JP2010158257A - Device and system for picking up radiation image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation image pickup device which makes a working range of each member composing the device large and thereby makes it possible to properly pick up an X-ray image without troubling an examinee in picking-up. <P>SOLUTION: The radiation image pickup device 1 is comprised of an object table 15 attached to a supporting base axis 4 extending from an up-and-down movable supporting base unit 3 in a substantially horizontal direction, a first arm 6 that extends in a substantially vertical direction with respect to the supporting base axis 4 and that is rotatable about the supporting base axis 4, a second arm 7 extending in the direction opposite to that of the first arm, an X-ray tube 10 attached to the first arm 6, and an X-ray detector 13 attached to the second arm 7. The focal diameter of the X-ray tube 10 can be set in the range of 300-2,000 μm and in the range of 10-300 μm, respectively, which are configured to be switchable, and a distance R1 between the X-ray tube 10 and the object table 15, a distance R2 between the object table 15 and the X-ray detector 13 and a distance R between the X-ray tube 10 and the X-ray detector 13 are made variable, respectively. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a radiographic image capturing apparatus and a radiographic image capturing system, and more particularly to a radiographic image capturing apparatus and a radiographic image capturing system capable of performing normal X-ray imaging and phase contrast imaging.

  The prevalence rate of rheumatic diseases in Japan has reached 1%, and is now regarded as a national disease. As initial symptoms, wear of the cartilage portion (cartilage destruction), fine bone shape and trabecular changes are observed, and when the symptoms progress, a large change in the shape of the bone portion is observed. Therefore, rheumatic diseases can be diagnosed by observing changes in the cartilage shape, fine bone shape, and trabecular bone, and treatment is based on early detection at the current stage where there is only a treatment method that stops the progression of symptoms. The transition to is important.

  However, the initial symptoms of rheumatic diseases are very difficult to detect on an X-ray photograph, which is a simple examination method, and it is difficult to determine whether or not it has developed.

  On the other hand, in order to discover a change in soft tissue, recently, a diagnosis using an image obtained by MRI (magnetic resonance imaging) or the like instead of radiographic imaging has been studied. Recently, a technique has been reported in which radiation light in which radiation goes straight in parallel is taken out of radiographic images, and the cartilage portion is imaged using this. However, MRI imaging is a burden on the subject from the viewpoint of cost and time required for medical examination, and it is difficult to incorporate it into general periodic medical examinations. There was a problem that it was difficult to observe the aging over time.

  Moreover, in order to perform imaging using synchrotron radiation, a huge imaging facility is required, and it may take several tens of minutes to perform imaging. Have difficulty. For these reasons, it is desired to be able to easily diagnose diseases of soft tissues such as fine changes in joint shape and bone shape and swelling at an early stage.

Here, as described above, for example, in order to make an early diagnosis of rheumatic disease, it is necessary to take a highly sharp radiographic image that can identify minute symptoms of the affected area. As a radiographic image capturing apparatus capable of obtaining the above, there is known a technique for capturing a phase contrast image using a radiographic image capturing apparatus as disclosed in Patent Documents 1 and 2, for example. According to this technique, an image in which the contrast of the edge portion (edge portion) is emphasized is obtained even for a subject with low X-ray absorption, for which a sufficient contrast cannot be obtained with a radiation image formed by normal absorption. be able to. In addition to the above joint diseases represented by rheumatism, this technique is mostly soft tissue, mammography that requires detection of fine calcification, and pediatric imaging where most of the bone is cartilage. It can be applied to various parts.
JP 2002-162705 A JP 2004-248699 A

  However, the radiographic imaging devices shown in Patent Documents 1 and 2 have a structure suitable for imaging a specific imaging region of a subject such as a hand or a breast, but other parts such as the head, legs, and trunk. It is not necessarily suitable for imaging of this part. Therefore, with these radiographic imaging devices, when trying to shoot the above parts, the subject has to take an unreasonable posture and the subject feels painful or the part to be photographed moves. There was a problem that.

  The present invention has been made in view of the circumstances described above, and increases the operating range of each member constituting the apparatus, and radiographic imaging capable of appropriately capturing an X-ray image without causing the subject to be forced during imaging. An object of the present invention is to provide an apparatus and a radiographic imaging system that processes the captured image.

In order to solve the above problem, the radiographic image capturing apparatus according to claim 1,
A support base having a support base shaft extending in a substantially horizontal direction and capable of moving up and down in a substantially vertical direction;
A subject table attached in an extending direction of the support base shaft;
A first arm extending substantially perpendicular to the support base axis and rotatable about the support base axis;
An X-ray tube attached to the first arm;
A second arm extending in a direction substantially opposite to the first arm with respect to the support base axis, and rotatable about the support base axis;
An X-ray detector attached to the second arm;
With
The X-ray tube is configured such that its focal diameter can be set within a range of 300 to 2000 μm and within a range of 10 to 300 μm, and they can be switched,
The distance between the X-ray tube and the object table and the distance between the object table and the X-ray detector, or the distance between the X-ray tube and the X-ray detector are variable. To do.

The invention according to claim 2 is the radiographic imaging device according to claim 1,
A first support shaft extending from the first arm so as to be substantially parallel to the support base shaft;
A second support shaft extending from the second arm so as to be substantially parallel to the support base shaft,
The X-ray tube and the X-ray detector are attached to the first support shaft and the second support shaft, respectively, and are rotatable around the first support shaft and the second support shaft, respectively. It is characterized by.

  According to a third aspect of the present invention, in the radiographic image capturing apparatus according to the first or second aspect, the subject table is rotatable around the support base axis.

  According to a fourth aspect of the present invention, in the radiographic image capturing apparatus according to any one of the first to third aspects, the object table is configured to emit X-rays from the X-ray tube toward the X-ray detector. It is possible to move to a position that does not obstruct the optical path.

  According to a fifth aspect of the present invention, in the radiographic image capturing apparatus according to any one of the first to fourth aspects, the subject table is detachable from the support base shaft. The radiographic imaging device according to any one of claims 1 to 4.

The invention according to claim 6 is a radiographic imaging system,
The radiographic imaging device according to any one of claims 1 to 5,
A subject placement device formed in a bed shape;
It is characterized by providing.

The invention according to claim 7 is a radiographic imaging system,
6. An X-ray detector provided in the radiographic imaging apparatus, which emits X-rays irradiated from the X-ray tube of the radiographic imaging apparatus according to any one of claims 1 to 5 and transmitted through a subject. A radiographic imaging system characterized by irradiating and detecting an X-ray detector different from the above.

  According to the present invention, the X-ray tube and the X-ray detector can be rotated around the support base axis, the distance between the X-ray tube and the object table, the distance between the object table and the X-ray detector, the X-ray tube and the X-ray detector. By using a so-called universal type in which the distance to the detector is variable, the operating range of each member constituting the radiographic image capturing apparatus is increased. Therefore, it is not necessary for the subject to take an unreasonable posture at the time of imaging, and X-ray imaging can be appropriately performed on a subject who stands up, sits down and lies down in a natural posture without overdoing it.

  Further, since the focal diameter of the X-ray tube can be set within a range of 300 to 2000 μm for close-contact imaging and within a range of 10 to 300 μm for phase contrast imaging, one radiographic image is captured. It is possible to switch between close-contact imaging and phase-contrast imaging as appropriate with an apparatus or a set of radiographic imaging systems, which makes the apparatus and system very convenient for both the photographer and the subject.

  Embodiments of a radiographic imaging apparatus and a radiographic imaging system according to the present invention will be described below with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples.

[Configuration of Radiation Imaging System]
The radiographic image capturing apparatus 1 according to the present embodiment, as shown in FIG. 1 (A), normal X-ray imaging in which the subject H is imaged in close contact with the X-ray detector 13 and as shown in FIG. 1 (B). The subject H is fixed to the subject table 15, and phase contrast imaging is performed in which imaging is performed with a distance (air gap) between the subject H and the X-ray detector 13. . The phase contrast imaging will be described later. Further, in order to clarify the distinction from the phase contrast imaging in FIG. 1B, the normal X-ray imaging shown in FIG. 1A is hereinafter referred to as contact imaging.

  As shown in FIGS. 2 and 3, the radiographic imaging apparatus 1 according to the present embodiment is provided with a support base 3 for a support base 2 fixed to a floor surface F with bolts or the like. In the present embodiment, the support base 3 can be moved up and down in a substantially vertical direction with respect to the support base 2 by driving of a drive device such as a drive motor (not shown).

  In addition, although this embodiment demonstrates the case where the support stand 2 is fixed to the floor surface F, besides this, for example, it is also possible to reverse the top and bottom, and to fix the support stand 2 to the ceiling which is not shown in figure. . Further, for example, the support base 2 is fixed to a pedestal (not shown) provided with wheels or the like and movable on the floor surface, or a rail or the like is provided on the ceiling, and the support base 2 is suspended from the rail or the like. And it is also possible to comprise so that the support stand 2 can move with respect to a floor surface or a ceiling. Furthermore, it is also possible to configure the support base 2 in a columnar shape and to support the support base 3 up and down along the column.

  A support base shaft 4 is provided on the upper side surface of the support base 3 so as to extend in a substantially horizontal direction. In the present embodiment, the support base shaft 4 is constituted by a cylindrical support outer tube 4 a and a support inner shaft 4 b inside thereof, and the support outer tube 4 a is a drive (not shown) disposed in the support base 3. By driving a driving device such as a motor, the outside of the support inner shaft 4b is rotated clockwise and counterclockwise when viewed from the front of the device. In the present embodiment, the support inner shaft 4b does not rotate.

  At the end of the support base 4 opposite to the support base 3 of the support outer cylinder 4a, the first arm 6 and the second arm 7 are respectively connected to the support base 4 via the rotation base 5 connected to the support outer cylinder 4a. It is attached so that it may extend in the substantially perpendicular direction with respect to the direction opposite to each other. As described above, the first arm 6 and the second arm 7 are supported via the rotation base 5 in accordance with the rotation of the support outer cylinder 4a that is rotatable clockwise and counterclockwise on the outside of the support inner shaft 4b. It can rotate around the base axis 4.

  The first arm 6 and the second arm 7 are configured so that their lengths can be expanded and contracted with the rotation base 5 as a base point. In the present embodiment, each is a telescopic type that slides a cylindrical piece, and the length thereof can be expanded and contracted by driving a driving device such as a driving motor (not shown).

  In the present embodiment, as will be described later, an X-ray tube 10 and an X-ray detector 13 are provided at the distal ends of the first arm 6 and the second arm 7, and the first arm 6 and the second arm 7 extend and contract. Thus, the distance R between the X-ray tube 10 and the X-ray detector 13 shown in FIG. 4 is variable. As will be described later, when the subject table 15 is provided between the X-ray tube 10 and the X-ray detector 13, the distance R <b> 1 between the X-ray tube 10 and the subject table 15, the subject table 15 and the X-ray detector 13. The distance R2 between the first arm 6 and the second arm 7 can also be changed.

  In the present invention, the distance between the X-ray tube 10 and other members accurately represents the distance between the focal point of the X-ray tube 10 and other members. Moreover, the radiographic imaging device 1 should just be able to adjust the said distance R, R1, R2 correctly within the tolerance | permissible_error, and is not limited to the said structure.

  That is, for example, the first arm 6 and the second arm 7 are each configured as a rod-like structure that does not expand and contract with the rotation base 5 as a base point, and the X-ray tube 10 and the X-ray detector 13 are the rod-like first arm 6. Alternatively, the distances R, R1, and R2 can be adjusted by moving along the second arm 7. Further, the first arm 6 and the second arm 7 do not have to be configured to extend in opposite directions exactly from each other with the rotation base 5 as a base point, and the X-ray tube 10 and the X-ray detector 13 are connected to each other. Further, any reference may be used as long as it provides a reference for adjusting the position with respect to the support base shaft 4 and can rotate the X-ray tube 10 and the X-ray detector 13 around the support base shaft 4.

  A first support shaft 8 extends from the tip of the first arm 6 on the side opposite to the rotation base 5 so as to be substantially parallel to the support base shaft 4. The X-ray irradiator 9 is attached so as to be rotatable around the central axis of the first support shaft 8. That is, as shown in FIG. 2, the X-ray irradiator 9 rotates around the support base shaft 4 as the first arm 6 rotates, and independently from around the first support shaft 8 when viewed from the front of the apparatus. It can be rotated clockwise and counterclockwise. The rotation around the first support shaft 8 of the X-ray irradiator 9 may be configured to be performed manually by the photographer, or may be configured to be performed by driving a driving device such as a driving motor.

  The X-ray irradiator 9 includes an X-ray tube 10 that irradiates X-rays, and an X-ray emission port of the X-ray tube 10 is provided with an aperture 11 for adjusting an X-ray irradiation field that can be opened and closed. It has been. The X-ray irradiation field can be set by adjusting the opening / closing amount of the diaphragm 11. The X-ray irradiator 9 is connected to a power supply unit (not shown) that supplies power to the X-ray tube 10.

  Examples of the X-ray tube 10 include a Coolidge X-ray tube widely used in medical sites and nondestructive inspection facilities, and a rotating anode X-ray tube. In the rotary anode X-ray tube, X-rays are generated when an electron beam emitted from the cathode collides with the anode. This is incoherent (incoherent) like natural light, and is not divergent X-rays but divergent light. If the electron beam continues to hit the place where the anode is fixed, the anode is damaged by the generation of heat. Therefore, in an X-ray tube that is usually used, the anode is rotated to prevent the anode from being shortened. An electron beam is made to collide with a surface of a certain size of the anode, and the generated X-rays are emitted toward the subject H from the plane of the certain size of the anode. The size of the plane viewed from the irradiation direction (subject direction) is called the actual focus (focus). The focal diameter (μm) can be measured by the method defined in (2.2) slit camera of 7.4.1 Focus test of JIS Z 4704-1994. Needless to say, the optional selection conditions in this measurement method can be measured with higher accuracy by selecting the conditions that give the highest accuracy in consideration of the measurement principle in accordance with the properties of the X-ray source.

  The X-ray tube 10 can set the focal diameter within a large focal diameter range of 300 to 2000 μm for close-contact imaging and within a small focal diameter range of 10 to 300 μm for phase contrast imaging. Moreover, they are configured to be switched by operating the operating device 16 (see FIG. 3). The range of the small focal diameter is more preferably in the range of 50 to 150 μm. Further, it is more preferable that the maximum current value is provided depending on the size of the focal diameter.

  More specifically, the smaller the focal diameter of the X-ray tube 10 is, the clearer the phase contrast image is obtained. However, since the maximum output current value is small, there is a problem that the imaging time becomes long. For this reason, the preferred focal spot size is determined by the region to be imaged. A relatively thin part such as a finger or a foot can reduce the original irradiation dose, so that the output may be relatively low, and it is preferable to select a small focus that emphasizes sharpness. Specifically, a range of 10 to 150 μm is preferable. Since the elbows and knees have a little thickness, they require a higher output than fingers and preferably have a slightly larger focal diameter. Specifically, a range of 50 to 200 μm is preferable. For thick parts such as the chest, abdomen, and lumbar vertebrae, high output is required, so that a large focal diameter is required. Specifically, the range of 100 to 300 μm is preferable. For thicker parts, in addition to increasing the irradiation dose, in order not to increase the exposure dose, increase the tube voltage (increase the X-ray energy), shorten the imaging distance (without increasing the exposure dose, It is also possible to cope with this by a method such as reducing the irradiation dose). In addition, there is a method of dealing with a thick part by close contact photographing.

  The X-ray tube 10 is preferably one that emits X-rays having an average energy of 15 to 60 keV. This is because when the average energy of X-rays to be irradiated is less than 15 keV, almost all of the X-rays to be irradiated are absorbed by the subject, so the exposure dose of the subject becomes very large, and clinical use is not possible. This is because it is not so preferable, and if the average energy of the irradiated X-ray is larger than 60 keV, sufficient contrast of the bones and soft tissues constituting the human body cannot be obtained, and the obtained X-ray image can be diagnosed. This is because there is a possibility that it cannot be used.

  As the X-ray tube 10, for example, a Coolidge X-ray tube or a rotary anode X-ray tube widely used in the medical field is preferably used. At that time, W (tungsten) used in general imaging, Mo (molybdenum) and Rh (rhodium) used in mammography are preferably used for the target (anode) of the X-ray tube. In particular, when W is used as a target, X-rays with tube voltage set values of 30, 50, 100, and 150 kVp and average energies of 22, 32, 47, and 60 keV, respectively, are normally irradiated.

  As described above, when W (tungsten) is used as the target of the X-ray tube, the tube voltage is set to 30 to 150 kVp, the current value is set to 1 to 300 mA, and the imaging time is set within the range of 1 millisecond to 10 seconds. It becomes possible. The upper limit value of the current value tends to be lower as the focal diameter is smaller. When the focal diameter is 100 μm, the upper limit value is about 40 to 50 mA.

  In addition to imaging of joint diseases represented by rheumatism with the radiographic imaging apparatus 1, mammography, most of which is soft tissue and detection of fine calcification is necessary, and children whose bones are mostly cartilage When performing imaging or the like, among the above X-ray energies, the sharpness is improved by the phase contrast effect and the diagnostic ability is improved particularly by X-ray irradiation with low X-ray energy (set to a low tube voltage). Therefore, when performing phase contrast imaging, the average energy of the irradiated X-rays is preferably 15 to 32 keV.

  More specifically, the lower the tube voltage (X-ray energy), the higher the contrast and the discriminating ability. However, there is a problem that the exposure dose increases. Therefore, a preferable tube voltage is determined depending on the part to be imaged. A relatively thin portion such as a finger or a foot can reduce the original irradiation dose, and therefore it is preferable that the tube voltage is relatively low. Specifically, a range of 20 to 50 kVp (18 to 32 keV) is preferable. Since the elbows and knees are somewhat thick, a high tube voltage is required compared to fingers. Specifically, a range of 30 to 60 kVp (22 to 35 keV) is preferable. High tube voltage is required for thick parts such as the chest, abdomen, and lumbar spine. Specifically, a range of 50 to 150 kVp (32 to 60 keV) is preferable.

  Further, when performing phase contrast imaging, if the focal diameter of the X-ray tube 10 is set to 1 μm or more as described above, X-rays within the above average energy range can be irradiated and practical output intensity can be obtained. . In order to obtain a sufficient X-ray intensity, the focal diameter is preferably 50 μm or more.

  The X-ray tube 10 is not limited to the above-mentioned Coolidge X-ray tube and rotary anode X-ray tube as long as these conditions are satisfied, and may be a microfocus X-ray source or the like.

  A second support shaft 12 extends so as to be substantially parallel to the support base shaft 4 at the distal end portion of the second arm 7 opposite to the rotation base portion 5. A detector holding base 14 that holds the X-ray detector 13 is rotatably mounted around the central axis of the second support shaft 12. That is, as shown in FIG. 2, the detector holding base 14 and the X-ray detector 13 rotate around the support base axis 4 as the second arm 7 rotates, and independently around the second support axis 12. When viewed from the front of the device, it can be rotated clockwise and counterclockwise. The rotation of the X-ray detector 13 around the second support shaft 12 may be configured to be performed manually by the photographer, or may be configured to be performed by driving a driving device such as a driving motor.

  As the X-ray detector 13, either an analog system using a screen or a film or a digital detector system for detecting X-ray dose as digital information may be used, and it is not necessary to use a film or the like to process data. An easy-to-use digital detector system is preferably used. In addition, a detector using an FPD (Flat Panel Detector), CR (Computed Radiography), or CCD (Charge Coupled Device) that detects the X-ray dose as digital information for each pixel is preferably used, and particularly an FPD excellent as a two-dimensional image sensor. Is preferred. The pixel size is preferably 10 to 200 μm, more preferably 50 to 150 μm.

  In the present embodiment, a detector using FPD is used as the X-ray detector 13, and the X-ray detector 13 is connected to a panel 13a, a detector control unit 13b, etc. via a bus as shown in FIG. Configured. The X-ray detector 13 detects the X-ray dose emitted from the X-ray tube 10 and transmitted through the subject H, and outputs the detected X-ray image data to an image processing apparatus (not shown).

  The size of the panel 13a of the X-ray detector 13 is appropriately selected. In FIG. 5, a cassette type detector is shown as the X-ray detector 13, but a so-called stationary type formed integrally with the detector holding base 14 can also be used.

  Further, as will be described later, the radiographic imaging apparatus 1 according to the present embodiment is used in various ways, and X-rays emitted from the X-ray tube 10 of the radiographic imaging apparatus 1 are used as the apparatus. In some cases, a separate X-ray detector is irradiated. In such a case, the X-ray detector 13 and the detector holding base 14 of the radiographic imaging apparatus 1 that are not used can be configured to be removable from the second support shaft 12 or can be rotated around the axis of the second arm 7. The detector holding base 14 is folded with the X-ray detector 13 removed, or the detector holding base 14 is folded with the X-ray detector 13 removed. For example, the X-ray detector 13 and the detector holding base 14 can be moved to a position that does not obstruct imaging.

  In the present embodiment, a phototimer (not shown) that detects the X-ray dose transmitted through the subject H is provided below the X-ray detector 13, that is, on the opposite side of the X-ray detector 13 (not shown). When the X-ray dose transmitted through the subject H reaches a predetermined dose, the phototimer transmits a signal for stopping X-ray irradiation from the X-ray tube 10 to a control unit (not shown) of the radiographic image capturing apparatus 1. It has become. When the X-ray detector 13 is the FPD described above, the FPD itself may be configured to have a function of detecting a signal instead of a phototimer.

  In addition, the lower side of the X-ray detector 13, the inside of the detector holder 14, etc. are covered with lead or the like that shields X-rays to prevent exposure to the human body below the X-ray detector 13 due to X-ray irradiation. A configured radiation shielding member (not shown) is provided.

  When performing close-contact imaging, for example, an X-ray detector 13 provided with a grid 13c for absorbing and removing X-ray scattering components on the top side of the panel 13a as shown in FIG. 5 may be used. Is possible. However, since the X-ray dose incident on the panel 13a of the X-ray detector 13 decreases when the grid 13c is used, it is preferable not to use the grid 13c when it is not necessary to use the grid 13c, particularly in the case of phase contrast imaging. Usually, the grid 13c is not used. Therefore, the grid 13c can be configured to be detachable from the X-ray detector 13.

  For example, as schematically shown in FIG. 6, a grid 13c is formed in advance on the detector holding base 14, and the X-ray detector 13 is connected to the first insertion portion 14a above the grid 13c and the second insertion portion below the grid 13c. It is also possible to configure the detector holding base 14 so that it can be inserted into any of 14b. According to this configuration, the X-ray detector 13 is inserted into the first insertion portion 14a in the phase contrast imaging or the close contact imaging not using the grid 13c, and the X-ray detector 13 is inserted in the close contact imaging using the grid 13c. It becomes possible to perform X-ray imaging by inserting the second insertion portion 14b.

  At the end of the support inner shaft 4b opposite to the support base 3, a flat object base 15 for fixing the position of the subject H is extended in the extending direction of the support inner shaft 4b. It is attached to 4b. The subject table 15 is made of a material having excellent X-ray permeability such as carbon, or is made hollow, for example, so as not to reduce the X-ray transmittance as much as possible. It is also possible to configure the subject table 15 with a honeycomb structure carbon plate or the like. In addition, for example, in order to fix the subject's hand that is the subject H so as not to move during photographing, the subject table 15 is formed of resin or the like, and the hand is placed on the surface portion of the subject table 15 on which the subject's hand is placed. It is also possible to form irregularities in the shape. The unevenness made of the resin or the like may be placed on a subject table such as a carbon plate.

  In the present embodiment, the subject table 15 can be detachably attached to the support inner shaft 4 b via a mounting jig (not shown), and the subject table 15 is supported via the support base shaft 4. The base 3 is moved up and down as the base 3 moves up and down.

  Further, in the present embodiment, the subject table 15 can be rotated around the central axis of the support inner shaft 4b independently of the support outer cylinder 4a, and can be supported within a range of a certain inclination angle. It can be tilted in any direction with respect to the shaft 4b. In this way, the subject table 15 is seated on, for example, the chair X while accurately photographing the subject H by moving the support base 3 up and down to adjust its height or tilting the support base 3 with respect to the support inner shaft 4b. The position is adjusted so that the examinee can take a posture in which it is difficult to get tired.

  Instead of making the subject table 15 attachable to and detachable from the support inner shaft 4b as in the present embodiment, the subject table 15 is centered on the contact with the support inner shaft 4b, for example, the support inner shaft 4b in FIG. The subject table 15 can be removed from the X-ray tube 10 by being configured such that the subject table 15 can be rotated in the left-right direction, or can be raised or lowered in the vertical direction, or the subject table 15 can be folded. It is also possible to configure so that the optical path of the X-ray toward the X-ray detector 13 can be moved to a position that does not interfere.

  Further, the subject table 15 is provided with a compression plate (not shown) that presses and fixes the subject H from above as needed, and a leg of the subject is placed under the subject table 15 or the like on the X-ray. A protector (not shown) or the like is appropriately provided so that the imaging position can be reached without being exposed to X-rays while preventing the detector 13 from being hit.

  In the imaging by the radiographic image capturing apparatus 1 of the present embodiment, various support jigs for fixing the body of the subject who is the subject H so as not to move are used particularly in the case of phase contrast imaging. However, these configurations will be described in the description of the operation of the radiation image capturing apparatus 1 and the radiation image capturing system described later.

  As shown in FIG. 3, an operation device 16 is connected to the radiation image capturing apparatus 1. The operation device 16 is provided with an input unit 16a including a keyboard for inputting instructions to the device 1, and a display unit 16b including a CRT (Cathode Ray Tube) display for displaying photographing conditions and the like. . FIG. 3 shows a case where the operating device 16 is installed in the same room as the device main body. However, for example, the operating device 16 is provided in a separate room, and the operating device 16 and the device main body are provided. It can also be configured to connect via a LAN (Local Area Network) or the like.

  In the operation device 16, a control device for making various settings for the radiographic imaging device 1 and controlling its operation is incorporated. The control device is configured by a computer in which a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like (not shown) are connected by a bus.

  FIG. 7 is a block diagram showing a control configuration of the radiographic image capturing apparatus 1 according to the present embodiment. As shown in FIG. 7, the control device 20 includes an X-ray tube 10, an aperture 11, an operation device 16 including an input unit 16 a and a display unit 16 b, a power supply unit 21 that supplies power to the device, and a support base 3. Elevation and rotation of the support outer cylinder 4a, expansion and contraction of the first arm 6 and the second arm 7, rotation of the X-ray irradiator 9 around the first support shaft 8, detection detector 14 and X around the second support shaft 12 Connected to each driving device 22 for driving the rotation of the line detector 13, each encoder 23 for measuring the moving distance and position of each member, a phototimer 24 for detecting the X-ray dose transmitted through the subject H, and the like.

  A memory such as a ROM of the control device 20 stores a control program and various processing programs for controlling each part of the radiographic imaging device 1, and the control device 20 is input from the input unit 16 a of the operation device 16. Based on the input of the operator, the control program and various processing programs are read from the memory, and the operation of each part of the radiographic imaging apparatus 1 is comprehensively controlled while displaying the control content on the display unit 16b of the operation device 16. ing.

  Here, the principle of contact imaging and phase contrast imaging scheduled in the radiographic imaging apparatus 1 according to the present embodiment will be briefly described.

  In close-contact imaging, as shown in FIG. 1A, the subject table 15 is removed or the subject table 15 is moved to a position that does not obstruct the X-ray optical path from the X-ray tube 10 to the X-ray detector 13. Imaging is performed with H in close contact with the X-ray detector 13. In close-contact imaging, the focal diameter of the X-ray tube 10 is normally set within the range of the large focal diameter of 300 to 2000 μm described above, and X-rays having a larger current value than that of phase contrast imaging are irradiated. X-ray imaging in a short time of about 10 milliseconds to several hundred milliseconds is performed.

  In close-contact imaging, as can be seen from FIG. 1A, the subject H is not enlarged, and an X-ray detector 13 detects an image that is the same size as the subject H.

  As described above, the close-contact imaging can be performed by irradiating the subject H with X-rays having a larger current value compared to the phase contrast imaging for a short time. An X-ray image with no image can be obtained.

  Further, in the soft tissue having a low density in the body of the subject, the difference in the refractive index of X-rays from the surrounding portion is small, so that the edge portion tends to be unclear. The edge portion becomes further unclear due to the large focal diameter of 10 and the scattering of X-rays in the panel 13a of the X-ray detector 13, and it is difficult to capture the soft tissue clearly. In this case, a grid 13c can be provided on the top plate side of the panel 13a of the X-ray detector 13 to absorb and remove scattered components of X-rays. However, the X-ray dose incident on the panel 13a is correspondingly increased. It is as having mentioned above about falling.

  On the other hand, in phase contrast imaging, as shown in FIG. 1B, the subject H is arranged between the X-ray tube 10 and the X-ray detector 13 by providing a subject table 15 or the like. That is, in FIG. 4, the distance R2 between the subject table 15 and the X-ray detector 13 is arranged to have a predetermined distance that is not 0 m.

  When the subject H is arranged in this way, as shown in FIG. 8A, the X-ray that has entered the subject H is refracted outward at a portion close to the edge of the subject H as opposed to a normal glass lens or the like. . Therefore, when the X-ray reaches the X-ray detector 13, the X-ray refracted at a portion close to the edge of the subject H overlaps with the X-ray passing through the edge portion of the subject H, and is shown in FIG. As described above, in the X-ray detector 13, X-rays that reach the edge portion of the subject H become dense, and the X-ray intensity of the portion becomes strong. On the other hand, in the X-ray portion transmitted through the inner portion far from the edge of the subject H, the X-ray becomes sparse and the X-ray intensity in that portion becomes weak. In this way, in phase contrast imaging, the detected X-ray image is an image in which the edge portion of the subject H, particularly the edge portion of the soft tissue of the subject's body existing at the edge portion of the subject H is emphasized.

  Further, in phase contrast imaging, not only the edge portion of the entire soft tissue of the subject H is emphasized as described above, but also the same edge enhancement is performed at the boundary portion where the refractive index is different from the surrounding portion inside the soft tissue. The effect of. For this reason, all the components such as bone, cartilage, and joint fluid existing in the joint portion of the human body have different refractive indexes with respect to X-rays. An image with a clear boundary can be obtained.

  In the present embodiment, as shown in FIG. 1B and FIG. 3, X-rays radiated from the X-ray tube 10 are X-rays that spread in a cone beam shape as the distance from the X-ray tube 10 increases. It has been. Therefore, in phase contrast imaging, an enlarged image of the subject H placed and fixed on the subject table 15 can be obtained.

As shown in FIG. 4, the enlargement ratio M with respect to the image (life size) in the case of an enlarged image taken at the same magnification is a distance R1 between the X-ray tube 10 and the subject table 15, and the subject table 15 and the X-ray detector 13. When the distance R2 is
M = (R1 + R2) / R1 (1)
Given in. If the distance R between the X-ray tube 10 and the X-ray detector 13 is used, the equation (1) is
M = R / R1 (2)
Can also be expressed.

  The enlargement ratio M is determined by an appropriate size depending on a region to be imaged or a size to be imaged for the region. If an attempt is made to photograph the entire large part such as the chest and abdomen, close-contact photography at the same magnification is required. However, in the case of fingers and feet, even when the whole is photographed, magnified photographing with an enlargement ratio of about 1.2 to 2 times is possible, and it is easy to obtain a phase contrast image. In addition, in the case of the chest and abdomen as well as in the case of fingers and toes, when photographing a part of those parts, it is a part of the part by an enlarged spot photographing of about 2 to 5 times. A very clear image can be obtained.

  Note that X-rays are partially scattered by the subject H, and if the distance R2 between the subject table 15 and the X-ray detector 13 is small, that is, if the subject H and the X-ray detector 13 are close to each other, the subject H is scattered. X-rays reach the X-ray detector 13 and reduce the contrast of the X-ray image. In order to solve this problem, a grid 13c may be provided on the panel 13a of the X-ray detector 13, but in this embodiment, the distance R2 between the subject table 15 and the X-ray detector 13 is a certain distance or more. Thus, that is, an air gap is provided so that scattered X-rays do not leak out of the X-ray detector 13 and reach the X-ray detector 13.

  In phase contrast imaging, when the distance R2 between the subject H and the X-ray detector 13 is large, the image enlargement ratio also increases and the edge enhancement effect also increases. In addition, the edge enhancement effect is different depending on the tube voltage applied to the X-ray tube 10. The higher the tube voltage applied to the X-ray tube 10, the smaller the edge enhancement effect becomes. The edge enhancement effect increases as the applied tube voltage decreases.

  Therefore, in phase contrast imaging, the tube voltage applied to the X-ray tube 10 is set lower than that in close contact imaging, and the focal diameter of the X-ray tube 10 is set within the range of the small focal diameter of 10 to 300 μm described above. Is done. The upper limit of the X-ray irradiation field is the distance R1 from the X-ray tube 10 to the subject table 15, the distance R2 from the subject table 15 to the X-ray detector 13, that is, the enlargement factor M, and the X-ray detector 13. It is determined by the area of the panel 13a.

  However, in phase contrast imaging, X-rays that are weaker than those in close-contact imaging are used in this way, so that the imaging time for X-ray imaging is relatively long. Therefore, if the body of the subject who is the subject H moves during that time, the photographed X-ray image is easily blurred.

  Note that the setting of imaging conditions in phase contrast imaging is comprehensively shown in the above-mentioned Patent Document 1 relating to the application of the present inventor, so please refer to it in detail. A brief description is given below.

  As described above, in the phase contrast image, the distance from the focus of the X-ray tube 10 to the subject table 15 (subject H) is R1, and the distance from the subject table 15 (subject H) to the X-ray detector 13 is R2. When the diameter is D, the image can be obtained by photographing so as to satisfy the conditions of 0.1 ≦ R1, 0.3 ≦ R2, and D ≦ 0.3 (mm). In the present embodiment, as described above, the distance R between the X-ray tube 10 and the X-ray detector 13 is also variable. However, when the setting of the distance R is limited, such as in the imaging room. The distance R is fixed, and within the fixed distance R, the ratio of the distances R1 and R2 can be changed to capture images under optimum conditions. For example, when R = 3.0 (m) is determined, for this distance R, R1 = 1.0 (m) and R2 = 2.0 (m). Considering the size of a general photography room, the range is 0.1 ≦ R1 ≦ 2.0, 0.3 ≦ R2 ≦ 2.0, 0.8 ≦ R ≦ 3.0, and the enlargement ratio M is 1. .5 ≦ M ≦ 10, and the focal diameter D is in the range of 0.005 (mm) ≦ D ≦ 0.2 (mm). The optimum distances R, R1, and R2, the enlargement ratio M, and the focal diameter D may be determined.

  By setting the focal point diameter D in such a range, the X-ray intensity is strong, imaging can be performed for a short time, and motion blur due to movement of the subject H can be reduced. More preferable distances satisfy the ranges of 0.5 ≦ R1 ≦ 1.2, 0.5 ≦ R2 ≦ 1.2, 1.0 ≦ R ≦ 2.5, and the enlargement ratio M is 3 ≦ M ≦ 8. The focal diameter D can be set to satisfy the range of 0.03 (mm) ≦ D ≦ 0.15 (mm).

  The control device 20 of the radiographic imaging device 1 according to the present embodiment controls the operation of each device and each member so as to take advantage of the features of the close contact imaging and the phase contrast imaging as described above.

  Specifically, the control device 20 is configured to set an imaging method for performing imaging by close-contact imaging or phase contrast imaging via the input unit 16 a of the operation device 16.

  When close-contact imaging is set as the imaging method, the control device 20 changes the focal diameter of the X-ray tube 10 to a focal diameter preset in the range of a large focal diameter of 300 to 2000 μm as described above. In addition, since the subject table 15 is not removed or moved, and the X-ray optical path from the X-ray tube 10 to the X-ray detector 13 is blocked by the subject table 15, the control device 20 includes the operation device 16. A warning is displayed on the display unit 16b, or a warning is issued by voice, to alert the photographer.

  In this embodiment, when close-contact shooting is set as the shooting method, a setting screen for numerical values to be input is displayed on the display unit 16b of the operation device 16, and the photographer sets the input unit 16a. To set those values. The values set in the close-contact imaging include, for example, an imaging region of the subject's body as the subject H, a distance R between the X-ray tube 10 and the X-ray detector 13, and the X-ray detector 13 is a cassette-type fitting type. When it is a detector, the kind etc. are mentioned.

  Also, the shooting direction is set. That is, the angle when the X-ray irradiation direction when the X-ray is irradiated from the X-ray tube 10 toward the X-ray detector 13 directly below the vertical direction is, for example, 0 degree is set by the photographer via the input unit 16a. Is set.

  When the distance R between the X-ray tube 10 and the X-ray detector 13 and the imaging direction are set, the control device 20 drives each driving device 22 while checking the values of the various encoders 23 to set the position of each member. adjust. Specifically, in this embodiment, the control device 20 expands and contracts the first arm 6 and the second arm 7 to adjust the distance between the X-ray tube 10 and the X-ray detector 13 to the set distance R. At the same time, the support outer cylinder 4a is rotated around the support base axis 4 by an angle set as the shooting direction to adjust the shooting direction.

  Further, the control device 20 reads the area of the panel 13a from the memory according to the type of the X-ray detector 13 installed in advance or the X-ray detector 13 fitted therein, and the read area, the X-ray tube 10 and the X-ray detector 10 The X-ray irradiation field is calculated from the distance R to the line detector 13, the opening / closing amount of the diaphragm 11 of the X-ray tube 10 is determined so as to realize the irradiation field, and the opening / closing amount of the diaphragm 11 is determined. Adjust the opening / closing amount. The irradiation field is set so as not to spread beyond the upper limit value determined by the above, but can be set as narrow as necessary.

  In addition, a table that determines the correlation between the distance R, the imaging region, the focal diameter of the X-ray tube 10 and the imaging conditions, that is, the tube voltage and the irradiation dose (mAs value), is created in advance and stored in the memory. When the imaging region is input as described above and the distance R and the focal diameter of the X-ray tube 10 are determined, the tube voltage to be applied to the X-ray tube 10 and the irradiation dose to be irradiated are determined with reference to the table. To do. The X-ray irradiation time is determined by the current flowing through the X-ray tube 10 and the irradiation dose.

  At the time of X-ray imaging, the control device 20 supplies power to the X-ray tube 10 from the power supply unit 21 to irradiate the subject H with X-rays. Further, when the X-ray dose transmitted through the subject H reaches a predetermined dose and a signal is transmitted from the phototimer 24, the control device 20 stops the supply of power from the power supply unit 21 to the X-ray tube 10. X-ray irradiation is stopped. The X-ray irradiation conditions are appropriately set in consideration of factors other than the X-ray dose detected by the phototimer 24, that is, for example, the type of the X-ray detector 13. Therefore, exactly, the control device 20 stops the X-ray irradiation when a preset irradiation condition such as a signal transmitted from the phototimer 24 is satisfied.

  On the other hand, when phase contrast imaging is set in the setting of the imaging method, the control device 20 presets the focal diameter of the X-ray tube 10 within a small focal diameter range of 10 to 300 μm as described above. Change to focal diameter. When the subject table 15 is not attached, the control device 20 alerts the photographer by displaying a warning on the display unit 16b of the operation device 16 or issuing a warning by voice. It has become.

  In this embodiment, when phase contrast imaging is set as an imaging method, a setting screen for numerical values to be input is displayed on the display unit 16b of the operation device 16, and the photographer inputs the input unit 16a. To set those values.

  As the values set in the phase contrast imaging, as in the case of the above-described close-contact imaging, the imaging direction, the imaging region of the subject's body as the subject H, and the X-ray detector 13 is a cassette-type fitting type detection. If it is a container, its type and the like can be mentioned.

  Further, as described above, since the magnification imaging can be performed in the phase contrast imaging, in this embodiment, when the imaging region is input, the control device 20 causes the display unit 16b of the operation device 16 to display an enlargement rate corresponding to the imaging region. The recommended value of M is displayed. That is, in the present embodiment, the imaging region, the recommended value of the magnification M, the distance R1 between the X-ray tube 10 and the subject table 15, the distance R2 between the subject table 15 and the X-ray detector 13, the X-ray tube A table for determining the correlation with the focal diameter of 10 and the imaging conditions, that is, the tube voltage and the irradiation dose (mAs value) is created and stored in advance. Note that the recommended value of the enlargement ratio M is appropriately set depending on the imaging region. Further, an upper limit value of the enlargement factor M is set for each imaging region so that the image to be imaged does not protrude from the X-ray detector 13, and when the imaging region is input, the upper limit value of the enlargement factor M is also displayed. It has become so. Alternatively, the distances R1 and R2 that protrude from the image may not be set.

  When the recommended value of the enlargement factor M is approved and set by the photographer, the control device 20 refers to the table based on the distance R1 and distance R2 corresponding to the imaging region and the focal diameter of the X-ray tube 10. The tube voltage to be applied to the X-ray tube 10 and the irradiation dose to be irradiated are determined. Further, the control device 20 calculates the X-ray irradiation field from the area of the panel 13a of the X-ray detector 13 read from the memory and the relationship between the distance R1 and the distance R2, and realizes the irradiation field. The opening / closing amount of the diaphragm 11 of the X-ray tube 10 is adjusted. And while confirming the value of each encoder 23, each drive device 22 is driven, the 1st arm 6 or the 2nd arm 7 is expanded-contracted, distance is adjusted, and the support outer cylinder 4a is made into the imaging | photography direction around the support base axis | shaft 4. Rotate the set angle to adjust the shooting direction.

  Further, in this embodiment, regardless of the recommended value of the enlargement factor M, the photographer himself can determine the distance R1 between the X-ray tube 10 and the subject table 15 and the distance R2 between the subject table 15 and the X-ray detector 13. Can also be entered. As described above, in the phase contrast imaging, the X-ray intensity emitted from the X-ray tube 10 is weaker than that in the case of close-contact imaging. If the distance R1 from the subject table 15 is shortened, it is possible to perform photographing in a shorter time. The above configuration is for making the distance R1 and the distance R2 variable according to the judgment of the photographer.

  The memory also has a table for the photographer to manually set the imaging conditions as described above. In the table, the distance R1, the distance R2 (or the magnification M), and the focal point of the X-ray tube 10 are prepared. Correlation with the diameter and imaging conditions (tube voltage, irradiation dose) is determined and created. In this table, in order to suppress blurring and geometrical unsharpness of the X-ray image to be taken, a maximum value of the enlargement factor M that can be set according to the focal diameter of the X-ray tube 10 is set. When the enlargement factor M calculated from the enlargement factor M or the distance R1 and the distance R2 in accordance with the above equation (1) increases and reaches the maximum value, the focal point diameter of the corresponding X-ray tube 10 is larger at a further enlargement factor M. Is set to be small.

  In the present embodiment, the upper limit of the imaging time is set in advance depending on the imaging region. For example, if the imaging region is the heart, the heart moves fast, so if the imaging time is long, the captured X-ray image will be blurred. Therefore, for example, the upper limit of the imaging time is set to 1/20 to 1/30 seconds if the imaging region is the heart and 0.3 to 0.5 seconds if the imaging region is the hand. When the X-ray irradiation time calculated from the imaging conditions, that is, the imaging time exceeds the upper limit, the control device 20 displays a warning on the display unit 16b of the operation device 16 or issues a warning by voice. It is designed to alert the photographer.

  Further, for example, when the subject is very fat, the X-ray transmittance is reduced and the X-ray dose incident on the detector is reduced. Therefore, it is necessary to increase the tube voltage to shorten the imaging time. Therefore, in this embodiment, it is possible to input the body shape, weight, etc. of the subject via the input unit 16a of the operation device 16, and the control device 20 is able to input the body shape, weight, etc. of the subject created in advance. The tube voltage is raised according to a table that defines the correlation between the value and the rise value of the tube voltage.

  Further, if the thickness of the imaging region is thick, it is necessary to increase the tube voltage to shorten the imaging time, and it may be better to change the X-ray dose to be irradiated depending on the age of the subject. As described above, the imaging conditions can be adjusted more finely according to the thickness, age of the subject, and the like.

  It is arranged that it is not necessary to issue a warning or to arrange the grid 13c when the focal diameter of the X-ray tube 10, the presence or absence of the subject table 15, the type or presence of the X-ray detector 13, etc. are not normal. In some cases, interlock control such as issuing a warning is appropriately performed. Needless to say, the reading gain of the X-ray detector 13 can be adjusted by the distance R and the distances R1 and R2.

[Configuration of first radiographic imaging system]
Next, a configuration of a radiographic image capturing system using the radiographic image capturing apparatus 1 will be described. In the following, each of the two systems will be described.

  As shown in FIG. 9, the first radiographic image capturing system 100 using the radiographic image capturing device 1 is configured to include the radiographic image capturing device 1 of the present embodiment and a bed-type subject placement device 30. ing. In this case, the radiographic image capturing apparatus 1 is normally used by being moved to a position where the subject table 15 is removed or does not obstruct photographing.

  As shown in FIG. 10, the subject placement device 30 includes a pedestal portion 31 and a subject pedestal portion 32 that is movable on the pedestal portion 31 in the direction of the arrow. It is also possible to configure so that the subject base part 32 can move in the vertical direction with respect to the base part 31.

  The subject table 32 is made of a generally used acrylic plate, a substance having excellent X-ray transparency, such as carbon, or the like, like the subject table 15 of the radiographic image capturing apparatus 1. It is also possible to configure the subject table 32 with a carbon plate having a honeycomb structure. Further, the portion of the projecting portion A of the subject base portion 32 where the imaging part is placed may be formed thin or a hole may be formed. Moreover, the position which should permeate | transmit X-ray of a part of acrylic board may be cut out, and the position may be made into a carbon plate.

  The X-ray detector 13 of the radiographic image capturing apparatus 1 is disposed below the protruding portion A of the subject base 32 protruding from the pedestal 31, and the X-ray tube 10 of the radiographic image capturing apparatus 1 sandwiches the protruding portion A. Thus, it is arranged on the opposite side of the X-ray detector 13, that is, above the protruding portion A in the case of FIG. It is also possible to arrange the X-ray tube 10 below the protruding portion A and arrange the X-ray detector 13 above the protruding portion A.

  The test subject places the imaging region as the subject H on the protruding portion A of the subject table 32. In this case, the subject himself / herself may sit or lie down on the subject table 32, or the imaging region may be placed on the protruding portion A of the subject table 32 by sitting on a chair.

  The subject H is imaged by the radiographic image capturing apparatus 1, and the control thereof is as described above. At that time, the control is performed with the distance R1 as the distance between the X-ray tube 10 and the subject table 32 and the distance R2 as the distance between the subject table 32 and the X-ray detector 13.

  Note that the bed-type subject placement device 30 is, for example, a normal bed type having four legs instead of a configuration in which the subject table 32 is cantilevered as shown in FIG. It is also possible to do. In this case, the subject platform 32 is supported by four legs. Further, any other configuration is possible as long as the X-ray detector 13 and the X-ray tube 10 of the radiographic image capturing apparatus 1 can be inserted below the subject table 32.

[Configuration of Second Radiation Imaging System]
As shown in FIG. 11, the second radiographic image capturing system 200 using the radiographic image capturing device 1 includes the radiographic image capturing device 1 of the present embodiment and an X-ray detector provided in the radiographic image capturing device 1. 13 is provided with an X-ray detector 50 different from 13. In this case, the subject table 15 and the X-ray detector 13 of the radiographic image capturing apparatus 1 may be attached or removed as long as they do not interfere with imaging.

  In the radiographic image capturing system 200 of the present embodiment, the X-ray irradiator 9 of the radiographic image capturing apparatus 1 is rotated around the first support shaft 8 extending from the distal end portion of the first arm 6 so as to be turned sideways. The X-rays emitted from the X-ray tube 10 and transmitted through the subject H are irradiated to the other X-ray detector 50 and detected.

  The photographing of the subject H in this case is performed by the entire radiographic image capturing system 200, and the control is performed in the same manner as when the radiographic image capturing apparatus 1 alone performs the capturing.

  FIG. 11 shows the case of close-contact imaging in which the subject H is imaged in close contact with the X-ray detector 50, but a subject table is appropriately disposed between the X-ray tube 10 and the X-ray detector 50. Thus, it can be configured to perform phase contrast imaging.

  In FIG. 11, another X-ray detector 50 is fixed to the support column and the position is fixed. However, the present invention is not limited to this, and another X-ray detector 50 can be moved. It is also possible to do. Further, at that time, it is possible to configure the X-ray detector 50 by various control methods such as moving the X-ray detector 50 in accordance with the movement of the X-ray tube 10 of the radiographic imaging apparatus 1.

[Action]
Next, operations of the radiographic image capturing apparatus 1 and the first and second radiographic image capturing systems 100 and 200 according to the present embodiment will be described.

  Various methods can be used as the X-ray imaging method by the radiographic image capturing apparatus 1 and the first and second radiographic image capturing systems 100 and 200.

  For example, first, the entire subject H is photographed at close magnification by close-contact photography, the position determined to be the affected part is identified from the X-ray image, and switched to phase contrast photography, so that the affected part is accurately photographed, and A clear X-ray image in which the edge portion of the soft tissue is emphasized can be obtained. If the position of the affected part is already known, phase contrast imaging may be performed from the beginning.

  Further, the X-ray tube 10 is weak when the subject table 15 or the subject table 32 is in contact with the X-ray detector 13 or another X-ray detector 50, that is, when the distance R2 is set to 0 m. The object H is moved by irradiating a line, so that an X-ray image is obtained in a moving image. Then, at the stage where the position determined to be an affected part is specified, the X-ray tube and the detector are moved to appropriate positions without changing the positions of the subject table 15 and the subject table part 32 and switched to phase contrast imaging. Even in this way, it is possible to obtain a clear X-ray image in which the affected part is accurately photographed and the edge part of the soft tissue is emphasized.

  In addition, for example, it is possible to perform functional diagnosis of the subject's body by photographing the subject while holding the hand or opening the subject, or photographing the knee flexion and extension at various knee angles. .

  In the radiographic image capturing apparatus 1 and the first and second radiographic image capturing systems 100 and 200 of the present embodiment, so-called tomosynthesis imaging can also be performed. Tomosynthesis imaging, as shown in FIG. 12, the subject H is photographed while the X-ray tube 10 and the X-ray detector 13 or another X-ray detector 50 are translated in opposite directions above and below the subject H. This is a technique for photographing the subject H three-dimensionally.

  In this case, in the second radiographic imaging system 200, the operation is controlled such that the X-ray tube 10 and another X-ray detector 50 move while maintaining the positional relationship as shown in FIG. Further, in the case of the radiographic image capturing apparatus 1 or the first radiographic image capturing system 100, as can be seen from the structure of the support base shaft 4, the first arm 6, the second arm 7, etc. of the radiographic image capturing apparatus 1, the X-ray tube. The first arm 6 and the second arm 7 can be expanded and contracted and their supporting base axes without rotating the 10 around the first support shaft 8 or the X-ray detector 13 around the second support shaft 12. It is possible to execute tomosynthesis imaging simply by adjusting the rotation of the four rotations, and tomosynthesis imaging can be realized very easily.

  Next, an example of X-ray imaging using the radiographic image capturing apparatus 1 of the present embodiment and the first and second radiographic image capturing systems 100 and 200 will be shown for each imaging region and imaging target.

  In the following embodiments, the radiographic imaging apparatus 1 and the first and second radiographic imaging systems 100 and 200 may not be described in some cases, but may be omitted depending on the apparatus or system in which the description is omitted. It goes without saying that the embodiment can be realized. In the following, the X-ray tube 10 and the X-ray detectors 13 and 50 are arranged in the vertical direction of the subject H, and the X-ray tube 10 and the X-ray detectors 13 and 50 and the subject H in the left-right direction. The case of arranging in the horizontal direction is called a horizontal direction. In vertical imaging, the X-ray tube 10 is disposed above the subject H and the X-ray detectors 13 and 50 are often disposed below the subject H. The X-ray detectors 13 and 50 can be arranged above the subject H to take images. Furthermore, it goes without saying that horizontal and vertical shooting can be performed even when only vertical shooting or horizontal shooting is described in the following embodiments.

  First, in photographing a hand or a finger, generally, as shown in FIG. 3, if the subject is seated on a chair X and the hand or finger is photographed in close contact, the X of the radiographic image capturing apparatus 1 is used. It is placed on the line detector 13, and if it is phase contrast photography, it is placed on the subject table 15 and photographing in the vertical direction is performed.

  As described above, since the imaging time tends to be longer in phase contrast imaging than in close-contact imaging, the subject H is fixed so that the hand or finger does not move. The object structure 15 is formed of resin or the like, and the surface portion of the object table 15 is formed with irregularities in the shape of a hand, or the compression plate that presses and fixes the object H appropriately from above is described in the above configuration. However, in addition to this, a triangular magnet 60 is disposed between the thumb and the index finger as shown in FIG. 13, and an arm holding portion 61 for holding the arm portion of the subject is provided as shown in FIG. It is also possible to do. In FIG. 14, 61a is an arm holding portion for the left arm, and 61b is an arm holding portion for the right arm.

  Moreover, as shown in FIG. 15, it is also possible to provide a removable band 62 for fixing the wrist, back of the subject, fingers and the like of the subject. In this way, the movement of the hand or finger can be prevented by fixing the arm, wrist, back of the hand, finger, or the like. Furthermore, although illustration is omitted, the support jig for fitting and fixing a finger can be made of foamed polystyrene having a low X-ray absorption rate.

  Note that X-ray imaging of hands and fingers can also be performed using the first radiographic imaging system 100. In this case, the same function can be achieved by applying the configuration of the subject table 15 of the radiographic image capturing apparatus 1 and the configuration of the support jig installed therein to the subject table section 32 of the subject placement device 30. .

  Next, in the case of photographing the elbow, the photographing can be performed in the same manner as the photographing of the hand or finger. In photographing the elbow, as shown in FIGS. 16A and 16B, the subject bent or stretched the elbow on the subject table 15, the subject table 32, or the X-ray detectors 13 and 50. Place in state. In this case also, when performing phase contrast imaging, the subject H moves by fixing the wrist, arm, etc. of the subject to the subject table 15 or the subject table 32 with a support jig such as a band 62. Can be prevented.

  Next, in shoulder imaging, lateral imaging can be performed using the radiographic imaging device 1 or the second radiographic imaging system 200. For example, when phase contrast imaging is performed with the radiographic image capturing apparatus 1, the first arm 6 and the second arm 7 are rotated approximately 90 ° around the support base axis 4 as shown in FIGS. 17 (A) and 17 (B). The subject table 15 is also rotated by approximately 90 ° with respect to the support inner shaft 4b.

  Then, the subject is placed on the side of the subject table 15 facing the X-ray tube 10 by, for example, sitting on the chair, and the subject's shoulder, which is the subject H, is placed at an appropriate position for photographing. In this case, the subject can be prevented from moving by fixing the armpit or chest of the subject with a support jig such as a band or by attaching the support jig to the shoulder. In close-contact imaging, the subject is placed in close contact with the X-ray detector 13 or another X-ray detector 50.

  It is also possible to take a picture of the shoulder by taking a picture in the vertical direction. In this case, for example, support jigs 63 and 64 as shown in FIG. The support jigs 63 and 64 are arranged on the subject table 15 or the subject table unit 32 with a certain interval. Then, as shown in FIG. 18B, with the subject's front chest in contact with the inclined surface B of the support jig 63 and with the subject's jaw in contact with the top surface C of the support jig 63, In this case, the right arm is placed on the support jig 64. Then, X-ray imaging is performed with the right shoulder positioned above the gap portion D of the support jigs 63 and 64.

  When photographing the left shoulder, the support jig 64 is disposed on the left side of the support jig 63. In addition to the case where the subject is photographed in a prone state as described above, the back surface of the subject is brought into contact with the inclined surface B of the support jig 63 and the back surface of the subject is brought into contact with the top surface C of the support jig 63. By placing the arm on the support jig 64 in such a state, it is possible to take a picture in a supine state.

  Next, in the imaging of the head and neck, the subject is placed on a chair or the like on the X-ray tube 10 side of the subject table 15 as shown in FIGS. In the seated state, the X-ray tube 10 and the X-ray detectors 13 and 50 can be arranged in the horizontal direction to perform horizontal imaging. Further, vertical imaging is performed in a state where the subject is lying on his / her face on the subject table 32 of the bed-type subject placement device 30 of the first radiographic imaging system 100 shown in FIG. 9. It can be carried out.

  In the imaging of the head and neck, not only when the subject faces the X-ray tube 10 or turns his back against the X-ray tube 10, but the subject lies sideways with respect to the X-ray tube 10. It is also possible to take a picture of the head and neck from the side by placing them facing each other. In the first radiographic imaging system 100 shown in FIG. 9, when imaging the head and neck from the side, the subject lies on the subject table 32 so as to face the right side or the left side in the drawing. In such a case, measures are taken such that a subject is not overwhelmed, for example, by placing a pillow-shaped support jig (not shown) between the head and the subject platform 32.

  The same applies to the imaging region other than the head and neck, and the imaging of the imaging target. However, the X-ray tube 10 and the X-ray detector 13 are placed horizontally with respect to the floor as shown in FIG. As shown in FIGS. 19 and 20, the subject H can be arranged so as to be photographed obliquely from above or obliquely below. The second radiographic image capturing system 200 can be similarly arranged. Further, in the first radiographic image capturing system 100, it is also possible to capture an image from diagonally above or diagonally below with the subject lying on the subject table 32.

  Next, in imaging of the chest, abdomen, and lower back, the X-ray detectors 13 and 50 and the subject table 15 are placed on the chest and back with the subject standing or sitting on a chair or the like, as in normal X-ray imaging. Photographed in a state of contact. Further, the subject is photographed in a state of lying on his / her face, lying down or lying down on the subject table 32 of the first radiographic image capturing system 100.

  In addition, a support jig etc. are used suitably as needed. It is also possible to set a hanging rod or the like above the subject and take a picture with the subject held on the rod or the like.

  Next, in photographing the legs including the knees, ankles, toes, etc., as shown in FIG. The leg portion of the subject sitting on the chair X between the X-ray tube 10 and the X-ray detectors 13 and 50 arranged in the direction is fixed to the support jig 65, and the support jig 65 is attached to the subject table 15. Shoot in a fixed position. In addition, the subject is photographed while the subject is lying on his / her back, lying down, or lying on the subject table 32 of the first radiographic imaging system 100.

  At this time, for example, as shown in FIG. 22, a support jig 65 for fixing the ankle includes a dog-shaped support jig 65 attached to a portion under the knee of the subject. By fixing the ankle with such a support jig 65, it is possible to prevent the subject's ankle from moving. Further, if the support jig 65 is fixed to the subject table 15 or the X-ray detectors 13 and 50, the subject can easily take an image.

  As shown in FIG. 21, instead of fixing the support jig 65 to the subject table 15 facing substantially the vertical direction, the support jig 65 may be fixed on the subject table 15 so as to face the substantially horizontal direction. Alternatively, for example, a table or table (not shown) may be placed on the floor surface F and fixed thereon. At this time, the mounting position of the support jig 65 to the subject table 15 and the height of the table or table are adjusted so that the height and horizontal position of the support jig 65 can be adjusted to appropriate positions. Further, the support jig 65 may be configured to be directly fixed to the support base shaft 4 of the radiation image capturing apparatus 1. Furthermore, the angle with respect to the long piece part 65b of the short piece part 65a of the support jig 65 can be varied, and it can also be comprised so that an angle may be adjusted and used.

  Further, as shown in FIG. 23A, if the support jig 65 is further provided with a band 66, the leg portion of the subject can be securely fixed and the movement thereof can be prevented more reliably. Further, when shooting in the vertical direction with respect to the ankle, as shown in FIG. 23 (B), the support jig 65 is provided with a wing piece portion 67 for clamping the leg portion from both side surfaces to be fixed. You may comprise.

  When photographing the subject's knee, the subject's legs can be fixed using the same support jig. Further, for example, when imaging the subject's knee on the subject table 32 of the first radiographic image capturing system 100, as shown in FIG. 24, the leg portion including the subject's knee is covered, and an opening is formed above and below the knee portion. The leg portion of the subject may be fixed by the support jig 68 provided with 68a.

  Further, the tip end portion of the protruding portion A of the subject platform 32 of the subject placement device 30 shown in FIG. 10 is bent as shown in FIG. 25, and a hole E is provided in the bent portion. Then, X-ray imaging is performed from above, below, diagonally above, or diagonally below with the subject seated on the subject table 32 so that the subject's knee is positioned above the hole E. If comprised in this way, a test subject can sit down easily and image | photograph in the state which stopped the motion of the knee and the leg part. At that time, fixing the subject's legs or the like with a support jig or the like is appropriately performed as necessary.

  Note that the subject platform 32 of the subject placement device 30 may be configured to be recessed in the shape of the subject's leg. When the leg is placed in the recessed portion, the leg is stabilized. It is also possible to configure the subject table portion 32 with a material having a normal cushioning property, and to configure the portion to be irradiated with X-rays with a window-like material having excellent X-ray permeability such as carbon.

  Next, in photographing a child or an infant, the first radiation image capturing system 100 is used, and the child or the infant is placed on the subject table 32 of the bed-type subject placement device 30 in the same manner as described above. It is possible to take a picture in a state where it is lying down or seated in a state and the imaging part and its vicinity are fixed with a support jig and do not move.

  For example, when using the radiographic imaging device 1 or the second radiographic imaging system 200, although not shown, the subject table 15 is configured as a nursery box, and an infant or the like is lying on its side and seated therein. It may be configured to perform X-ray imaging.

[effect]
As described above, according to the radiographic image capturing apparatus 1 and the first and second radiographic image capturing systems 100 and 200 according to the present embodiment, the X-ray tube 10 and the X-ray detector 13 are rotated around the support base axis 4. The distance R1 between the X-ray tube 10 and the subject table 15, the distance R2 between the subject table 15 and the X-ray detector 13, and the distance R between the X-ray tube 10 and the X-ray detector 13 are variable. Thus, the operating range of each member constituting the radiographic image capturing apparatus 1 is increased. Therefore, it is not necessary for the subject to take an unreasonable posture at the time of imaging, and X-ray imaging can be appropriately performed on a subject who stands up, sits down and lies down in a natural posture without overdoing it.

  Further, since the focal diameter of the X-ray tube 10 can be set within a range of 300 to 2000 μm for close-contact imaging and within a range of 10 to 300 μm for phase contrast imaging, one radiation image The imaging apparatus 1 and the set of radiographic imaging systems 100 and 200 can switch between close-contact imaging and phase contrast imaging as appropriate, which makes the apparatus and system very convenient for both the photographer and the subject.

  Furthermore, the radiographic image capturing apparatus 1 and the subject placement device 30 formed in a bed shape constitute the radiographic image capture system 100, so that the subject sits on the subject table 32 of the subject placement device 30 and is lying down. Since the X-ray imaging can be performed in the above state, the above-described effect is more effectively exhibited.

  Further, X-rays irradiated from the X-ray tube 10 of the radiographic imaging apparatus 1 and transmitted through the subject H are sent to an X-ray detector 50 different from the X-ray detector 13 provided in the radiographic imaging apparatus 1. By configuring the radiographic imaging system 200 to detect by irradiation, the radiographic imaging apparatus 1 is provided, for example, on the configuration of the radiographic imaging apparatus 1 or on the configuration of the installation space where the radiographic imaging apparatus 1 is installed. Even if the X-ray detector 13 does not detect X-rays transmitted through the subject H, it can be separated by installing another X-ray detector 50 and irradiating it, as in the case of the radiographic imaging apparatus 1 alone. The X-ray detector 50 can accurately receive and detect X-rays, and this radiographic imaging system 200 can obtain the same effects as those of the radiographic imaging apparatus 1 described above.

(A) It is a figure which shows the example of normal X-ray imaging, ie, close_contact | adherence imaging, (B) It is a figure which shows the example of phase contrast imaging. It is a front view of the structural example of the radiographic imaging apparatus which concerns on this embodiment. It is a side view of the structural example of the radiographic imaging apparatus which concerns on this embodiment. It is a figure explaining the distance of a X-ray tube and a to-be-photographed object table, the distance of a to-be-photographed object table and a X-ray detector, and the distance of a X-ray tube and a X-ray detector. It is a figure which shows the structural example and grid of an X-ray detector. It is a schematic cross section which shows the grid, the 1st insertion part, and the 2nd insertion part which were provided in the detector holding stand. It is a block diagram which shows the control structure of the radiographic imaging apparatus which concerns on this embodiment. 2A and 2B are diagrams for explaining the principle of phase contrast imaging, in which FIG. 1A illustrates X-rays refracted at an edge portion of a subject, and FIG. 2B illustrates X-ray intensity that is strongly detected at the edge portion of the subject. It is a figure which shows the structure of the 1st radiographic imaging system which concerns on this embodiment. It is a perspective view explaining the composition of a subject placement device. It is a figure which shows the structure of the 2nd radiographic imaging system which concerns on this embodiment. It is a figure explaining the method of tomosynthesis imaging | photography. It is a figure which shows the magnet arrange | positioned at a to-be-photographed object base. It is a figure which shows the arm holding | maintenance part arrange | positioned at a to-be-photographed object base. It is a figure which shows the band which fixes a test subject's wrist etc. FIG. (A) It is a figure which shows the elbow mounted in the bent state, (B) It is a figure which shows the elbow mounted in the extended state. It is a figure which shows the radiographic imaging apparatus by which an X-ray tube, an X-ray detector, etc. are arrange | positioned in the horizontal direction, (A) is a front view, (B) is a top view containing a to-be-photographed object. (A) It is a figure which shows the example of a set of support jig | tool used for imaging | photography of a shoulder, (B) It is a figure which shows the example which image | photographs a shoulder using a support jig | tool. It is a figure explaining the state which image | photographs a to-be-photographed object from diagonally upward. It is a figure explaining the state which image | photographs a to-be-photographed object from diagonally downward. It is a figure which shows the example in the case of image | photographing a test subject's leg part. It is a figure which shows the example of the support jig | tool which fixes an ankle etc. (A) It is a figure which shows the band used in combination with the support jig | tool of FIG. 22, (B) It is a figure which shows the wing | blade piece part provided in the support jig | tool of FIG. It is a figure which shows the support jig | tool which covered the test subject's leg part and was provided with the opening of the part of the knee. It is a figure which shows the to-be-photographed object base part of the to-be-photographed object mounting apparatus by which the front-end | tip part was bent and the hole was provided.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Radiographic imaging device 3 Support base part 4 Support base shaft 6 First arm 7 Second arm 8 First support shaft 10 X-ray tube 12 Second support shaft 13 X-ray detector 15 Subject stand 30 Subject placement device 50 Another X Line detector 100, 200 Radiation imaging system.
H Subject R1 Distance between X-ray tube and subject table R2 Distance between subject table and X-ray detector R Distance between X-ray tube and X-ray detector

Claims (7)

A support base having a support base shaft extending in a substantially horizontal direction and capable of moving up and down in a substantially vertical direction;
A subject table attached in an extending direction of the support base shaft;
A first arm extending substantially perpendicular to the support base axis and rotatable about the support base axis;
An X-ray tube attached to the first arm;
A second arm extending in a direction substantially opposite to the first arm with respect to the support base axis, and rotatable about the support base axis;
An X-ray detector attached to the second arm;
With
The X-ray tube is configured such that its focal diameter can be set within a range of 300 to 2000 μm and within a range of 10 to 300 μm, and they can be switched,
The distance between the X-ray tube and the object table and the distance between the object table and the X-ray detector, or the distance between the X-ray tube and the X-ray detector are variable. A radiographic imaging device. A first support shaft extending from the first arm so as to be substantially parallel to the support base shaft;
A second support shaft extending from the second arm so as to be substantially parallel to the support base shaft,
The X-ray tube and the X-ray detector are attached to the first support shaft and the second support shaft, respectively, and are rotatable around the first support shaft and the second support shaft, respectively. The radiographic imaging apparatus according to claim 1.   The radiographic image capturing apparatus according to claim 1, wherein the subject table is rotatable about the support base axis.   4. The apparatus according to claim 1, wherein the object table is movable to a position that does not obstruct an optical path of X-rays from the X-ray tube toward the X-ray detector. 5. The radiographic imaging apparatus as described.   The radiographic imaging apparatus according to claim 1, wherein the subject table is detachable from the support base shaft. The radiographic imaging device according to any one of claims 1 to 5,
A subject placement device formed in a bed shape;
A radiographic imaging system comprising:   6. An X-ray detector provided in the radiographic imaging apparatus, which emits X-rays irradiated from the X-ray tube of the radiographic imaging apparatus according to any one of claims 1 to 5 and transmitted through a subject. Radiation imaging system characterized by irradiating and detecting an X-ray detector different from the above.

Images