JP2012243663A - X ray generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct sufficient heat radiation and shielding of scattered X rays in an X ray generator provided at a bone mineral density measurement system or the like.SOLUTION: A structure 44 is provided at an upper part of an X ray generation unit 14. The structure 44 is provided around a filter unit 42 and is composed of one horizontal plate 52 and multiple vertical plates 54. When scattered X rays occur in the filter unit 42, the scattered X rays are shielded by the structure 44. Further, an X ray tube is efficiently cooled by heat radiation action of the structure 44. The structure 44 achieves electromagnetic shield action.

Description

  The present invention relates to an X-ray generator, and more particularly to a heat dissipation structure in an X-ray generator.

  Bone density measuring devices, X-ray devices, CT devices, and the like are known as devices that measure a subject using X-rays. These devices include an X-ray generator (Patent Documents 1 and 2). The X-ray generation device includes an X-ray generation unit, which includes an X-ray generation tube and a shielding case that accommodates the X-ray generation tube. Insulating oil is sealed in the shielding case. It exhibits an insulating action and a heat dissipation action. A high voltage is applied to the X-ray generation tube, and much of the implantation energy becomes thermal energy.

  In the bone density measuring apparatus, the X-rays emitted from the X-ray generation unit are usually irradiated to the subject through the filter unit. X-rays transmitted through the subject are detected by an X-ray detector. In the bone density measurement, a high voltage and a low voltage are periodically switched as the voltage supplied to the X-ray generation tube, and a filter is periodically inserted on the X-ray beam path. There are cases where a filter is inserted only at the time of high-energy X-ray irradiation, and cases where a unique filter is inserted for each of high-energy X-ray irradiation and low-energy X-ray irradiation. In any case, since it is necessary to periodically insert and remove the filter, a rotating plate or a cylindrical plate is used in the filter unit. In the former, one or more fan-shaped filters are incorporated in the rotating plate, and the rotating plate is driven to rotate around a rotation axis parallel to the X-ray beam. In the latter, one or a plurality of curved filters are incorporated on the side surface of the cylindrical plate (Patent Document 3). The axis of rotation of the cylindrical plate is orthogonal to and crosses the X-ray beam.

JP 2007-149521 A JP 2007-026800 A Patent No. 4499593

  In the X-ray generator as described above, it is necessary to sufficiently dissipate heat, but in the past, this is not always sufficient. In the configuration in which the filter unit is mounted on the top plate of the X-ray generation unit, X-rays are easily scattered in the filter unit, that is, scattered X-rays are easily emitted therefrom. In order to sufficiently shield it only with the case of the filter unit, it is necessary to make the whole case sufficiently thick. Further, since a high voltage is applied to the X-ray generator, electromagnetic noise is likely to be generated, and it is expected that the leakage is alleviated to some extent. Furthermore, the X-ray generator is heavy, and there is a demand for convenience in carrying it. It is required to solve at least one of these problems.

  An object of the present invention is to provide an X-ray generator that can effectively shield scattered X-rays simultaneously with heat dissipation. Alternatively, an object of the present invention is to provide a highly practical X-ray generator.

An X-ray generation apparatus according to the present invention includes an X-ray generation unit that generates an X-ray beam and a shielding case that accommodates the X-ray generation unit, and an X-ray irradiation port in the X-ray generation unit. A filter unit which is provided on the top plate and selectively inserts a filter on the path of the X-ray beam; and a heat dissipating structure provided on the top plate and around the filter unit.

  According to the above configuration, the heat dissipation structure that transmits heat from the X-ray generation source is provided around the filter unit, and cooling of the X-ray generation source can be promoted by the heat dissipation action of the heat dissipation structure. In the filter unit, the filter member is driven, and scattered X-rays are likely to be generated in various directions depending on the passage state of the X-ray beam. Since many of such scattered X-rays pass through the heat dissipation structure provided around the filter unit, a shielding effect there can be expected. When a unit having a cylindrical filter drum is used as the filter unit, scattered X-rays are likely to be generated irregularly over a wide area. In such a case, the heat dissipation structure functions more effectively as an X-ray shielding member. To do.

  Preferably, the heat dissipation structure includes a plurality of vertical walls standing up with respect to the top plate and at least one horizontal wall parallel to the top plate, wherein the plurality of vertical walls and the horizontal wall Is made of a material having an X-ray attenuation effect. If only a heat dissipation action is expected, a plurality of vertical walls may be provided. However, if a shielding action is also expected, it is desirable to provide a horizontal wall, that is, scattering in various horizontal and vertical directions. It is desirable to determine the structure of the heat dissipation structure so that the shielding member crosses the X-ray. In addition, when such a wall cannot be provided, the thickness of the filter unit case may be partially increased to enhance the shielding action there. If you only want to increase the shielding effect, the entire filter unit case can be made thicker. However, in order to reduce the shielding effect, heat dissipation effect, and weight, the heat dissipation structure can be used for shielding, and the resulting shielding effect. It is desirable to take care, such as partially increasing the thickness of the case, in a portion where the shortage is insufficient. Note that fins may be provided on the surface of the filter unit case.

  Desirably, the heat dissipation structure has a plurality of ducts, each duct functions as an air flow passage, and air blowing means is provided for circulating air in the plurality of ducts. Air cooling can be promoted by forming an appropriate air flow by the plurality of ducts and the air blowing means. Preferably, a cable for supplying electric power to the X-ray generation source is inserted into a specific duct among the plurality of ducts. According to this, the electromagnetic shielding action of the heat dissipation structure can be expected. Even if all of the cables are not accommodated in the duct, leakage of electromagnetic waves can be prevented or reduced for at least some of the cables.

  It is also possible to extend the end of the horizontal wall horizontally to function as a handle, and to make the end of each vertical wall have a spire shape in order to promote air flow Good. The above configuration can be applied to various apparatuses using X-rays, but it is particularly preferable to apply to a bone density measuring apparatus (bone mineral content measuring apparatus).

  According to the present invention, it is possible to provide an X-ray generator capable of effectively shielding scattered X-rays simultaneously with heat dissipation. Or according to this invention, a highly practical X-ray generator can be provided.

It is a block diagram which shows the bone density measuring device system provided with the X-ray generator which concerns on this invention. It is sectional drawing of an upper unit. It is a figure which shows the rotating drum in a filter unit. It is a top view of an upper unit. It is a figure which shows the modification of a structure. It is a figure which shows the other modification of a structure.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.

  FIG. 1 shows a bone density measuring apparatus provided with an X-ray generator according to the present invention. This bone density measuring system is installed in a medical institution. The X-ray generator according to the present invention can be applied to other systems using X-rays in addition to the bone density measuring system.

  The bone density measuring system shown in FIG. 1 is a system that measures the bone mineral content of bones in a subject, and is roughly composed of a measuring unit 10 and a calculation control unit 12. The measurement unit 10 is a part that acquires X-ray detection data for obtaining bone mineral content by X-ray irradiation and detection, and the arithmetic control unit 12 is a part that controls the measurement unit 10 and processes the detection data.

  The measuring unit 10 will be described in detail. The measurement unit 10 includes an X-ray generation unit 14 and an upper unit 18. Specifically, the units 14 and 18 are provided in the lower part of the bed 20. The X-ray generation unit 14 and the upper unit 18 together constitute an X-ray generation apparatus, and the detailed configuration will be described in detail later with reference to FIGS. The X-ray generation unit 14 includes an X-ray generation tube 16 in which X-rays, specifically, X-rays having a fan beam shape are generated. In this embodiment, the upper unit 18 has a filter unit and a structure (heat dissipation structure). The structure has a heat dissipation effect, a shielding effect, an electromagnetic shielding effect and the like as will be described in detail later.

  A subject 22 is placed on the bed 20. In FIG. 1, a fan beam extending in the YZ plane is shown. The X-ray detection unit 20 includes a plurality of detection sensors, and detection data is output from the X-ray detection unit 24. Reference numeral 26 denotes a housing in the measurement unit. In this embodiment, the X-ray generation unit 14 and the upper unit 18 and X provided to the X-ray generation unit 14 and the upper unit 18 via the subject 22 by a scanning mechanism (not shown). The line detection unit 24 is conveyed in the horizontal direction.

  Next, the arithmetic control unit 12 will be described. The control unit 30 controls the operation of the entire system, and in particular controls the rotational operation of the power supply 32 and the filter unit. The bone density calculation unit 28 calculates bone density using first detection data obtained by irradiation with high energy X-rays and second detection data obtained by irradiation with low energy X-rays. A bone density image obtained thereby is output to the display unit 34. In addition to the bone density image, the display unit 34 displays an average bone density value and the like by numerical values. Incidentally, the voltage of the power source is switched in accordance with the irradiation of the high energy X-ray and the irradiation of the low energy X-ray, and the rotation of the filter is controlled.

  FIG. 2 shows a cross section of the upper unit 18 shown in FIG. Below that is an X-ray generation unit 14. The X-ray generation unit 14 has a case 38 made of brass or lead having an X-ray shielding function. The interior 40 is filled with insulating oil, and the interior 42 is provided with the X-ray generator tube 16. Insulating oil exhibits heat dissipation and insulation. The top plate 38B in the case 38 is formed with a slit as a radiation port through which the X-ray beam 36 passes. It has a structure that does not allow insulating oil to flow out.

  The upper unit 18 includes a filter unit 42 and a structure 44. Specifically, the structure 44 is provided so as to surround the periphery of the filter unit 42. The filter unit 42 has a rotating drum 46 therein, and a plurality of filter members are provided on the rotating drum. This will be described later with reference to FIG. A filter unit case 48 is provided around the rotary drum 46, and has a side plate 48B and a top plate 48A. The upper surface plate 48A is formed to be slightly thicker than the side surface plate 48B, and a slit 48C through which the X-ray beam 36 passes is formed at the center. The slit 48C functions as a collimator. A plurality of fins 50 are formed on the outer surface of the side plate 48B, and the heat radiating action is also exhibited in the filter unit case 48. The filter unit case 48 is made of, for example, brass or lead, that is, a member having an X-ray shielding action. Although there is a possibility that some scattered X-rays leak particularly in the horizontal direction, the thickness of the upper surface plate 48A is set so that almost no leakage of scattered X-rays occurs in the upper direction. Incidentally, the arrow indicated by reference numeral 56 conceptually indicates scattered X-rays.

  In the example shown in FIG. 2, the structure 44 includes a horizontal plate 52 and a plurality of vertical plates 54 integrated therewith. A plurality of ducts 60 are formed between the plurality of vertical plates 54 and below the horizontal plate 52, and each duct 60 functions as an air flow passage. Cables 58 are inserted into the two ducts at the right end and the left end in the duct row, respectively, and these cables 58 supply power to a fan for circulating air.

  In FIG. 2, the electromagnetic shielding action for a specific duct 60 through which the cable 58 is inserted is indicated by reference numeral 62. The structure 44 is made of a member that shields or attenuates scattered X-rays, and is made of a metal such as lead or brass. Of course, you may comprise by members, such as aluminum. In any case, it is desirable to use a member that causes X-ray shielding or attenuation. Further, since the plurality of vertical plates 54 are arranged in the horizontal direction, the X-ray attenuation effect can be enhanced in that direction. Further, since the horizontal plate 52 having a certain thickness in the vertical direction is provided, X-ray attenuation in that direction can be expected. The X-rays emitted in the Y direction as viewed from the filter unit 42, that is, in the direction perpendicular to the paper surface of FIG. 2, cannot be attenuated by the structure 44, but in order to attenuate such X-rays, the filter unit case The thickness of the vertical plate existing at the end of 48 in the Y direction is increased. That is, the thickness of the filter unit case 48 is increased at the upper plate 48A and at the end portion in the Y direction. Conversely, the thickness of the vertical side plates present on both sides in the X direction is reduced. However, the scattered X-rays that have passed there are sufficiently attenuated by the plurality of vertical plates 54 described above.

  The structure 44 is composed of the horizontal plate 52 and the plurality of vertical plates 54 as described above, and the surface area thereof is increased, and a sufficient heat radiation action can be generated by the fin effect. Since the structure 44 is connected to the case 38 in the X-ray generation unit 14, specifically, the structure 44 is connected to the top plate 38 </ b> B, the heat generated in the X-ray generation tube 16 passes through the insulating oil through the case. The heat generated in the X-ray generating tube 16 is effectively released by the heat radiation action. In order to further promote such heat dissipation, a plurality of fans are provided as will be described later.

  FIG. 3 schematically shows a rotating drum provided in the filter unit 42 shown in FIG. The rotating drum 46 has a plurality of members 104 and 106 and a plurality of openings 102 along the circumferential direction thereof. The member 104 is a filter member or a shielding member, and the member 106 is a filter member. In this way, by arranging a plurality of members in the electron direction or providing the opening 102 between them, it is possible to perform filtering corresponding to high energy X-rays and low energy X-rays. For example, when attention is paid to the member 104, X-rays hit the edge 104A depending on the rotation angle, and scattered X-rays are generated in various directions. This is indicated by the dashed arrows in FIG. As shown in FIG. 2, such scattered X-rays are first attenuated in the filter unit case 48, and scattered X-rays that are exclusively emitted in the horizontal direction, particularly in the X direction, are effectively shielded by the structure 44.

  FIG. 4 shows a top view of the upper unit. As described above, the upper unit has a structure 44, which has a horizontal plate 52 and a plurality of vertical plates 54. As a result, a plurality of ducts 60 are formed. In the figure, each duct 60 is configured as a tunnel extending in the Y direction. A plurality of fans 62A and 62B are provided on one side (the left side in FIG. 4) of the plurality of ducts 60, and air is forced into the plurality of ducts 60 by such fans. The flow is indicated by a plurality of arrows in FIG. In addition to the plurality of ducts 60, the air that is sent is also sent to a plurality of grooves formed on the upper side of the horizontal plate 52, so that the entire surface of the structure 44 has a heat radiation effect effectively. Incidentally, reference numeral 58 denotes a cable connected to the two fans 62A and 62B, and a main portion of the cable is drawn into a specific duct. In that particular duct, the surrounding structural part exhibits an electromagnetic shielding effect. As a result, leakage of electromagnetic noise can be reduced. Incidentally, one end of the cable 58 is connected to the fan, the lower end thereof is drawn into the X-ray generation unit, and a part of a concentrated cable (not shown) extending from the X-ray generation unit is a power cable for the fan.

  In FIG. 4, the end portion in the Y direction of the filter unit case in the filter unit 48, that is, the side plate 48D is thicker than the side plate 48B present at the end in the X direction, and the axial direction of the rotary drum, that is, the Y direction. When scattered X-rays are generated, the side plate 48D shields it.

  5 and 6 show a modification of the structure 44. FIG. Similar to the structure shown in FIG. 2, the structure 44 shown in FIG. 5 includes a horizontal plate 52 and a plurality of vertical plates 54. However, in the example shown in FIG. 5, the end portion in the Y direction of the horizontal plate 52 extends in the horizontal direction, and the portion functions as handles 52 </ b> A and 52 </ b> B protruding horizontally. The X-ray generation unit 14 and the upper unit 18 are structurally connected, and by gripping such a pair of handle portions, the entire X-ray generation apparatus can be securely held and conveyed.

  In the modification shown in FIG. 6, the air inlet side ends of the plurality of vertical walls 54 have a tapered shape 54A, so that the resistance during the intake of air is reduced. In the above-described embodiment, the structure is constituted by one horizontal plate and a plurality of vertical plates. However, one or a plurality of horizontal plates may be added, and more complicated for increasing the surface area. Such a structure may be adopted. In any case, it is desirable to employ a structure that effectively generates heat dissipation and shielding. In the above embodiment, the structure is not provided on the upper portion of the filter unit. However, the structure of the structure can be changed so as to exhibit an attenuation action and a heat dissipation action also in this portion.

  10 measurement units, 12 calculation control units, 14 X-ray generation units, 18 upper units, 42 filter units, 44 structures.

FIG. 2 shows a cross section of the upper unit 18 shown in FIG. The lower side is an X-ray generation unit 14. The X-ray generation unit 14 has a case 38 made of brass or lead having an X-ray shielding function. The interior 40 is filled with insulating oil, and the interior 42 is provided with the X-ray generator tube 16. Insulating oil exhibits heat dissipation and insulation. The top plate 38B in the case 38 is formed with a slit as a radiation port through which the X-ray beam 36 passes. It has a structure that does not allow insulating oil to flow out. As illustrated, the top plate 38B is a member that extends along the XY plane (in parallel with the XY plane).

The upper unit 18 includes a filter unit 42 and a structure 44. Specifically, the structure 44 is provided so as to surround the periphery of the filter unit 42. The filter unit 42 has a rotating drum 46 therein, and a plurality of filter members are provided on the rotating drum. This will be described later with reference to FIG. A filter unit case 48 is provided around the rotary drum 46, and has a side plate 48B and a top plate 48A. The upper surface plate 48A is formed to be slightly thicker than the side surface plate 48B, and a slit 48C through which the X-ray beam 36 passes is formed at the center. The slit 48C functions as a collimator. A plurality of fins 50 are formed on the outer surface of the side plate 48B, and the heat radiating action is also exhibited in the filter unit case 48. The filter unit case 48 is made of, for example, brass or lead, that is, a member having an X-ray shielding action. Although there is a possibility that some scattered X-rays leak particularly in the horizontal direction, the thickness of the upper surface plate 48A is set so that almost no leakage of scattered X-rays occurs in the upper direction. Incidentally, the arrow indicated by reference numeral 56 conceptually indicates scattered X-rays. The rotation axis of the rotary drum is parallel to the Y direction.

In the example shown in FIG. 2, the structure 44 includes a horizontal plate 52 and a plurality of vertical plates 54 integrated therewith. As illustrated, the horizontal plate 52 is a member that extends along the XY plane. Each vertical plate 54 is a member extending along the YZ plane. A plurality of ducts 60 are formed between the plurality of vertical plates 54 and below the horizontal plate 52, and each duct 60 functions as an air flow passage. Cables 58 are inserted into the two ducts at the right end and the left end in the duct row, respectively, and these cables 58 supply power to a fan for circulating air.

Claims (4)

An X-ray generation unit having an X-ray generation source for generating an X-ray beam and a shielding case for accommodating the X-ray beam;
A filter unit that is provided on a top plate having an X-ray irradiation port in the X-ray generation unit and selectively inserts a filter on the path of the X-ray beam;
A heat dissipation structure provided on the top plate and around the filter unit;
X-ray generator characterized by including. The apparatus of claim 1.
The heat dissipation structure is
A plurality of vertical walls standing up against the top plate;
At least one horizontal wall parallel to the top plate;
Including
The X-ray generator according to claim 1, wherein the plurality of vertical walls and the horizontal wall are made of a material having an X-ray attenuation effect. The apparatus of claim 2.
The heat dissipation structure has a plurality of ducts, and the inside of each duct functions as an air flow path,
An X-ray generation device, characterized in that an air blowing means is provided for circulating air in the plurality of ducts. The apparatus of claim 3.
An X-ray generation apparatus, wherein a cable for supplying electric power to the X-ray generation source is inserted into a specific duct among the plurality of ducts.

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