JP2015051067A - X-ray diagnostic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray diagnostic apparatus which collects an image of a pre-stage detector excellent in resolution regardless of the size of a designated region of interest.SOLUTION: An X-ray diagnostic apparatus 1 includes: an X-ray source; a post-stage detector; a pre-stage detector the maximum visual field size of which is smaller than the maximum visual field size of the post-stage detector and which can detect X-rays at a stage more preceding than the post-stage detector; and switch control means 138 which controls SID of the pre-stage detector according to a visual field size of the pre-stage detector corresponding to a designated region of interest when the region of interest is designated on an image by the post-stage detector.

Description

  The present embodiment as one aspect of the present invention relates to an X-ray diagnostic apparatus that performs fluoroscopy and imaging.

  Conventionally, in a medical field such as a medical examination, radiation (typically, X-rays) is irradiated to an imaging region of a subject, and an intensity distribution of the radiation that has passed through the imaging region is detected to obtain an image of the imaging region. X-ray diagnostic apparatuses are widely used.

  In an examination using an X-ray diagnostic apparatus, a region of interest is narrow, but there is a desire to clearly observe an intended region with a higher resolution. In order to realize this demand, there is a technique in which a front-stage detector is combined with a normal rear-stage detector and either one of the detectors is switched according to a diagnostic application (see, for example, Patent Document 1).

  The post-stage detector is an FPD (flat panel detector), the pixel size is 150-200 μm, and the maximum field size is 20 cm-40 cm. The front detector is a detector having a high definition (high resolution) but a narrow field of view as compared with the rear detector, and has a pixel size of about 20 μm and a maximum field size of about 20-30 mm.

Japanese Patent No. 4570942

  However, according to the X-ray diagnostic apparatus in the prior art, it is necessary to perform positioning when using the front detector while looking at the image of the front detector, but from the viewpoint of manufacturing the front detector, a large panel cannot be manufactured. Positioning is difficult because the field of view is narrow. Furthermore, since the pre-stage detector has a small pixel, it is necessary to increase the X-ray dose in order to display with good S / N (signal-to-noise ratio). While observing, positioning should not be performed when using the pre-stage detector.

  In view of this, it is conceivable to perform positioning when the front detector is used by allowing the operator to designate the region of interest of the front detector on the image of the rear detector. However, if the designated region of interest is relatively small, the image is captured with a field size smaller than the maximum field size of the front detector, and the resolution of the collected image is reduced. On the other hand, when the designated region of interest is relatively large, it is necessary to collect a plurality of images corresponding to a plurality of positions with a pre-stage detector in order to generate a long image by joining a plurality of images. It was very troublesome for the operator to manually change the position.

  In order to solve the above-described problem, the X-ray diagnostic apparatus of the present embodiment includes an X-ray source that emits X-rays, a rear-stage detector that detects the X-rays, and a maximum field size that is the maximum field of view of the rear-stage detector. A pre-stage detector that is smaller in size and capable of detecting the X-rays before the post-stage detector, and when a region of interest is designated on the image by the post-stage detector, the pre-stage detection corresponding to the designated region of interest Control means for controlling the SID of the preceding detector according to the visual field size of the detector.

Schematic which shows the structure of the X-ray diagnostic apparatus of this embodiment. The figure which shows a SID correspondence table. The figure which shows the structure relevant to imaging | photography using a front | former stage detector. The figure for demonstrating the designation | designated method of the region of interest of a front | former stage detector. The figure which shows an example of the moving mechanism of a front | former stage detector. The block diagram which shows the function of the X-ray diagnostic apparatus of this embodiment. (A)-(F) are the figures which show the relationship between the designated region of interest and the visual field size corresponding to it. The figure which shows the relationship between SID at the time of use of a back | latter stage detector, and SID in the case of the largest visual field size. The figure which shows the relationship between SID at the time of use of a back | latter stage detector, and SID in the case of the largest visual field size. The figure which shows the relationship between SID at the time of use of a back | latter stage detector, and SID in the case of the largest visual field size. The figure which shows the relationship between SID at the time of use of a back | latter stage detector, and SID in the case of the largest visual field size. The figure which shows the relationship between the designated region of interest and the visual field size corresponding to it. The figure which shows the relationship between SID at the time of use of a front | former stage detector, and SID in the case of the largest visual field size. (A), (B) is a figure which shows the setting method of several set positions. (A), (B) is a figure which shows the region of interest designated on the image of a back | latter stage detector, and the display screen containing the simulated image of a region of interest. (A), (B) is a figure which shows the region of interest designated on the image of a back | latter stage detector, and the display screen containing the simulated image of a region of interest. The flowchart which shows operation | movement of the X-ray diagnostic apparatus of this embodiment. The flowchart which shows operation | movement of the X-ray diagnostic apparatus of this embodiment. The flowchart which shows operation | movement of the X-ray diagnostic apparatus of this embodiment.

  The X-ray diagnostic apparatus of this embodiment will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram showing the configuration of the X-ray diagnostic apparatus of the present embodiment.

  FIG. 1 shows an X-ray diagnostic apparatus 1 according to this embodiment. The X-ray diagnostic apparatus 1 mainly includes an X-ray generation unit 2, an X-ray detection unit 3, a mechanism unit 4, a high voltage generation unit 5, a C arm (support unit) 6, a top plate (mounting unit) 7, an image. A processing unit 8, a display unit 9, an operation unit 10, a storage unit 11, an IF (interface) 12, and a system control unit 13 are provided. Hereinafter, as shown in FIG. 1, description will be made using an X-ray diagnostic apparatus 1 having only a floor-standing C-arm (under tube type). The X-ray diagnostic apparatus according to the present invention includes an overhead traveling type Ω arm and a floor standing type C arm, an overhead traveling type C arm, and an overhead traveling type Ω arm alone, in addition to the floor standing type C arm. It may be a line diagnostic apparatus. The X-ray diagnostic apparatus according to the present invention may be an X-ray diagnostic apparatus including an overtube type C-arm.

  The X-ray generator 2 is a device that generates X-rays that are irradiated onto a subject (imaging site) S on the top board 7. The X-ray generator 2 includes an X-ray source (X-ray tube) 21 that generates X-rays using the high voltage supplied from the high voltage generator 5 and a part of the X-rays generated by the X-ray tube 21. An X-ray diaphragm 22 that controls the irradiation field by shielding is provided. Note that a radiation quality adjustment filter (not shown) for adjusting the quality of the X-rays generated by the X-ray tube 21 may be provided in the previous stage of the X-ray tube 21.

  The X-ray detection unit 3 is an apparatus that detects X-rays transmitted through the subject S and generates image data. The X-ray detector 3 includes a rear detector 31a, which is a flat detector normally used when imaging the subject S, and a maximum visual field size smaller than the maximum visual field size of the rear detector 31a. A front-stage detector 31b capable of detecting X-rays at the set position; a gate driver 32 that extracts charges from the rear-stage detector 31a; and a charge / voltage converter 33 that converts charges detected by the rear-stage detector 31a into voltages. An A / D converter 34 for converting the voltage converted by the charge / voltage converter 33 into a digital value is provided. The pre-stage detector 31b is used for detailed observation of a lesioned part or the like with a small visual field and high definition.

  The mechanism unit 4 is a device that moves the detectors 31a and 31b, the C-arm 6 and the top plate 7 as moving objects. The mechanism unit 4 includes a detector moving mechanism 41 that slides the detectors 31 a and 31 b, a C arm moving mechanism 42 that rotates, arcs, and slides the C arm 6, and slides the top plate 7. And a mechanism control unit 44 that controls the detector moving mechanism 41, the C arm moving mechanism 42, and the top plate moving mechanism 43 based on an instruction from the system control unit 13. Although not shown, the mechanism unit 4 is also a device that moves the diaphragm blades (not shown) of the X-ray diaphragm 22.

  The high voltage generator 5 is a device that supplies a high voltage required for the X-ray generator 2 to generate X-rays. The high voltage generation unit 5 includes an X-ray control unit 51 that controls generation of X-rays by controlling generation of high voltage based on an instruction from the system control unit 13, and a high voltage generator 52 that generates high voltage. Provide.

  The C arm 6 is an arm that holds the X-ray generator 2 and the detectors 31a and 31b.

  The top plate 7 has a structure on which the subject S can be placed.

  The image processing unit 8 is a processing unit that processes the image data generated by the X-ray detection unit 3. The image processing unit 8 includes an image calculation circuit 81 that performs reconstruction calculation, subtraction calculation, and the like, and an image data storage circuit 82 that stores image data generated by the image calculation circuit 81.

  The display unit 9 is a device that displays an image stored in the image data storage circuit 82 of the image processing unit 8. The display unit 9 includes a display control unit 91 that controls display on the monitor 92, a monitor 92 that displays an image, and a pointing device 93 (shown in FIG. 3).

  The operation unit 10 is a console including a switch that receives an operation by an operator such as an operator or an assistant.

  The storage unit 11 is configured by an HDD (hard disk drive) or a memory. The storage unit 11 stores fluoroscopic images (real-time images) and captured images (one-shot images) collected by the detectors 31a and 31b. The storage unit 11 also includes an SID in which a plurality of SIDs (source-to-image distance) of the upstream detector 31b are associated with an irradiation angle (FOV: field of view) of the upstream detector 31b corresponding to each SID. Store the correspondence table. The SID correspondence table includes a SID (hereinafter referred to as “maximum visual field size”) for detecting X-rays at a predetermined irradiation angle of the front detector 31b and a maximum visual field size of the front detector 31b at a predetermined irradiation angle. SID ”).

  FIG. 2 shows a SID correspondence table.

  As shown in FIG. 2, in the SID correspondence table, the SID “SF0” in the case of the irradiation angle F0 and the maximum visual field size is associated with the irradiation angle F0 of the upstream detector 31b. Similarly, in the case of the irradiation angles F1, F2, and F3 of the upstream detector 31b, the SIDs “SF1”, “SF2”, and “SF3” in the case of the maximum visual field size are associated with each other. Referring to the SID correspondence table shown in FIG. 2, when imaging and fluoroscopy (hereinafter simply referred to as “imaging”) are performed at a predetermined irradiation angle using the upstream detector 31b, the maximum visual field size is obtained. The SID can be obtained.

  Returning to the description of FIG. 1, the IF 12 includes a connector that conforms to a parallel connection specification or a serial connection specification. The IF 12 has a function of performing communication control according to each standard and connecting to the network N, thereby connecting the X-ray diagnostic apparatus 1 to the network N network.

  The system control unit 13 includes a CPU (central processing unit) and a memory (not shown). The system control unit 13 controls the entire X-ray diagnostic apparatus 1 based on an operation by an operator.

  Next, photographing using the upstream detector 31b will be described.

  FIG. 3 is a diagram illustrating a configuration related to imaging using the upstream detector 31b.

  As shown in FIG. 3, the mechanism control unit 44 includes a rear-stage detector control section 44a for the rear-stage detector 31a and a front-stage detector control section 44b for the front-stage detector 31b. The monitor 92 includes a first monitor 92a for the rear detector 31a and a second monitor 92b for the front detector 31b.

  The display control unit 91 displays an image of the subject S (shown in FIG. 1) on the first monitor 92a. Then, the display control unit 91 accepts designation of a region of interest by the operator via a pointing device 93 such as a mouse for the displayed image of the subject S.

  FIG. 4 is a diagram for explaining a method of specifying a region of interest of the upstream detector 31b.

  As shown in FIG. 4, the region of interest A is designated by the operator via the pointing device 93 on the image Ia by the post-stage detector 31 a displayed on the first monitor 92 a (shown in FIG. 3). Based on the position of the region of interest A, one or more set positions of the upstream detector 31b on the XZ plane (shown in FIG. 5) are set. A method of setting a plurality of set positions of the upstream detector 31b in the XZ plane (shown in FIG. 5) will be described later with reference to FIGS.

  Further, the SID when the front detector 31b is used is calculated from the visual field size of the front detector 31b based on the designated region of interest A.

  Returning to the description of FIG. 3, the system control unit 13 instructs the front-stage detector control unit 44 b of the mechanism control unit 44 to move the front-stage detector 31 b on the XZ plane (shown in FIG. 5). Move to one or more set positions for positioning. When a plurality of set positions are set, the front detector 31b is sequentially moved to the plurality of set positions and positioned in order to sequentially perform photographing at the plurality of set positions. Specifically, the system control unit 13 converts coordinates in the screen coordinate system of the region of interest A (shown in FIG. 4) designated on the first monitor 92a into coordinates in the physical coordinate system of the upstream detector 31b, The front-stage detector control unit 44b is instructed to move the front-stage detector 31b. Then, the upstream detector control unit 44b controls the detector moving mechanism 41 (shown in FIG. 1) to move the upstream detector 31b.

  FIG. 5 is a diagram illustrating an example of a moving mechanism of the upstream detector 31b.

  FIG. 5 shows a moving mechanism of the upstream detector 31b when the SID direction is the Y direction and the two directions orthogonal to the Y direction are the X and Z directions. The upper part of FIG. 5 shows the side surface (YZ plane) of the moving mechanism of the front detector 31b, and the lower part of FIG. 5 shows the upper surface (XZ plane) of the moving mechanism of the front detector 31b. The detector moving mechanism 41 (shown in FIG. 1) includes a Z-direction drive mechanism 41a that moves the front detector 31b in the Z direction (d1 direction) with respect to the rear detector 31a as a moving mechanism of the front detector 31b. And an X-direction drive mechanism 41b that moves in the X direction (d2 direction). The X-direction drive mechanism 41a moves the front detector 31b from the home position (retracted position) side to the set position side (leftward in the d1 direction) or moves from the set position side to the home position side (in the d1 direction). To the right).

  Returning to the description of FIG. 3, when the pre-stage detector 31b is moved and positioned to the set position on the XZ plane (shown in FIG. 5) set on the first monitor 92a, the system control unit 13 The current SID of the upstream detector 31b is changed to the SID when using the upstream detector 31b calculated based on the region of interest A (shown in FIG. 4), and positioning in the Y direction (shown in FIG. 5) is performed. .

  The display control unit 91 receives an image signal generated based on the X-ray detected by the X-ray detector 31b. Then, the display control unit 91 displays an image based on the image signal on the second monitor 92b.

  As described above, the system control unit 13 converts the coordinates in the screen coordinate system of the region of interest A (shown in FIG. 4) set on the first monitor 92a into the coordinates in the physical coordinate system, and the former detector control unit 44b. By instructing the movement of the pre-stage detector 31b, the pre-stage detector control unit 44b controls the detector moving mechanism 41 to move the pre-stage detector 31b. Can display in high definition.

  Also, the display control unit 91 may display the image Ib from the upstream detector 31b so as to overlap the region of interest A (shown in FIG. 4) designated by the operator on the image Ia from the downstream detector 31a. In this case, the operator can observe the lesioned part or the like in detail while comparing it with the surrounding area.

  Here, the image Ia obtained by the rear detector 31a is a photographed image immediately before the front detector 31b moves, but a fluoroscopic image obtained by the rear detector 31a can also be displayed as the image Ia obtained by the rear detector 31a. . Further, the image Ib obtained by the upstream detector 31b can be a captured image or a perspective image.

  FIG. 6 is a block diagram showing functions of the X-ray diagnostic apparatus 1 of the present embodiment.

  When the system control unit 13 shown in FIG. 1 executes the program, as shown in FIG. 6, the X-ray diagnostic apparatus 1 includes an alignment unit 131, an imaging control unit 132, an operation reception unit 133, a visual field size setting unit 134, It functions as an SID setting unit 135, a simulated image generation unit 136, an X-ray dose calculation unit 137, and a switching control unit 138. Note that some or all of the units 131 to 138 as functions of the system control unit 13 may be provided as hardware in the X-ray diagnostic apparatus 1.

  The alignment means 131 is a three-dimensional image that is collected and reconstructed by the post-stage detector 31a after the subject S is placed on the top 7 (shown in FIG. 1), or an image such as an X-ray CT apparatus. Using the three-dimensional image collected by the diagnostic device (modality) and transmitted via the IF 12 (shown in FIG. 1), the mechanism unit 4 is controlled according to the operation by the operation unit 10, and the subject on the top 7 Position the moving object with respect to S.

  The imaging control unit 132 controls the X-ray generation unit 2, the X-ray detection unit 3, the mechanism unit 4, the high voltage generation unit 5, the image processing unit 8, the display unit 9, and the storage unit 11 according to the operation by the operation unit 10. Thus, it has a function of controlling imaging of the subject S on the top board 7. The photographing control unit 132 displays an image obtained by photographing through the display unit 9 or stores it in the storage unit 11.

  The operation accepting unit 133 has a function of accepting an operation for designating a region of interest of the upstream detector 31b from the operation unit 10 during imaging using the downstream detector 31a by the imaging control unit 132. Further, the operation accepting unit 133 has a function of accepting a switching operation of the use detector to the former detector 31b during photographing using the latter detector 31a by the photographing control unit 132. The operation accepting unit 133 may accept a direct switching operation when accepting a switching operation from the latter detector 31a to the former detector 31b while using the latter detector 31a, or may be set in advance. You may receive selection operation of FOV corresponding to the front | former stage detector 31b by the operation part 10 from several FOV. Further, the operation accepting unit 133 has a function of accepting a switching operation to the subsequent detector 31a of the use detector during photographing using the front detector 31b by the photographing control unit 132.

  The field-of-view size setting unit 134 has a function of setting the field-of-view size of the upstream detector 31b based on the designated region of interest when the operation receiving unit 133 receives the operation of specifying the region of interest of the upstream detector 31b.

  FIGS. 7A to 7F are diagrams showing the relationship between the designated region of interest and the visual field size corresponding thereto.

  In FIG. 7A, the designated region of interest A1 is set as the visual field size Cs. The visual field size Cs matches the maximum visual field size Cmax.

  FIG. 7B shows a case where the designated region of interest A2 is smaller than the maximum field size Cmax of the front detector 31b only in the Z direction. In this case, the square visual field size Cs formed by the larger length of the lengths of the region of interest A2 in the X and Z directions is set. The visual field size Cs matches the maximum visual field size Cmax.

  FIG. 7C shows a case where the designated region of interest A3 is smaller than the maximum visual field size Cmax of the front detector 31b in the X and Z directions. In this case, a square visual field size Ct formed by the larger length of the lengths of the region of interest A3 in the X and Z directions is set. The visual field size Ct is smaller than the maximum visual field size Cmax.

  FIG. 7D shows a case where the designated region of interest A4 is larger than the maximum visual field size Cmax of the upstream detector 31b only in the Z direction. In this case, a square visual field size Cu formed by the larger length of the lengths of the region of interest A4 in the X and Z directions is set. The visual field size Cu is larger than the maximum visual field size Cmax.

  FIG. 7E shows a case where the designated region of interest A5 is larger than the maximum visual field size Cmax of the upstream detector 31b in the X and Z directions. In this case, a square visual field size Cu formed by the larger length of the lengths of the region of interest A5 in the X and Z directions is set. The visual field size Cu is larger than the maximum visual field size Cmax.

  FIG. 7F shows a case where the designated region of interest A6 is larger than the maximum visual field size Cmax of the upstream detector 31b in the X direction and smaller than the maximum visual field size Cmax of the upstream detector 31b in the Z direction. In this case, the square visual field size Cu formed by the larger length of the lengths of the region of interest A6 in the X and Z directions is set. The visual field size Cu is larger than the maximum visual field size Cmax.

  In addition, although the case where the shape of the visual field size Cs, Ct, Cu shown in FIGS. 7A to 7F is a square has been described, this is based on the assumption that the detection surface of the upstream detector 31b is a square. ing. When the shape of the detection surface of the upstream detector 31b is rectangular, the shapes of the visual field sizes Cs, Ct, and Cu are set according to the shape.

  Returning to the description of FIG. 6, when the operation accepting unit 133 accepts the region of interest designation operation of the upstream detector 31b, the SID setting unit 135 determines whether the SID setting unit 135 is based on the visual field size set by the visual field size setting unit 134. It has a function of setting the SID when the detector 31b is used. The SID setting unit 135 calculates the current irradiation angle of the front detector 31b based on the visual field size and the current SID of the front detector 31b, and refers to the irradiation angle in the SID correspondence table. It is set as the SID when using the upstream detector 31b.

  8 to 11 are diagrams showing the relationship between the SID when the rear detector 31b is used and the SID when the maximum visual field size is used.

  8 to 11 are side views (XY plan views) of the X-ray tube 21 and the upstream detection unit 31b. Since the YZ plane can be considered in the same manner as the XY plane, description thereof is omitted.

  FIG. 8 shows an irradiation angle F1 calculated based on the visual field size Cs (also shown in FIGS. 7A and 7B) and the current SID “SF0” of the upstream detector 31 as an SID correspondence table (FIG. 2). The case where the SID “SF1” obtained with reference to FIG. 5 matches the current SID “SF0” of the upstream detector 31b is shown. In this case, the current SID “SF0” of the upstream detector 31b is set as it is as the SID when the upstream detector 31b is used. The visual field size Cs of the upstream detector 31b matches the maximum visual field size Cmax.

  FIG. 9 shows the irradiation angle F2 calculated based on the visual field size Ct (also shown in FIG. 7C) and the current SID “SF0” of the upstream detector 31b in the SID correspondence table (shown in FIG. 2). The case where the current SID “SF0” of the upstream detector 31b is smaller than the SID “SF2” obtained by reference is shown. In this case, the SID “SF2” in the case of the maximum visual field size is set as the SID when the front detector 31b is used. The field size Ct ′ of the upstream detector 31b corresponding to the SID “SF2” and the irradiation angle F2 in the case of the maximum field size matches the maximum field size Cmax.

  Note that the SID is limited by the mechanism, and the SID “SF2” in the case of the maximum visual field size may not be set as the SID when using the upstream detector 31b. In that case, as shown in FIG. 10, the maximum SID “Smax” of the limit on the mechanism is set as the SID when the front detector 31b is used. Although the visual field size Ct ″ of the upstream detector 31b corresponding to the maximum SID “Smax” and the irradiation angle F2 is smaller than the maximum visual field size Cmax, the visual field size Ct is closer to the maximum visual field size Cmax.

  FIG. 11 shows an irradiation angle F3 calculated based on the visual field size Cu (also shown in FIGS. 7D to 7F) and the current SID “SF0” of the upstream detector 31b. The case where the current SID “SF0” of the upstream detector 31b is larger than the SID “SF3” obtained by referring to FIG. In this case, the SID “SF3” in the case of the maximum visual field size is set as the SID when the front detector 31b is used. The field size Cu ′ of the upstream detector 31b corresponding to the SID “SF3” and the irradiation angle F3 in the case of the maximum field size is equal to the maximum field size Cmax.

  The SID is mechanically limited, and the height of the subject S (shown in FIG. 1) and the top plate 7 (shown in FIG. 1) is limited, and the SID “SF3” in the case of the maximum visual field size is the front detector. It may not be set as the SID when using 31b. Such a case will be described with reference to FIGS.

  FIG. 12 is a diagram illustrating a relationship between a designated region of interest and a corresponding field size.

  FIG. 12 is a modification of FIG. 7E, and shows a case where the designated region of interest A7 is larger than the maximum visual field size Cmax of the front detector 31b in the X and Z directions. A square visual field size Ck formed by the larger length of the lengths of the region of interest A7 in the X and Z directions is calculated.

  However, since the visual field size Ck is too large, it is impossible to photograph the visual field size Ck with the maximum visual field size of the upstream detector 31b due to the limitation on the mechanism. In that case, a plurality of set positions of the upstream detector 31b are set along the X direction, and imaging is performed a plurality of times at the plurality of set positions.

  FIG. 13 is a diagram showing the relationship between the SID when the front detector 31b is used and the SID when the maximum visual field size is used.

  FIG. 13 is a side view (XY plan view) of the X-ray tube 21 and the upstream detection unit 31b. As shown in FIG. 13, the minimum SID “Smin”, which is the limit on the mechanism, is set as the SID when the front detector 31b is used. The irradiation angle can be obtained by referring to the SID correspondence table with the minimum SID “Smin”, and the field size Cm of the upstream detector 31b corresponding to the minimum SID “Smin” and the irradiation angle matches the maximum field size Cmax. . When there is a means for detecting that the minimum SID is further restricted due to the restriction of the height of the subject S (shown in FIG. 1) and the top plate 7 (shown in FIG. 1), the subject S and the top The minimum SID associated with the height of the plate 7 can be set as “Smin”.

  14A and 14B are diagrams showing a method for setting a plurality of set positions.

  FIG. 14A shows the length Cmx in the X direction of the three regions W1, W2, and W3 formed by the visual field size Cm (shown in FIG. 13), and the adjacent regions (between W1-W2 and W2). And the length amin of the minimum overlapping portion (between -W3). Based on the length Cmx, the minimum length amin of the overlapping portion, and the number of regions n (n = 2, 3, 4,...) Formed by the field size Cm, the length is calculated using the following formula. L [n] is calculated.

  L [n] = n × (Cmx−amin) + (n−1) × amin

  The lengths L [2], L [3], L [4],... Calculated by sequentially substituting 2, 3, 4,... For n in the above equation are the lengths Ax in the X direction of the region of interest A7. The minimum number n in the case of exceeding is set as the number of regions formed by the visual field size.

  Then, as shown in FIG. 14B, the length a of the overlapping portion between adjacent regions is adjusted so as to be within the length Ax in the X direction of the region of interest A7, and the region of interest A7 and the visual field size Cm ( The relationship with the number of regions formed is determined by (shown in FIG. 13). A plurality of set positions along the X direction that can respectively collect images of a plurality of regions arranged in this way are set. 14A and 14B show a case where the minimum number of regions exceeding the length Ax in the X direction of the region of interest A7 is n = 3 (L [3]> Ax).

  14A and 14B, the relationship between the region of interest A7 in the X direction and the number of regions formed by the visual field size Cm (shown in FIG. 13) has been described. The relationship between the region A7 and the number of regions formed by the visual field size Cm (shown in FIG. 13) can be similarly determined.

  Returning to the description of FIG. 6, when the operation accepting unit 133 accepts a designation operation for the region of interest A (shown in FIG. 4) on the image Ia (shown in FIG. 4), the simulated image generating unit 136 accepts the image Ia ( And a function of generating an enlarged image (simulated image) of the region of interest A based on FIG. The simulated image generated by the simulated image generation unit 136 is displayed on the display unit 9.

  15A and 15B show a region of interest A2 (also shown in FIG. 7B) designated on the image Ia of the post-stage detector 31a and a display screen including a simulated image of the region of interest A2. FIG. 16A and 16B are views showing a region of interest A7 (also shown in FIG. 12) designated on the image Ia of the post-stage detector 31a and a display screen including a simulated image of the region of interest A7. is there.

  FIG. 15A shows a region of interest A2 designated on the image Ia of the post-stage detector 31a and its X and Z directions. FIG. 15B shows a display screen including a simulated image (low resolution) of the region of interest A2 based on the image Ia. In this case, as described with reference to FIG. 9, the SID “SF2” is set.

  As shown in FIG. 15B, the display screen includes “130 cm” as the SID “SF2” (shown in FIG. 9) in the case of the maximum visual field size. The display screen may include an X-ray condition in the SID “SF2” in the case of the maximum visual field size. Further, the display screen may include the number of set positions (number of times of photographing) in the SID “SF2”. Note that, when a high-resolution image of the region equivalent to the simulated image is collected by the upstream detector 31b, the width of the region of interest A2 in the Z direction is smaller than the width of the region of interest A2 in the X direction. Both end regions of the image are shielded by the X-ray diaphragm 22 (shown in FIG. 1) and imaged.

  FIG. 16A shows a region of interest A7 designated on the image Ia of the post-stage detector 31a and its X and Z directions. FIG. 16A shows a display screen including a simulated image (low resolution) of the region of interest A7 based on the image Ia. In this case, as described with reference to FIG. 13, the minimum SID “Smin” is set.

  As shown in FIG. 16B, the display screen includes “100 cm” as the SID “Smin” (shown in FIG. 13). The display screen may include an X-ray condition for the SID “Smin”. Further, the display screen may include the number of set positions (number of times of photographing) in the SID “Smin”. In addition, the simulated image on the display screen may show frames of a plurality of areas W1 and W2 having a visual field size Cm (shown in FIG. 13). Note that, when a high-resolution image of the region equivalent to the simulated image is collected by the upstream detector 31b, the width of the region of interest A2 in the Z direction is smaller than the width of the region of interest A2 in the X direction. Both end regions of the image are shielded by the X-ray diaphragm 22 (shown in FIG. 1) and imaged.

  Returning to the description of FIG. 6, the X-ray dose calculating unit 137 determines that the current SID is smaller than the SID when using the upstream detector 31b set by the SID setting unit 135 (in the case illustrated in FIGS. 9 and 10). It has a function of calculating the X-ray dose corresponding to the set SID when using the upstream detector 31b. The X-ray dose calculated by the X-ray dose calculating means 137 is displayed on the display unit 9. The X-ray dose calculating means 137 calculates a larger X-ray dose as the SID is larger. The operator can check the displayed X-ray dose and determine whether or not to adopt the set SID when using the upstream detector 31b.

  The switching control unit 138 controls the mechanism unit 4 when the operation receiving unit 133 receives the region of interest designation operation and the usage detector switching operation is received, as described with reference to FIG. , And a function of switching the use detector from the post-stage detector 31a to the pre-stage detector 31b. In that case, the switching control unit 138 controls the mechanism unit 4 to position the front-stage detector 31b on the XZ plane (shown in FIG. 5), and the front-stage detector 31b set by the SID setting unit 135. Based on the SID at the time of use, positioning is performed in the Y direction (shown in FIG. 5), that is, in the SID direction. When changing the SID, the switching control unit 138 controls the mechanism unit 4 to move the X-ray detection unit 3 (or X-ray generation unit 2) in the Y direction (shown in FIG. 5).

  Then, the photographing control unit 132 performs photographing with the SIDs “SF1”, “SF2”, “Smax”, and “SF3” shown in FIGS. 8 to 11 respectively. Therefore, since the photographing is performed with the visual field sizes Cs, Ct ′, Ct ″, or Cu ′ shown in FIGS. 8 to 11, it is possible to collect optically high-resolution images as compared with the prior art. . Further, the photographing control unit 132 performs photographing at the SID “Smin” shown in FIG. 13 at each of a plurality of set positions on the XZ plane (shown in FIG. 5) set automatically. Therefore, since shooting is performed with the field of view size Cm shown in FIG. 13 at each of a plurality of set positions on the XZ plane (shown in FIG. 5), the operator can compare with the prior art. Regardless of the operation of changing the set position, an optically high resolution image can be automatically collected.

  Subsequently, the operation of the X-ray diagnostic apparatus 1 of the present embodiment will be described with reference to FIGS. 1 and 17 to 19.

  17 to 19 are flowcharts showing the operation of the X-ray diagnostic apparatus 1 of the present embodiment.

  The X-ray diagnostic apparatus 1 includes an X-ray generation unit according to an operation by the operation unit 10 after the mechanism unit 4 is controlled according to an operation by the operation unit 10 and the moving object is positioned with respect to the subject S on the top plate 7. 2, the X-ray detection unit 3, the mechanism unit 4, the high voltage generation unit 5, the image processing unit 8, the display unit 9, and the storage unit 11 are controlled by the post-stage detector 31a of the subject S on the top 7 Shooting is started (step ST1). The X-ray diagnostic apparatus 1 displays an image obtained by imaging in step ST1 via the first monitor 92a (shown in FIG. 2) or stores it in the storage unit 11.

  When the imaging by the post-stage detector 31a is started in step ST1, the X-ray diagnostic apparatus 1 has designated the region of interest A (shown in FIG. 4) and has accepted the operation of switching the use detector to the pre-stage detector 31b. It is determined whether or not (step ST2). When the determination in step ST2 is YES, that is, when it is determined that the switching operation to the subsequent detector 31a of the use detector is accepted, the X-ray diagnostic apparatus 1 is started in step ST1 (or FIG. 19 described later). The imaging by the post-stage detector 31a (resumed in step ST28) is terminated (step ST3).

  If the determination in step ST2 is NO, that is, if it is determined that the switching operation to the downstream detector 31a of the usage detector is not accepted, the X-ray diagnostic apparatus 1 determines whether or not to finish imaging of the subject S. Is determined (step ST4). If YES in step ST4, that is, if it is determined that the imaging of the subject S is to be terminated, the X-ray diagnostic apparatus 1 ends the operation. On the other hand, if the determination in step ST4 is NO, that is, if it is determined not to end imaging of the subject S, the X-ray diagnostic apparatus 1 returns to step ST2.

  Subsequent to step ST3, the X-ray diagnostic apparatus 1 controls the mechanism unit 4 so that the upstream detector 31b is set on the XZ plane (shown in FIG. 5) based on the region of interest A (shown in FIG. 4). And is aligned on the XZ plane (shown in FIG. 5) (step ST5). Then, the X-ray diagnostic apparatus 1 sets a visual field size based on the designated region of interest A (shown in FIG. 4) (step ST6). The field-of-view size setting method in step ST6 is as described with reference to FIGS. 7A to 7F and FIG.

  The X-ray diagnostic apparatus 1 calculates the irradiation angle of the pre-stage detector 31b based on the current SID of the pre-stage detector 31b and the visual field size set in step ST6, and the irradiation angle is set in the SID correspondence table (FIG. 2). SID is obtained by referring to FIG.

  The X-ray diagnostic apparatus 1 determines whether or not the current SID of the upstream detector 31b matches the SID in the case of the maximum visual field size obtained in step ST7 (step ST8). If YES in step ST8, that is, if it is determined that the current SID matches the SID in the case of the maximum visual field size (as illustrated in FIG. 8), the current SID of the upstream detector 31b is not changed. The X-ray diagnostic apparatus 1 controls the X-ray generation unit 2, the X-ray detection unit 3, the mechanism unit 4, the high voltage generation unit 5, the image processing unit 8, the display unit 9, and the storage unit 11 to Imaging of the subject S on the plate 7 by the upstream detector 31b is started (step ST9 in FIG. 19). The X-ray diagnostic apparatus 1 displays an image obtained by imaging in step ST9 via the second monitor 92b (shown in FIG. 3) or stores it in the storage unit 11. While the former detector 31b is being used, the SID may be changed based on the SID changing operation.

  On the other hand, if the determination in step ST8 is NO, that is, if it is determined that the current SID of the upstream detector 31b does not match the SID in the case of the maximum visual field size, the X-ray diagnostic apparatus 1 determines that the upstream detector 31b It is determined whether or not the current SID is smaller than the SID in the case of the maximum visual field size obtained in step ST7 (step ST10 in FIG. 18). If YES in step ST10, that is, if it is determined that the current SID of the upstream detector 31b is smaller than the SID in the case of the maximum visual field size, the current SID of the upstream detector 31b is set to the maximum obtained by step ST7. It is determined whether or not it is possible to enlarge and change to the SID in the case of the field size (step ST11). If YES in step ST11, that is, if it is determined that the current SID of the upstream detector 31b can be enlarged and changed to the SID in the case of the maximum visual field size (in the case illustrated in FIG. 9), X-rays The diagnostic apparatus 1 generates a simulated image (shown in FIG. 15B) relating to the designated region of interest based on the image Ia (shown in FIG. 4) of the post-stage detector 31a and displays it on the display unit 9, The X-ray dose corresponding to the SID in the case of the maximum visual field size obtained in step ST7 is calculated and displayed on the display unit 9 (step ST12).

  The X-ray diagnostic apparatus 1 controls the mechanism unit 4 to obtain the current SID of the upstream detector 31b in step ST7 when the allowable operation of the X-ray dose displayed in step ST11 is performed (step ST13). The SID is enlarged and changed to the Y direction (shown in FIG. 5) for the maximum field size (step ST14). Then, the X-ray diagnostic apparatus 1 starts imaging of the subject S on the top board 7 by the front detector 31b (step ST9 in FIG. 19).

  When NO is determined in step ST11, that is, when it is determined that the current SID of the front detector 31b cannot be enlarged and changed to the SID in the case of the maximum visual field size (in the case illustrated in FIG. 10). The X-ray diagnostic apparatus 1 obtains the maximum SID on the mechanism (step ST15). Then, the X-ray diagnostic apparatus 1 generates a simulated image related to the designated region of interest based on the image Ia (illustrated in FIG. 4) of the post-stage detector 31a and displays it on the display unit 9, and is obtained by step ST15. The X-ray dose corresponding to the maximum SID is calculated and displayed on the display unit 9 (step ST16).

  The X-ray diagnostic apparatus 1 controls the mechanism unit 4 when the allowable operation of the X-ray dose displayed in step ST16 is performed (step ST17), and the current SID of the upstream detector 31b is obtained in step ST15. The image is enlarged and changed to the maximum SID and aligned in the Y direction (shown in FIG. 5) (step ST18). Then, the X-ray diagnostic apparatus 1 starts imaging of the subject S on the top board 7 by the front detector 31b (step ST9 in FIG. 19).

  In Step ST10, NO, that is, if it is determined that the current SID of the front detector 31b is larger than the SID in the case of the maximum visual field size, the X-ray diagnostic apparatus 1 determines that the current SID of the front detector 31b. It is determined whether or not it is mechanically possible to reduce and change to SID in the case of the maximum visual field size obtained in step ST7 (step ST19). If YES in step ST19, that is, if it is determined that the current SID of the upstream detector 31b can be reduced and changed to the SID in the case of the maximum visual field size (in the case illustrated in FIG. 11), X-rays Based on the image Ia (illustrated in FIG. 4) of the post-stage detector 31a, the diagnostic apparatus 1 generates a simulated image related to the designated region of interest and displays it on the display unit 9 (step ST20).

  The X-ray diagnostic apparatus 1 controls the mechanism unit 4 to reduce the current SID of the upstream detector 31b to the SID in the case of the maximum visual field size obtained in step ST7 and to change the Y direction (shown in FIG. 5). ) (Step ST21). Then, the X-ray diagnostic apparatus 1 starts imaging of the subject S on the top board 7 by the front detector 31b (step ST9 in FIG. 19).

  If NO in step ST19, that is, if it is determined that the current SID of the upstream detector 31b cannot be reduced to the SID in the case of the maximum visual field size (in the case illustrated in FIG. 13) The X-ray diagnostic apparatus 1 obtains the minimum SID on the mechanism (step ST22). The X-ray diagnostic apparatus 1 sets a plurality of set positions on the XZ plane (shown in FIG. 5) (step ST23). The method for setting a plurality of set positions in step ST23 is as described with reference to FIGS. 14 (A) and 14 (B). Then, the X-ray diagnostic apparatus 1 generates a simulated image (shown in FIG. 16B) relating to the designated region of interest based on the image Ia (shown in FIG. 4) of the post-stage detector 31a, and displays the display unit 9 (Step ST24).

  The X-ray diagnostic apparatus 1 controls the mechanism unit 4 to reduce the current SID of the upstream detector 31b to the minimum SID obtained in step ST22 and align it in the Y direction (shown in FIG. 5). (Step ST25). Then, the X-ray diagnostic apparatus 1 starts imaging of the subject S on the top board 7 by the front detector 31b (step ST9 in FIG. 19).

  Subsequent to step ST9, the X-ray diagnostic apparatus 1 determines whether or not a switching operation to the downstream detector 31a of the use detector has been accepted (step ST26). If YES in step ST26, that is, if it is determined that a switching operation to the subsequent detector 31a of the usage detector has been received, the X-ray diagnostic apparatus 1 performs imaging by the upstream detector 31b started in step ST9. The process ends (step ST27). The X-ray diagnostic apparatus 1 controls the X-ray generation unit 2, the X-ray detection unit 3, the mechanism unit 4, the high voltage generation unit 5, the image processing unit 8, the display unit 9, and the storage unit 11 to control the top plate 7. Imaging by the latter detector 31a of the upper subject S is resumed (step ST28), and the process returns to step ST2 in FIG.

  If NO in step ST26, that is, if it is determined that the switching operation to the downstream detector 31a of the usage detector is not accepted, the X-ray diagnostic apparatus 1 switches to the downstream detector 31a of the usage detector. Wait until the operation is accepted.

  According to the X-ray diagnostic apparatus 1 of the present embodiment, it is possible to collect images of the upstream detector 31b having excellent resolution regardless of the size of the region of interest designated on the image by the downstream detector 31a. Further, according to the X-ray diagnostic apparatus 1 of the present embodiment, it is possible to improve the operability when changing the position of the upstream detector 31b and collecting a plurality of images corresponding to a plurality of positions.

  Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 X-ray diagnostic apparatus 2 X-ray generation part 3 X-ray detection part 6 C arm (support part)
7 Top plate (mounting part)
10 Operation unit 11 Storage unit 12 IF
13 System control unit 31a Rear stage detector 31b Front stage detector 41 Detector moving mechanism 131 Positioning means 132 Imaging control means 133 Operation accepting means 134 Field size setting means 135 SID setting means 136 Simulated image generating means 137 X-ray dose calculating means 138 Switching Control means

Claims (9)

An X-ray source emitting X-rays;
A subsequent detector for detecting the X-ray;
A front-stage detector having a maximum visual field size smaller than the maximum visual field size of the rear-stage detector and capable of detecting the X-rays before the rear-stage detector;
When a region of interest is designated on the image by the latter detector, the SID (source-to-image distance) of the former detector is set according to the visual field size of the former detector corresponding to the designated region of interest. Control means for controlling;
X-ray diagnostic apparatus.   2. The X-ray diagnostic apparatus according to claim 1, wherein the control unit enlarges and changes the SID when a field size of the front detector corresponding to the region of interest is smaller than a maximum field size of the front detector. . SID setting means for obtaining an SID when the size of the visual field size of the front detector corresponding to the region of interest matches the maximum visual field size of the front detector;
The X-ray diagnostic apparatus according to claim 2, wherein the control unit enlarges and changes the SID so as to be the obtained SID.   The X-ray diagnostic apparatus according to claim 3, wherein the control unit enlarges and changes the SID so that the maximum SID is obtained when the SID cannot be enlarged and changed up to the obtained SID due to the mechanism.   The X-ray diagnostic apparatus according to claim 3, further comprising an X-ray dose calculating unit that calculates an X-ray dose in the SID after the enlargement change and displays the X-ray dose on a display unit.   The control means reduces or changes the SID when the size of the visual field size of the front detector corresponding to the region of interest is larger than the maximum visual field size of the front detector. The X-ray diagnostic apparatus according to Item. SID setting means for obtaining an SID when the size of the visual field size of the front detector corresponding to the region of interest matches the maximum visual field size of the front detector;
The X-ray diagnosis apparatus according to claim 6, wherein the control unit reduces and changes the SID so that the obtained SID is obtained.   The X-ray diagnostic apparatus according to claim 7, wherein when the SID cannot be reduced and changed to the obtained SID due to the mechanism, the control unit reduces and changes the SID so that the SID becomes a minimum SID.   9. The apparatus according to claim 8, further comprising means for setting a plurality of imaging positions with the minimum SID and the maximum field size of the front detector in order to obtain an image of the designated region of interest as a long image. X-ray diagnostic equipment.