JP2006038975A - Medical x-ray radiographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray radiographic apparatus in which an influence of back scattering ray is removed by a sheet body at X-ray radiographing, and also, nearly a fixed distance can be maintained between the sheet body and a recording plate. <P>SOLUTION: The medical X-ray radiographic apparatus is prepared for radiographing an object with X-ray, and the apparatus is provided with the recording plate B arranged in nearly parallel to the object to record image information by the X-ray transmitted through the object, a reading part for reading the image information from the recording plate, and an X-ray absorption sheet 22 arranged on the side opposite to the object of the recording plate so as to remove the back scattering ray, and also, constituted by dispersing or mixing at least one heavy metal excluding lead in or to a flexible base material. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a medical X-ray imaging apparatus that performs X-ray imaging of a subject.

  In the medical field, lead foil (sheet) has been widely used for shielding X-rays and radiation. This lead material is a preferable material from the viewpoint of the shielding function of X-rays and radiation (see Patent Document 1 below), but is not a preferable material from the viewpoint of environmental impact, and its use is severely restricted in general parts and general equipment. Therefore, “managed disposal” is also required for lead-containing medical parts, medical devices, etc., and the search for lead substitute materials is urgent, especially in the medical device field. In addition, when the lead sheet is used in a cassette to remove the effect of backscattering, it is generally used by being affixed to each member around the recording medium, and the distance between the recording medium and the lead sheet surface. Are configured to be uniform.

  On the other hand, in a so-called saddle-type X-ray imaging apparatus in which a patient is laid on a bed and X-ray imaging is performed, in order to eliminate the backscattering effect, a recording made of a stimulable phosphor arranged substantially horizontally at the time of imaging is performed. A structure is used in which the back side of the plate is entirely covered with a lead sheet, and at the time of reading, the lead sheet is retracted from the moving path of the reading unit.

As described above, a lead sheet is also used in the X-ray imaging apparatus, and usually the state where the back side of the plate is entirely covered. Therefore, the lead sheet is exposed to the influence of gravity for a long time, and is bent two-dimensionally downward. For this reason, the distance between the lead sheet and the recording plate gradually becomes different, which leads to a difference in the backscattered ray removing function, which is not preferable. Furthermore, if the difference in position is to be corrected by image processing, two-dimensional correction must be applied, which complicates control. Also, in the case of a configuration in which the lead sheet is retracted, if the lead sheet is wound, the distance between the lead sheet and the recording plate is similarly different.
JP 59-17198

  The present invention provides an X-ray imaging apparatus capable of removing the influence of backscattered rays during X-ray imaging and maintaining a substantially constant distance from the recording plate in view of the above-described problems of the prior art. The purpose is to do.

  In order to achieve the above object, a medical X-ray imaging apparatus according to the present invention is a medical X-ray imaging apparatus that performs X-ray imaging of a subject, and is disposed substantially parallel to the subject and transmits the subject. A recording plate that records image information by X-rays, a reading unit that reads image information from the recording plate, and a lead that is provided on the non-subject side of the recording plate to remove backscattered rays and has flexibility. And a sheet body obtained by dispersing or kneading at least one kind of heavy metal excluding.

  According to this medical X-ray imaging apparatus, since the sheet provided on the side opposite to the subject of the recording plate disperses or kneads at least one heavy metal excluding lead in a flexible material, The removal effect can be obtained, and the flexibility (hardness of curling) and elasticity of the sheet body can be improved, so that the sheet body can maintain a substantially constant distance from the recording plate.

  In the medical X-ray imaging apparatus, the sheet member can be drawn out to remove backscattered rays during X-ray imaging and wound up when reading from the recording plate. As a result, the sheet body can be retracted (wound state) and extended (drawn state), and the apparatus can be downsized (thinned), but the flexibility and elasticity of the sheet body are improved. Therefore, when retracted, the sheet body can be wound around a small radius of curvature, and the device can be further downsized (thinned). On the other hand, it can be kept at a substantially constant distance.

  In addition, the material of the sheet body is preferable because the fibers are extended at least in the drawing / winding direction, so that curling wrinkles are more difficult to stick. In addition, although the fiber of the raw material of a sheet | seat may extend in the direction corresponding to a drawing / winding direction, it may extend in two directions orthogonal to the drawing / winding direction.

  In addition, the medical X-ray imaging apparatus can be configured to perform X-ray imaging in a supine manner while keeping the body axis of the subject in a direction orthogonal to the direction of gravity. In this case, since the sheet body has improved flexibility and elasticity, even if gravity acts on the entire plane of the sheet body, it is difficult for the recording plate to be two-dimensionally bent. It can be kept at a substantially constant distance.

  The medical X-ray imaging apparatus may be configured to perform X-ray imaging in a standing manner while keeping the body axis of the subject in the direction of gravity. In this case, gravity acts in substantially the same direction as the plane of the sheet body, and the recording plate is unlikely to be two-dimensionally bent. On the other hand, it can be kept at a substantially constant distance.

  According to the X-ray imaging apparatus of the present invention, the sheet body can remove the influence of backscattered rays during X-ray imaging and can maintain a substantially constant distance from the recording plate.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a diagram schematically showing a state in which the supine type medical X-ray imaging apparatus according to the present embodiment is used. FIG. 2 is a diagram schematically showing an internal configuration of the medical X-ray imaging apparatus of FIG. FIG. 3 is a cross-sectional view showing the positions of the sheet member and the scanning unit in FIG. 2 during X-ray imaging. FIG. 4 is a diagram illustrating a configuration example of the scanning unit of FIG.

  As shown in FIG. 1, the medical X-ray imaging apparatus 1 according to the present embodiment is provided below the imaging bed 102, and the body axis of the subject patient P is placed on the imaging bed 102 in a direction perpendicular to the direction of gravity. The X-ray 100 transmitted from the X-ray source 101 placed above to the patient P who is placed in a supine position and transmitted through the imaging target region of the patient P is stored inside the apparatus. Recording is performed on a recording plate B disposed on the upper surface substantially parallel to the patient P.

  When the recording plate B is irradiated with X-rays, a part of the X-ray energy is accumulated. After that, when the recording plate B is irradiated with excitation light such as laser light, the recording plate B exhibits stimulable light emission according to the accumulated X-ray energy. It is composed of a phosphor.

  As shown in FIG. 2, the medical X-ray imaging apparatus 1 includes an upper surface cover 23 that is configured by an X-ray transmission window 24 and an outer frame 25 that are disposed on the upper surface side and is positioned substantially parallel to the patient P. In addition, the recording plate B disposed in the X-ray transmission window 24, the scanning unit A that irradiates the recording plate B with scanning light and reads image information, drive control of the scanning unit A, X-ray exposure timing, and image And a control unit 26 that controls reading and the like in an integrated manner.

  Inside the main body of the medical X-ray imaging apparatus 1, as shown in FIG. 2, the scanning unit A is guided in the horizontal direction by transporting the scanning unit A in the horizontal direction and the scanning unit A formed with a ball screw. A guide shaft 15 is disposed. A power supply line and a signal line to the scanning unit A are connected to a control unit 26 installed on the bottom side inside the apparatus by a cable 27 having a length that does not stretch even when the scanning unit A is transported.

  As shown in FIGS. 2 and 3, an X-ray absorbing sheet 22 configured in a sheet shape is disposed in the vicinity of the back side of the recording plate B in order to remove the influence of backscattered rays during X-ray imaging. The X-ray absorbing sheet 22 is wound around the roller 22a on one end side and can be pulled out from the roller 22a, and the other end is fixed to the scanning unit A. For this reason, the X-ray absorbing sheet 22 is wound and pulled out by the roller 22a in accordance with the horizontal movement of the scanning unit A.

  That is, at the time of X-ray imaging, the scanning unit A moves toward the right end of the drawing in the medical X-ray imaging apparatus 1 as shown in FIG. 3, and with this movement, the X-ray absorbing sheet 22 moves from the roller 22a in the direction Y ′. To the recording plate B. Further, the X-ray absorbing sheet 22 moves in the direction Y along with the return of the scanning unit A by applying an urging force by a constant load spring (not shown) to the roller 22a for winding. It is wound up. Further, the urging force of the constant load spring pulls the X-ray absorbing sheet 22 drawn in the direction Y ′ from the roller 22a as shown in FIG. 3 to generate a predetermined tension.

  As shown in FIG. 2, a reading window 16 and a plate-shaped X-ray absorber 19 for reading an image recorded on the recording plate B are provided on the front surface of the scanning unit A. At the time of X-ray imaging, the X-ray absorbing sheet 22 and the plate-like X-ray absorbing material 19 drawn out from the roller 22a can sufficiently prevent the X-ray from entering the inside of the apparatus, and scattered rays due to the X-rays entering the inside of the apparatus Can be sufficiently prevented that the recording plate B is irradiated and noise is included in the X-ray image.

  As shown in FIG. 4, in the scanning unit A, the semiconductor laser unit 2 composed of a semiconductor laser, a collimator lens, or the like outputs a laser beam 3, and the laser beam 3 passes through a filter 4 and enters a scanner 5 to perform main scanning. Scanned in the direction. The scanner 5 may be a galvanometer mirror, a rotary polygon mirror, or the like.

  Scanning light 6 scanned by the scanner 5 is reflected by the mirrors 7 a and 7 b toward the recording plate B to form a scanning line 9 on the scanning surface 8 of the recording plate B. On the scanning line 9, a laser beam is used as excitation light to generate stimulated emission light from the recording plate B, and the light is collected on the elongated light-receiving surface of the light collector 10, and is detected by a photomultiplier tube. Guided to the vessels 11a and 11b.

  The electrical signals photoelectrically converted by the photodetectors 11 a and 11 b are subjected to image processing by the image processing unit of the control unit 26 and output as image signals from the image output unit of the control unit 26. This image signal is sent to a database server and stored, or sent to a printer to form an image on a film and output it.

  Further, the scanning unit A moves in the direction perpendicular to the scanning line 9 (main scanning direction) by moving the sub scanning shaft 14 in the horizontal direction in FIG. 4 while being guided by the guide shaft 15 by the rotation of the motor 13. Is done.

  Next, the X-ray absorption sheet 22 will be described with reference to FIGS. FIG. 5 is a plan view of the fibrous body of the X-ray absorbing sheet of FIGS. FIG. 6 is a diagram showing a cross-sectional configuration of the X-ray absorbing sheet of FIG.

  As shown in FIGS. 5 and 6, the X-ray absorbing sheet 22 is flexible and at least removes lead between a pair of fiber bodies 31 and 32 in which fibers extend in the winding direction Y and the drawing direction Y ′. It consists of a composite material sheet formed with a composite material 33 in which one kind of heavy metal is dispersed. The composite material 33 is a composite material in which, for example, tungsten powder as a heavy metal is dispersed in a styrene elastomer or rubber material, and has a good flexibility and a sufficient X-ray shielding effect.

  As described above, since the X-ray absorbing sheet 22 is formed by sandwiching a flexible composite material between the flexible fibrous bodies 31 and 32, the flexibility and the elastic force are improved. It is difficult to curl, and the fibers extending in one direction in the winding direction Y and the drawing direction Y ′ are difficult to stretch even if a load is applied in the directions Y and Y ′, and the curl is more difficult to stick. Yes.

  Next, the operation of the medical X-ray imaging apparatus 1 shown in FIGS. 1 to 6 will be described. The operations described below are controlled by the control unit 26.

  First, before the start of X-ray imaging, the scanning unit A is moved in the direction Y ′ in FIGS. 2 and 3 by the sub-scanning shaft 14 being rotated by the motor 13 in FIG. 4 and retracted to the right end position in FIG. . With this movement, the X-ray absorbing sheet 22 is pulled out in the pulling direction Y ′ from the roller 22 a and covers the back side of the recording plate B.

  Next, as shown in FIG. 1, X-rays transmitted through the imaging target region of the patient P by irradiating the X-ray 100 from the upper X-ray source 101 to the patient P in the lying position on the imaging bed 102. Image information is recorded on the recording plate B.

  Next, the scanning unit A reads image information from the recording plate B while moving in the sub-scanning direction Y in FIG. As the scanning unit A moves, the X-ray absorbing sheet 22 moves in the winding direction Y and is wound around the roller 22a. As described above, when the scanning unit A completes the sub-scanning movement and the reading of the read image information is completed, the scanning unit A is moved while irradiating the erasing light from the erasing light source (not shown) attached to the scanning unit A. The image is erased from the photostimulable phosphor on the recording plate B.

  As described above, X-ray imaging is performed by the medical X-ray imaging apparatus 1 and image information recorded from the recording plate B can be read. At this X-ray imaging, the X-ray absorbing sheet 22 is A state in which a flexible composite material in which heavy metals are dispersed is sandwiched between the flexible fiber bodies 31 and 32, and the flexibility and elasticity are improved, and the state is pulled with a predetermined tension. Therefore, even if gravity acts on the entire plane of the X-ray absorbing sheet 22 in the gravitational direction g, it is difficult for the X-ray absorbing sheet 22 to be bent in two dimensions, as shown in FIG. The distance d between the line absorbing sheet 22 and the recording plate B can be kept substantially constant. Therefore, there is almost no difference in the backscattered ray removing function of the X-ray absorbing sheet 22 due to the fluctuation of the distance d between the X-ray absorbing sheet 22 and the recording plate B. For this reason, the position of the X-ray absorbing sheet 22 It is not necessary to correct the difference two-dimensionally by image processing, and control is not complicated.

  Even if the device itself or the X-ray absorbing sheet should be discarded, the X-ray absorbing sheet 22 is made of a composite material sheet in which tungsten powder is dispersed without using lead, as in the present embodiment. There is no such regulation.

  Further, the X-ray absorbing sheet 22 is configured to be drawn out for removing the backscattered rays at the time of X-ray imaging and wound up at the time of reading from the recording plate B, thereby reducing the size and thickness of the apparatus. However, since the flexibility and elastic force of the X-ray absorbing sheet 22 are improved, the X-ray absorbing sheet 22 can be wound around the roller 22a with a small radius of curvature when retracted, and the apparatus can be made smaller. Can be made thinner and thinner.

  Next, a medical X-ray imaging apparatus configured to perform X-ray imaging in a standing position while keeping the body axis of the subject in the direction of gravity will be described with reference to FIG. FIG. 9 is a side view schematically showing a standing medical X-ray imaging apparatus.

  The medical X-ray imaging apparatus 1A of FIG. 9 irradiates a patient P standing in front of the apparatus with X-rays 100 from the X-ray source 101, and displays image information by X-rays transmitted through the imaging target region of the patient P. Recording is performed on a recording plate B disposed substantially parallel to the patient P on the inner front surface of the apparatus.

  The medical X-ray imaging apparatus 1 </ b> A is configured in the same manner as that described with reference to FIGS. 2 to 6, but gravity acts in substantially the same direction as the plane of the X-ray absorption sheet 22, and the X-ray absorption sheet 22 Although it is difficult for two-dimensional bending to occur, when the X-ray absorbing sheet 22 is pulled out and wound up in the same manner as in FIGS. It can be kept at a certain distance.

  As described above, the best mode for carrying out the present invention has been described. However, the present invention is not limited to these, and various modifications are possible within the scope of the technical idea of the present invention. For example, the X-ray absorption sheet 22 may have a cross-sectional configuration as shown in FIG. The X-ray absorbing sheet 22 of FIG. 7 is a composite material in which at least one heavy metal excluding lead is dispersed on both sides of a fiber body 34 that is flexible and has fibers extending in the winding direction Y and the drawing direction Y ′. It consists of the composite material sheet in which 35 and 36 were formed. The composite materials 35 and 36 are composite materials in which, for example, tungsten powder as a heavy metal is dispersed in a styrene elastomer or rubber material, and has a good flexibility and a sufficient X-ray shielding effect.

  Further, the X-ray absorbing sheet 22 having a cross-sectional configuration as shown in FIGS. 6 and 7 may be changed to a fiber body 42 as shown in FIG. The fiber body 42 extends in two directions, ie, a direction that coincides with the drawing / winding directions Y and Y ′, and is perpendicular to the drawing / winding direction, and is difficult to extend in the directions Y and Y ′ and hardly bends. It has become.

  Moreover, you may use what made the resin itself of the composite material which disperse | distributed heavy metal in the above-mentioned X-ray absorption sheet 22 into fiber form beforehand. In addition to tungsten, for example, molybdenum or copper may be used as the heavy metal excluding lead.

It is a figure which shows roughly the state which uses the supine type medical X-ray imaging apparatus by this Embodiment. It is a figure which shows schematically the internal structure of the medical X-ray imaging apparatus of FIG. It is sectional drawing which shows the position of the sheet | seat body and scanning unit of FIG. 2 at the time of X-ray imaging. It is a figure which shows the structural example of the scanning unit of FIG. It is a top view of the fiber body of the X-ray absorption sheet of FIG. 2, FIG. It is a figure which shows the cross-sectional structure of the X-ray absorption sheet of FIG. It is a figure which shows the modification of the cross-sectional structure of the X-ray absorption sheet of FIG. It is a top view which shows the modification of the fiber body of the X-ray absorption sheet of FIG. 1 is a side view schematically showing a standing medical X-ray imaging apparatus according to the present embodiment.

Explanation of symbols

1,1A Medical X-ray equipment 22 X-ray absorption sheet (sheet body)
22a roller 23 upper surface cover 31, 32 fiber body 33 composite material 34 fiber body 35, 36 composite material 42 fiber body A scanning unit B recording plate P patient (subject)
Y Winding direction Y 'Pulling direction d Interval g Gravity direction

Claims (5)

A medical X-ray imaging apparatus that performs X-ray imaging of a subject,
A recording plate for recording image information by X-rays arranged substantially parallel to the subject and transmitted through the subject;
A reading unit for reading image information from the recording plate;
A sheet member provided on the opposite side of the recording plate for removing backscattered rays and having a flexible material in which at least one heavy metal excluding lead is dispersed or kneaded. Medical X-ray equipment.   2. The medical device according to claim 1, wherein the sheet body is drawn out for removing backscattered rays at the time of X-ray imaging, and wound up when reading from the recording plate. X-ray imaging equipment.   The medical X-ray imaging apparatus according to claim 2, wherein the material of the sheet body has at least fibers extending in a drawing / winding direction.   The medical X-ray imaging apparatus according to claim 1, wherein X-ray imaging is performed in a supine manner while maintaining the body axis of the subject in a direction orthogonal to the direction of gravity. The medical X-ray imaging apparatus according to claim 1, 2 or 3, wherein X-ray imaging is performed in a standing manner while maintaining the body axis of the subject in the direction of gravity.

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