JP5689058B2 - X-ray diagnostic apparatus and X-ray image trimming processing method - Google Patents

Description

  The present invention relates to an X-ray diagnostic apparatus, and more particularly to a technique for displaying an X-ray image of a subject obtained by the X-ray diagnostic apparatus.

  Patent Document 1 discloses an X-ray diagnostic apparatus that extracts an irradiation field region by using edge information of a diaphragm in an X-ray image.

JP 2008-200075 A

  Although the X-ray diagnostic apparatus of Patent Document 1 can extract the irradiation field area in the image, the entrance imaging for tilting the X-ray tube and the trimming process for imaging by rotating the aperture It was not considered.

  The present invention has been made in view of the above circumstances, and provides an X-ray diagnostic apparatus and an X-ray image trimming processing method capable of displaying an X-ray image by effectively utilizing a display area while preventing a decrease in resolution. With the goal.

  In order to solve the above problems, an X-ray diagnostic apparatus according to the present invention includes an X-ray generator for generating X-rays, an X-ray diaphragm means for defining an irradiation range of the X-rays, and the X-ray generator. An X-ray flat panel detector that is arranged opposite to detect transmitted X-rays of the subject and outputs a transmitted X-ray signal, and an irradiation field that detects positional information of the X-ray irradiation field region with respect to the X-ray flat panel detector Cutout position candidate point calculation for calculating position information of a cutout position candidate point of a rectangular area circumscribing the irradiation field area in the image based on the transmission X-ray signal based on the position information of the irradiation field area Means, a rectangular area position calculating means for calculating the position information of the rectangular area based on the position information of the candidate point, and a rectangular area display means for displaying the rectangular area.

  The above-mentioned `` rectangular area circumscribing the irradiation field area in the image by the transmitted X-ray signal '' includes all the irradiation field areas in the image in the image by the transmitted X-ray signal detected from the X-ray flat panel detector, Further, it means a rectangular area excluding an area where no X-rays are incident in the pixel column along either the X-axis direction or the Y-axis direction of the image.

  According to the present invention, it is possible to display a rectangular area that includes the entire X-ray irradiation field area and circumscribes the irradiation field area, and can effectively use the display area while preventing a decrease in resolution.

Schematic diagram showing schematic configuration of X-ray diagnostic equipment The flowchart which shows the flow of a process of the X-ray diagnostic apparatus 1 which concerns on this embodiment Schematic diagram showing an example of the positional relationship of the irradiation field region 40 with respect to the X-ray incident surface 30 of the X-ray flat detector 13 detected by the irradiation field region detection means 21 The flowchart which shows the flow of a cut-out position candidate point calculation process Schematic diagram showing the contents of the extraction position candidate point calculation process Flowchart showing the flow of cutout region position calculation processing

  Hereinafter, embodiments to which the present invention is applied will be described. Hereinafter, in all the drawings for explaining the embodiments of the present invention, those having the same function are denoted by the same reference numerals, and repeated explanation thereof is omitted.

  The X-ray diagnostic apparatus according to this embodiment is an X-ray diagnostic apparatus that can perform so-called fluoroscopy (moving image mode) and imaging (still image mode). Hereinafter, a schematic configuration of the X-ray diagnostic apparatus according to the present embodiment will be described with reference to FIG. FIG. 1 is a schematic diagram showing a schematic configuration of an X-ray diagnostic apparatus.

  The X-ray diagnostic apparatus 1 according to the present embodiment includes an X-ray generator 11 that generates X-rays to be irradiated on the subject 2, and an X-ray irradiated to the subject 2 in order to reduce exposure to the subject 2. An X-ray diaphragm 12 that limits the irradiation field area of the X-ray, an X-ray flat panel detector 13 that is disposed opposite to the X-ray generator 11 and detects the transmitted X-ray of the subject 2 and outputs a transmitted X-ray signal; Connected to the control unit 14 and the control unit 14 for generating an X-ray image of the subject 2 based on the X-ray signal and controlling the X-ray generator 11, the X-ray diaphragm 12 and the X-ray flat panel detector 13. And a display device 15 composed of a CRT or the like for displaying an X-ray image. The control unit 14 temporarily stores CPUs and MPUs constituting the control / arithmetic apparatus, various programs and transmitted X-ray signals, and programs and various data necessary for image clipping processing (also referred to as trimming processing) according to the present embodiment. And a storage device composed of a memory or a magnetic disk that stores data in a fixed or fixed manner. The control unit 14 is connected to an input device (not shown) for setting parameters for setting X-ray conditions and trimming processing.

  The control unit 14 includes an irradiation field region detection unit 21 that detects position information of a region irradiated with X-rays to the X-ray flat panel detector 13 (hereinafter referred to as “irradiation field region”), and an irradiation field region detection unit 21. The irradiation field region storage means 22 for storing the position information of the irradiation field region detected in step (b), and the position information of the candidate point of the cutout position of the rectangular region circumscribing the irradiation field region in the image by the transmitted X-ray signal, Cutout position candidate point calculation means 23 for calculating based on the position information of the rectangular area, rectangular area position calculation means 24 for calculating the position of the rectangular area based on the position information of the candidate point, image size of the rectangular area and rectangular area display means On the basis of the ratio of the display area size to the thinning number determining means 25 for determining the thinning number of the image of the rectangular area, and based on the position information obtained by the thinning number determining means 25 and the rectangular area position calculating means 24 , Clipping process (`` tri Consisting ing process "also referred to) rectangular area display means 26 for the X-ray image of the subject 2 consisting of a rectangular area on the display device 15.

  The storage means of the control unit 14 stores an image display program that performs the clipping process according to the present embodiment and displays an image obtained by performing the clipping process. The image display program includes an irradiation field region detection unit, a cutout position candidate point calculation unit, a rectangular region position calculation unit, a thinning number determination unit, and a rectangular region display control unit. The image display program is executed by the hardware constituting the control unit 14 and the functions of the respective units are realized, so that the irradiation field region detection unit 21, the cutout position candidate point calculation unit 23, and the rectangular region position calculation unit 24 are realized. The thinning number determining means 25 and the rectangular area displaying means 26 are configured. The irradiation field area storage means 22 is provided in the control unit 14 and is configured by a storage device that stores the position of the irradiation field area detected by the irradiation field area detection means 21.

  Next, a processing flow of the X-ray diagnostic apparatus 1 according to the present embodiment will be described based on FIG. FIG. 2 is a flowchart showing a process flow of the X-ray diagnostic apparatus 1 according to the present embodiment. Hereinafter, it demonstrates along the step of this flowchart.

(Step S1)
The examiner performs X-ray imaging of the subject 2, the X-ray flat detector 13 detects the X-ray transmitted through the subject 2, outputs a transmitted X-ray signal according to the detected X-ray intensity, and is controlled The data is transmitted to the unit 14 (S1). The transmitted X-ray signal is stored in a storage device in the control unit 14.

(Step S2)
The irradiation field region detecting means 21 detects an X-ray irradiation field region with respect to the X-ray incident surface of the X-ray flat detector 13 (S2).

  The irradiation field region detecting means 21 may detect the irradiation field region based on the system information of the X-ray diagnostic apparatus 1. For example, the X-ray diaphragm 12 and the X-ray plane detector 13 are an integrated X-ray diagnostic apparatus 1, and the controller 14 drives the X-ray diaphragm 12 and the X-ray plane detector 13 to perform alignment. When the present embodiment is applied to the line diagnostic apparatus 1, the potentials of the X-ray diaphragm 12 and the X-ray flat detector 13 are matched in advance, that is, a certain point in space is set to the origin (0, 0, 0), and the spatial coordinates indicating the position of the X-ray diaphragm 12 and the spatial coordinates indicating the position of the X-ray plane detector 13 are defined with reference to the origin. Then, the position where the control unit 14 drives the X-ray diaphragm 12 and the X-ray plane detector 13 is indicated by spatial coordinates, and the control unit 14 positions the X-ray diaphragm 12 and the X-ray plane detector 13 along the spatial coordinates. At the same time, the spatial coordinates may be output to the irradiation field region detecting means 21.

  In addition, when the present embodiment is applied to an X-ray diagnostic apparatus in which the X-ray diaphragm 12 and the X-ray flat detector 13 are configured separately, for example, a roundabout car (mobile X-ray imaging apparatus), A position sensor such as a magnetic sensor or an optical sensor for detecting the relative positional relationship between the line stop 12 and the X-ray flat panel detector 13 is provided, and the sensor mounting position of the X-ray stop 12 is set to the origin (0, 0). , 0), and the spatial coordinates indicating the position of the X-ray plane detector 13 are detected with this origin as a reference. Then, information indicating the spatial coordinates may be output to the irradiation field region detecting means 21.

  The irradiation field region detecting means 21 according to the present embodiment is configured to irradiate on a two-dimensional plane including the X-ray incident surface of the X-ray flat detector 13 based on the positional relationship between the X-ray diaphragm 12 and the X-ray flat detector 13. Calculate the field. More specifically, the coordinates of the irradiation field area on the two-dimensional plane described above are calculated from the positional relationship between the X-ray diaphragm 12 and the X-ray plane detector 13, and one point among the four vertices of the X-ray incident surface is calculated. The coordinates of each vertex of the X-ray incident surface and each vertex of the irradiation field area are converted into two-dimensional coordinates as the origin. Thereby, the irradiation field region can be calculated on a two-dimensional plane with the X-ray incident surface as a reference.

  The irradiation field area detection means 21 performs image processing based on the X-ray image taken by the X-ray diagnostic apparatus 1, detects the irradiation field area in the X-ray image, and extracts the edge of this irradiation field area By doing so, the irradiation field region may be detected. In this case, an irradiation field area for the X-ray image is detected. In the following description, the irradiation field region for the X-ray incident surface 30 of the X-ray flat detector 13 is obtained. However, as described above, the irradiation field region for the X-ray image may be obtained. Thus, the irradiation field region detection means 21 is based on the real space coordinates of the X-ray flat detector 13 and the X-ray diaphragm 12, and the real space coordinates of the irradiation field region on the X-ray flat detector 13 or the X-ray incident surface. Or two-dimensional coordinates on the X-ray image of the irradiation field region may be obtained, and the method is not limited.

  The calculation of the irradiation field area will be described with reference to FIG. FIG. 3 is a schematic diagram showing an example of the positional relationship of the irradiation field region 40 with respect to the X-ray incident surface 30 of the X-ray flat detector 13 detected by the irradiation field region detection means 21. As shown in FIG. FIG. 3 shows a case where the X-ray stop 12 is rotated 45 degrees with respect to the substantially square X-ray incident surface 30. With respect to the X-ray detection surface 30, the rectangular irradiation field region 40 rotates at an angle of 45 degrees, and a part of the positional relationship protrudes. The vertices of the X-ray incident surface 30 are referred to as A, B, C, and D, and the vertices of the irradiation field region 40 are referred to as P, Q, R, and S.

  In the present embodiment, the spatial coordinates indicating the position of the X-ray plane detector 13 are the spatial coordinates (X1, Y1, Z1), (X2, Y2, Z2), (X3, Y3) of the vertices A, B, C, and D. , Z3), (X4, Y4, Z4). Further, as the spatial coordinates indicating the position of the irradiation field region 40, the spatial coordinates (X5, Y5, Z5), (X6, Y6, Z6), (X7, Y7, Z7) of the four vertices P, Q, R, S , (X8, Y8, Z8).

  Irradiation field area detection means 21 has spatial coordinates (X1, Y1, Z1), (X2, Y2, Z2), (X3, Y3, Z3), (X4, Y4, Z4) of vertices A, B, C, D And spatial coordinates (X5, Y5, Z5), (X6, Y6, Z6), (X7, Y7, Z7), (X8, Y8, Z8) of the four vertices P, Q, R, and S of the irradiation field area Based on the above, on the X-ray incident surface 30, one of the four vertices of the X-ray incident surface 30, for example, the two-dimensional coordinate system having the vertex A as the origin (0, 0), the spatial coordinates ( X1, Y1, Z1), (X2, Y2, Z2), (X3, Y3, Z3), (X4, Y4, Z4), (X5, Y5, Z5), (X6, Y6, Z6), (X7, Y7, Z7) and (X8, Y8, Z) are converted. The converted coordinates are stored in the irradiation field area storage means 22.

(Step S3)
The cut-out position candidate point calculating means 23, based on the coordinates of each point obtained in step S2, in the image by the transmitted X-ray signal detected from the entire X-ray incident surface 30, the X-ray irradiation field in the image Cutout candidate points (hereinafter abbreviated as “candidate points”) for cutting out a rectangular region circumscribing the region are calculated.

  The process of this step will be described with reference to FIGS. FIG. 4 is a flowchart showing the flow of processing in this step, that is, the flow of cutout position candidate point calculation processing. FIG. 5 is a schematic diagram showing the contents of the cut-out position candidate point calculation process. Hereinafter, description will be made along each step of FIG.

(Step S301)
The cutout position candidate point calculation means 23 loops the four vertices of the irradiation field region 40 in FIG. 3 (eg, P → Q → R → S), and calculates cutout candidate points based on the respective vertices. First, in the first loop (i = 0), a vertex (for example, P) to be processed first is determined (S301).

(Step S302)
The cut-out position candidate point calculation unit 23 determines whether or not the coordinates of the processing target vertex (for example, the vertex P) are within the range of the X-ray incident surface 30 (S302). If it is within the range, the process proceeds to step S303, and if it is out of the range, the process proceeds to step S304.

(Step S303)
The cut-out position candidate point calculation unit 23 sets a vertex (eg, vertex P) to be processed as a candidate point (S303), saves the coordinates, and then proceeds to step S310.

(Step S304)
The cut-out position candidate point calculation means 23 is a vertex to be processed (for example, vertex Q) and a vertex adjacent to the vertex and to be processed next in the loop described in step S301 (hereinafter referred to as “next vertex”). An intersection of a straight line (for example, QR) connecting the vertex R with respect to the vertex Q and the four sides of the X-ray incident surface 30 or an extension line of the four sides is calculated (S304).

(Step S305)
It is determined whether or not the intersection calculated in step S304 is within the range between the vertices to be processed and the next vertex (S305). If so, the process proceeds to step S307.

(Step S306)
The cut-out position candidate point calculation unit 23 deletes the intersection point outside the range between the vertices from the candidate point (S306), and proceeds to step S310.

(Step S307)
The clipping position candidate point calculation means 23 determines whether or not the intersection is within the range of the X-ray incident surface 30 (in the range of the X-ray plane detector 13 when the X-ray plane detector 13 is used as a reference), that is, (0 (X (orY) coordinate of intersection point) <Maximum value X _max (orY _max ) of the X (orY) coordinate of the X-ray incident surface 30) (S307) If it is out of the range, the intersection is set as a holding point, and the process proceeds to step S309.

(Step S308)
The cut-out position candidate point calculation means 23 sets the intersection point between the straight line connecting the vertex to be processed and the next vertex and the side of the X-ray incident surface 30 as a candidate point (S308), and proceeds to step S310.

(Step S309)
The cut-out position candidate point calculation means 23 moves the reservation point to the nearest point within the range of the X-ray incidence surface 30 along the side of the X-ray incidence surface 30 where the reservation point is located or an extension line of the side. To correct. In other words, this correction is made so that when the coordinates of the X axis and / or Y axis of the holding point are negative values, the negative value is corrected to 0, and the X axis and / or Y axis of the holding point is corrected. If the coordinates exceed the maximum value X _{max in} the X-axis direction and / or the maximum value Y _max in the Y-axis direction of the X-ray incident surface 30, the value exceeding the maximum value is the maximum value X _{max in the} X-axis direction. And / or correction to the maximum value Y _max in the Y-axis direction. Then, the coordinates of the reserved point after correction are stored as the coordinates of the candidate point (S309), and the process proceeds to step S310.

(Step S310)
The cut-out position candidate point calculation unit 23 returns to step S301 to change the processing target vertex to the next vertex of the loop, increments the argument i indicating the processing target vertex by one, and performs the processing from step S302 to step S309 again. repeat. This loop processing is sequentially performed for all four vertices of the irradiation field region, and the process proceeds to step S4.

  Next, an example of the extraction position candidate point calculation process will be described based on FIG. FIG. 5 is a schematic diagram showing the contents of the cut-out position candidate point calculation process, and shows a state in which candidate points are calculated in the positional relationship between the X-ray incident surface 30 and the irradiation field region 40 shown in FIG.

  (1) In the case of the vertex P: Since the vertex P is within the range of the X-ray detector 13 (in this embodiment, the range of the X-ray incident surface 30 is used as a reference for the sake of more accuracy), the above-described step S302 Proceeding to step S303, the coordinates of the vertex P are stored as the coordinates of the candidate point (black circle) (one candidate point).

(2) In the case of the vertex Q; since the vertex Q is outside the range of the X-ray incident surface 30, the process proceeds from step S302 to step S304. In step S304, the coordinates I ₁ , I ₂ , I ₃ , and I ₄ of the intersections between the straight line QR connecting the vertex Q and the next vertex R, the side of the X-ray incident surface 30 and its extension line are calculated. As a result of the determination in step S305, since the two intersections I ₂ and I ₃ are between QRs (intervertex range), the two intersections I ₂ and I ₃ proceed to S307. Since the other two intersections I ₁ and I ₄ are outside the range between the vertices, they are deleted from the candidate points in S306. In step S307, it is determined whether or not the holding points I ₂ and I ₃ are within the range of the X-ray incident surface 30. As a result of the determination, since the holding points I ₂ and I ₃ are out of the range, the process proceeds to step S309. In step S309, correction for moving the X-ray incident surface 30 is performed. With this correction, the holding points I ₂ and I ₃ move to the vertex A. Therefore, the coordinates of the vertex A are stored as the coordinates of the candidate point (one candidate point).

(3) In the case of the vertex R: Since the vertex R is outside the range of the X-ray incident surface 30, the process proceeds from step S302 to step S304. In step S304, the coordinates I ₅ , I ₆ , I ₇ , and I ₈ of the intersections between the straight line RS connecting the vertex R and the next vertex S, the side of the X-ray incident surface 30 and its extension line are calculated. As a result of the determination in step S305, since the two intersections I ₆ and I ₇ are between RSs (inter-vertex range), the two intersections I ₆ and I ₇ go to S307. Since the other two intersections I ₅ and I ₈ are outside the range between the vertices, they are deleted from the candidate points in S306. Next, two holding points I _6, I ₇ it is determined whether or not within the scope of the X-ray incidence plane 30 in step S307, because it is in the range, the two hold points in Step S308 I _6, I Save ₇ as the coordinates of the candidate point (two candidate points).

(4) In the case of the vertex S: Since the vertex S is outside the range of the X-ray incident surface 30, the process proceeds from step S302 to step S304. In step S304, the coordinates I ₉ , I ₁₀ , I ₁₁ , and I ₁₂ of the intersections between the straight line SP connecting the vertex S and the next vertex P, the side of the X-ray incident surface 30 and its extension line are calculated. The determination in the step S305, 1 single intersection I ₁₀ is pending point because it is between SP (vertex range), the process proceeds to S307. The other three intersections I ₉ , I ₁₁ , and I ₁₂ are outside the inter-vertex range, and are deleted from the candidate points in S306. Next, hold point I ₁₀ at step S307 it is determined whether or not within the scope of the X-ray incident surface 30, because in the range, to store the hold point I ₁₀ as the coordinates of the candidate points in step S308 ( One candidate point).

  Therefore, in the example of FIG. 5, there are a total of five candidate positions for cutout positions. Subsequently, the process proceeds to step S4 of the flowchart of FIG.

(Step S4)
In step S4, the rectangular area position calculating means 24 calculates the position of the cutout area based on the coordinates of the candidate points obtained in step S3 (S4). In the present embodiment, in particular, in order to calculate the position of a rectangular cutout area, the cutout area is referred to as a rectangular area.

  The rectangular area position calculation means 24 uses the minimum coordinates of the X and Y coordinates of the candidate point as the cut start point. Further, regarding the X-axis direction, the maximum coordinate of the X coordinates of the candidate points is set as the cut-out end point in the X-axis direction. Similarly, regarding the Y-axis direction, the maximum coordinate of the Y coordinates of the candidate points is set as the cut-out end point in the Y-axis direction. The processing of this step will be described based on FIG. FIG. 6 is a flowchart showing the flow of the cutout region position calculation process. In the cutout region position calculation process in FIG. 6, the minimum coordinate and maximum coordinate calculation process of the X-axis coordinate and the minimum coordinate and maximum coordinate calculation process of the Y-axis coordinate are performed, respectively. In the following description, it is assumed that the process for the X-axis coordinates is first performed.

(Step S401)
The rectangular area position calculation means 24 sequentially performs the following processing for the five candidate points obtained in step S3. First, in the first loop (i = 0), a candidate point (for example, vertex A) to be processed first is determined (S401).

(Step S402)
The rectangular area position calculating unit 24 determines whether or not the candidate point to be processed (for example, the X-axis coordinate of the vertex A) is the minimum coordinate (S402). As shown in FIG. 5, when the origin is included in the irradiation field region, the X-axis coordinate 0 is the minimum coordinate. If it is the minimum coordinate, the process proceeds to step S403, and if it is not the minimum coordinate, the process proceeds to step S404.

(Step S403)
The rectangular area position calculation means 24 cuts out the candidate point to be processed and stores it as the start point coordinates (step S403). Then, the process proceeds to step S407.

(Step S404)
The rectangular area position calculating unit 24 determines whether or not the candidate point to be processed (for example, the X-axis coordinate of the vertex A) is the maximum coordinate (S404). If it is the maximum coordinate, the process proceeds to step S405, and if it is not the maximum coordinate, the process proceeds to step S406.

(Step S405)
The rectangular area position calculation means 24 cuts out the candidate points to be processed and stores them as the coordinates of the end points (S405). Then, the process proceeds to step S407.

(Step S406)
The rectangular area position calculation means 24 cuts out the candidate point to be processed and deletes it from the candidate position of the end point, and proceeds to step S407 (S406).

(Step S407)
The rectangular area position calculation means 24 returns to step S401 to change the candidate point to be processed to the next candidate point, increments the argument i indicating the candidate point to be processed by one, and again from step S401 to step S407. Repeat the process. This loop processing is sequentially performed for all five candidate points, and the process proceeds to step S5.

The processing from step S401 to S407 is performed for each of the X-axis coordinates and the Y-axis coordinates. In the example of FIG. 5, the minimum coordinates of the X-axis coordinates and the Y-axis coordinates of the five candidate points are (0, 0). The maximum X-axis coordinate is the X-axis coordinate of the vertex P. The maximum Y-axis coordinate is a value calculated from the vertices I ₇ and I ₁₀ (X-ray incident surface 30_size Y _max ). When a rectangular area is set with the minimum coordinate as the cut start point and the maximum coordinate of the X axis coordinate and the maximum coordinate of the Y axis coordinate as the end points, the cut area becomes a rectangular area 50 (thick frame dotted line area) in FIG.

The rectangular area 50 is a rectangular area that circumscribes the irradiation field area 40 in the X-ray incident surface 30.
That is, the region cut out as the rectangular region 50 is a pixel column along the X-axis direction of the X-ray incident surface 30 and a pixel column along the Y-axis direction (for example, when the X-ray incident surface 30 is 3000 × 3000 pixels, In a row consisting of 3000 pixels (in the X-axis direction) and a column consisting of 3000 pixels (in the Y-axis direction)), an area consisting of pixel columns in which no transmitted X-ray signal from the subject 2 has been detected This is a rectangular region formed by removing from the incident surface 30. In the present embodiment, the rectangular area is a rectangle having a long side in the Y axis direction, but when the cutout start point is the origin (0, 0) and the maximum coordinate of the X axis coordinate and the maximum coordinate of the Y axis coordinate are equal, The rectangular area may be a square.
Subsequently, the process proceeds to step S5 of the flowchart of FIG.

(Step S5)
The thinning number determining means 25 determines a thinning number necessary for displaying the cutout area in the display area (S5), and the rectangular area display means 26 performs a thinning process according to the calculated thinning number. For example, when the cutout area is 2100 pixels × 3000 pixels and the display area is 1000 pixels × 1000 pixels, the thinning number is set to 3. Three-thinning is synonymous with sampling every three pixels. In this example, the image size of the cut-out area after three thinnings is 700 pixels × 1000 pixels. When displaying the image of the subject 2 on the entire display screen, the entire display screen becomes the display area, but the attribute information of the subject (for example, the name of the subject) is displayed in a partial area of the display screen, and the rest When the image of the subject is displayed in the display screen, the size of the display area in the remaining display screen is the display area size for determining the thinning number. Note that if the image size of the cutout area is smaller than the size of the display area and the entire area of the cutout area can be displayed without being thinned, this step is omitted because the thinning process is not performed.

(Step S6)
The rectangular area display means 26 displays the cutout area in the display area for displaying the image of the subject 2 on the display screen of the display device 15 (S6).

  According to the present embodiment, it is possible to display the irradiation field region by making the best use of the display region, and it is possible to minimize resolution degradation.

  In the above embodiment, the calculation method in the case of rotational imaging in which the irradiation field region 40 is rotated 45 degrees with respect to the X-ray flat panel detector 13 is described, but normal imaging (square or rectangular aperture) or incident imaging Even when shooting (trapezoidal diaphragm), rectangular cutout is possible.

  1 X-ray diagnostic device, 2 subject, 11 X-ray generator, 12 X-ray diaphragm, 13 X-ray flat panel detector, 14 control unit, 15 display device

Claims (7)

An X-ray generator for generating X-rays, an X-ray diaphragm means for defining the X-ray irradiation range, and an X-ray generator disposed opposite to the X-ray generator to detect a transmitted X-ray of the subject and transmit a transmitted X-ray signal An X-ray flat panel detector for outputting, an irradiation field area detecting means for detecting position information of the X-ray irradiation field area with respect to the X-ray flat panel detector, and the irradiation field area in the image by the transmitted X-ray signal Cutout position candidate point calculation means for calculating position information of candidate points of the cutout position of the circumscribed rectangular area based on the position information of the irradiation field area, and position information of the rectangular area based on the position information of the candidate point A rectangular area position calculating means for calculating the rectangular area, and a rectangular area display means for displaying the rectangular area ,
When the vertex of the polygonal irradiation field region is within the X-ray incidence plane of the X-ray flat detector, the cut-out position candidate point calculation unit sets the vertex as the candidate point, and the vertex is the X When it is outside the line incident surface, the intersection of the straight line connecting the vertex and the other vertex of the irradiation field area adjacent to the vertex and the side of the X-ray incident surface or an extension of the side An X-ray diagnostic apparatus characterized in that position information is calculated, and according to the position information of the intersection, the intersection or a point obtained by correcting the intersection in the X-ray incidence plane is calculated as the candidate point . The cut-out position candidate point calculation means corrects the coordinate value of the intersection point to the minimum value when the coordinate value of the intersection point is smaller than the minimum coordinate value indicating the X-ray incident surface, and the coordinate value of the intersection point 2. The X-ray diagnostic apparatus according to claim 1 , wherein when the coordinate value indicating the X-ray incident surface is larger than a maximum coordinate value, the coordinate value of the intersection is corrected to the maximum value . An X-ray generator for generating X-rays, an X-ray diaphragm means for defining the X-ray irradiation range, and an X-ray generator disposed opposite to the X-ray generator to detect a transmitted X-ray of the subject and transmit a transmitted X-ray signal An X-ray flat panel detector for outputting, an irradiation field area detecting means for detecting position information of the X-ray irradiation field area with respect to the X-ray flat panel detector, and the irradiation field area in the image by the transmitted X-ray signal Cutout position candidate point calculation means for calculating position information of candidate points of the cutout position of the circumscribed rectangular area based on the position information of the irradiation field area, and position information of the rectangular area based on the position information of the candidate point A rectangular area position calculating means for calculating the rectangular area, and a rectangular area display means for displaying the rectangular area,
The rectangular area position calculation means is configured to calculate the position of the candidate point from the minimum value of the X-axis coordinate of the candidate point within the area from the minimum value of the X-axis coordinate of the candidate point to the maximum value of the X-axis coordinate of the candidate point. An X-ray diagnostic apparatus characterized in that the area up to the maximum value of the Y-axis coordinates is calculated as the position of the rectangular area . Further comprising thinning number determination means for determining a thinning number of the image of the rectangular area based on a ratio between the image size of the rectangular area and the size of the display area of the rectangular area display means,
4. The X-ray diagnostic apparatus according to claim 1, wherein the rectangular area display means displays the rectangular area that has been subjected to the thinning process according to the thinning number in the display area. . X-ray generator and X-ray flat detector are arranged opposite to each other, and an X-ray diagnostic apparatus that defines an irradiation range of X-rays generated by the X-ray generator by an X-ray diaphragm means can capture an X-ray image. A method for trimming a line image,
A step of generating X-rays, a step of defining an X-ray irradiation range, a step of detecting transmitted X-rays of a subject and outputting a transmitted X-ray signal, and the X-rays for the X-ray flat panel detector Detecting the position information of the irradiation field region, and the position information of the candidate points of the cutout position of the rectangular region circumscribing the irradiation field region in the image by the transmitted X-ray signal based on the position information of the irradiation field region Calculating the position information of the rectangular area based on the position information of the candidate point, and displaying the rectangular area,
The step of calculating the position information of the candidate point of the cutout position calculates the vertex as the candidate point when the vertex of the polygonal irradiation field region is within the X-ray incidence plane of the X-ray flat panel detector. When the vertex is outside the X-ray incident surface, a straight line connecting the vertex and the other vertex of the irradiation field region adjacent to the vertex and the side of the X-ray incident surface or the side of the side The position information of the intersection with the extension line is calculated, and according to the position information of the intersection, the intersection or a point obtained by correcting the intersection in the X-ray incident plane is calculated as the candidate point. X-ray image trimming method. X-ray generator and X-ray flat detector are arranged opposite to each other, and an X-ray diagnostic apparatus that defines an irradiation range of X-rays generated by the X-ray generator by an X-ray diaphragm means can capture an X-ray image. A method for trimming a line image,
A step of generating X-rays, a step of defining an X-ray irradiation range, a step of detecting transmitted X-rays of a subject and outputting a transmitted X-ray signal, and the X-rays for the X-ray flat panel detector Detecting the position information of the irradiation field region, and the position information of the candidate points of the cutout position of the rectangular region circumscribing the irradiation field region in the image by the transmitted X-ray signal based on the position information of the irradiation field region Calculating the position information of the rectangular area based on the position information of the candidate point, and displaying the rectangular area ,
The step of calculating the position information of the rectangular area includes the step of calculating the position information in the area from the minimum value of the X-axis coordinate of the candidate point to the maximum value of the X-axis coordinate of the candidate point, and from the minimum value of the Y-axis coordinate of the candidate point. A method for trimming an X-ray image , wherein an area within a candidate point up to a maximum value of a Y-axis coordinate is calculated as a position of the rectangular area . Determining a thinning number of the image of the rectangular area based on a ratio between the image size of the rectangular area and the size of the display area;
7. The X-ray image trimming according to claim 5 , wherein the step of displaying the rectangular area comprises displaying the rectangular area that has been thinned according to the thinning number in the display area. Processing method.

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