X-ray image diagnostic apparatus and data generation method for controlling diaphragm blade of x-ray image diagnostic apparatus

Abstract

To automatically and accurately obtain relationships between a visual field size or the position of a diaphragm blade and output of a position detector of the diaphragm blade.SOLUTION: Output A of a position detector for arranging a diaphragm blade at a position L determined beforehand is obtained from initial correspondence data determined beforehand. The diaphragm blade is arranged at a position where the output of the position detector is the output A. An X-ray is exposed to acquire an X-ray image and the position L' of the diaphragm blade is calculated from the position of an image in an X-ray irradiation area. Comparison is made between the position L' and the position L, and the position of the diaphragm blade is adjusted so that the position L' coincides with the position L. The output A' of the position detector when the position L' coincides with the position L is recorded in correspondence with the position L. Data on the correspondence is generated by repeating the operations mentioned above while changing the position L to a plurality of types.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an X-ray diagnostic imaging apparatus, and more particularly to an X-ray adjustable aperture. [Background technology]

[0002] X-ray imaging diagnostic equipment is configured to be able to control the irradiation area of ​​the X-rays irradiated on the subject to a desired area by blocking part of the X-rays irradiated from the X-ray source to the subject with multiple movable aperture blades of the X-ray aperture. By irradiating X-rays only to the area of ​​interest with the X-ray aperture, it is possible to adjust the field of view size of the image and reduce unnecessary radiation exposure to the subject.

[0003] For example, Patent Document 1 discloses an X-ray image diagnostic device equipped with a mechanism for moving the aperture blades to a field of view size designated by the photographer. In this device, when setting the field of view size, the operator selects a range of interest using a switch on an operation unit. This activates a drive mechanism for the aperture blades of the X-ray aperture to move the aperture blades. The drive mechanism is provided with a potentiometer whose output voltage changes with the movement of the aperture blades. The potentiometer has a variable terminal disposed in contact with a resistor shaped like a winding or the like, and the output voltage changes as the variable terminal moves with the movement of the aperture blades. The drive mechanism moves the aperture blades until the voltage output by the potentiometer matches the voltage value corresponding to the aperture blade position of the range of interest set by the switch on the operation unit. In this way, the field of view size is set to a range desired by the photographer.

[0004] In the device of Patent Document 1, the relationship between the voltage output by the potentiometer and the position of the diaphragm blade is determined in advance and stored in memory in the form of a table, etc. When actually moving the diaphragm blade, the control unit refers to the data in the memory, determines the value of the output voltage of the potentiometer corresponding to the desired position of the diaphragm blade, and controls the drive mechanism so that the actual output voltage of the potentiometer becomes the determined output voltage value. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2021-194060 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the technology of Patent Document 1, in order to move the diaphragm blades to a position of the field of view size specified by the photographer, the relationship between the potentiometer output voltage and the diaphragm blade positions, which is obtained in advance, is referenced. Therefore, the accuracy of the diaphragm blade positions after movement depends on the accuracy of the correspondence data.

[0007] The relationship between the output voltage of the potentiometer and the position of the aperture blades is obtained in advance, for example, by the following procedure. The worker manually moves the aperture blades of the X-ray imaging device to the desired first field of view size, irradiates X-rays from the X-ray source, and detects them with the X-ray detector to capture an X-ray image. The worker enlarges and displays the captured image on the monitor at a magnification that displays the first field of view size on the entire screen. The worker visually checks whether the aperture blades are reflected in the monitor screen, and if they are reflected, determines that the position of the aperture blades is inside the desired field of view, moves the aperture blades slightly outward, and captures an X-ray image again. This adjustment and capture of the X-ray image are repeated until the aperture blades are no longer reflected in the monitor screen. When the aperture blades are no longer reflected in the monitor screen, the output voltage of the potentiometer at that time is recorded. This makes it possible to obtain the output voltage of the potentiometer for capturing an image with the first field of view size.

[0008] The operator repeats the adjustment and photographing for other field sizes (e.g., second, third, and fourth field sizes). After determining the output voltage of the potentiometer for all field sizes, the field sizes are associated with the output voltage of the potentiometer and stored in memory.

[0009] This method requires an operator to visually determine whether the aperture blades are reflected in the X-ray image for each field of view size and adjust the position of the aperture blades, which takes time and requires the operator to be tied up during that time.

[0010] In addition, since the determination of whether the aperture blades are reflected on the monitor display screen is made by the worker visually, there is a possibility that the data obtained will differ depending on the worker.

[0011] Furthermore, if the aperture blades are arranged larger than the field of view, the blades will not be reflected on the entire screen of the monitor, and this state may be determined to be the position of the aperture blades for the field of view size, and the correspondence data may be created. In that case, when an actual subject is imaged, X-rays are irradiated over a wider area than the required field of view size, resulting in ineffective exposure.

[0012] An object of the present invention is to provide an X-ray image diagnostic apparatus having a function for automatically and accurately determining the relationship between the field of view size or the position of the aperture blades and the output of a position detector for the aperture blades. [Means for solving the problem]

[0013] In order to achieve the above-mentioned object, according to the present invention, there is provided an X-ray imaging diagnostic apparatus having a tabletop for placing a subject on it, an X-ray source for irradiating X-rays towards the subject, an X-ray focusing device arranged between the X-ray source and the subject, an X-ray detector for detecting the X-rays that have passed through the subject, an image processing unit for generating an image from an output signal from the X-ray detector, a control unit, and a calculation unit.

[0014] The X-ray aperture device includes one or more aperture blades that block a portion of the X-rays, a drive unit that moves the one or more aperture blades, and one or more position detectors whose output changes with changes in the position of the aperture blades.

[0015] The control unit includes a memory. The memory stores a correspondence relationship between the positions of the diaphragm blades and the output of the position detector, which is determined in advance. When the control unit moves the diaphragm blades to a desired position, the control unit determines the output of the position detector corresponding to the desired position by referring to the correspondence relationship, and operates the drive unit to move the diaphragm blades until the actual output of the position detector matches the determined output of the position detector.

[0016] In order to obtain the correspondence relationship, the calculation unit has a correspondence relationship between the positions of the diaphragm blades and the output of the position detector that is determined in advance as initial data.

[0017] The calculation unit is An output A of the position detector for placing the diaphragm blades at a predetermined position L is obtained from the initial data. The diaphragm blades are positioned by the drive unit at a position where the output of the position detector becomes output A. X-rays are emitted from the X-ray source, detected by the X-ray detector, an image is generated by the image processing unit, and the position L' of the aperture blades is calculated from the position of the image of the X-ray irradiation area of ​​the image. Position L' is compared with position L, and the position of the diaphragm blade is adjusted so that position L' coincides with position L; When position L' coincides with position L, the output A' of the position detector is recorded in correspondence with position L; By repeatedly recording the output A' of the position detector while changing the position L to a number of different values, the corresponding relationship is found and stored in memory. Effect of the Invention

[0018] According to the present invention, the relationship between the field of view size or the position of the aperture blade and the output of the aperture blade position detector can be automatically determined with high accuracy. [Brief description of the drawings]

[0019] [Figure 1] 1 is a block diagram showing the configuration of an X-ray image diagnostic apparatus according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a bottom view of the X-ray focusing device of the X-ray image diagnostic apparatus according to the first embodiment. [Diagram 3] 1 is a block diagram of an X-ray diaphragm device of the X-ray image diagnostic apparatus of the first embodiment. [Figure 4] 3 is a circuit diagram of a potentiometer which is a position detector of the X-ray aperture device of the X-ray image diagnostic apparatus of the first embodiment. [Diagram 5] FIG. 2 is a top view of an operation unit 111 of the X-ray image diagnostic apparatus according to the first embodiment. [Figure 6] Graphs (a) and (c) show how to determine the correspondence between the position (opening) of the aperture blades in the vertical and horizontal directions of the X-ray aperture device and the voltage value of the potentiometer, and graphs (b) and (d) show the determined correspondence between the position (opening) of the aperture blades in the vertical and horizontal directions and the voltage value of the potentiometer. [Figure 7] 4 is a flowchart showing the operation of a calculation unit 108 of the X-ray image diagnostic apparatus of the first embodiment. [Figure 8] FIG. 8 is a diagram showing coordinates detected and calculated in steps S15 and S17 in FIG. 7. [Figure 9] FIG. 11 is a bottom view of an X-ray focusing device of the X-ray image diagnostic apparatus according to the second embodiment. [Figure 10] 14A to 14C are diagrams showing images of the aperture blades in the second embodiment and coordinates detected and calculated in steps S15 and S217 in FIG. 13. [Figure 11] FIG. 11 is a block diagram of an X-ray diaphragm device of an X-ray image diagnostic apparatus according to a second embodiment. [Figure 12] 13(a) to 13(d) are graphs showing a method for determining the correspondence between the positions of the aperture blades on the top, bottom, left, and right sides of the X-ray aperture device and the voltage value of a potentiometer, and the obtained correspondence. [Figure 13] 10 is a flowchart showing the operation of a calculation unit 108 of the X-ray image diagnostic apparatus of the second embodiment. [Figure 14](a) An explanatory diagram showing the tilt of an X-ray imaging diagnostic apparatus of the third embodiment, (b) An explanatory diagram showing the movement of the aperture blades due to the tilt, (c) A diagram showing an image in which the aperture blades are reflected due to the movement of the aperture blades due to the tilt, (d) An explanatory diagram showing the positioning of the aperture blades taking the tilt into consideration, (e) A diagram showing an image in which the aperture blades are not reflected due to the positioning of the aperture blades taking the tilt into consideration. [Figure 15] 10 is a flowchart showing the operation of a calculation unit 108 of the X-ray image diagnostic apparatus of the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0021] <<First embodiment>> An X-ray image diagnostic apparatus according to a first embodiment of the present invention will now be described with reference to the accompanying drawings.

[0022] In all the drawings, components having the same functions are given the same reference numerals, and repeated explanations are omitted.

[0023] Fig. 1 is a diagram showing an example of the overall configuration of an X-ray image diagnostic apparatus according to this embodiment. Fig. 2 and Fig. 3 are a top view and a block diagram of an X-ray focusing device 104.

[0024] The X-ray imaging diagnostic apparatus shown in Fig. 1 includes a tabletop 102 on which a subject 101 is placed, an X-ray source 103 that irradiates the subject 101 with X-rays, an X-ray focusing device 104 that sets an X-ray irradiation region for the subject 101, an X-ray detector 112 that detects X-rays that have passed through the subject 101, and a stand 90. The stand 90 is provided with a support arm (not shown), and a support base 105 is supported at the tip of the support arm. A rotation mechanism 91 is mounted on the support arm between the support base 105 and the stand 90. A support column 100 is mounted on the rotation mechanism 91. The central axis of the support arm is parallel to the minor axis direction of the tabletop 102.

[0025] The top board 102 is mounted on a support base 105. The X-ray source 103 and the X-ray focusing device 104 are supported by a support column 100. A rotation mechanism 121 is built into the stand 90. The rotation mechanism 121 rotates the support arm about its central axis. As a result, the X-ray source 103 and the X-ray focusing device 104 rotate (raise or lower) about a rotation axis parallel to the short axis direction of the top board 102 while maintaining their positional relationship. In addition, the rotation mechanism 91 tilts the support column 100 with respect to the top board 102 by rotating the support column 100.

[0026] The X-ray image diagnostic apparatus further includes a high voltage generator 106, an image processing unit 107, a calculation unit 108, a control unit 110, a display device 109, and an operation unit 111. The high voltage generator 106 supplies power to the X-ray source 103. The image processing unit 107 generates an X-ray image using an X-ray signal output by the X-ray detector 112. The display unit 109 displays the X-ray image and the like generated by the image processing unit 107. The operation unit 111 receives instructions from an operator and outputs the received instructions to the control unit 110. The operations of the calculation unit 108 and the control unit 110 will be described in detail later.

[0027] The X-ray source 103 has an X-ray tube that generates X-rays by receiving power from a high voltage generator 106. The X-ray source 103 may also include an X-ray filter that selectively transmits X-rays of a specific energy.

[0028] As shown in a top view in FIG. 2 and a block diagram in FIG. 3, the X-ray aperture device 104 comprises a plurality of (four in this case) aperture blades 113-116 arranged to surround the optical axis 103a of the X-rays, a drive mechanism 122 for the aperture blades 113-116, a drive source (not shown) such as a motor that operates the drive mechanism 122, and potentiometers 117 and 118 which are aperture position detection units that detect the positions of the aperture blades 113-116.

[0029] The aperture blades 113-116 are made of rectangular lead plates. The aperture blades 113-116 are arranged in pairs, with the pair of aperture blades 113, 114 facing each other across the optical axis 103a of the X-rays with their longitudinal direction parallel to the minor axis direction of the tabletop 102. On the other hand, the pair of aperture blades 115, 116 facing each other across the optical axis 103a of the X-rays with their longitudinal direction parallel to the major axis direction of the tabletop 102.

[0030] The driving mechanism 122 moves one pair of aperture blades 113, 114 in the long axis direction of the tabletop 102 (= head-to-foot direction of the subject 101 = up-down direction in the image) in a direction away from the X-ray optical axis 103a (arrow (3) in Figure 2) or toward the optical axis 103a (arrow (4) in Figure 2). The driving mechanism 122 also moves another pair of aperture blades 115, 116 in the short axis direction of the tabletop 102 (= left-right direction of the subject 101 = left-right direction in the image) in a direction away from the X-ray optical axis 103a (direction (1) in Figure 2) or toward the optical axis 103a (direction (2) in Figure 2). As a result, the area surrounded by the aperture blades 113-116 after movement by the driving mechanism 122 becomes the area (field of view) where the subject 101 is irradiated with X-rays.

[0031] Potentiometers 117 and 118 are disposed as position detectors on one of the diaphragm blades 113 and 114, and on one of the diaphragm blades 115 and 116, respectively. As shown in Fig. 4, the potentiometers 117 and 118 are configured to include a resistor 307, a power source 301 connected to the resistor 307, a movable terminal 303 that is movable while in contact with the resistor 307, and a voltage detector 306 that detects the voltage of the movable terminal 303. The movable terminal 303 is connected to the diaphragm blades 113 to 116, or to a member that moves together with the diaphragm blades 113 to 116 in the drive mechanism 122. As a result, when the drive mechanism 122 moves the aperture blades 113, 114 and the apertures 115, 116, the contact position 302 between the movable terminal 303 and the resistor 307 moves in conjunction with the movement, and the ratio of the distance between the position 302 and both ends 304, 305 of the resistor 307 changes, so that the voltage value detected by the voltage detector 306 changes.

[0032] As shown in FIG. 5, the operation unit 111 includes field size selection buttons 111a to 111d for selecting any one of a plurality of pre-registered field sizes, and field size adjustment slide bars 111e and 111f for continuously changing the field size in the vertical direction of the X-ray image (the major axis direction of the top plate 102 = the head-foot direction of the subject 101) and the horizontal direction of the X-ray image (= the minor axis direction of the top plate 102 = the left-right direction of the subject 101), an exposure button 111g, and a monitor (display unit) 111h for displaying imaging conditions and the like.

[0033] <During X-ray image acquisition> When performing X-ray imaging, the operator operates the field size selection buttons 111a to 111d or the field size adjustment slide bars 111e and 111f on the operation unit 111 to select or set a desired field size, and then presses the exposure button 111g.

[0034] The control unit 110 receives the field size set on the field size selection buttons 111a to 111d or the field size adjustment slide bars 111e and 111f from the operation unit 111. The control unit 110 calculates the positions (opening degrees) of the aperture blades 113, 114 and the aperture blades 115, 116 that realize the field size from the relationship between the predetermined field size and the positions (opening degrees) of the aperture blades.

[0035] The control unit 110 incorporates a memory 110a. In the memory 110a, data indicating the correspondence between the positions (opening degrees) of the aperture blades and the output data of the potentiometers 117, 118 (FIGS. 6(b), (d), hereinafter also referred to as "correspondence data") is stored for each set of aperture blades. The control unit 110 calculates the voltage values of the potentiometers 117, 118 that realize the set field size with reference to the correspondence data.

[0036] The control unit 110 operates the drive mechanism 122 until the actual voltage values ​​output by the potentiometers 117 and 118 reach the calculated voltage values, respectively, to move the aperture blades 113 and 114 and the aperture blades 115 and 116. In this way, the control unit 110 places the aperture blades 113 and 114 and the aperture blades 115 and 116 in positions (openings) that realize the field of view size set in the operation unit 111.

[0037] Next, the control unit 110 instructs the high voltage generator 106 to supply power to the X-ray source 103. This causes the X-ray source 103 to emit X-rays, which are irradiated onto the subject 101 within the field of view range set by the aperture blades 113 to 116. The X-rays that have passed through the subject 101 are detected by the X-ray detector 112.

[0038] The image processor 107 receives the output of the X-ray detector 112 , generates an X-ray image, and causes the display device 109 to display it.

[0039] <Generating data on the correspondence between aperture blade opening and potentiometer voltage> The calculation unit 108 generates "correspondence data" (Figure 6(b)) indicating the correspondence relationship between the position (opening) of the pair of aperture leaves 113, 114 that sets the vertical size of the image and the output voltage of potentiometer 117, and "correspondence data" (Figure 6(d)) indicating the correspondence relationship between the position (opening) of the pair of aperture leaves 115, 116 that sets the horizontal size of the image and the output voltage of potentiometer 118, prior to imaging of the subject 101, and stores them in memory 110a of the control unit 110.

[0040] The procedure for the calculation unit 108 to generate the correspondence data will be described below with reference to the flow chart in Fig. 7. Unadjusted initial data is stored in the memory 110a of the control unit 110. The initial data is a set of predetermined functions or data such as the straight lines 601 and 602 in Figs. 6(a) and (c), and is stored for the up-down direction and the left-right direction, respectively. Also, previously generated correspondence data stored in the memory 110a may be used instead of the initial data.

[0041] Using the default data of straight lines 601 and 602, the calculation unit 108 accurately generates data (correspondence data) indicating the relationship between the actual positions (openings) of the aperture leaves 113, 114 and 115, 116 and the voltage values ​​of the potentiometers 117, 118 through each step of the flow in Figure 7.

[0042] The functions of the calculation unit 108 can be realized by software. In this case, the calculation unit 108 is configured by a computer or the like equipped with a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit) and a memory, and the CPU reads and executes a program stored in the memory to realize the processing of the calculation unit 108 shown in the flow of Fig. 7. It is also possible to configure a part or the whole of the calculation unit 108 by hardware. For example, a circuit design can be performed to realize the processing of the calculation unit 108 using a custom IC such as an ASIC (Application Specific Integrated Circuit) or a programmable IC such as an FPGA (Field-Programmable Gate Array).

[0043] <Step S10> When the calculation unit 108 receives an instruction from the operator to start creating the correspondence data, it instructs the control unit 110 to set the maximum field of view size (here, the maximum field of view size B4 of the operation unit 111).

[0044] The operator may press the maximum visual field size selection button 111d of the operation unit 111 to select the maximum visual field size (B4).

[0045] <Step S11> The operator presses the exposure button 111 g of the operation unit 111 .

[0046] When the calculation unit 108 receives a signal from the operation unit 111 indicating that the exposure button 111g of the operation unit 111 has been pressed, the process proceeds to step S12.

[0047] In this embodiment, the process proceeds to step S12 when the operator presses the exposure button 111g, but step S11 may be omitted.

[0048] <Step S12> The calculation unit 108 instructs the control unit 110 to move the aperture blades 113, 114 and 115, 116.

[0049] The control unit 110 refers to a table obtained in advance or calculates the opening degree of the aperture blades 113, 114 and the aperture blades 115, 116 corresponding to the field of view size (here, the maximum field of view size) set by the calculation unit 108 from a predetermined formula. Here, the value of the opening degree of the aperture blades 113, 114 in the vertical direction (the distance between the aperture blades 113, 114) corresponding to the maximum field of view size is 2, and the value of the opening degree of the aperture blades 115, 116 in the horizontal direction (the distance between the aperture blades 115, 116) is also 2 (see FIGS. 6(a) and (c)).

[0050] Next, the control unit 110 refers to the initial data (straight lines 601, 602 in Figures 6(a) and 6(c)) stored in the built-in memory 110a, and determines voltage values ​​A and B of potentiometers 117 and 118 corresponding to opening value 2 of the vertical diaphragm blades 113 and 114 and opening value 2 of the horizontal diaphragm blades 115 and 116, respectively.

[0051] The control unit 110 operates the drive mechanism 122 until the actual voltage values ​​output by the potentiometers 117 and 118 reach the voltage values ​​A and B, respectively. As a result, the control unit 110 places the aperture blades 113 and 114 and the aperture blades 115 and 116 at the position of aperture 2, which is the maximum field of view size.

[0052] <Step S13> When the arrangement of the aperture leaves 115 and 116 is complete, the calculation unit 108 instructs the control unit 110 to instruct the high voltage generator 106 to supply power to the X-ray source 103 .

[0053] As a result, X-rays are emitted from the X-ray source 103, and the irradiated X-rays within the field of view range set by the aperture blades 113 to 116 are detected by the X-ray detector 112.

[0054] <Step S14> The image processor 107 receives the output of the X-ray detector 112 and generates an X-ray image.

[0055] <Steps S15 and S16> The image processing unit 107 detects the coordinates of the four corners H, I, J, and K of the field of view (X-ray irradiation area) of the generated image (see FIG. 8), and outputs them to the calculation unit .

[0056] <Step S17> The calculation unit 108 calculates the coordinates of the midpoint L1 of the upper side, the midpoint L2 of the lower side, the midpoint M1 of the left side, and the midpoint M2 of the right side of the field of view of the image, respectively, using the following equations. L1=(H+I) / 2 L2=(J+K) / 2 M1=(H+J) / 2 M2=(I+K) / 2 Furthermore, the calculation unit 108 calculates the actual aperture blade L from the following formula: R , M R Calculate the opening degree.

[0057] Aperture of aperture blades 113 and 114 L R = |y coordinate of L1| + |y coordinate of L2| Aperture of aperture blades 115 and 116 M R = |x coordinate of M1| + |x coordinate of M2| For example, in the example of FIG. 8, the coordinates of the four corners are H(-0.9,1.1), I(0.9,1.1), J(-0.9,-1.1), and K(0.9,-1.1), and the coordinates of the midpoints are L1(0.0,1.1), L2(0.0,-1.1), M1(-0.9,0.0), and M2(0.9,0.0). Therefore, Aperture of aperture blades 113 and 114 L R =|-1.1|+|1.1|=2.2 Aperture of aperture blades 115 and 116 M R=|-0·9|+|0·9|=1.8 It is calculated as follows.

[0058] <Step S18> The calculation unit 108 calculates the actual aperture L of the aperture blades 113 and 114 calculated in step S17. R , M R It is determined whether or not the openings L and M match the openings L and M obtained in step S12.

[0059] If they do not match, the calculation unit 108 proceeds to step S19.

[0060] <Step S19> The calculation unit 108 uses the data in the memory 110a (lines 601 and 602 in Figures 6(a) and (c)) to calculate the voltage values ​​A' and B' of the potentiometers 117 and 118 for bringing the aperture blades 113, 114 and 115, 116 closer to the opening degrees L and M corresponding to the field of view determined and set in step S12.

[0061] For example, the aperture L (=2) of the aperture blades 113 and 114 that realizes the set field of view size and the current aperture L R The difference ΔL (=-0.2) between this voltage value A and the voltage (-ΔA) corresponding to the difference ΔL (=-0.2) is calculated based on the correspondence equation, and the voltage value A' (=A+(-ΔA)) is added to the voltage value A to calculate the adjusted voltage value A'.

[0062] Similarly, the aperture M (=2) of the aperture blades 115 and 116 that realizes the set field size and the current aperture M R (=1.8), the difference ΔM (=0.2) between this and the voltage value B is calculated, and the voltage (ΔB) corresponding to the calculated difference ΔM (=0.2) is added to the voltage value B to calculate the adjusted voltage value B' (=B+ΔB).

[0063] The calculation unit 108 instructs the control unit 110 to move the diaphragm blades 113, 114 and 115, 116 to the calculated voltage values ​​A', B' of the potentiometers 117, 118, and the process returns to step S13.

[0064] The above steps S13 to S19 are carried out with the actual aperture L of the aperture blades 113 and 114 calculated in step S17. R , M R This is repeated until the openings L and M match the openings L and M corresponding to the set field of view obtained in step S12.

[0065] <Step S20> In step S18, the actual aperture L of the aperture blades 113 and 114 calculated in step S17 is R , M R If these values ​​match the openings L and M corresponding to the field of view determined and set in step S12, the current voltage values ​​A' and B' of potentiometers 117 and 118 are recorded as the voltage values ​​corresponding to the openings L and M of aperture blades 113, 114 and 115, 116 in step S12.

[0066] <Steps S21 and S22> Steps S11 to S20 are repeated for a plurality of predefined field of view sizes.

[0067] As a result, the calculation unit 108 can generate the correspondence between the openings of the aperture blades 113, 114 and 115, 116 and the voltage values ​​of the potentiometers (correspondence data, FIGS. 6(b) and (d)) for a plurality of predetermined field sizes (four points in the example of FIGS. 6(a) and (c)). The calculation unit 108 stores the obtained data in the memory 110a of the control unit 110.

[0068] The plurality of predetermined visual field sizes may be any sizes as long as they are visual field sizes for which initial data or past correspondence data is stored in memory 110a. For example, they may be the visual field sizes of visual field size selection buttons 111a, 111b, 111c, and 111d of operation unit 111, or other visual field sizes.

[0069] Before performing X-ray imaging of the subject 101, the control unit 110 connects the openings of the diaphragm blades 113, 114 and 115, 116 for the multiple (four here) field sizes recorded in step S20 with the corresponding voltage values ​​of the potentiometers 117, 118 using straight lines or curves, and uses the resulting data as correspondence data. This reduces the amount of data stored in the memory 110a to only the multiple (four here) points of data, thereby reducing the memory capacity.

[0070] As described above, in the X-ray image diagnostic apparatus of the first embodiment, the operator only needs to instruct the start of generation of the correspondence data, and the calculation unit 108 can generate data indicating the correspondence between the aperture of the aperture blade and the output voltage of the potentiometer with high accuracy (FIGS. 6(b) and 6(d)). By using this data to control the movement of the aperture blade during X-ray photography, it is possible to accurately prevent the subject from being exposed to unnecessary radiation and to accurately prevent the aperture blade from being reflected in the X-ray image. In addition, since the generated correspondence data does not require manual intervention in determining the positions of the aperture blades, it is not affected by the individual skills of the operator involved in the creation, and data can always be generated with a certain level of accuracy. In addition, there is no need to tie up an operator for a long time in order to generate the correspondence data.

[0071] In this embodiment, since the maximum field of view is set in the first step S10, the position of the diaphragm blades can be adjusted for a plurality of field of view sizes within the maximum field of view range. However, the field of view does not have to be the maximum field of view that is set first, and for example, the diaphragm blades may be adjusted while successively increasing the field of view size from the minimum field of view to the maximum field of view.

[0072] In the first embodiment, a potentiometer is used to detect the positions (openings) of the aperture leaves 113 to 116, but it is not limited to the potentiometer, and any detector that can detect the change in the positions (openings) of the aperture leaves 113 to 116 as a change in output value can be used instead of the potentiometer. For example, an encoder or the like can also be used.

[0073] In this embodiment, the procedure for an operator to generate correspondence data before shipment of an X-ray imaging diagnostic apparatus or when installing the apparatus has been described. However, for an apparatus actually used in clinical practice, it is also possible to obtain current correspondence data by implementing the flow in FIG. 7 when updating the correspondence data.

[0074] <<Second embodiment>> The X-ray image diagnostic apparatus of the second embodiment will be described with reference to FIGS.

[0075] 9 and 10, the X-ray aperture device 104 of the X-ray image diagnostic apparatus of the second embodiment is a single-acting aperture in which four aperture blades 113-116 are arranged to surround the optical axis 103a of the X-ray source 103, and each of them is moved independently by a drive mechanism 122. Therefore, as shown in Fig. 11, potentiometers 117a, 117b, 118a, and 118b are connected to the four aperture blades 113, 114, 115, and 116, respectively, to detect the positions (opening degree).

[0076] Therefore, memory 110a of control unit 110 stores correspondence data indicating the correspondence between the position (opening) of each of diaphragm blades 113, 114, 115, and 116 and the output voltage values ​​of potentiometers 117a, 117b, 118a, and 118b.

[0077] When taking X-ray images, the control unit 110 calculates the positions of the aperture blades 113, 114 and the aperture blades 115, 116 that realize the field of view size set on the field of view size selection buttons 111a to 111d or the field of view size adjustment slide bars 111e, 111f of the operation unit 111, from the relationship between the field of view size determined in advance and the positions (opening) of the aperture blades.

[0078] The control unit 110 refers to data (Figures 12(a) to (d)) stored in the built-in memory 110a indicating the correspondence between the positions (openings) of the aperture leaves 113, 114, 115, 116 and the output data of the potentiometers 117a, 117b, 118a, 118b for each of the four aperture leaves 113, 114, 115, 116, and calculates voltage values ​​for the potentiometers 117a, 117b, 118a, 118b for positioning the four aperture leaves 113, 114, 115, 116 at the calculated positions (openings).

[0079] The control unit 110 operates the drive mechanism 122 until the actual voltage values ​​output by the potentiometers 117a, 117b, 118a, and 118b reach the calculated voltage values, thereby moving the diaphragm blades 113, 114, 115, and 116. In this way, the control unit 110 places the diaphragm blades 113, 114, 115, and 116 in positions (openings) that realize the field of view size set in the operation unit 111.

[0080] Meanwhile, the calculation unit 108 generates data (FIGS. 12(a) to (d)) indicating the corresponding relationship between the positions (openings) of the diaphragm blades 113, 114, 115, and 116 and the voltages of the potentiometers 117a, 117b, 118a, and 118b as shown in the flow of FIG 13. In FIG 13, steps that perform the same processes as those in the flow of FIG 7 of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0081] <Steps S10 to S11> As in the first embodiment, the calculation unit 108 instructs the control unit 110 to set the maximum field of view size, and when the operator presses the exposure button 111g, the process proceeds to step S212.

[0082] <Step S212> The control unit 110 determines the position (opening) L of the aperture blades 113, 114, 115, and 116 corresponding to the maximum field of view size. U ,L D ,M L ,M R is calculated by referring to a table obtained in advance or by using a predetermined formula.

[0083] Next, the control unit 110 refers to the initial data (the straight lines 701 to 704 in FIGS. 12(a) to 12(d)) stored in the built-in memory 110a, and calculates the positions (openings) L of the diaphragm blades 113 to 116. U ,L D ,M L ,M R The voltage value A of the potentiometers 117a, 117b, 118a, and 118b to U ,A D ,B L ,B R Request.

[0084] The control unit 110 determines whether the actual voltage values ​​output by the potentiometers 117a, 117b, 118a, and 118b are voltage values ​​A U ,A D ,B L ,B R The control unit 110 operates the driving mechanism 122 until the aperture reaches the maximum field of view size (aperture).

[0085] <Steps S13 to S16> Once the positioning of the aperture leaves 115, 116 has been completed, the calculation unit 108 irradiates X-rays, generates an X-ray image, and detects the coordinates of the four corners H, I, J, and K of the field of view (X-ray irradiation area) of the generated image, as in steps S13 to S16 of the first embodiment 1 (see FIG. 10). <Step S217> The calculation unit 108 calculates the coordinates of the midpoint L1 of the upper side, the midpoint L2 of the lower side, the midpoint M1 of the left side, and the midpoint M2 of the right side of the field of view of the image, respectively, using the following equations. L1=(H+I) / 2 L2=(J+K) / 2 M1=(H+J) / 2 M2=(I+K) / 2 Furthermore, the calculation unit 108 calculates the actual positions (openings) L of the diaphragm blades 113 to 116 from the following formula: UR ,L DR ,M LR ,M RRRequest.

[0086] Position of upper aperture blade 113 (opening) L UR =|y coordinate of L1| Position (opening) of lower aperture blade 114 L DR =|y coordinate of L2| Position of left aperture blade 115 (opening) M LR = |x coordinate of M1| Position of right aperture blade 116 (opening) M RR = |x coordinate of M2| For example, in the example of FIG. 10, the coordinates of the four corners are H(-0.3,1.0), I(0.8,1.0), J(-0.3,-0.8), and K(0.8,-0.8), and the coordinates of the midpoints are L1(0.25,1.0), L2(0.25,-0.8), M1(-0.3,0.1), and M2(0.8,0.1). Position of upper aperture blade 113 (opening) L UR =|y coordinate of L1|=1.0 Position (opening) of lower aperture blade 114 L DR =|y coordinate of L2|=0.8 Position of left aperture blade 115 (opening) M LR =|x coordinate of M1|=0.3 Position (opening) of right aperture blade 116 M RR =|x coordinate of M2|=0.8 It is calculated as follows.

[0087] <Step S218> The calculation unit 108 calculates the actual positions (openings) L of the diaphragm blades 113 to 116 calculated in step S17. UR ,L DR ,M LR ,M RR The position (opening) L obtained in step S212 U ,L D ,M L ,M R Determine whether it matches.

[0088] If they do not match, the calculation unit 108 proceeds to step S19.

[0089] <Step S219> The calculation unit 108 calculates the position (opening) L U ,L D ,M L ,M R The voltage value A of the potentiometers 117 and 118 for moving the aperture blades 113, 114 and 115, 116 closer to each other U ',A D ',B L ',B R ' is calculated using the data in the memory 110a (the straight lines 701 to 702 in FIGS. 6(a) to 6(d)).

[0090] For example, the position (opening) of the aperture blades 113 to 116 that realizes the set field of view size is L U ,L D ,M L ,M R and the current position (opening) L UR ,L DR ,M LR ,M RR Difference ΔL U ,ΔL D ,ΔM L ,ΔM R Calculate the difference ΔL U ,ΔL D ,ΔM L ,ΔM R The voltage ΔA corresponding to U ,ΔA D ,ΔB L ,ΔB R Based on the corresponding equation, the voltage ΔA U ,ΔA D ,ΔB L ,ΔB R Voltage value A U ,A D ,B L ,B R Voltage value A added to each U ',A D ',B L ',B R ' is the adjusted voltage value.

[0091] The calculation unit 108 calculates the voltage values ​​A of the potentiometers 117a, 117b, 118a, and 118b.U ',A D ',B L ',B R Then, the control unit 110 is instructed to move the diaphragm blades 113, 114, 115, and 116 to the position indicated by the arrow A', and the process returns to step S13.

[0092] The above steps S13 to S19 are performed based on the actual position (opening) L of the diaphragm blades 113 and 114 calculated in step S17. UR ,L DR ,M LR ,M RR The position (opening) L obtained in step S212 U ,L D ,M L ,M R Repeat until it matches.

[0093] <Step S220> In step S218, the actual positions (openings) L of the diaphragm blades 113 and 114 calculated in step S17 are UR ,L DR ,M LR ,M RR The position (opening) L obtained in step S212 U ,L D ,M L ,M R If they match, the current voltage value A of the potentiometers 117a, 117b, 118a, and 118b U ',A D ',B L ',B R ' is the position (opening degree) L of the aperture blades 113, 114, 115, and 116 in step S212. U ,L D ,M L ,M R Record the voltage value corresponding to

[0094] <Steps S21 and S22> Steps S11 to S20 are repeated for a plurality of predefined field of view sizes.

[0095] As a result, the calculation unit 108 can generate correspondence relationships (correspondence data, FIGS. 12(a) to (d)) between the positions (openings) of the diaphragm blades 113, 114, 115, and 116 and the voltage values ​​of the potentiometers 117a, 117b, 118a, and 118b for a plurality of predetermined field of view sizes (four points in the example of FIGS. 12(a) to (d)). The calculation unit 108 stores the obtained data in the memory 110a of the control unit 110.

[0096] In this way, according to the second embodiment, even for the single-action X-ray aperture device 104, the calculation unit 108 can accurately generate the correspondence relationship (correspondence data, Figures 12(a) to (d)) between the positions (openings) of the aperture leaves 113, 114, 115, and 116 and the voltage values ​​of the potentiometers 117a, 117b, 118a, and 118b.

[0097] In the X-ray image diagnostic apparatus of the second embodiment, the configuration, operation and effects other than those described above are similar to those of the first embodiment, and therefore description thereof will be omitted.

[0098] <<Third embodiment>> An X-ray image diagnostic apparatus according to the third embodiment will be described.

[0099] The X-ray image diagnostic apparatus of the third embodiment has the same configuration as that of the first embodiment, and includes a rotation mechanism 121 as shown in Fig. 1. The rotation mechanism 121 rotates (raise and lower) the support column 100 and the top plate 102 while maintaining the positional relationship between the X-ray source 103 and the X-ray focusing device 104 and the top plate 102 as shown in Fig. 14(a).

[0100] When the X-ray aperture device 104 is tilted as shown in FIG. 14(a), the aperture blades 113 to 116 tilt, and the drive mechanism 122 and the support column 100 supporting the aperture blades 113 to 116 bend due to gravity, and the positions of the aperture blades 113 to 116 move slightly downward.

[0101] Among the aperture blades 113-116 surrounding the field of view, the aperture blade that is positioned at the highest position due to the inclination (lower aperture blade 114 in FIG. 14(b)) moves downward due to gravity and enters the set field of view. Therefore, when an X-ray image is displayed on the display device 109 as shown in FIG. 14(c), the image of the lower aperture blade 114 is displayed within the set field of view. Also, the upper aperture blade 113 moves outside the field of view due to gravity and is not displayed on the display device 109, but causes ineffective exposure of the subject 101.

[0102] Therefore, in the third embodiment, in consideration of the inclination of the X-ray aperture device 104, the aperture blades 113-116 are arranged at a position higher by the amount of movement of the aperture blades 113-116 due to gravity, according to the angle of rotation (raising and lowering) of the rotation mechanism 121. Therefore, the calculation unit 108 generates data indicating the correspondence between the positions (opening degrees) of the aperture blades and the output data of the potentiometers 117 and 118 for each inclination angle.

[0103] Specifically, the calculation unit 108 generates data (correspondence data) indicating the relationship between the positions (openings) of the diaphragm blades 113, 114 and 115, 116 and the voltage values ​​of the potentiometers 117, 118 for each of a plurality of predetermined tilt angles according to the flow of FIG.

[0104] Steps S10 to S21 in the flow of FIG. 15 are similar to the flow of FIG. 7, but steps S301 and S302 are added.

[0105] In step S301, the calculation unit 108 determines whether steps S10 to S21 have been completed for all of the predetermined tilt angles, and if not, proceeds to step S302 to instruct the rotation mechanism 121 to change the tilt angle. The rotation mechanism 121 rotates the X-ray source 103, the X-ray focusing device 104, and the tabletop 102 to change the tilt angle. This is repeated in step S301 until steps S10 to S21 have been completed for all of the predetermined tilt angles.

[0106] In this way, it is possible to generate data (correspondence data) indicating the relationship between the positions (openings) of the diaphragm blades 113, 114 and 115, 116 and the voltage values ​​of the potentiometers 117, 118 for all of a plurality of predetermined tilt angles. The generated correspondence data is stored in memory 110a of control unit 110.

[0107] When performing X-ray imaging, the control unit 110 rotates the rotation mechanism 121 in response to an instruction from an operator, and sets the inclinations of the X-ray source 103, the X-ray aperture device 104, and the tabletop .

[0108] The operator operates the visual field size selection buttons 111a to 111d or the visual field size adjustment slide bars 111e and 111f on the operation unit 111 to select or set a desired visual field size, and then presses the exposure button 111g.

[0109] Next, the control unit 110 receives the field of view size set from the operation unit 111, and also receives the tilt angle from the rotation mechanism 121. The control unit 110 selects correspondence data corresponding to the tilt angle from the memory 110a. The control unit 110 uses the selected correspondence data to calculate the voltage values ​​of the potentiometers 117 and 118 that realize the field of view size.

[0110] The control unit 110 operates the drive mechanism 122 until the actual voltage values ​​output by the potentiometers 117 and 118 reach the calculated voltage values, respectively, to move the diaphragm blades 113 and 114 and the diaphragm blades 115 and 116.

[0111] As a result, as shown in FIG. 14(d), the control unit 110 can position the aperture blades 113-116 at a position (opening) that achieves the field of view size set in the operation unit 111, and that takes into account the amount of downward movement of the aperture blades 113-116 due to gravity caused by the set tilt.

[0112] Therefore, even if the X-ray source 103 and the X-ray aperture device 104 are tilted, the aperture blades 113 to 116 will not enter the set field of view due to gravity, and an image can be displayed appropriately as shown in Figure 14(e).

[0113] In the third embodiment, the configuration, operation, and effects other than those described above are similar to those of the first embodiment, and therefore description thereof will be omitted.

[0114] Furthermore, by executing the flow of FIG. 13 instead of S10 to S22 of the flow of FIG. 15, even in an X-ray image diagnostic device equipped with an X-ray aperture device 104 having single-acting aperture leaves 113 to 116, it is possible to appropriately display images taking into account the movement of the aperture leaves 113 to 116 due to tilt. [Explanation of symbols]

[0115] 90 Stand 91 Rotation mechanism 100 posts 101 Subject 102 Tabletop 103 X-ray source 103a Optical axis 104 X-ray aperture device 105 Support stand 106 High Voltage Generator 107 Image Processing Unit 108 Arithmetic section 109 Display device 110 Control section 110a Memory 111 Operation section 111a Field of view size selection button 111b Field of view size selection button 111d Field of view size selection button 111e Slider bar for adjusting field of view size 111f Slider for adjusting field of view size 112 X-ray detector 113 Aperture blades 114 Aperture blades 115 Aperture blades 116 Aperture Blades 117 Potentiometer 117a Potentiometer 117b Potentiometer 118 Potentiometer 118a potentiometer 118b Potentiometer 121 Rotation mechanism 122 Drive mechanism 301 Power supply 302 Contact position 303 Movable terminal 304 Both ends 306 Voltage Detector 307 Resistance 601 straight line 602 straight line 701 straight line 702 straight line 703 straight line 704 straight line

Claims

1. the apparatus includes a tabletop for placing an object on which the object is placed, an X-ray source for irradiating X-rays toward the object, an X-ray focusing device disposed between the X-ray source and the object, an X-ray detector for detecting the X-rays that have passed through the object, an image processing unit for generating an image from an output signal of the X-ray detector, a control unit, and a calculation unit; the X-ray aperture device includes one or more aperture blades that block a portion of the X-rays, a drive unit that moves the one or more aperture blades, and one or more position detectors whose output changes with a change in position of the aperture blades; the control unit includes a memory, and a correspondence relationship between the positions of the diaphragm blades and the output of the position detector, which is determined in advance, is stored in the memory, and when the control unit moves the diaphragm blades to a desired position, the control unit determines the output of the position detector corresponding to the desired position by referring to the correspondence relationship, and operates the drive unit to move the diaphragm blades until the actual output of the position detector coincides with the determined output of the position detector; the calculation unit has a correspondence relationship between the positions of the diaphragm blades and the output of the position detector, the correspondence relationship being determined in advance as initial data in order to obtain the correspondence relationship, The calculation unit is determining an output A of the position detector for disposing the diaphragm blade at a predetermined position L from the initial data; The diaphragm blade is disposed by the drive unit at a position where the output of the position detector becomes an output A; X-rays are emitted from the X-ray source, detected by the X-detector, an image is generated by the image processing unit, and a position L' of the diaphragm blade is calculated from a position of an image of an X-ray irradiation area of ​​the image, comparing the position L' with the position L, and adjusting the position of the diaphragm blades so that the position L' coincides with the position L; an output A' of the position detector when the position L' coincides with the position L is recorded in correspondence with the position L; and repeating the operation of recording the output A' of the position detector while changing the position L to a plurality of different values, thereby obtaining the correspondence relationship and storing it in the memory.

2. 2. The X-ray imaging diagnostic apparatus according to claim 1, wherein the position L at which the calculation unit initially places the diaphragm blades in order to obtain the correspondence relationship is a position corresponding to a predetermined maximum field of view size.

3. 2. The X-ray image diagnostic apparatus according to claim 1, wherein the plurality of aperture blades are arranged in pairs, and the pair of aperture blades is disposed opposite to each other across an optical axis of the X-ray source, and the drive unit moves the pair of aperture blades in an interlocking manner so that the distances from the optical axis are equal, The X-ray image diagnostic apparatus according to claim 1, wherein the calculation unit determines one of the correspondence relationships for the set of aperture blades and stores the relationship in the memory.

4. 2. The X-ray image diagnostic apparatus according to claim 1, wherein the plurality of aperture blades are arranged to surround an optical axis of the X-ray source, and the driving unit moves each of the aperture blades, The X-ray image diagnostic apparatus according to claim 1, wherein the calculation unit determines the correspondence relationship for each of the aperture blades and stores the correspondence relationship in the memory.

5. 2. The X-ray image diagnostic apparatus according to claim 1, further comprising a rotation mechanism for tilting the X-ray focusing device with respect to a vertical direction, the calculation unit calculates the correspondence relationship while tilting the X-ray focusing device at a predetermined tilt angle by the rotation mechanism, thereby calculating the correspondence relationship for each of a plurality of tilt angles and storing the calculated correspondence relationship in the memory; the control unit selects from the memory the correspondence relationship corresponding to the tilt angle set by the rotation mechanism, and moves the aperture blades using the selected correspondence relationship.

6. 1. A method for generating data on a correspondence relationship between positions of a plurality of aperture blades of an X-ray aperture device of an X-ray image diagnostic device and an output from a position detector for the aperture blades, the data being used for controlling the plurality of aperture blades of the X-ray aperture device of an X-ray image diagnostic device, the method comprising: a first step of determining an output A of the position detector for disposing the diaphragm blade at a predetermined position L from predetermined initial correspondence data; a second step of disposing the diaphragm blade at a position where an output of the position detector of the X-ray image diagnostic apparatus becomes an output A; a third step of irradiating X-rays from an X-ray source of the X-ray imaging diagnostic device, detecting the X-rays with an X-detector of the X-ray imaging diagnostic device, generating an image in an image processing unit of the X-ray imaging diagnostic device, and calculating a position L' of the diaphragm blades from a position of an image of an X-ray irradiation area of ​​the image; a fourth step of comparing the position L' with the position L and adjusting the position of the diaphragm blades so that the position L' coincides with the position L; a fifth step of recording an output A' of the position detector when the position L' coincides with the position L in association with the position L; a sixth step of generating data on the correspondence relationship by repeating the first to fifth steps while changing the position L into a plurality of types; 13. A data generation method for controlling aperture blades of an X-ray image diagnostic apparatus, comprising:

7. 7. A data generation method for controlling the aperture blades of an X-ray imaging diagnostic apparatus according to claim 6, characterized in that, when the first step is executed for the first time, the position L at which the aperture blades are disposed is a position corresponding to a predetermined maximum field of view size.

8. 7. A data generation method for controlling aperture blades of an X-ray image diagnostic apparatus according to claim 6, wherein the plurality of aperture blades are arranged in pairs, and the pair of aperture blades is configured such that the two aperture blades are arranged opposite each other across an optical axis of the X-ray source and move in conjunction with each other so that the distances from the optical axis are equal, An X-ray image diagnostic apparatus, characterized in that one of the correspondence relationships is obtained for the set of aperture blades by the first to sixth steps.

9. 7. A data generation method for controlling aperture blades of an X-ray image diagnostic apparatus according to claim 6, wherein the plurality of aperture blades are arranged to surround an optical axis of the X-ray source and each of the aperture blades moves independently, A data generation method for controlling aperture blades of an X-ray image diagnostic apparatus, comprising the steps of: determining the correspondence relationship for each of a plurality of aperture blades through the first to sixth steps.

10. 7. A data generation method for controlling aperture blades of an X-ray imaging diagnostic apparatus according to claim 6, comprising the steps of: a rotation mechanism for tilting the X-ray aperture device at a predetermined tilt angle, and executing the first to sixth steps to determine the correspondence relationship for each of a plurality of tilt angles, thereby determining the correspondence relationship for each of a plurality of predetermined tilt angles.

Images