WO2012160967A1

WO2012160967A1 - X-ray generator

Info

Publication number: WO2012160967A1
Application number: PCT/JP2012/061819
Authority: WO
Inventors: 宮本　高敬
Original assignee: 日立アロカメディカル株式会社
Priority date: 2011-05-23
Filing date: 2012-05-09
Publication date: 2012-11-29
Also published as: JP2012243663A; CN103548424A; TWI482535B; TW201249261A; JP5081314B1; CN103548424B

Abstract

An X-ray generator provided in a bone densitometry system, etc., has a structure (44) above an X-ray generation unit (14). Specifically, the structure (44) is provided around a filter unit (42), and the structure (44) comprises one horizontal plate (52) and multiple vertical plates (54). In the event of scattered X-rays inside the filter unit (42), the scattered X-rays are shielded by the structure (44). The X-ray tube is effectively cooled due to the heat radiation function of the structure (44). The structure (44) also exerts an electromagnetic shielding function.

Description

X-ray generator

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

As a device for measuring a subject using X-rays, a bone density measuring device, an X-ray imaging device, a CT imaging device, and the like are known. These devices include an X-ray generator (see Patent Documents 1 and 2 below). The X-ray generation apparatus includes an X-ray generation unit, and the X-ray generation unit includes an X-ray generation tube and a shielding case that accommodates the X-ray generation tube. In the shielding case, insulating oil is sealed together with the X-ray generating tube. Insulating oil exhibits an insulating action and a heat dissipation action. A high voltage is applied to the X-ray generator tube. In the X-ray generation tube, much of the injected electric energy becomes thermal energy.

In the bone density measuring device, X-rays emitted from the X-ray generation unit are usually irradiated to the subject through the filter unit. X-rays that have passed through the subject are detected by an X-ray detector. In bone density measurement, a high voltage and a low voltage are alternately applied to the X-ray generation tube. Accordingly, one or more filters are selectively inserted on the X-ray beam path. For example, a filter may be inserted only during high-energy X-ray irradiation, and a dedicated filter may be inserted during high-energy X-ray irradiation and low-energy X-ray irradiation. In any case, it is necessary to periodically put in and out one or more filters. For this reason, a disk unit or a cylindrical unit is used as the filter unit. In the disk-type unit, a disk in which one or more fan filters are incorporated is used. The disk rotates about an axis of rotation parallel to the X-ray beam. In the cylindrical unit, a cylinder in which one or a plurality of curved filters are incorporated is used (see Patent Document 3 below). The cylinder rotates about a rotation axis orthogonal to the X-ray beam.

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

In the X-ray generator as described above, since a large amount of heat is generated, it is necessary to sufficiently dissipate heat. However, in the prior art, sufficient heat dissipation is not always performed. In the configuration in which the filter unit is mounted on the top plate (subject side plate) of the X-ray generation unit, X-rays are easily scattered in the filter unit, that is, scattered X-rays are easily emitted from there. In order to shield the scattered X-rays only by the case of the filter unit, the entire case must be formed with a sufficient thickness. Since a high voltage is applied to the X-ray generator, electromagnetic noise is easily generated in the X-ray generator. It is expected to eliminate or reduce the leakage of electromagnetic noise. Furthermore, it is desired to make the X-ray generator easily portable. It is required to solve at least one of the above-mentioned problems.

An object of the present invention is to provide an X-ray generator that can effectively shield scattered X-rays simultaneously with heat radiation. 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 source that generates an X-ray beam, and a shielding case that includes the front plate that houses the X-ray generation source and has an X-ray irradiation port. A generating unit, a filter unit provided on the front plate in the X-ray generating unit, having at least one filter, and inserting the at least one filter on a path of the X-ray beam; and on the front plate And a heat dissipating structure provided 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 the cooling of the X-ray generation source can be promoted by the heat dissipation action of the heat dissipation structure. In the filter unit, one or a plurality of filters are driven, and scattered X-rays are likely to be generated in various directions depending on the passage state of the X-ray beam in the filter unit. Many of the scattered X-rays pass through the heat dissipation structure provided around the filter unit, so that the scattered X-ray shielding effect 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.

Preferably, the heat dissipation structure includes a plurality of vertical walls standing up with respect to the front plate and at least one horizontal wall parallel to the front plate, wherein the plurality of vertical walls are attenuated by X-rays. The horizontal wall is made of a material having an action, and the horizontal wall is made of a material having an X-ray attenuation action. 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 further provide a horizontal wall, that is, the light exits in various directions such as a horizontal direction and a vertical direction. It is desirable to determine the structure of the heat dissipation structure so that scattered X-rays cross any of the shielding members. While providing the heat dissipation structure and increasing the thickness of all or part of the case of the filter unit, the shielding effect of scattered X-rays can be further enhanced. A plurality of fins may be provided on the surface of the filter unit case.

Desirably, the heat dissipation structure has a plurality of ducts, and the inside of each duct functions as an air flow passage, and air blowing means for circulating air in the plurality of ducts is provided. 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 the entire cable is not accommodated in the duct, leakage of electromagnetic waves can be prevented or reduced at least for a part of the cable if it is accommodated.

It should be noted that the end of the horizontal wall can be extended horizontally to function as a handle. Moreover, you may make it make the edge part of each vertical wall into a spire shape in order to promote the distribution | circulation of air. The above-described configuration can be applied to various devices using X-rays, but it is particularly preferable to apply to a bone density measuring device (bone mineral content measuring device).

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.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a bone density measuring system 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 a bone density measuring system.

The bone density measuring system shown in FIG. 1 is a system for measuring the bone mineral density of bone in a subject. It is roughly divided into a measurement unit 10 and a calculation control unit 12. The measurement unit 10 is a part that acquires X-ray detection data for bone mineral content calculation by X-ray irradiation and detection. The arithmetic control unit 12 controls the measurement unit 10 and processes 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 is configured by combining both the X-ray generation unit 14 and the upper unit 18. The detailed configuration will be described later in detail 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). As will be described later in detail, the structure exhibits a heat dissipation effect, a shielding effect, an electromagnetic shielding effect, and the like.

The subject 22 is placed on the bed 20. In FIG. 1, a fan beam extending in the YZ plane is shown. An X-ray detection unit 20 is provided above the subject 22. The X-ray detection unit 20 includes a plurality of detection sensors. The X-ray detection unit 24 outputs detection data. Reference numeral 26 denotes a housing in the measurement unit. In the present embodiment, the X-ray generation unit 14, the upper unit 18, and the X-ray detection unit 24 are conveyed in the horizontal direction by a scanning mechanism (not shown). An X-ray generator may be provided above the subject, and an X-ray detection unit may be provided below the subject.

Next, the arithmetic control unit 12 will be described. The control unit 30 controls the operation of the entire system, and particularly controls the power supply 32 and the filter unit. The bone density calculation unit 28 calculates the 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 according to the irradiation with the high energy X-ray and the irradiation with the low energy X-ray, and the rotation operation of the filter is controlled.

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 a material having an X-ray shielding function, such as brass or lead. The interior 40 is filled with insulating oil, and the interior 40 is provided with an X-ray generation tube 16. Insulating oil exhibits heat dissipation and insulation. A slit 38 </ b> A that functions as a radiation port through which the X-ray beam 36 passes is formed in a top plate 38 </ b> B as a front plate in the case 38. It has a structure that does not allow insulating oil to flow out. The top plate 38B is a member that spreads along the XY plane (that is, parallel to 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 rotary drum 46 provided therein, and the rotary drum 46 has a plurality of filter members. 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 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 of the upper surface plate 48A. The slit 48C functions as a collimator. A plurality of fins 50 are formed on the outer surface of the side plate 48B. Thereby, the heat dissipation action of the filter unit case 48 is enhanced. The filter unit case 48 is made of, for example, brass or lead, that is, a member having an X-ray shielding action. The thickness of the upper surface plate 48A is sufficiently large so that scattered X-rays do not leak upward from the inside of the filter unit. Incidentally, an arrow indicated by reference numeral 56 conceptually indicates scattered X-rays emitted in the horizontal direction from the rotating drum. 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. 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 partitioned by a plurality of vertical plates 54 are formed below the horizontal plate 52. Each duct 60 functions as an air flow path. Cables 58 are inserted through the two ducts at the right end and the left end in the duct row, respectively. These cables 58 supply electric power to two fans for circulating air.

2, the electromagnetic shielding action for the 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, the structural body 44 may be made of a member such as aluminum. In any case, it is desirable that the structural body 44 is constituted by a member that shields or attenuates X-rays. In the structure 44, since the plurality of vertical plates 54 are arranged in the horizontal direction, the X-ray attenuation effect can be enhanced in the horizontal direction. Since the structure 44 includes the horizontal plate 52 having a certain large thickness, an X-ray attenuation effect in the vertical direction can also be obtained. For X-rays that are emitted from the filter unit 42 in the Y direction (that is, the direction perpendicular to the paper surface of FIG. 2), the X-ray attenuation action by the structure 44 cannot be expected, but in order to attenuate such X-rays, The thickness of the two side plates present at both ends in the Y direction of the filter unit case 48 is increased. That is, in the filter unit case 48, the thickness of the upper surface plate 48A and the thickness of the two side surface plates arranged in the Y direction are increased. Conversely, the thickness of the two vertical side plates present at both ends in the X direction is thin. However, scattered X-rays that have passed through them are sufficiently attenuated by the plurality of vertical plates 54 described above.

As described above, the structure 44 includes the horizontal plate 52 and the plurality of vertical plates 54, and the surface area of the structure 44 is increased. Thereby, it is possible to generate a sufficient heat dissipation action in the structure 44. The structure 44 is connected to the case 38 in the X-ray generation unit 14, specifically, connected to the top plate 38 </ b> B. Therefore, the heat generated in the X-ray generation tube 16 is transmitted to the case 38 through the insulating oil, and further transmitted from the case 38 to the structure 44. The heat generated by the X-ray generation tube 16 is effectively released to the outside by the heat radiation action in the structure 44. In order to further promote such a heat radiation action, a plurality of fans described later are provided.

FIG. 3 schematically shows the rotating drum 46. The rotating drum 46 is provided in the filter unit 42 shown in FIG. The rotating drum 46 includes a plurality of

members

104 and 106 and a plurality of openings 102 arranged along the circumferential direction. The member 104 is a filter member or a shielding member, and the member 106 is a filter member. Filtering for generating high energy X-rays and low energy X-rays can be performed by arranging a plurality of members in the circumferential direction as described above or by providing an opening 102 between adjacent members. is there. For example, when attention is paid to the member 104, X-rays hit the edge 104A of the member 104 at a specific rotation angle, and scattered X-rays are generated in various directions. This is indicated in FIG. 3 by a plurality of broken lines with arrows. Such scattered X-rays are first attenuated in the filter unit case 48, as shown in FIG. Furthermore, scattered X-rays that exit 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 includes the structure 44, and the structure 44 includes the horizontal plate 52 and the plurality of vertical plates 54. A plurality of ducts 60 are formed by these plates. In FIG. 4, each duct 60 is a tunnel extending in the Y direction. A plurality of

fans

62A and 62B are provided on one side (left side in FIG. 4) of the plurality of ducts 60, and air is forcibly sent into the plurality of ducts 60 by the

fans

62A and 62B. The air flow is indicated by arrows in FIG. In addition to the plurality of ducts 60, the air to be fed is also sent to a plurality of grooves formed on the upper side of the horizontal plate 52. Therefore, the heat radiation effect is effectively exhibited on the entire surface of the structure 44. Incidentally, reference numeral 58 denotes a cable connected to the two

fans

62A and 62B. The main part of the cable 58 is drawn into a specific duct. A structural part existing around the specific duct exhibits an electromagnetic shielding effect. As a result, leakage of electromagnetic noise can be prevented or reduced. Incidentally, one end of each cable 58 is connected to each fan, and the lower end of each cable 58 is drawn into the X-ray generation unit. A part of a collective cable (not shown) extending from the X-ray generation unit is a fan power cable.

4, the end portion of the filter unit case in the Y direction of 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. When scattered X-rays are generated in the axial direction of the rotating drum, that is, in the Y direction, the scattered X-rays are blocked by the side plate 48D.

5 and 6 show two modified examples related to the structure 44. 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, both ends of the horizontal plate 52 in the Y direction extend in the horizontal direction. The two extending portions are horizontally protruding portions, and they function as the

handles

52A and 52B. The X-ray generation unit 14 and the upper unit 18 are structurally connected. By grasping the pair of handle portions, the entire X-ray generation apparatus can be firmly held and transported.

In the modification shown in FIG. 6, the end of each vertical wall 54 on the air inlet side has a tapered shape 54a, that is, the resistance when air is taken in is reduced. In the above-described embodiment, the structure is configured by one horizontal plate and a plurality of vertical plates. However, one or a plurality of horizontal plates may be added, and more complicated in order to increase the surface area. 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 part of the filter unit. However, the structure of the structure can be changed so that attenuation and heat dissipation are also exhibited in the portion.

Claims

An X-ray generation unit comprising: an X-ray generation source that generates an X-ray beam; and a shielding case that contains the X-ray generation source and includes a front plate having an X-ray irradiation port;
A filter unit provided on the front plate in the X-ray generation unit, having at least one filter, and inserting the at least one filter on a path of the X-ray beam;
A heat dissipation structure provided on the front 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 front plate;
At least one horizontal wall parallel to the front plate;
Including
The plurality of vertical walls are made of a material having an X-ray attenuation action, and the horizontal walls are made of a material having an X-ray attenuation action.
An X-ray generator characterized by that.
The apparatus of claim 2.
The heat dissipation structure has a plurality of ducts,
The inside of each duct functions as an air flow path,
Blower means for circulating air in the plurality of ducts was provided,
An X-ray generator characterized by that.
The apparatus of claim 3.
A cable for supplying power to the X-ray generation source is inserted into a specific duct among the plurality of ducts.
An X-ray generator characterized by that.
The apparatus of claim 2.
The front plate is a member extending along the XY plane,
An X-ray beam extending along the YZ plane is output from the X-ray irradiation port,
Each vertical wall is a member extending along the YZ plane,
The at least one horizontal wall is a member extending along the XY plane;
An X-ray generator characterized by that.
The apparatus of claim 5.
The filter unit includes a drum that includes the at least one filter and rotates about a rotation axis parallel to the Y direction.
An X-ray generator characterized by that.
The apparatus of claim 2.
At least one of the one end and the other end of each vertical wall has a tapered shape,
An X-ray generator characterized by that.
The apparatus of claim 2.
One end and the other end of the horizontal wall function as a handle,
An X-ray generator characterized by that.
The apparatus of claim 1.
The X-ray generator is used in a bone density measuring system.
An X-ray generator characterized by that.