motor  33  is connected in series with each rotation axis  30  of the respective shielding slats  27  and a plurality of the respective motors  33  are rotated in synchronism with one another to rotate the respective shielding slats  27 . 
     In addition, the configuration wherein the slat rotation mechanism  42  rotates automatically the shielding slats  27  using such as the motor  33  is not limited thereto and the shielding slats  27  can be rotated manually. One example of such as the manual rotation may be the configuration in which the slat rotation mechanism  42  may comprise only the rotation gears  29  and the occlusion gear  31 . Specifically, the operator S rotates manually the shielding slats  27  while holding one of the shielding slats  27 , so that the rotation force of the shielding slat  27  being held can be transferred to all shielding slats  27  through the rotation gears  29  and the occlusion gear  31 . As results, all shielding slats  27  can be rotated manually in synchronism with one another. 
     (3) According to the present invention set forth above, the table angle detection element  43  that detects the tilt angle R1 of the table 3 if needed, according to the configuration in which the angle of the shielding slats  27  in the shielding state is corrected when the table 3 is tilted relative to the horizontal plane, but the embodiment is not limited thereto. The other embodiment to correct the angle of the shielding slats  27  may be the configuration in which the tilt angle storing element instead of the table angle detection element  43  is included to memorize the information as to the tilt angle R1 of the table 3 which the operator S inputs the input element  37 . 
     According to the present Embodiment, when the operator S performs an operation to tilt the table 3, the information of the tilt angle R1 of the table 3 input by the operator S is sent from the tilt angle storage element to the slat angle correction element  45  through the control element  38 , and then the slat angle correction element  45  rotates arbitrary the shielding slats  27  based on the information of the tilt angle R1, so that the angles of the shielding slats  27  can be corrected as the free ends of the shielding slats  27  face in the perpendicular direction. 
     (4) According to the present invention set forth above, the value of the rotation angle R3 of the shielding slats  27  when switching the shielding state to the releasing state is not limited to the value obtained by the above formula (A) and can be arbitrary set up to the other value. Specifically, the rotation angle R3 can be calculated using the calculation formula different from the above formula (A). In addition, the tilt angle of the table 3 relative to the horizontal plane can be set the rotation angle R3 to be e.g., 90° regardless the degree of the tilt angle of the table 3. 
     (5) According to the present invention set forth above, the X-ray detector  8  in the imaging system is installed above the table 3, but it is not limited thereto and the X-ray tube  5  of the imaging system may be installed above the table 3. When the X-ray tube  5  is installed above the table 3, the X-ray shielding unit  19  is supported by the X-ray tube  5  or the member embedding with the X-ray tube  5 . 
     REFERENCE OF SIGNS 
     
         
           1  X-ray fluoroscopy imaging apparatus 
           3  Table 
           5  X-ray tube 
           7  X-ray detection unit 
           8  X-ray detector 
           15  Operation panel 
           17  Operation grip 
           19  X-ray shielding unit 
           27  Shielding slat 
           29  Rotation gear 
           31  Occlusion gear 
           33  Motor 
           37  Input element 
           38  Control element 
           39  Imaging system driving element 
           40  Table driving element 
           41  Shielding switching element 
           42  Slat rotation mechanism 
           43  Table angle detection element 
           45  Slat angle correction element 
       
    
     Although only a few embodiments have been disclosed in detail above, other embodiments are possible, and the inventors intend these to be encompassed within this specification. The specification describes certain technological solutions to solve the technical problems that are described expressly and inherently in this application. This disclosure describes embodiments, and the claims are intended to cover any modification or alternative or generalization of these embodiments which might be predictable to a person having ordinary skill in the art of x-ray imaging devices and the complex arrangements therein, including electronics engineers, software engineers, circuit design engineers and related individuals having advanced technical degrees, and as a result basic component elements will be easily understood by those of such skill in the art. 
     Also, the inventors intend that only those claims which use the complete words “means for” are intended to be interpreted under 35 USC 112 paragraph. Moreover, no limitations from the specification are intended to be read into any claims, unless those limitations are expressly included in the claims. 
     Having described at least one of the preferred embodiments of the present invention with reference to the accompanying drawings, it will be apparent to those skills that the invention is not limited to those precise embodiments, and that various modifications and variations can be made in the presently disclosed system without departing from the scope or spirit of the invention. Thus, it is intended that the present disclosure cover modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalents.