JP7376445B2 - radiography equipment - Google Patents

Description

The technology of the present disclosure relates to a radiographic apparatus.

Patent Document 1 describes a radiation imaging apparatus that performs radiation imaging. The radiation imaging system described in Patent Document 1 includes a radiation source that irradiates radiation (for example, X-rays) toward a radiation image detector, and a support that supports the radiation source in a movable manner. The column extends vertically from the ceiling, and an X-ray source is provided at the lower end of the column. The radiation source is not only rotatable around the axis of the column, but also rotatable around the focal point from which the radiation is emitted.

JP 2019-122589 Publication

Depending on the purpose of radiography, there is a desire to finely adjust the direction of radiation irradiation. For example, when photographing a knee joint, etc., it may be necessary to make adjustments such as slightly changing the incident angle of the radiation. Like the radiation source described in Patent Document 1, the direction of radiation irradiation can be adjusted by rotating around the focal point.

However, an SID (Source Image receptor Distance) is ensured between the focal point and the radiation image detector where the subject is located. Therefore, when rotating the radiation source around the focal point, not only the radiation irradiation direction changes, but also the position of the radiation irradiation field relative to the unit rotation angle of the radiation source shifts. If the positional deviation of the irradiation field is large, it may be difficult to make fine adjustments to the irradiation direction, such as changing only the incident angle of the radiation to the subject, for example, with the irradiation field aligned with the subject.

An object of the technology of the present disclosure is to provide a radiation imaging apparatus that allows fine adjustment of the radiation irradiation direction more easily than in the past.

The radiographic apparatus of the first aspect includes an irradiation unit that irradiates radiation toward a radiation image detector, a support that displaceably supports the irradiation unit, and a first center line that is attached to the support and that passes through the focal point of the irradiation unit. a first rotating part capable of first rotation about a rotation center; and a second rotating part that is attached to the first rotating part and rotates about a second center line located closer to the radiation image detector than the first center line in the radiation irradiation direction. The radiation imaging apparatus is equipped with a second rotating part that is capable of a second rotation about the center, and is capable of first and second rotations of the irradiation part by the first rotating part and the second rotating part.

The radiographic apparatus of the first aspect includes a first rotating part capable of first rotation, and a second rotating part capable of second rotation about a second center line located closer to the radiation image detector than the first center line. It is equipped with The second rotation allows adjustment of the irradiation direction based on the radiation image detector side where the subject is located, so the first rotation with the focus as the rotation center allows adjustment of the irradiation direction to align the radiation irradiation field with the subject. It is easy to make fine adjustments to the irradiation direction, such as making a rough adjustment and then adjusting the incident angle of the radiation to the subject using a second rotation.

In the radiographic apparatus of the second aspect, the first center line and the second center line are parallel to each other in the radiographic apparatus of the first aspect.

In the radiographic apparatus of the second aspect, after the radiation irradiation position is aligned with the position of the subject by a first rotation about the first center line, the radiation irradiation position is aligned with the subject by a second rotation about the second center line. It becomes possible to finely adjust the direction of radiation irradiation.

The radiation imaging apparatus of the third aspect is the radiation imaging apparatus of the second aspect, wherein the irradiation section has an irradiation aperture for irradiating radiation, and the irradiation aperture and the detection surface of the radiation image detector face each other directly. In the case where the perpendicular line drawn from the focal point to the detection surface is assumed, the second center line intersects with the perpendicular line.

In the radiographic apparatus of the third aspect, compared to the case where the second center line does not intersect the perpendicular line drawn from the focal point to the detection surface, when the direction of radiation irradiation to the subject is finely adjusted by the second rotation, the radiation The amount of deviation of the irradiation range from the subject is small.

A radiographic apparatus according to a fourth aspect is the radiographic apparatus according to any one of the first to third aspects, in which the first rotating part includes an arc-shaped guide surface that becomes a part of the rotation locus of the second rotation. , the second rotating part is slidably attached to the first rotating part along the guide surface.

In the radiation imaging apparatus of the fourth aspect, it is possible to rotate the second rotating section without providing a physical rotation axis on the second center line. The second center line is located on the radiation image detector side, so if you try to place a physical rotation axis here, you will need an arm with a length equal to the radius of the second rotation, which will make the second rotation part larger. .

Therefore, compared to the case where a physical axis of rotation is provided on the second center line, by performing the second rotation using the arc-shaped guide surface, the arm becomes unnecessary and the second rotation part can be downsized.

In the radiographic apparatus of the fifth aspect, in the radiographic apparatus of the fourth aspect, when the radiation irradiation direction is set to the front and the opposite direction is set to the rear with respect to the focal point, the guide surface is arranged behind the focal point. There is.

In the radiographic apparatus of the fifth aspect, when the direction in which the first center line extends is taken as the depth direction of the radiation generating apparatus, the guide surface is arranged behind the focal point, so that the guide surface and the irradiation section overlap in the depth direction. Since the guide surfaces can be wrapped, the size of the device in the depth direction can be reduced compared to a case where the guide surfaces are arranged side by side in the depth direction.

In the radiographic apparatus of the sixth aspect, in the radiographic apparatus of the fourth aspect, when the direction in which the first center line extends is defined as the depth direction, the irradiation section and the guide surface are arranged side by side in the depth direction.

In the radiographic apparatus of the sixth aspect, when the direction in which the first center line extends is taken as the depth direction of the radiation generating apparatus, the irradiation section and the guide surface are arranged with an interval in the depth direction, so that the guide surface Since the radius of curvature of the guide surface can be made smaller than when the guide surface is placed behind the focal point, the length of the circular arc of the guide surface can also be made shorter.

In the radiographic apparatus according to a seventh aspect, in the radiographic apparatus according to any one of the first to sixth aspects, the holding section is provided in the second rotating section and holds the irradiation section, and the holding section is arranged on the first center line. It has a holding part that holds the irradiation part so as to be capable of third rotation about a third center line orthogonal to the third center line.

In the radiation imaging apparatus of the seventh aspect, the irradiation unit can be rotated in a direction different from the first rotation. Compared to the case without the third rotation, the degree of freedom in adjusting the radiation irradiation direction is high.

In the radiographic apparatus according to any one of the first to seventh aspects, the radius of rotation of the second rotation, which is the distance from the center of rotation of the second rotation to the focal point, is from 400 mm to 1,000 mm. 000 mm, and the rotatable rotation angle of the second rotation is in the range of 0° or more and 15° or less with respect to the reference position in each of the positive direction and the negative direction.

In the radiographic apparatus of the eighth aspect, when imaging is performed with an SID of about 1,000 mm, which is considered to be frequently used, the radius of rotation of the second rotation and the rotatable rotation angle of the second rotation are set as described above. If the range is set, it is possible to downsize the apparatus without sacrificing the ease of confirming the image when adjusting the radiation irradiation direction while performing pre-imaging.

A radiographic apparatus according to a ninth aspect is a radiographic apparatus according to any one of the first to eighth aspects, including a first rotation regulating section that regulates the first rotation of the first rotating section, and a second rotation regulating section that regulates the first rotation of the first rotating section. It is provided with a second rotation restriction section that restricts two rotations, and has a processor that controls the first rotation restriction section and the second rotation restriction section.

In the radiographic apparatus of the ninth aspect, careless rotation of the first rotating section and the second rotating section can be suppressed.

The radiography apparatus of the tenth aspect is the radiography apparatus of the ninth aspect, and has a first rotation regulation state in which the first rotation is allowed and the second rotation is regulated by the second rotation regulation part; An operation section is provided for setting a second rotation regulation state in which the first rotation is regulated by the regulation part and a second rotation is allowed.

In the radiographic apparatus of the tenth aspect, when one of the first rotating part and the second rotating part is rotated, careless rotation of the other can be suppressed, and the rotation operation becomes easy.

A radiographic apparatus according to an eleventh aspect is the radiographic apparatus according to any one of the first to tenth aspects, wherein the irradiation section has an irradiation aperture, and irradiates radiation by changing the aperture size of the irradiation aperture. It has an irradiation field limiter that limits the field, and includes a processor that executes at least one of irradiation control of the irradiation unit and control of the irradiation aperture of the irradiation field limiter.

In the radiographic apparatus of the eleventh aspect, irradiation control of the irradiation section (changing the irradiation mode, stopping in an emergency, etc.), adjusting the irradiation aperture, etc. can be easily performed.

A radiographic apparatus according to a twelfth aspect is the radiographic apparatus according to the eleventh aspect, wherein the processor is capable of acquiring a signal indicating whether or not the second rotation is permitted, and whether the second rotation is permitted. If so, control is executed to adjust the aperture size of the irradiation aperture, and the adjusted aperture size is such that the irradiation aperture and the detection surface of the radiation image detector directly face each other, and the perpendicular line drawn from the focal point to the detection surface Even when the rotation angle of the second rotation is the maximum, the amount of protrusion of the irradiation field from the image detection area of the radiation image detector is equal to or less than a predetermined value, assuming that It is.

In the radiographic apparatus of the twelfth aspect, when the second rotation is performed, the amount of protrusion of the radiation irradiation field from the image detection area of the radiation image detector can be suppressed from exceeding a predetermined value.

A radiographic apparatus according to a thirteenth aspect is the radiographic apparatus according to the eleventh or twelfth aspect, in which the processor rotates the first rotation angle of the first rotation, the second rotation angle of the second rotation, and the second rotation angle of the second rotation. An index value indicating at least one of the third rotation angles of the third rotation around the third center line perpendicular to the first center line, and the distance between the focal point of the irradiation unit and the detection surface of the radiation image detector. The position of the radiation irradiation field with respect to the image detection area of the radiation image detector is derived based on the SID, which is the distance between If it is detected that the amount of protrusion exceeds a predetermined value, or if it is detected that there is a risk of exceeding a predetermined value, irradiation of the irradiation part is prohibited.

In the radiographic apparatus of the thirteenth aspect, the amount of protrusion of the irradiation field of the irradiation section from the image detection area can be suppressed from exceeding a predetermined value.

A radiation imaging apparatus according to a fourteenth aspect is the radiation imaging apparatus according to any one of the ninth to thirteenth aspects, in which the irradiation section has an irradiation mode for irradiating radiation, and an irradiation mode for video imaging, which is set in advance. The irradiation mode has at least two irradiation modes selected from among an irradiation mode for continuous shooting to continuously acquire a number of still images, and an irradiation mode for shooting one still image.

The radiation imaging apparatus of the fourteenth aspect has a plurality of irradiation modes, so it is possible to perform imaging according to the purpose.

The radiographic apparatus according to a fifteenth aspect is the radiographic apparatus according to the fourteenth aspect, wherein the processor generates a signal indicating whether or not the radiographic image detector is housed in the radiographing table which detachably accommodates the radiographic image detector. If the radiation image detector is accommodated in the imaging table, the processor allows the irradiation mode for video recording, and if the imaging table does not accommodate the radiation image detector, the processor allows the irradiation mode for video recording. Prohibits illumination mode for photography.

In the radiographic apparatus of the fifteenth aspect, when the radiographic image detector is not housed in the radiographic table, execution of the irradiation mode for video capturing can be suppressed.

A radiographic apparatus according to a sixteenth aspect is the radiographic apparatus according to any one of the first to fifteenth aspects, wherein the support is a ceiling-suspended support that can travel on the ceiling, or a support that is suspended from the ceiling. It is an upright support that stands up from the floor surface on which it can run.

In the radiographic apparatus of the sixteenth aspect, the position of the irradiation unit can be changed by the support column running on the ceiling or the floor.

According to the technology of the present disclosure, it is easy to finely adjust the radiation irradiation direction.

FIG. 1 is a perspective view showing a ceiling-suspended radiographic apparatus according to a first embodiment. FIG. 2 is an enlarged perspective view of the radiographic apparatus of the first embodiment. FIG. 3 is an enlarged perspective view of the radiographic apparatus of the first embodiment. FIG. 4 is an exploded perspective view partially enlarging the radiographic apparatus of the first embodiment. FIG. 5 is an explanatory diagram of the irradiation section in the radiation imaging apparatus of the first embodiment. FIG. 6 is an explanatory diagram of the radiation irradiation mode of the radiation imaging apparatus of the first embodiment. FIG. 7 is a partially enlarged plan view of the radiographic apparatus of the first embodiment. FIG. 6 is a partially enlarged side view of the radiographic apparatus of the first embodiment. FIG. 9 is a front view showing the radiographic apparatus of the first embodiment in a state in which it is in the reference position, in a state in which it has been rotated for the first time in the negative direction, and in a state in which it has been rotated for the first time in the positive direction. FIG. 10 is a side view showing the radiographic apparatus of the first embodiment in a usage state different from that in FIG. 2. FIG. 11 is a front view showing the radiographic apparatus of the first embodiment in a reference position. FIG. 12 is a front view showing the radiographic apparatus of the first embodiment in a second rotated state in the negative direction and a second rotated state in the positive direction. FIG. 13 is a front view showing the radiographic apparatus of the first embodiment in a state in which it is at the reference position, in a state in which it has been rotated a second time in a negative direction, and in a state in which it has been rotated a second time in a positive direction. FIG. 14 is a flowchart and an explanatory diagram showing an example of the irradiation range adjustment process in the radiation imaging apparatus of the first embodiment. FIG. 15 is an explanatory diagram showing a radiation irradiation apparatus according to the second embodiment. FIG. 16 is a table showing the relationship between the rotation restriction state and the state of the rotation restriction section in the radiation imaging apparatus of the second embodiment. FIG. 17 is a flowchart showing control of the irradiation aperture in the radiation imaging apparatus of the second embodiment. FIG. 18 is an explanatory diagram showing the relationship between the irradiation aperture of the aperture member and the irradiation field in the radiation imaging apparatus of the second embodiment. FIG. 19 is an explanatory diagram showing a radiation imaging apparatus according to the third embodiment. FIG. 20 is an explanatory diagram showing the vicinity of the imaging bed in the radiation imaging apparatus of the third embodiment. FIG. 21 is a perspective view showing a state in which radiation is being irradiated in the radiation imaging apparatus of the third embodiment. FIG. 22 is a flowchart of radiation protrusion suppression processing in the radiation imaging apparatus of the third embodiment. FIG. 23 is a flowchart of moving image mode restriction processing in the radiation imaging apparatus of the third embodiment. FIG. 24A is an enlarged perspective view of the radiographic apparatus of the fourth embodiment. FIG. 24B is an enlarged perspective view of the radiation imaging apparatus of the fourth embodiment. FIG. 25A is an enlarged side view showing the radiation imaging apparatus of the fourth embodiment. FIG. 25B is an enlarged front view of the radiation imaging apparatus of the fourth embodiment. FIG. 26 is an explanatory diagram showing the radiation irradiation range in the radiographic apparatus. FIG. 27 is an explanatory diagram showing the radiation irradiation range in the radiographic apparatus. FIG. 28 is an explanatory diagram showing the radiation irradiation range in the radiographic apparatus. FIG. 29 is an explanatory diagram showing the radiation irradiation range in the radiographic apparatus. FIG. 30 is an explanatory diagram showing the radiation irradiation range in the radiographic apparatus. FIG. 31 is an explanatory diagram showing the radiation irradiation range in the radiographic apparatus. FIG. 31 is a perspective view showing the radiation irradiation range in the radiographic apparatus. FIG. 33A is an explanatory diagram showing the amount of deviation of the radiation irradiation range in the radiographic apparatus. FIG. 33B is an enlarged explanatory diagram showing the amount of deviation of the radiation irradiation range in the radiographic apparatus. FIG. 34 is an explanatory diagram showing the position of the guide surface in the radiographic apparatus. FIG. 35 is a front view showing the radiographic apparatus according to the technology of the present disclosure as a floor-mounted type. FIG. 36 is a front view showing the radiographic apparatus according to the technology of the present disclosure as a floor-mounted type.

[First embodiment]
Hereinafter, a first embodiment will be described with reference to the drawings.

In FIG. 1, a radiography system 100 is a system for performing radiography, and includes a radiography apparatus 102, an electronic cassette 104, a supine radiography table 106, a standing radiography table 111, and the like. The radiographic apparatus 102 includes a radiation source 112 and a column 114 to which the radiation source 112 is attached. The radiation source 112 has an irradiation section 113 that irradiates radiation.

The support column 114 is attached to a ceiling traveling device 126 and is movable within a plane parallel to the ceiling 128 and the floor surface 172. The support column 114 extends from the ceiling traveling device 126 in the vertical direction (Z direction). A radiation source 112 is provided at the lower end of the column 114. The irradiation unit 113 is not only rotatable around the axis of the support column 114 extending in the Z direction, but also displaceable with respect to the support column 114 as described later.

Electronic cassette 104 is an example of a radiation image detector. The electronic cassette 104 has, for example, a detection section having a TFT (Thin Film Transistor) matrix substrate on which a plurality of pixels are arranged two-dimensionally, and the detection section generates electricity according to the amount of radiation incident on each pixel. Output a signal. The electronic cassette 104 generates a radiation image based on electrical signals corresponding to each pixel, and transmits the generated radiation image to the cassette control device 105 wirelessly or by wire.

During radiography, an operator OP such as a radiologist aligns the imaging region of the subject H with the detection surface 104A of the electronic cassette 104, and also adjusts the position and orientation of the detection surface 104A of the electronic cassette 104. Accordingly, the irradiation direction of the irradiation section 113 is adjusted. In this state, radiation is irradiated from the irradiation unit 113 toward the electronic cassette 104. The electronic cassette 104 receives radiation that has passed through the imaging site of the subject H, detects a radiation image representing the imaging site of the subject H, and transmits the detected radiation image to the cassette control device 105 . The cassette control device 105 not only displays the received radiation image on the display 166, but also transmits the received radiation image to an external server via the network. The electronic cassette 104 is capable of video shooting, still image shooting, continuous shooting, and the like.

The supine photographing table 106 includes a bed 107 on which the subject H lies supine and a housing section 108 that accommodates the electronic cassette 104, and is a photographing table for photographing the subject H in the supine position. The top plate of the bed 107 is made of a material that transmits radiation, and the electronic cassette 104 can be housed in the housing section 108 to perform imaging. It is also possible to perform so-called free photography, in which the electronic cassette 104 is placed at an arbitrary position on the bed 107 and photography is performed.

The standing photographing table 111 includes a stand 110 and a housing section 109 that stores the electronic cassette 104, and is a photographing table for photographing a subject H in a standing posture.

As shown in FIGS. 2 to 4, the radiation source 112 includes, in addition to the irradiation section 113, a radiation source control section 122 (see FIG. 4) that controls the irradiation section 113, an operation panel 156 (see also FIG. 4), It has an irradiation switch 168, a first rotating section 116, a second rotating section 118, and a mounting section 130. In this example, as shown in FIG. 4, the radiation source control section 122 is provided inside the operation panel 156, but the radiation source control section 122 may be provided outside the operation panel 156. You can leave it there.

As shown in FIG. 5, the irradiation unit 113 includes, for example, a radiation tube 117 and an irradiation field limiter 154. The radiation tube 117 has a cathode and an anode, and generates radiation by colliding an electron beam generated from the cathode with the anode. The focal point F is the point where radiation is generated by collision of the electron beams at the anode. A high voltage generator (not shown) for applying a high voltage to the radiation tube 117 is connected to the irradiation unit 113 .

The irradiation field limiter 154 has an irradiation aperture 164 that irradiates the radiation generated by the radiation tube 117 to the outside. Limit field LF. As described below, the size of the irradiation aperture 164 is variable. The irradiation field limiter 154 is also called a collimator.

The irradiation aperture 164 is defined, for example, by a plurality of shielding plates 154A that shield radiation. The irradiation aperture 164 has a rectangular shape, and the plurality of shielding plates 154A are arranged at positions corresponding to the four sides of the irradiation aperture 164, respectively. By moving the positions of the plurality of shielding plates 154A in parallel, it is possible to adjust the aperture size of the irradiation aperture 164. The movement of the shielding plate 154A is performed by an actuator 154B such as a motor. Since the X-rays emitted from the radiation tube 117 pass through the irradiation aperture 164, by adjusting the aperture size of the irradiation aperture 164, the divergence angle of the X-rays that diverge from the focal point F can be regulated. Thereby, it is possible to easily adjust the size of the irradiation field LF.

In the example shown in FIG. 5, the irradiation aperture 164 directly faces the detection surface 104A. Here, "directly facing" refers to a state in which, assuming a plane FP whose outline is the inner edge of the irradiation aperture 164, the assumed plane FP and the detection surface 104A are parallel.
Also, assume here that a perpendicular line NL is drawn from the focal point F of the irradiation section 113 to the detection surface 104A in a state where the irradiation aperture 164 and the detection surface 104A face each other. FIG. 5 shows a state in which the focal point F of the irradiation unit 114 and the center CP of the detection surface 104A are located at corresponding positions, and both the focal point F and the center CP pass through the perpendicular line NL.
Further, in a state where the irradiation aperture 164 and the detection surface 104A face each other, the perpendicular line NL also coincides with the optical axis OA, which is the central axis of the X-ray beam LB that diverges in a conical shape from the focal point F.

The radiation source control unit 122 is a control circuit configured by, for example, a processor such as a CPU (Central Processing Unit) and a memory built into or connected to the processor. The CPU functions as the radiation source control unit 122 by executing various control programs.

The radiation source control unit 122 controls irradiation timing such as starting and stopping radiation irradiation. As shown in FIG. 4, an irradiation switch 168 is connected to the radiation source control unit 122. When the irradiation switch 168 is operated by the operator OP, the radiation source control section 122 starts irradiation of radiation by operating the irradiation section 113. At this time, the radiation source control unit 122 performs synchronization control to synchronize the timing at which the irradiation unit 113 irradiates radiation and the timing at which the electronic cassette 104 detects the radiation by communicating with the cassette control device 105 . The radiation source control unit 122 also controls radiation irradiation conditions such as tube voltage, tube current, and irradiation time. The irradiation conditions can be set by transmission from an external device, or can also be set from the operation panel 156.

The radiation source control unit 122 also controls driving of the actuator 154B. Thereby, the aperture size of the irradiation aperture 164 is adjusted under the control of the radiation source control unit 122. In addition to adjusting the aperture size of the irradiation aperture 164 based on operation instructions from the operation panel 156, the radiation source control unit 122 can also adjust the aperture size of the irradiation aperture 164 at preset timing.

Furthermore, the radiation source control unit 122 can control the X-ray irradiation mode. As shown in FIG. 6, the irradiation unit 113 can adopt at least three irradiation modes: "moving image mode," "continuous shooting mode," and "still image mode." The moving image mode is, for example, an irradiation mode in which X-rays are continuously irradiated with a constant irradiation amount per unit time. In the moving image mode, for example, irradiation continues while the irradiation switch 168 is operated. Further, in the video mode, when the irradiation switch 168 is operated once, irradiation may be continued for a preset time. The continuous shooting mode is a mode in which, for example, when the irradiation switch 168 is operated once, pulse irradiation for a plurality of images is performed, and is used when a plurality of still images are continuously taken. The still image mode is an irradiation mode in which one image is irradiated when the irradiation switch 168 is operated once. The amount of X-ray irradiation per unit time is variable depending on the settings. For example, the amount of irradiation per unit time in a moving image mode in which continuous irradiation is performed can be lower than that in a still image mode.

Further, the moving image mode can be used when adjusting the relative positions of the radiation source 112 and the electronic cassette 104. In this case, for example, preliminary photography is performed with a lower dose per unit time in video mode than in actual photography. The operator OP can adjust the irradiation direction of the irradiation unit 113 and the positions and postures of the electronic cassette 104 and the subject H while checking the image on the display 166. It is possible to reduce the amount of radiation to which the subject H is exposed by lowering the amount of radiation for pre-photography. As described above, the radiation imaging apparatus 102 has a plurality of irradiation modes, so that imaging can be performed according to the purpose.

Returning to FIG. 4, the operation panel 156 is provided with a display section 160 that displays set irradiation conditions, status information, etc., and various operation buttons 162. The operation buttons 162 include, in addition to buttons used for inputting irradiation conditions, operation buttons operated when adjusting the aperture size of the irradiation aperture 164, and restriction release buttons operated when displacing the irradiation section 113. be. The radiation source 112 is provided with a first rotation restriction section 204 and a second rotation restriction section 206 (see FIG. 15), which are brakes for preventing the irradiation section 113 from moving inadvertently. In the initial state, the rotation of the irradiation unit 113 is restricted, and by operating the restriction release button, the rotation restriction is canceled. The operator OP displaces the irradiation unit 113 while operating the restriction release button.

The operation panel 156 is provided with a display section 160 in addition to operation buttons 162. The display unit 160 displays set information such as irradiation conditions and the current irradiation mode. Further, the display unit 160 is, for example, a touch panel display, and the operator OP can also perform various settings through a setting screen displayed on the display unit 160. Operation information input through the operation buttons 162 and the display unit 160 is input to the radiation source control unit 122. The operation panel 156 is attached to one surface of the irradiation section 113.

An operation handle 170 is attached to the operation panel 156. The operation handle 170 of this example has a shape in which a pipe-shaped member is bent so as to surround both side surfaces and the top surface of the operation panel 156. The operator OP can direct the irradiation unit 113 in a desired direction by grasping and operating the operating handle 170. Of course, it is also possible to direct the irradiation unit 113 in a desired direction by directly operating the irradiation unit 113 or the like without using the operation handle 170.

The radiation source 112 includes a mounting section 130, a first rotating section 116, and a second rotating section 118 as a configuration for displacing the irradiating section 113.

The attachment part 130 is a member for attaching the radiation source 112 to the support column 114. The attachment part 130 is attached to the lower part of the column 114 so as to be rotatable about the column center line JR in the direction of arrow Z. The mounting portion 130 has a rotary seat portion 132 whose normal is the column center line JR, and an upright portion 134 rising from the rotary seat portion 132 at right angles. The rotating seat portion 132 is provided with a rotating shaft 136 . By attaching the rotating shaft 136 to the column 114, the attachment portion 130 rotates with respect to the column 114 (hereinafter referred to as "rotation around the column") about the column center line JR.

A first rotating shaft 142 is provided in the upright portion 134 . The first rotating portion 116 is attached to the first rotating shaft 142 . By being attached to the first rotating shaft 142, the first rotating part 116 can rotate about the first center line J1 (hereinafter referred to as "first rotation"). The first center line J1 is a straight line passing through the focal point F (see FIG. 6, etc.). Furthermore, the attachment portion 130 is provided with a first rotation restriction portion 204 (see FIG. 15) that restricts rotation of the first rotation portion 116 with respect to the attachment portion 130.

The first rotating part 116 has an arm part 138 extending parallel to the upright part 134 and an extending part 116A extending from the tip side of the arm part 138 at right angles to the arm part 138. . A clamping portion 140 is provided on the extending portion 116A. The clamping part 140 has an outer clamping plate 140A and an inner clamping plate 140B, and an arcuate gap is formed between the inner clamping plate 140B and the outer clamping plate 140A. A part of the second rotating part 118 is inserted into the arc-shaped gap. The holding part 140 holds the second rotating part 118 by holding a part of the second rotating part 118 inserted into the arc-shaped gap.

The second rotating portion 118 has an arcuate portion 143 having an arcuate outer peripheral surface. In the second rotating part 118 , the arcuate part 143 is inserted into the arcuate gap of the clamping part 140 and is clamped by the clamping part 140 . When the circular arc portion 143 is inserted into the arc-shaped gap of the clamping portion 140, the clamping outer plate 140A and the clamping inner plate 140B face the upper and lower surfaces of the circular arc portion 143 in FIG. 4, respectively. Each facing surface serves as a guide surface 150 that slides into contact with the arcuate portion 143. The holding part 140 of the first rotating part 116 holds the arcuate part 143 slidably along the guide surface 150. The guide surface 150 and the radius of curvature of the upper and lower surfaces of the arc portion 143 are the same, and the center of the arc is the second center line J2 as described later (see FIGS. 11, 12, etc.). That is, the second rotating part 118 is slidably held by the holding part 140 of the first rotating part 116, so that the second rotating part 118 rotates (hereinafter referred to as (referred to as "second rotation"). The guide surface 150 is an example of an arc-shaped guide surface that becomes a part of the rotation locus of the second rotation.

In this example, the second centerline J2 is parallel to the first centerline J1 (see FIG. 8). However, the second center line J2 does not pass through the focal point F, and as shown in FIG. and see also Figure 13). Furthermore, in this example, the second center line J2 intersects with the optical axis OA of the X-rays. More specifically, in this example, the second center line J2 is orthogonal to the optical axis OA. When the irradiation aperture 164 and the detection surface 104A face each other directly, the second center line J2 also intersects the perpendicular line NL. Further, the optical axis OA is a straight line with the focal point F as the base point. Since the first center line J1 passes through the focal point F, the fact that the second center line J2 intersects the optical axis OA means that the rotation center of the first rotation and the rotation center of the second rotation are both on the optical axis OA. means that it is located in

Here, with the focal point F as a reference, the direction of X-ray irradiation is the front, and the opposite direction is the back. In FIGS. 8 and 11, the downward direction is the front. In this example, the guide surface 150 is located behind the focal point F. Therefore, the arcuate portion 143 of the second rotating portion 118 that comes into sliding contact with the guide surface 150 is also located behind the focal point F.

Further, as shown in FIG. 4, a guide groove 146 is formed in the arc portion 143, and a guide pin 148 that fits into the guide groove 146 is formed in the sandwiching outer plate 140A. The fitting between the guide pin 148 and the guide groove 146 prevents the second rotating part 118 from falling off from the holding part 140. Furthermore, a bearing 145 is provided inside the holding part 140. The bearing 145 allows the second rotating part 118 to slide smoothly with respect to the holding part 140. Furthermore, the holding part 140 is provided with a second rotation regulating part 206 (see FIG. 15) that restricts rotation of the second rotating part 118 with respect to the holding part 140.

The second rotating portion 118 has an arcuate portion 143 and a pair of holding plate portions 144 extending from both ends of the arcuate portion 143 . The pair of holding plate sections 144 are arranged at positions that sandwich the irradiation section 113 from both side surfaces. The second rotating section 118 has a generally U-shape as a whole, and is arranged so as to surround the upper surface and both side surfaces of the irradiating section 113 in FIG. 4 .

Each of the pair of holding plate parts 144 is provided with a third rotation shaft 152 on a surface facing the side surface of the irradiation part 113. The third rotating shaft 152 fits into a fitting hole 113A formed on the side surface of the irradiation section 113. Through this fitting, the irradiation section 113 is rotatably attached to the second rotation section 118 about the third center line J3 passing through the center of the third rotation shaft 152. The third center line J3 is perpendicular to the first center line J1. In this example, the third center line J3 passes through the focal point F like the first center line J1, but the third center line J3 does not necessarily have to pass through the focal point F. The holding plate section 144 is an example of a holding section.

With the above configuration, the irradiation section 113 is displaced as shown in FIGS. 7 to 13. First, as shown in FIG. 7, the mounting portion 130 rotates around the support center line JR of the support support 114, thereby allowing the irradiation unit 113 to rotate around the support support. Moreover, as shown in FIG. 8, the irradiation part 113 is rotatable with respect to the second rotation part 118 about the third center line J3.

As shown in FIG. 9, when the first rotation section 116 makes a first rotation about the first center line J1, the irradiation section 113 can also make a first rotation. In the example shown in FIG. 9, the first rotation is shown, with the clockwise direction being the positive direction and the counterclockwise direction being the negative direction. As described above, the first center line J1 is a straight line passing through the focal point F, which will be described later. By first rotating the irradiation unit 113, the irradiation direction of the radiation from the irradiation unit 113 can be rotated around the focal point F.

Further, by this first rotation, for example, as shown in FIG. It can be directed toward the detection surface 104A of the cassette 104.

Furthermore, as shown in FIGS. 11 to 13, the second rotating section 118 is capable of a second rotation about the second center line J2 relative to the first rotating section 116. Therefore, by rotating the second rotation unit 118 for a second time, the irradiation unit 113 can be rotated for a second time about the second center line J2.

FIG. 11 shows a state in which the irradiation unit 113 is in a neutral position between the first rotation and the second rotation. The state shown in FIG. 11 is taken as the reference position of the irradiation unit 113. Further, FIG. 11 shows a state in which the irradiation section 113 and the detection surface 104A of the electronic cassette 104 are directly opposed, similarly to FIG. 8.

As shown in FIGS. 12 and 13, the second rotating section 118 can perform a second rotation about the second center line J2 with respect to the first rotating section 116, so the irradiating section 113 also A second rotation about centerline J2 is possible. With respect to the reference position shown in FIGS. 11 and 13, the irradiation unit 113 can make a second rotation in the positive direction and the negative direction.

To summarize the above, in addition to the first rotation about the first center line J1 passing through the focal point F, the irradiation unit 113 rotates the second center line J2, which is located closer to the electronic cassette 104 than the first center line J1. A second rotation about the center is possible. In this example, the second center line J2 is parallel to the first center line J1, and both the first center line J1 and the second center line J2 are orthogonal to the optical axis OA. Therefore, for example, it is possible to finely adjust the irradiation direction of the irradiation unit 113 by performing two rotations, the first rotation and the second rotation, with respect to the position and orientation of the detection surface 104A of the electronic cassette 104.

Next, the operation of the radiation imaging apparatus 102 of the first embodiment will be explained with reference to the flowchart shown in FIG.

When performing radiography, the operator OP performs positioning to adjust the relative positional relationship of the radiation source 112, electronic cassette 104, and subject H. In positioning, when performing radiography using the supine imaging table 106 as shown in FIG. Match. In the example of FIG. 1, the electronic cassette 104 is placed on the supine imaging platform 106, so the operator OP positions the detection surface 104A of the electronic cassette 104 on the supine imaging platform 106 at the imaging site of the subject H. match.

Thereafter, as positioning of the radiation source 112, the operator OP adjusts the irradiation direction of the irradiation unit 113. The irradiation unit 113 is capable of a first rotation about a first center line J1 passing through the focal point F and a second rotation about a second center line J2 that is closer to the electronic cassette 104 than the first center line J1. be. Moreover, the first center line J1 and the second center line J2 are perpendicular to the optical axis OA, and the rotation centers of the first rotation and the second rotation are located on the optical axis OA.

Considering the subject H located on the electronic cassette 104 side as a reference, the first center line J1 is farther from the subject H than the second center line J2. Therefore, the amount of change in the irradiation field LF for the subject H per unit rotation angle due to the first rotation is larger than the amount of change in the irradiation field LF for the subject H per unit rotation angle due to the second rotation. In this example, the second center line J2 is near the detection surface 104A and almost coincides with the position of the subject H, so even if the irradiation unit 113 is rotated for the second time, the position of the irradiation field LF with respect to the subject H is remains almost unchanged. Therefore, by rotating the irradiation unit 113 for a second time, it is possible to adjust the incident angle of the X-rays with respect to the subject H while aligning the position of the irradiation field LF with the subject H.

Therefore, as shown in the flowchart of FIG. 14, the operator OP can adjust the irradiation direction of the irradiation unit 113 in two stages: coarse adjustment in step S102 and fine adjustment in step S106. The coarse adjustment in step S102 is adjustment of the irradiation direction of the irradiation unit 113 by first rotation. The operator OP aligns the irradiation field LF of the irradiation unit 113 with the subject H through this rough adjustment. The fine adjustment in step S106 is adjustment of the irradiation direction of the irradiation unit 113 by second rotation. Through this fine adjustment, the operator OP adjusts the incident angle of the X-rays with respect to the subject H while aligning the irradiation field LF of the irradiation unit 113 with the subject H. Adjusting the incident angle of X-rays is very effective, for example, when it is desired to slightly change the viewpoint when photographing the knee joint of the subject H. Photography in which the incident angle of X-rays is oblique to the subject H is called oblique photography. Fine adjustment by the second rotation is very effective in oblique photography.

In the fine adjustment in step S106, since a slight change in viewpoint becomes a problem, it is very easy for the operator OP to perform the fine adjustment if he or she can confirm the image. Therefore, before performing the fine adjustment in step S106, it is preferable to cause the irradiation unit 113 to start pre-imaging as shown in step S104, and to perform the fine adjustment in step S106 while performing the pre-imaging. Pre-imaging is performed by causing the irradiation unit 113 to execute a moving image mode with a low amount of X-ray irradiation per unit time. Thereby, the operator OP can perform the fine adjustment in step S106 while checking the image through the display 166. After the irradiation direction of the irradiation unit 113 has been adjusted in this way, the main photographing in step S108 is performed.

As explained above, in the radiation imaging apparatus 102 of the first embodiment, the irradiation unit 113 can perform the first rotation and the second rotation. The first rotation is a rotation about the first center line J1 passing through the focal point, and the second rotation is a rotation about the electronic cassette 104 (radiation This is rotation around a second center line J2 located on the side of the image detector (an example). In this way, since the second rotation is possible in addition to the first rotation, it is easier to finely adjust the X-ray irradiation direction in the radiographic apparatus 102, compared to a configuration in which the second rotation is not possible.

In this example, since the first center line J1 and the second center line J2 are parallel, compared to the case where they are not parallel, the coarse adjustment of the irradiation direction by the first rotation is compared to the fine adjustment of the irradiation direction by the second rotation. Easy to do.

Also, like the first center line J1, the second center line J2 intersects the optical axis OA, so the second rotation changes the direction of radiation irradiation to the subject H compared to the case where the second center line J2 does not intersect with the optical axis OA. When making fine adjustments, the amount of deviation of the radiation irradiation range from the subject is small.

The radiation imaging apparatus 102 of the first embodiment includes an irradiation field limiter 154 having an irradiation aperture 164, as shown in FIG. The radiation source control unit 122 is capable of controlling one or both of irradiation control of the radiation source 112 and control of the irradiation aperture 164. The radiation source 112 is easy to use because the radiation source control unit 122 performs irradiation control and controls the irradiation aperture 164.

Further, the first rotating section 116 includes an arc-shaped guide surface 150 that becomes a part of the rotation locus of the second rotation, and the second rotating section 118 is slidably attached to the first rotating section 118 along the guide surface 150. 116. Since the second rotation is achieved by the arcuate guide surface 150, there is no need to provide a physical rotation axis at the second center line J2. Therefore, the device configuration of the radiation source 112 can be downsized.

Furthermore, the radiographic apparatus 102 of the first embodiment includes a holding plate part 144 as an example of a holding part that is provided in the second rotating part 118 and holds the irradiation part 113. The holding plate part 144 holds the irradiation part 113 so as to be able to perform a third rotation about a third center line J3 perpendicular to the first center line J1. Since the irradiation unit 113 can perform a third rotation in addition to the first rotation and the second rotation, the radiation imaging apparatus 102 has a high degree of freedom in adjusting the irradiation direction.

[Second embodiment]
Next, a second embodiment will be described. In the second embodiment, the same elements, members, etc. as in the first embodiment are given the same reference numerals as in the first embodiment, and detailed description thereof will be omitted. Further, since the overall configuration of the radiographic apparatus in the second embodiment is the same as that of the radiographic apparatus 102 in the first embodiment, illustration thereof is omitted.

As shown in FIG. 15, the first rotation shaft 142 of the attachment portion 130 is provided with a first rotation restriction portion 204. The first rotation regulating portion 204 has the function of providing resistance to the first rotation and regulating the first rotation. Specifically, the first rotation regulating section 204 moves a circular friction plate coaxially arranged on the first rotation shaft 142 in the axial direction and presses it against the pad, thereby creating frictional resistance against the first rotation. This is an electromagnetic brake applied. The first rotation regulating section 204 is controlled by the radiation source control section 122. The state in which the first rotation is restricted will hereinafter be referred to as a "first rotation restriction state." The first rotation restriction section 204 is in a first rotation restriction state when it is not energized, and is released from the first rotation restriction state when it is energized.

Furthermore, the clamping section 140 of the first rotating section 116 is provided with a second rotation regulating section 206 . The second rotation regulating portion 206 has the function of providing resistance to the second rotation and regulating the second rotation. Specifically, the second rotation regulating section 206 is an electromagnetic brake that applies frictional resistance to the second rotation by pressing a friction pad provided in the clamping section 140 against the circular arc section 143 of the second rotating section 118. It is. The second rotation regulating section 206 is controlled by the radiation source control section 122. The state in which the second rotation is restricted will hereinafter be referred to as a "second rotation restriction state." Similarly to the first rotation regulating section 204, the second rotation regulating section 206 is also in a second rotation regulating state when not energized, and is released from the second rotation regulating state when energized.

The operator OP can use the operation panel 156 to select either the first rotation restriction state or the second rotation restriction state. Since the first rotation regulation state and the second rotation regulation state are controlled by the radiation source control unit 122, the operator OP can easily regulate the rotation of the first rotation and the second rotation.

Moreover, in the second embodiment, as shown in FIG. 16, the radiation source control unit 122 can control and interlock the first rotation restriction state and the second rotation restriction state. That is, when the first rotation restriction state is selected, the radiation source control unit 122 turns off the first rotation restriction unit 204 (allows the first rotation) and turns on the second rotation restriction unit 206 (restricts the second rotation). ). Further, when the second rotation restriction state is selected, the radiation source control unit 122 turns on the first rotation restriction unit 204 (regulates the first rotation) and turns off the second rotation restriction unit 206 (allows the second rotation). ).

By interlocking the first rotation restriction state and the second rotation restriction state in this manner, when one of the first rotation and the second rotation is performed, the other is restricted. Therefore, when one of the first rotation and the second rotation is performed, the other rotation is not performed carelessly, resulting in good operability.

Furthermore, in the second embodiment, it is possible to control the irradiation aperture shown in FIG. 17 as an example. The control of the irradiation aperture shown in FIG. 17 is a control that automatically adjusts the aperture size of the irradiation aperture 164 of the irradiation field limiter 154 according to the regulation state of the second rotation and the irradiation state of the irradiation section 113.

In FIG. 17, in step S202, the radiation source control unit 122 determines whether the second rotation is permitted based on input information from the operation panel 156. If this determination is negative (N in step S202), this determination is continued in step S202.

If it is determined in step S202 that the second rotation is permitted (Y in step S202), the radiation source control unit 122 determines in step S204 whether or not there has been an instruction to start pre-imaging to the irradiation unit 113. judge. Determination as to whether the second rotation is permitted or not and whether an instruction to start pre-photography has been given is made based on, for example, an operation signal from the operation panel 156 and an operation signal from the irradiation switch 168.

If the determination in step S204 is negative (N in step S204), this determination is continued in step S204.

If it is determined in step S204 that there is an instruction to start pre-imaging (Y in step S204), the radiation source control unit 122 proceeds to step S206, and in step S206, the radiation source control unit 122 narrows down the irradiation aperture 164 of the irradiation field limiter 154. Even when the rotation angle of the second rotation is the maximum, control is executed to prevent the irradiation field LF from protruding from the image detection area VF, as will be described later.

Then, in step S210, the radiation source control unit 122 determines whether or not there is an instruction to end pre-imaging. If the determination in step S210 is affirmative (Y in step S210), the radiation source control unit 122 ends the control of the irradiation aperture, and if the determination in step S210 is negative (N in step S210), the process returns to step S202 and the irradiation aperture is Continue to control.

In other words, the control shown in FIG. 17 is such that when the radiation source control unit 122 can acquire a signal indicating whether or not the second rotation is permitted, the radiation source control unit 122 controls the is a control for narrowing down the aperture size of the irradiation aperture 164. By controlling the irradiation aperture in this manner, the following effects can be obtained.

FIG. 18 shows the relationship between the image detection area VF in the electronic cassette 104 and the X-ray irradiation field LF, depending on the size of the irradiation aperture 164. The example in FIG. 18 is an example based on the positional relationship between the irradiation unit 113 and the electronic cassette 104 shown in FIG. 5. That is, in FIG. 5, the irradiation aperture 164 and the detection surface 104 are directly opposite each other, and the perpendicular line NL passes through the focal point F. The example shown in FIG. 18 is the positional relationship between the image detection area VF and the irradiation field LF in this state. When the irradiation aperture 164 indicated by <irradiation aperture: large> in FIG. 18 is relatively large, it will be hereinafter referred to as a case where the aperture size is large. Further, in FIG. 18, when the irradiation aperture 164 indicated by <irradiation aperture: small> is relatively small, it will be hereinafter referred to as a case where the aperture size is small. In FIG. 18, the irradiation field LF before the second rotation is distinguished as the irradiation field LF1, and the irradiation field LF after the second rotation is distinguished as the irradiation field LF2 in cases where the aperture size is large and when the aperture size is small. . Naturally, the irradiation field LF when the aperture size is large is wider than the irradiation field LF when the aperture size is small. In the example shown in FIG. 18, the irradiation field LF1 before the second rotation when the aperture size is large generally coincides with the image detection area VF. Here, the image detection area VF is an effective pixel area in the electronic cassette 104 in which pixels contributing to generation of a radiation image are arranged.

As shown in FIG. 14, fine adjustment of the irradiation direction by second rotation may be performed while performing preliminary imaging. As described in the first embodiment, if the second center line J2, which is the rotation center of the second rotation, is close to the subject H, the amount by which the position of the irradiation field LF is shifted by the second rotation is small; Misalignment of LF occurs. Moreover, if the second center line J2 is closer to the first center line J1 and is further away from the subject H, or if the rotation angle of the second rotation is large, the second rotation will position the irradiation field LF. The amount of deviation becomes larger.

As shown in FIG. 18, when the second rotation is performed when the aperture size of the irradiation aperture 164 is large, the irradiation field LF tends to protrude from the image detection area VF compared to when the aperture size is small. In FIG. 18, symbol TF indicates an area where the irradiation field LF protrudes from the image detection area VF.

In the standards for radiographic apparatuses, there is, in principle, a provision that requires the amount of protrusion of the irradiation field LF from the image detection area VF to be less than or equal to a predetermined value. Therefore, even when performing the second rotation while performing pre-photography, it is necessary to conform to the above standards. Therefore, as shown in FIG. 17, the radiation source control unit 122 executes control to adjust the aperture size of the irradiation aperture 164 when pre-imaging is performed when the second rotation is permitted. In this control, the adjusted aperture size is adjusted to the following size. That is, as shown in FIG. 5, it is assumed that the irradiation aperture 164 and the detection surface 104A of the electronic cassette 104 directly face each other, and that the perpendicular line NL drawn from the focal point F to the detection surface 104A passes through the center of the detection surface 104A. In this case, even when the rotation angle of the second rotation is the maximum, the amount of protrusion of the irradiation field LF from the image detection area VF of the electronic cassette 104 is such that it is equal to or less than a predetermined value. In this way, the radiation source control unit 122 sets the irradiation aperture to a size such that the amount of protrusion of the irradiation field LF from the image detection area VF is equal to or less than a predetermined value even when the rotation angle of the second rotation is the maximum. Narrow down to 164. As a result, compared to the case where preliminary imaging is performed with a large aperture size, it is possible to suppress the protrusion of the irradiation field LF from the image detection area VF, and to suppress the protrusion amount from exceeding a predetermined value. can do.

In the second embodiment, the control for interlocking the first rotation restriction and the second rotation restriction shown in FIG. 16 and the control of the aperture size of the irradiation aperture shown in FIGS. 17 and 18 are performed separately. Good too.

[Third embodiment]
Next, a third embodiment will be described. In the third embodiment, the same elements, members, etc. as in the first embodiment are given the same reference numerals as in the first embodiment, and detailed description thereof will be omitted. Further, since the overall configuration of the X-ray irradiation device in the third embodiment is the same as that of the radiation imaging device 102 in the first embodiment, illustration thereof is omitted.

The radiation imaging apparatus 102 of the third embodiment includes a support rotation angle sensor 304, a first rotation angle sensor 306, a second rotation angle sensor 308, and a third rotation angle sensor 310, as shown in FIG.

The column rotation angle sensor 304 is provided on the rotation shaft 136 (see FIG. 4), and an index value of the rotation angle around the column is sent to the radiation source control unit 122. The first rotation angle sensor 306 is provided on the first rotation shaft 142, and an index value of the first rotation angle is sent to the radiation source control unit 122. The second rotation angle sensor 308 is provided in the clamping part 140 of the first rotation part 116, and the index value of the second rotation angle is sent to the radiation source control part 122. The third rotation angle sensor 310 is provided on the third rotation shaft 152, and an index value of the third rotation angle is sent to the radiation source control unit 122. The radiation source control unit 122 can obtain information about the attitude of the irradiation unit 113 from these rotation angles.

As the support angle sensor 304, the first rotation angle sensor 306, the second rotation angle sensor 308, and the third rotation angle sensor 310, for example, a potentiometer, a variable resistor, a rotary encoder, or an acceleration sensor may be used alone, or They can be used in appropriate combinations.

Furthermore, the third embodiment includes a ranging sensor 314 that detects the SID. The detected SID value is sent to the radiation source control unit 122. The SID may be input by the operator OP from the operation panel 156.

As shown in FIG. 20, the supine imaging platform 106 is equipped with a cassette sensor 312. The cassette sensor 312 is a sensor that detects whether or not the electronic cassette 104 is present in the storage section 108. The cassette sensor 312 is composed of a photosensor, a microswitch, or the like. Further, the cassette sensor 312 detects the cassette size when the electronic cassette 104 is present. Information on the cassette size is sent to the radiation source control section 122. Note that the information on the cassette size may be input by the operator OP from the operation panel 156.

The radiation source control unit 122 controls the index values of the first rotation angle of the first rotation, the second rotation angle of the second rotation, and the third rotation angle of the third rotation of the irradiation unit 113, the SID, and the aperture of the irradiation aperture 164. Based on the size, the position of the X-ray irradiation field LF with respect to the image detection area VF is derived. Thereby, the radiation source control unit 122 can grasp the positional relationship between the irradiation field LF and the detection surface 104A of the electronic cassette 104 (more specifically, the image detection area VF) as shown in FIG. 21 as an example. .

By grasping such a positional relationship, the radiation source control unit 122 can execute a process of suppressing the extension of the irradiation field LF when performing preliminary imaging, as shown in FIG. 22.

In the protrusion suppression process, in step S302, the radiation source control unit 122 acquires the SID, cassette size, and cassette position. Next, in step S304, the radiation source control unit 122 acquires the attitude of the irradiation unit 113 and the aperture size of the irradiation field limiter 154. The radiation source control unit 122 derives the position of the X-ray irradiation field LF with respect to the image detection area VF of the electronic cassette 104 based on this information.

Then, in step S306, the radiation source control unit 122 starts pre-imaging based on the operation instruction from the operator OP. As described above, the operator OP can easily adjust the X-ray irradiation direction by visually confirming the image obtained by pre-imaging.

Next, in step S308, the radiation source control unit 122 determines that the amount of protrusion of the X-ray irradiation field LF from the image detection area VF of the detection surface 104A is a predetermined value based on the derived position of the irradiation field LF. Determine whether there is a risk of exceeding the limit.

If the determination in step S308 is negative (N in step S308), the determination in step S310 is continued while pre-photography is performed.

On the other hand, if the determination in step S308 is affirmative (Y in step S308), the radiation source control unit 122 prohibits the radiation source 112 from irradiating X-rays in step S310. Thereby, it is possible to suppress the irradiation field LF from protruding from the image detection area VF.

The radiation source control unit 122 continues this protrusion suppression process until the pre-imaging is completed. When the fear that the amount of protrusion of the irradiation field LF exceeds a predetermined value is eliminated by changing the posture of the irradiation unit 113 by the operator OP, the radiation source control unit 122 cancels the irradiation prohibition, and Pre-photography may be restarted.

In the radiation imaging apparatus of the third embodiment, when pre-imaging is performed, by performing the protrusion suppression process of the irradiation field LF, the amount of protrusion of the X-ray irradiation field LF from the image detection area VF is set in advance. Exceeding the numerical value can be suppressed.

In the radiation imaging apparatus of the third embodiment, the radiation source control unit 122 can also execute the moving image mode restriction process shown in FIG. 23.

In the video mode restriction process, in step S402, it is determined whether or not there is an electronic cassette 104 in the storage unit 108 based on information acquired from the cassette sensor 312. If the determination in step S402 is affirmative (Y in step S402), the video mode restriction process is not executed.

If the determination in step S402 is negative (N in step S402), the radiation source control unit 122 prohibits the moving image mode in step S404. Thereby, when the electronic cassette 104 is not present in the housing section 108, continuous irradiation of X-rays in the moving image mode can be suppressed.

If the electronic cassette 104 is not present in the storage unit 108, there is a high possibility that free photography will be performed in which the electronic cassette 104 is placed at an arbitrary position and photography is performed. In such a case, if a video mode in which X-rays are continuously irradiated is executed, there is a high possibility of unnecessary radiation exposure, so the video shooting mode is prohibited. On the other hand, when the electronic cassette 104 is present in the housing section 108, the position of the electronic cassette 104 is fixed, so even if the video mode is allowed, there is a low possibility of unnecessary exposure.

The video mode restriction process in FIG. 23 and the protrusion suppression process in FIG. 22 may be combined. In this case, for example, when the video mode is allowed in FIG. 23, the protrusion suppression process shown in FIG. 21 is executed.

[Fourth embodiment]
Next, a fourth embodiment will be described. In the fourth embodiment, elements, members, etc. that are similar to those in the first embodiment are given the same reference numerals as in the first embodiment, and detailed description thereof will be omitted. Further, since the overall configuration of the X-ray irradiation device in the fourth embodiment is the same as that of the radiation imaging device 102 in the first embodiment, illustration thereof is omitted.

As shown in FIGS. 24A and 24B, in the radiation imaging apparatus 402 of the fourth embodiment, the configurations of the first rotating section and the second rotating section are different from those of the first embodiment. The main difference, in the radiation imaging apparatus 402 of the fourth embodiment, is the position of the arcuate guide surface that enables the second rotation. In the radiation imaging apparatus 102 of the first embodiment, the arc-shaped guide surface 150 is arranged behind the irradiation section 113, and when the direction in which the first center line J1 extends is taken as the depth direction, the arc-shaped guide surface 150 is and the guide surface overlap in the depth direction. On the other hand, in the radiation imaging apparatus 402 of the fourth embodiment, the irradiation section 113 and the guide surface 150 do not overlap in the depth direction but are arranged side by side.

Specifically, as shown in FIGS. 25A and 25B, the first rotating section 404 of the radiation imaging apparatus 402 of the fourth embodiment includes an arm section 408 and an arc section 410.

Like the arm portion 138 of the first embodiment, the arm portion 408 is parallel to the upright portion 134 of the mounting portion 130 and is attached to the upright portion 134 by a first rotation shaft 142 so as to be able to rotate in a first manner.

The arc portion 410, like the arc portion 143 of the first embodiment, has a guide surface 150 that is curved in an arc shape about the second center line J2. The guide surfaces 150 are formed on the upper and lower surfaces of the arc portion 410, as shown in FIG. 25B.

The second rotating section 406 of the fourth embodiment includes a clamping section 412 and a holding plate section 414. The clamping part 412 has a clamping outer plate 414A and a clamping inner plate 414B that clamp the circular arc part 410 in the thickness direction. That is, in the fourth embodiment, the holding part 412 is provided in the second rotating part 406, and this holding part 412 holds the arcuate part 410 of the first rotating part 404, so that the second center line J2 is The structure is such that the second rotating part 406 is attached to the first rotating part 404 so as to be rotatable about the center.

The holding plate portion 414 of the second rotating portion 406 is a pair of plate-shaped members extending in parallel from the sandwiching outer plate 414A. Between the holding plate parts 414, the irradiation part 113 is attached so as to be rotatable about the third rotation shaft 152.

As shown in FIG. 25A, in the fourth embodiment, when the first rotating section 404 and the second rotating section 406 are at the reference position, the irradiating section 113 and the guide surface 150 are arranged at the depth that the first center line J1 extends. spaced apart in the direction. Therefore, compared to the case where the guide surface 150 is arranged behind the focal point F as in the first embodiment, when the radius of rotation of the second rotation is the same, the radius of curvature R1 of the guide surface 150 is made smaller. be able to. Therefore, the length of the arc of the guide surface 150 can also be shortened.

In the first embodiment, as shown in FIG. 6, the guide surface 150 is arranged behind the focal point F (above in FIG. 6), so the guide surface 150 and the irradiation section 113 can be overlapped in the depth direction. I can do it. Therefore, compared to the case where the guide surfaces 150 are arranged side by side in the depth direction as in the fourth embodiment, the size of the radiation imaging apparatus 102 in the depth direction can be made smaller. In this way, both the first embodiment and the fourth embodiment have their own merits.

[Preferred parameters]
In the following, preferred ranges of parameters such as the rotation radius R2 of the second rotation and the range of the rotation angle of the second rotation will be explained.

In the case of shooting with a frequently used SID of about 1,000 mm, the rotation radius R2 of the second rotation is in the range of 400 mm to 1,000 mm, and the rotatable rotation angle range A of the second rotation is , is preferably in the range of 0° or more and 15° or less with respect to the reference position in both the positive direction and the negative direction with respect to the reference position (see FIGS. 11 and 12). The reason is as follows.

As shown in FIG. 26, the second center line J2, that is, the rotation center O2 of the second rotation is located on the detection surface 104A of the electronic cassette 104, and the radius of rotation R2 of the second rotation coincides with SID. is ideal. This is because, in this case, as shown in FIG. 27, the second rotation is performed with the rotation center O2 on the detection surface 104A as the base point, so that the X-rays on the detection surface 104A of the electronic cassette 104 during the second rotation This is because the amount of positional deviation of the irradiation field LF is minimized. As described above, there is a standard that the irradiation field LF of the X-rays irradiated from the irradiation unit 113 must not deviate significantly from the X-ray image detection area VF (see FIG. 18). When the amount of positional deviation of the X-ray irradiation field LF during the second rotation is small, the range of the rotation angle of the second rotation can be made larger than when the amount of positional deviation is large.

However, as the rotation radius R2 increases, the length of the arc of the guide surface 150 (see FIGS. 4 and 25B) for ensuring the maximum rotation angle becomes longer. Therefore, when considering miniaturization of the device, it is preferable that the rotation radius R2 does not exceed 1,000 mm.

When the SID is assumed to be about 1,000 mm, it is also possible to make the rotation radius R2 shorter than 1,000 mm.

In this case, for example, as shown in FIG. 28, the rotation center O2 of the second rotation is shifted from the detection surface 104A of the electronic cassette 104 to the focal point F side in the optical axis OA direction. In this way, as the shift amount of the rotation center O2 from the detection surface 104A becomes larger, as shown in FIG. . Therefore, when the amount of positional deviation Z1 of the X-ray irradiation field LF is large, for example, as shown in FIG. It becomes necessary to narrow down the irradiation field LF. This is the content explained in FIG. 17 as control to narrow down the aperture size of the irradiation aperture 164 during preliminary imaging.

However, if the irradiation field LF is made smaller during preliminary imaging, the confirmation image becomes smaller, making confirmation difficult. Therefore, it is preferable that the lower limit of the rotation radius R2 is 400 mm. For example, the example shown in FIGS. 31 and 32 has an SID of 1000 mm and a rotation radius R2 of 900 mm, and is an example of a preferable embodiment. The radius of rotation R2 is preferably set appropriately in the range of 400 mm to 1,000 mm, taking into consideration the length of the arc of the guide surface 150, the amount of positional deviation of the irradiation field LF, and the like.

Moreover, the wider the range A of the rotation angle of the second rotation, the wider the adjustment range, which is preferable, but if it is too wide, the device such as the arc-shaped guide surface 150 will become larger. Therefore, the rotatable rotation angle range A of the second rotation is preferably in the range of 0° or more and 15° or less in both the positive direction and the negative direction with respect to the reference position (see FIGS. 11 and 12). . In FIGS. 27, 29, and 30, the case where the rotation angle range A is 15 degrees in the counterclockwise direction (negative direction) is illustrated.

From the above, when shooting with an SID of about 1,000 mm, which is considered to be frequently used, it is preferable to set the rotation radius R2 and rotation angle range A to the above ranges. Thereby, when adjusting the irradiation direction of X-rays while performing pre-imaging, it is possible to downsize the apparatus without sacrificing ease of image confirmation.

FIGS. 33A and 33B are examples of a method for calculating the amount of protrusion when the irradiation field LF protrudes from the detection surface 104A due to the second rotation. In the example shown in FIG. 33A, SID is 1000 mm, rotation radius R2 is 1000 mm, and rotation angle range A is 15 degrees. Further, the panel size b, which is the size of the image detection area VF, is 431.8 mm, and the irradiation angle c is 77.8 degrees. The value of 431.8 mm is based on the assumption that the 17-inch electronic cassette 104 is used frequently. In FIGS. 33A and 33B, it is assumed that the panel size b and the size of the detection surface 104A are the same. Further, the irradiation angle c is the angle that the outermost line EL of the X-ray flux forms with the detection surface 104A. In addition, in FIGS. 33A and 33B, the detection surface 104A is rotated instead of rotating the position of the focal point F, but the rotation between the focal point F and the detection surface 104A is relative, and in reality, the second rotation The same relationship holds true when the focal point F of the irradiation unit 113 is rotated a second time around the rotation center O2. In FIGS. 33A and 33B, the detection surface 104A before the second rotation, which is the reference position, is shown by a solid line, and the detection surface 104A in a state where the second rotation angle is 15 degrees is shown by a two-dot chain line, respectively.

As shown in FIG. 33B, a perpendicular line drawn from the end 104AE of the detection surface 104A at the reference position to the detection surface 104A at a rotation angle of 15° is an auxiliary line L1, and this auxiliary line L1 is centered around the end 104AE. The line obtained when the rotation angle is rotated by 7.5 degrees, which is half of the rotation angle of 15 degrees, is defined as an auxiliary line L2. The length D1 of the auxiliary line L1 is 0.5×b×sin(A). Further, the amount of deviation S2 between the tip L1T of the auxiliary line L1 and the tip L2T of the auxiliary line L2 is S1×tan(A/2). Further, the amount of deviation S3 between the end 104AE of the detection surface 104A at a rotation angle of 15° and the outermost line EL of the X-ray irradiation field LF is S1/tan(c-A). The amount of protrusion S4 of the irradiation field LF from the detection surface 104A after the second rotation is S4=S3-S2, and when this value is calculated by including the above values, S4=21.3 mm. It is preferable to take such protrusion amount S4 into consideration when determining the rotation angle range A of the second rotation, or the aperture amount of the aperture size of the irradiation field LF when performing preliminary imaging. For example, assuming an SID of 1,000 mm, which is frequently used, and a size of the electronic cassette 104 of 17 inches, if the protrusion amount S4 is 21.3 mm, it is possible to reduce the aperture size of the irradiation field LF. , it is possible to suppress protrusion. Even taking into consideration the calculation result of the amount of protrusion S4, it is preferable that the range A of the rotation angle of the second rotation is in the range of 0° or more and 15° or less in each of the positive direction and the negative direction with respect to the ± reference position. .

In addition, the radiographic apparatus of the present disclosure can be modified in various ways, as shown in FIGS. 34 to 36.

"Modification 1"
FIG. 34 shows a modification of the guide surface 150 of the fourth embodiment shown in FIGS. 24A to 25B. The height of the guide surface 150 in the optical axis OA direction of the fourth embodiment is at almost the same position as the focal point F of the irradiation unit 113, but as shown in FIG. It may be arranged close to the two center lines J2. In this configuration, when realizing the rotation radius R2 of the second rotation, which is the same as the fourth embodiment, the radius of curvature of the guide surface 150 is made smaller than the rotation radius R2 by the amount that the guide surface 150 approaches the second center line J2 from the focal point F. Also, the length of the arc of the guide surface 150 can be shortened. However, in the example of FIG. 34, the guide surface 150 is located closer to the electronic cassette 104 than the irradiation section 113. In this case, since the guide surface 150 enters the space between the radiation source 112 and the electronic cassette 104, the guide surface 150 tends to get in the way of positioning. Furthermore, as the distance between the irradiation section 113 and the guide surface 150 increases, the size of the member that connects them also increases.

On the other hand, as shown in FIG. 11 in the first embodiment, when the guide surface 150 is located behind the focal point F, the guide surface 150 does not interfere with positioning. Furthermore, as described above, behind the focal point F, the irradiation section 113 and the guide surface 150 can be overlapped in the depth direction in which the first center line J1 extends. Therefore, the degree of freedom in arranging the guide surface 150 with respect to the irradiation section 113 is relatively increased, and there is also the advantage that the guide surface 150 can be easily attached. Further, if the guide surface 150 is arranged behind the focal point F, the radius of curvature of the guide surface 150 can be made larger than the radius of rotation R2 of the second rotation, which has the advantage of making it easier to form the guide surface 150.

[Modified example of pillar]
In the technology of the present disclosure, the support 114 is not limited to an example in which it is suspended from the ceiling, but may be a support 114 that stands up from the floor surface 172, as shown in FIGS. 35 and 36, for example. This support column 114 can run on the floor surface 172 while maintaining a state in which it stands up from the floor surface 172, as shown by the two-dot chain line in FIG. The position of the radiation source 112 can be changed by the support column 114 traveling on the floor 172.

Further, in the state attached to the support column 114, the first rotation is possible, as shown by the solid line and the two-dot chain line in FIG. 36, and furthermore, the second rotation and the third rotation are also possible.

In the above embodiment, the first center line J1 and the second center line J2 are parallel, and the second center line J2 also intersects the optical axis OA like the first center line J1. However, the second center line J2 does not need to be parallel, and the second center line J2 does not need to intersect with the optical axis OA. Even in this case, fine adjustment of the irradiation unit 113 is possible if the irradiation unit 113 can be rotated a second time around the rotation center located on the radiation image detector side in addition to the first rotation. Of course, as in the above embodiment, the first center line J1 and the second center line J2 are parallel, and like the first center line J1, the second center line J2 also intersects the optical axis OA. is preferred. This is because the irradiation unit 113 can be rotated within a parallel plane in each of the coarse adjustment and fine adjustment of the irradiation direction.

Furthermore, regardless of the above embodiments, various modifications can be made without departing from the spirit of the technology of the present disclosure.

Reference Signs List 100 Radiography system 102 Radiography apparatus 104 Electronic cassette 104A Detection surface 104AE End portion 105 Cassette control device 106 Recumbent imaging table 107 Beds 108, 109 Accommodation section 110 Stand 111 Upright imaging table 112 Radiation source 113 Irradiation part 113A Fitting hole 114 Support column 116 First rotating section 116A Extension section 117 Radiation tube 118 Second rotating section 122 Radiation source control section 126 Ceiling traveling device 128 Ceiling 130 Mounting section 132 Rotating seat section 134 Standing section 136 Rotating shaft 138 Arm section 140 Holding section 140A Clamping outer plate 140B Clamping inner plate 142 First rotating shaft 143 Arc portion 144 Holding plate portion 145 Bearing 146 Guide groove 148 Guide pin 150 Guide surface 152 Third rotating shaft 154 Irradiation field limiter 154A Shield plate 154B Actuator 156 Operation panel 160 Display section 162 Operation button 164 Irradiation aperture 166 Display 168 Irradiation switch 170 Operation handle 172 Floor surface 204 First rotation restriction section 206 Second rotation restriction section 304 Post circumference angle sensor 306 First rotation angle sensor 308 Second rotation angle sensor 310 Three-rotation angle sensor 312 Cassette sensor 314 Distance sensor 402 Radiography device 404 First rotating section 406 Second rotating section 408 Arm section 410 Arc section 412 Clamping section 414 Holding plate section 414A Clamping outer plate 414B Clamping inner plate 2019 JP-A Rotation angle range EL Outermost line F Focus H Subject J1 First center line J2 Second center line J3 Third center line JR Support center line LF Irradiation field NL Perpendicular O2 Center of rotation OA Optical axis OP Operator R1 Radius of curvature R2 Radius of rotation VF image detection area

Claims (16)

an irradiation unit that irradiates radiation toward a radiation image detector;
a pillar that movably supports the irradiation section;
a first rotation part that is attached to the support and capable of first rotation about a first center line passing through the focal point of the irradiation part;
A second rotating part that is slidably attached to the first rotating part and whose rotation center is a second center line that is located closer to the radiation image detector than the first center line in the radiation irradiation direction by sliding . It is equipped with a second rotary part that can rotate,
A radiation imaging apparatus in which the irradiation unit can be rotated in the first rotation and the second rotation by the first rotation unit and the second rotation unit. The radiographic apparatus according to claim 1, wherein the first center line and the second center line are parallel. The irradiation unit has an irradiation opening that irradiates the radiation,
When assuming a perpendicular line drawn from the focal point to the detection surface with the irradiation aperture and the detection surface of the radiation image detector directly facing each other,
The radiographic apparatus according to claim 2, wherein the second center line intersects the perpendicular line. The first rotation part includes an arcuate guide surface that becomes a part of the rotation locus of the second rotation,
The radiographic apparatus according to any one of claims 1 to 3, wherein the second rotating section is attached to the first rotating section so as to be slidable along the guide surface. 5. The radiographic apparatus according to claim 4, wherein the guide surface is arranged behind the focal point, where the direction of irradiation of the radiation is forward and the opposite direction is rearward with respect to the focal point. The radiation imaging apparatus according to claim 4, wherein the irradiation section and the guide surface are arranged side by side in the depth direction, where the direction in which the first center line extends is defined as the depth direction. A holding part that is provided in the second rotation part and holds the irradiation part, the holding part being capable of third rotation about a third center line perpendicular to the first center line. The radiographic apparatus according to any one of claims 1 to 6, further comprising a holding section for holding the radiation imaging apparatus. The rotation radius of the second rotation, which is the distance from the rotation center of the second rotation to the focal point, is in the range of 400 mm to 1,000 mm, and the rotatable rotation angle of the second rotation is in the positive direction and the negative direction. The radiation imaging apparatus according to any one of claims 1 to 7, wherein each of the above ranges from 0° to 15° with respect to the reference position. a first rotation regulating section that regulates the first rotation of the first rotating section; and a second rotation regulating section that regulates the second rotation of the second rotating section;
The radiation imaging apparatus according to any one of claims 1 to 8, further comprising a processor that controls the first rotation restriction section and the second rotation restriction section. a first rotation restriction state in which the first rotation is allowed and the second rotation is restricted by the second rotation restriction part; and a first rotation restriction state in which the first rotation is restricted by the first rotation restriction part, and The radiation imaging apparatus according to claim 9, further comprising an operation section for setting the second rotation restriction state and the second rotation restriction state in which the second rotation is permitted. The irradiation unit has an irradiation aperture and an irradiation field limiter that limits the irradiation field of the radiation by changing the aperture size of the irradiation aperture,
Radiography according to any one of claims 1 to 10, further comprising a processor that executes at least one of irradiation control of the irradiation unit and control of the irradiation aperture of the irradiation field limiter. Device. The processor is capable of acquiring a signal indicating whether or not the second rotation is permitted, and if the second rotation is permitted, executes control to adjust the aperture size of the irradiation aperture. death,
The aperture size after the adjustment is based on the assumption that the irradiation aperture and the detection surface of the radiation image detector directly face each other, and that a perpendicular line drawn from the focal point to the detection surface passes through the center of the detection surface. 12. In the case, the amount of protrusion of the irradiation field from the image detection area of the radiation image detector is such that even when the rotation angle of the second rotation is maximum, the amount is not more than a predetermined value. radiographic equipment. The processor calculates a first rotation angle of the first rotation, a second rotation angle of the second rotation, and a third rotation angle whose rotation center is a third center line passing through the focal point and perpendicular to the first center line. an index value indicating at least one of the three rotation angles, an SID that is the distance between the focal point of the irradiation unit and the detection surface of the radiation image detector, and an aperture size of the irradiation aperture of the irradiation field limiter. Deriving the position of the radiation irradiation field with respect to the image detection area of the radiation image detector based on
If it is detected that the amount of the radiation irradiation field protrudes from the image detection area exceeds a predetermined value, or if it is detected that there is a risk of exceeding a predetermined value, the radiation part The radiation imaging apparatus according to claim 11 or 12, wherein irradiation of the radiation is prohibited. The irradiation unit has an irradiation mode for emitting radiation, an irradiation mode for video shooting, an irradiation mode for continuous shooting that continuously acquires a preset number of still images, and an irradiation mode for shooting one still image. The radiographic apparatus according to any one of claims 9 to 13, having at least two irradiation modes selected from irradiation modes for. The processor is capable of acquiring a signal indicating whether or not the radiation image detector is housed in an imaging table that removably houses the radiation image detector,
The processor allows the irradiation mode for video imaging when the radiographic image detector is housed in the imaging stand, and when the radiographic image detector is not accommodated in the imaging stand, The radiation imaging apparatus according to claim 14, wherein the irradiation mode for video imaging is prohibited. Any one of claims 1 to 15, wherein the support is a ceiling-suspended support that can run on the ceiling, or an upright support that stands up from the floor and can run on the floor. The radiographic apparatus described in Section 1.