JP4957096B2 - X-ray diagnostic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray diagnostic apparatus requiring no complicated configuration, which can enlarge an X-ray radiation field for radiography and prevent a deterioration in image quality. <P>SOLUTION: The X-ray diagnostic apparatus comprises a tilt control part 43 to control driving of a tilt drive motor 47 to tilt an X-ray tube 1, and a tilt memory part 25 to memorize a plurality of angles at which the X-ray tube 1 is tilted corresponding to a plurality of X-ray radiation field sizes detected by an X-ray detector 3. The tilt control part 43 controls the driving of the tilt drive motor 47 so that the X-ray tube 1 corresponding to the X-ray radiation field size indicated by an indication part 21 and memorized in the tilt memory part 25, could be tilted from the X-ray radiation field size indicated by the indication part 21, which allows to detect the X-ray radiation field at the size thereof to be detected by the X-ray detector 3 indicated by the indication part 21 when the X ray is outputted from the X-ray tube 1. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention detects an X-ray generated from an X-ray tube and transmitted through a subject by an X-ray detector, and acquires an X-ray image based on the X-ray detected by the X-ray detector. In particular, the present invention relates to a technique for improving the image quality of an X-ray image.

  A conventional X-ray diagnostic apparatus will be described with reference to FIGS. FIG. 6 is a schematic diagram showing a state in which the X-ray tube is not inclined with respect to the X-ray detector. FIG. 7 is a schematic diagram showing a state in which the X-ray tube is inclined with respect to the X-ray detector. As shown in FIG. 6, there are an X-ray tube 51, a collimator 53 that narrows down the X-rays output from the X-ray tube 51, an X-ray detector 55 arranged opposite to the collimator 53, and the like. . The X-ray output from the X-ray tube 51 and focused by the collimator leaf 54 of the collimator 53 passes through the subject (patient) and is converted into an electrical signal by the X-ray detector 55. The electrical signal is subjected to image processing by the image processing unit, and an X-ray image of the subject is displayed on the monitor.

  The X-ray tube 51 includes a filament (cathode) 57 that generates thermoelectrons, a target (anode) 59 that outputs X-rays when the thermoelectrons generated from the filament 57 collide with each other. The filament 57 and the target 59 are disposed so as to face each other. The surface of the target 59 facing the filament 57 is an inclined surface, and the thermal electrons collide with the inclined surface, and the X-ray focal point XS to X Output as a line. Further, the X-ray from the X-ray focal point XS of the target 59 is output within a predetermined range, for example, the range from the X-ray direction a to e shown in FIG. Here, the intensity of the X-ray output in the range from the X-ray direction c to e is weaker than the X-ray intensity in the range from the X-ray direction a to c because of the structure. Further, based on the X-rays output in the X-ray direction a to c in FIG. 6, the X-ray irradiation field (field size) detected by the X-ray detector 55 is small (for example, about 9 inches). It can be carried out. Further, when imaging with a large X-ray irradiation field (for example, about 17 inches), X-rays output in the range from the X-ray direction c to e are required, but in the state shown in FIG. The X-rays output from the X-ray focal point XS are not output to the left side of the X-ray direction a due to the inclined surface of the target 59.

Therefore, as shown in FIG. 7, the opening formed by the collimator leaf 54 of the collimator 53 is set so that X-rays output in the X-ray direction c to e range are output to the X-ray detector 55 side. Further, by attaching the X-ray tube 51 and the collimator 53 with an inclination of, for example, about 2 degrees, f that is the center direction of the X-rays output in the range from the X-ray direction a to e shown in FIG. By setting the direction opposite to the line detector 55, imaging is performed with a large X-ray irradiation field ranging from the X-ray direction a to e centering on the X-ray direction f. In other words, the X-ray tube 51 is tilted and the collimator 53 is widened to fix an image with a large X-ray irradiation field. In addition, in order to secure a large X-ray irradiation field, there is one that moves the X-ray receiver and rotates the X-ray tube while synchronizing it (see Patent Document 1).

  However, the conventional X-ray diagnostic apparatus has the following problems. That is, as shown in FIG. 7, the opening of the collimator 53 is widened and the X-ray tube 51 is tilted with respect to the X-ray detector 55 so that X-ray imaging can be performed even when the X-ray irradiation field is large. When fixed, the X-ray irradiation field is determined based on the center of the X-ray detector 55. In FIG. 7, when the X-ray irradiation field is small, the range between the X-ray direction g and the X-ray direction h. become. Therefore, X-rays in the X-ray directions a to b with high X-ray intensity are not used, and X-rays with low X-ray intensity must be used for imaging, and only when the X-ray irradiation field is small. There is a problem that the image quality is deteriorated as compared with the case where imaging can be performed, and a complicated configuration for obtaining an X-ray image by moving the X-ray receiver and rotating the X-ray tube while synchronizing with the X-ray receiver is necessary. There is a problem that.

  The present invention has been made in view of such circumstances, and does not require a complicated configuration, can widen an X-ray irradiation field for performing X-ray imaging, and reduces image quality. An object of the present invention is to provide an X-ray diagnostic apparatus that can be reduced.

In order to achieve such an object, the present invention has the following configuration.
That is, the invention described in claim 1 includes (A) X-ray output means for outputting X-rays, (B) X-ray detection means for detecting X-rays output from the X-ray output means, and (C ) Tilt drive means for driving to tilt the X-ray output means; (D) Tilt control means for controlling drive of the tilt drive means; and (E) Multiple X-ray irradiations detected by the X-ray detection means. Inclination storage means for storing a plurality of angles at which the X-ray output means is inclined with respect to the field size, and (F) the sizes of the plurality of X-ray irradiation fields detected by the X-ray detection means. (G) the X-ray output means includes a filament that generates thermoelectrons, and heat generated by the filament at an end portion of the X-ray irradiation field. An inclined surface where electrons collide is provided, and thermal electrons collide with the inclined surface. A target that outputs X-rays in a predetermined angle range from a direction along the inclined surface in front of the end, and ( H ) the inclination control means is the instruction means The angle associated with the size of the X-ray irradiation field instructed by the instruction means stored in the tilt storage means based on the designation of the size of any one X-ray irradiation field in And (I) the angle is output in the direction opposite to the filament side along the inclined surface of the target. The end of the line is an angle irradiated to the end opposite to the filament side of the X-ray irradiation field instructed by the instruction means .

[Operation and Effect] The operation of the invention of claim 1 is as follows.
First, the tilt storage means stores a plurality of angles at which the X-ray output means tilts in association with a plurality of X-ray irradiation field sizes detected by the X-ray detection means obtained in advance by experiments or the like. . Next, for the size of a plurality of X-ray irradiation fields detected by the X-ray detection means, in order to perform X-ray imaging when the X-ray irradiation field is large, the instruction means indicates that the X-ray irradiation field is large. I do. The tilt control means is associated with the large X-ray irradiation field instructed by the instruction means stored in the tilt storage means based on the instruction means instructing that the X-ray irradiation field is large. The drive of the tilt driving means is controlled so that the X-ray output means tilts at a certain angle. Therefore, when X-rays are output from the X-ray output means, detection can be performed when the X-ray irradiation field detected by the X-ray detection means is large.

  Next, in order to perform X-ray imaging when the X-ray irradiation field is small with respect to the sizes of the plurality of X-ray irradiation fields detected by the X-ray detection unit, an instruction indicating that the X-ray irradiation field is small from the instruction unit I do. The tilt control means is associated with the small X-ray irradiation field instructed by the instruction means stored in the tilt storage means based on the instruction means instructing that the X-ray irradiation field is small. The drive of the tilt driving means is controlled so that the X-ray output means tilts at a certain angle. Therefore, when X-rays are output from the X-ray output means, detection with a small size of the X-ray irradiation field detected by the X-ray detection means can be performed.

  Therefore, a complicated configuration is not required, and X-ray imaging can be performed even when the X-ray irradiation field is large. In X-ray imaging when the X-ray irradiation field is small, it is necessary when the X-ray irradiation field is large. X-ray imaging is not performed using X-rays with low X-ray intensity, and deterioration in image quality can be reduced.

The X-ray output means includes a filament and a target. The filament generates thermoelectrons, and the target is provided with an inclined surface on which the thermoelectrons generated by the filament collide, and the inclined surface. When the thermal electrons collide with each other, X-rays are output in a predetermined angle range from the direction along the inclined surface in front of the end portion. Here, the plurality of angles at which the X-ray output means stored in the tilt storage means tilt is such that the end of the X-ray output in the direction opposite to the filament side along the tilted surface of the target is the indication means. One end of the X-ray irradiation field in the size detected by the instructed X-ray detection means (the end opposite to the filament side) is irradiated, and the other end of the X-ray irradiation field is This is the angle at which X-rays output at a predetermined angle from the direction along the inclined surface of the target are irradiated. In other words, the X-ray output means always irradiates the end portion of the X-ray output in the direction opposite to the filament side along the inclined surface of the target even when the size of the X-ray irradiation field changes. One end of the field (the end opposite to the filament side) is irradiated, and the other end of the X-ray irradiation field is output at a predetermined angle from the direction along the inclined surface of the target. X-rays are irradiated. Therefore, imaging can always be performed using X-rays with high X-ray intensity output in the direction opposite to the filament side along the inclined surface of the target, and deterioration in image quality can be reduced. .

Further, in the X-ray diagnostic apparatus according to claim 2 , an X-ray diaphragm means for narrowing the X-rays output from the X-ray output means by changing the size of the opening, and the X-ray diaphragm means A diaphragm control means for performing control to change the size of the opening, and a plurality of openings variable by the X-ray diaphragm means with respect to the sizes of the plurality of X-ray irradiation fields detected by the X-ray detection means. Aperture storage means for storing the size in association with each other, and the aperture control means is configured to specify the size of any one X-ray irradiation field by the instruction means, and the aperture storage means. And performing variable control so as to be the size of the opening of the X-ray diaphragm means associated with the size of the X-ray irradiation field indicated by the instruction means stored in Is.

[Operation / Effect] According to the invention of claim 2 , the X-ray diaphragm means for the size of a plurality of X-ray irradiation fields detected by the X-ray detection means previously obtained by experiment or the like in the aperture storage means. Are stored in association with the sizes of the plurality of openings that can be changed in step (b). Next, for the size of a plurality of X-ray irradiation fields detected by the X-ray detection means, in order to perform X-ray imaging when the X-ray irradiation field is large, the instruction means indicates that the X-ray irradiation field is large. I do. The aperture control means responds to the large X-ray irradiation field instructed by the instruction means stored in the aperture storage means based on the instruction means indicating that the X-ray irradiation field is large. The attached control is performed so as to change the size of the opening of the X-ray diaphragm means. Therefore, when X-rays are output from the X-ray output unit, the X-rays are focused by the opening of the X-ray diaphragm unit when the X-ray irradiation field is large, and the X-ray field detected by the X-ray detection unit. It is possible to detect when is large.

  Next, in order to perform X-ray imaging when the X-ray irradiation field is small with respect to the sizes of the plurality of X-ray irradiation fields detected by the X-ray detection unit, an instruction indicating that the X-ray irradiation field is small from the instruction unit I do. The diaphragm control means is associated with the small X-ray irradiation field instructed by the instruction means stored in the aperture storage means based on the instruction means instructing that the X-ray irradiation field is small. Control is performed so that the size of the opening of the X-ray diaphragm means becomes variable. Therefore, when X-rays are output from the X-ray output unit, the X-rays are focused by the opening of the X-ray diaphragm unit according to the small X-ray irradiation field, and the X-ray detection field is small by the X-ray detection unit. In some cases, detection can be performed.

  Therefore, when the X-ray irradiation field detected by the X-ray detection means is large or X-ray imaging is performed in any case where the X-ray irradiation field is small, X-rays are irradiated to a range other than the X-ray irradiation field. And secondary irradiation such as out-of-focus X-rays and scattered rays other than X-rays from the X-ray detection means can be prevented, and as a result, the reduction in image quality can be reduced, Irradiating the subject with unnecessary X-rays can be reduced.

  According to the present invention, it is possible to perform X-ray imaging even when the X-ray irradiation field is large without requiring a complicated configuration. In X-ray imaging when the X-ray irradiation field is small, the X-ray irradiation field is large. In this case, X-ray imaging is not performed using X-rays having a low X-ray intensity, and deterioration of image quality can be reduced.

  The X-ray diagnostic apparatus will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of the X-ray diagnostic apparatus. FIG. 2 is a schematic diagram showing a state where the X-ray tube is tilted and a state where the X-ray detector is not tilted with respect to the X-ray detector. FIG. 3 is a schematic diagram showing the relationship among the X-ray tube, collimator, and X-ray detector. FIG. 4 is a perspective view showing the configuration of the collimator leaf. FIG. 5 is a schematic diagram showing an inclination angle at which the X-ray tube is inclined with respect to the size of the X-ray irradiation field.

  The overall configuration of the X-ray diagnostic apparatus will be described with reference to FIG. As shown in FIG. 1, the X-ray diagnostic apparatus uses an X-ray tube 1 that irradiates a subject (patient) M with X-rays and an X-ray output from the X-ray tube 1 through an opening K (FIG. 3). The size of the reference) is varied, the X-ray detector 3 that detects the X-ray output from the X-ray tube 1 and is narrowed by the collimator 2, and the top plate on which the subject M is placed. 5, image processing is performed based on the X-ray detection signal detected by the X-ray detector 3 and converted into a digital signal by the A / D converter 13. An image processing unit 15, a control unit 17 that performs various controls related to X-ray diagnosis, an irradiation control unit 19 that controls the X-ray tube 1 based on the control from the control unit 17, and an instruction unit 21 that can be instructed Display unit 23 for displaying X-ray images and the like, storage unit 24 for storing various programs and data, and indispensable for X-ray diagnosis. It comprises an input unit 27 which can perform the Do input and an input device such as a keyboard or a mouse as possible. This X-ray diagnostic apparatus performs X-ray imaging (perspective).

  As shown in FIG. 2, the X-ray tube 1 includes a filament (cathode) 31 that generates thermoelectrons, a target (anode) 33 that outputs X-rays when the thermoelectrons generated from the filament 31 collide, and the like. Yes. The filament 31 and the target 33 are arranged so as to face each other, and the surface facing the filament 31 at the end of the target 33 is an inclined surface, and the thermoelectrons collide with the inclined surface, from the X-ray focal point XS. Output as X-rays. The X-ray tube 1 described above corresponds to the X-ray output means in the present invention.

  As shown in FIG. 3, the collimator 2 is attached so as to be fixed at a position where the X-ray tube 1 is not in contact with the tilted state. Further, the collimator 2 is provided with a collimator leaf 35 for focusing X-rays. As shown in FIG. 4, the collimator leaf 35 includes an X-direction collimator leaf 37 that narrows the width of the X-ray in the X direction and a Y-direction collimator leaf 39 that narrows the width of the X-ray in the Y direction. Further, the X-direction collimator leaf 37 is configured by two leaves 37a and 37b, and each leaf is configured to be opened and closed in synchronization with the X direction. The Y-direction collimator leaf 39 is also composed of two leaves 39a and 39b, and each leaf is configured to be opened and closed in synchronization with the Y direction. These leaves 37a, 37b, 39a, 39b are made of an X-ray shielding member such as lead, and the X-rays irradiated from the X-ray focal point XS in the X-ray tube 1 are emitted from the leaves 37a, 37b, 39a, It is squeezed by being shielded by 39b. The subject M is irradiated with X-rays that have passed through the opening K formed by the X-direction collimator leaf 37 and the Y-direction collimator leaf 39. That is, by changing the size of the opening K, it is possible to adjust the X-ray irradiation field that is the field size of the X-rays irradiated to the X-ray detector 3. 4 indicates an X-ray irradiation field that is a range in which the X-ray irradiated from the X-ray focal point XS of the X-ray tube 1 is irradiated by the X-ray detector 3. . The collimator 2 described above corresponds to the X-ray diaphragm means in the present invention.

  The X-ray detector 3 detects the X-ray incident on the X-ray detector 3 and converts it into an X-ray detection signal having a magnitude corresponding to the intensity of the incident X-ray. This is output to the A / D converter 13 to be processed. For example, the X-ray detector 3 uses a 17-inch square direct conversion type flat panel detector (FPD). The FPD has a configuration in which X-ray detection elements are arranged vertically and horizontally on a detection surface, and an area where the one X-ray detection element is arranged becomes one detection area. The X-ray detection elements are arranged vertically and horizontally in a matrix of 2880 × 2880 on the X-ray detection surface. The X-ray detector 3 described above corresponds to the X-ray detection means in the present invention.

  The storage unit 24 is a memory such as a RAM or a ROM, and includes an inclination storage unit 25, an opening storage unit 26, and the like. The tilt storage unit 25 stores a plurality of angles at which the X-ray tube 1 is tilted in association with a plurality of X-ray irradiation field sizes that can be detected by the X-ray detector 3. The aperture storage unit 26 stores the sizes of the plurality of apertures K variable by the collimator 2 in association with the sizes of the plurality of X-ray irradiation fields that can be detected by the X-ray detector 3. . Here, as the size of the plurality of X-ray irradiation fields detected by the X-ray detector 3, for example, as shown in FIG. 5, a 9 inch square (range of 23 cm × 23 cm) in which the X-ray irradiation field is small is shown. ) To a 17 inch square (range of 43 cm × 43 cm) where the X-ray field is large, there is a size of the X-ray field per inch.

  In addition, as a plurality of angles at which the X-ray tube 1 is inclined with respect to the size of the X-ray irradiation field per inch detected by the X-ray detector 3, X output from the direction along the inclined surface of the target 33 is used. A line is irradiated to one end of the X-ray irradiation field at a size detected by the X-ray detector 3, and the other end of the X-ray irradiation field is along the inclined surface of the target 33. This is an angle at which X-rays output at a predetermined angle from the direction are irradiated, and an optimum value is obtained in advance based on measurement results such as experiments. For example, as shown in FIG. Specifically, FIG. 5 is a schematic diagram showing an inclination angle at which the X-ray tube 1 is inclined with respect to the size of the X-ray irradiation field. In the case of a 9 inch square where the X-ray irradiation field is small, This is 0 °, that is, a state in which the X-ray detector 3 is not inclined, and the X-ray detector 3 is parallel to the X-ray tube 1 and the collimator 2. Further, in the case of a 17-inch square in which the X-ray irradiation field is large, the 2 ° X-ray tube 1 and the collimator 2 are also inclined together.

  The size of the plurality of openings K that can be changed by the collimator 2 with respect to the size of the X-ray irradiation field for each inch detected by the X-ray detector 3 will be described below with reference to FIG. First, the reference numerals shown in FIG. 3 will be described. The distance between the X-ray tube 1 (X-ray tube focal point XS) and the collimator 2 (collimator leaf 35) is Dcc, the distance between the collimator leaf 35 and the X-ray detector 3 is Dcd, and the opening K ( The width of the X-ray irradiation field in the X-ray detector 3 is Dd. Here, the distance between the X-ray tube 1 and the X-ray detector 3 is Dcc + Dcd. Further, as shown in FIG. 3, Dc and Dd indicate widths in the same direction (here, the X direction).

The relationship between these Dcc, Dcd, Dc, and Dd is shown in FIG. 3 in that the triangle T1 having the X-ray focal point XS as the apex and the base as Dc and the height as Dcc, and the X-ray focus XS as the apex and the base as Dd and high It is represented by a triangle T2 where the height is (Dcc + Dcd). Since the triangle T1 and the triangle T2 are similar, the ratio of Dcc, which is the height of the triangle T1, to (Dcc + Dcd), which is the height of the triangle T2, is
It can be shown as Dcc: (Dcc + Dcd) = Dc: Dd.
Dc = DccDd / (Dcc + Dcd) (1)
Since Dcc, Dcd, and Dd are known values, Dc can be obtained from equation (1). The value of Dc is the size of a plurality of openings K that can be varied by the collimator 2 with respect to the size (Dd) of the X-ray field per inch detected by the X-ray detector 3. The storage unit 25 described above corresponds to a storage unit in the present invention.

  The instruction unit 21 is configured to be able to instruct the size of any one of the X-ray irradiation fields detected by the X-ray detector 3. Here, any one of the X-ray irradiation fields shown in FIG. 5 can be instructed. For example, the instruction unit 21 is a monitor (not shown) that can be input from the outside, such as a touch panel. A screen for instructing a plurality of X-ray irradiation fields is displayed, and an operation of instructing can be performed by touching an operator (such as an X-ray imaging engineer) with a hand. In addition, the instruction | indication part 21 mentioned above is corresponded to the instruction | indication means in this invention.

  As shown in FIG. 1, the control unit 17 includes an aperture control unit 41 and an inclination control unit 43. The aperture control unit 41 receives the X-ray irradiation instructed by the instruction unit 21 stored in the aperture storage unit 26 based on the instruction unit 21 instructing the size of any one X-ray irradiation field. Control is performed so that the size of the opening K of the collimator 2 is associated with the size of the field. Specifically, the aperture controller 41 controls the collimator leaf drive motor 45 that opens and closes the X-direction collimator leaf 37 and the Y-direction collimator leaf 39 of the collimator leaf 35, thereby controlling the X-direction collimator leaf 37 and the collimator leaf 37. The size of the opening K formed by the Y-direction collimator leaf 39 is changed.

  In addition, the tilt control unit 43 receives the X-ray instructed by the instruction unit 21 stored in the storage unit 25 based on the instruction unit 21 instructing the size of any one X-ray irradiation field. The tilt drive motor 47 is driven and controlled so that the X-ray tube 1 associated with the size of the irradiation field is tilted with reference to the X-ray focal point XS of the target 33 of the X-ray tube 1. Specifically, the tilt control unit 43 controls the driving of the tilt drive motor 47, transmits the power from the tilt drive motor 47 to the X-ray tube 1 via a gear, and these X-ray tubes 1. And the collimator 2 are inclined. The diaphragm control unit 41 described above corresponds to the diaphragm control unit in the present invention, the tilt control unit 43 described above corresponds to the tilt control unit in the present invention, and the tilt drive motor 47 described above is the tilt control unit in the present invention. It corresponds to the driving means.

  The X-ray tube 1, the collimator 2, and the X-ray detector 3 are held by a holding device. For example, the holding device is provided with a C-type arm moving mechanism disposed on the support base. An X-ray tube 18 and a collimator 2 are attached to one of both ends of the C-type arm of this C-type arm moving mechanism, and an X-ray detector 9 is attached to the other, and they are in a state of facing each other. Also, the C-type arm can be moved in the longitudinal direction of the arm along the bending of the arm, and the C-type arm can be slid, or the C-type arm can be rotated horizontally around the horizontal line transverse to the C-type arm. It is configured. As a result, the X-ray tube 1 and the X-ray detector 3 move around the subject M as the C-type arm slides by the C-type arm moving mechanism and rotates horizontally. While irradiating M with X-rays, an X-ray image can be acquired in accordance with an X-ray detection signal output from the X-ray detector 3 along with the X-ray irradiation.

  Next, operations of the X-ray tube 1 and the collimator 2 that are variable with respect to the size of the X-ray irradiation field will be described. First, an operator (such as an X-ray radiographer) operates the input unit 27 such as a keyboard or a mouse to operate the input device 27 so that the X-ray tube 1 is inclined at a plurality of angles corresponding to the size of the X-ray irradiation field. Enter. For example, a screen showing the contents as shown in FIG. 5 is displayed on the input unit 27, and in the column of the X-ray irradiation field [inch] in this display, as an X-ray irradiation field that can be instructed by the X-ray diagnostic apparatus, Values from 1 to 9 from 9 to 17 are displayed. Next, when the tilt angle of the X-ray tube 1 corresponding to the X-ray irradiation field is “9” by using a keyboard or a mouse, “0” is entered in the “tilt angle” column. When the X-ray irradiation field is “17”, “2” is input in the “tilt angle” field.

  Further, when the input unit 27 inputs the tilt angle of the X-ray tube 1 corresponding to the size of the X-ray irradiation field, the control unit 17 performs processing based on this input, and the tilt storage unit 25 stores the process. The inclination angle of the X-ray tube 1 corresponding to the size of the X-ray irradiation field is stored.

  In addition, the sizes of the plurality of openings K that can be changed by the collimator 2 corresponding to the size of the X-ray irradiation field are obtained in advance, and the results are stored in the opening storage unit 26. . Specifically, based on Dc = DccDd / (Dcc + Dcd) which is the expression (1) described above, the collimator 2 can vary the size of the X-ray irradiation field for each inch detected by the X-ray detector 3. The size of the plurality of openings K is calculated. Here, the distance Dcc between the X-ray tube 1 (X-ray tube focal point XS) and the collimator 2 (collimator leaf 35) is a fixed value determined in advance in the structure and is stored in the aperture storage unit 26. The distance Dcd between the collimator leaf 35 and the X-ray detector 3 is variable depending on the diagnosis contents, but before the diagnosis, the value of Dcd is manually measured and input by the input unit 27 or automatically. Is measured, and the measured value of Dcd is stored in the opening storage unit 26. Further, the width Dd of the X-ray irradiation field in the X-ray detector 3 is, for example, the size of the X-ray irradiation field per inch from 9 inches (23 cm) to 17 inches (43 cm). Nine X-ray irradiation field sizes are set. Therefore, Dcc, Dcd, and Dd are known values, and the control unit 17 reads out the values of Dcc and Dcd stored in the aperture storage unit 26, and sets (1 for every nine X-ray field sizes. ), The width Dc of the opening K of the collimator leaf 35 is calculated, and this result is used as the size of the opening K of the collimator 2 corresponding to the size of the X-ray irradiation field. 26 is stored.

  In addition, before performing X-ray imaging (fluoroscopy), the operator designates the X-ray irradiation field to the instruction unit 21 in order to obtain an X-ray image of a necessary X-ray imaging range (X-ray irradiation field) of the subject M. Instruct by. Here, the monitor (touch panel) of the instructing unit 21 has nine screens per inch from “9” X-ray irradiation field to “17” X-ray irradiation field ”for instructing a plurality of X-ray irradiation fields. A value is displayed and the surgeon instructs by touching one of these X-ray fields. For example, when the X-ray irradiation field is small and 9 inches are indicated, “X-ray irradiation field 9 inches” is indicated. When the X-ray irradiation field is large and 17 inches are indicated, “X-ray irradiation” is indicated. "No 17".

  Further, when a predetermined X-ray irradiation field is instructed by the instruction unit 21, based on this instruction, the diaphragm control unit 41 of the control unit 17 is instructed by the instruction unit 21 stored in the opening storage unit 26. The size of the opening K of the collimator 2 that is associated with the size of the X-ray irradiation field is read out, and the diaphragm control unit 41 further adjusts the size of the opening K of the collimator 2 that is read out. The collimator leaf drive motor 45 is controlled. Based on this control, the collimator leaf drive unit 17 drives the collimator leaf 35 to have the size of the opening K stored in the opening storage unit 26.

  Further, when a predetermined X-ray irradiation field is instructed by the instruction unit 21, the inclination control unit 43 corresponds to the size of the X-ray irradiation field instructed by the instruction unit 21 stored in the inclination storage unit 25. The attached tilt angle of the X-ray tube 1 is read out, and the tilt drive motor 47 is controlled so as to tilt at this angle. Based on this control, the gear is rotated by the tilt drive motor 47 and the X-ray tube 1 stored in the tilt storage unit 25 is tilted.

  Next, after the X-ray irradiation field is instructed, the X-ray output from the X-ray tube 1 is narrowed by the opening K of the collimator leaf 35 of the collimator 2 and detected by the X-ray detector 3. Will be described with reference to FIGS. First, as illustrated in FIG. 1, when an operation for performing X-ray imaging (perspective) is performed from the input unit 27, the control unit 17 controls the irradiation control unit 19. Further, the irradiation controller 19 controls the X-ray tube 1. Further, as shown in FIG. 2, thermoelectrons are output from the filament 31 of the X-ray tube 1, collide with the target 33, and output as X-rays from the X-ray focal point XS.

  Further, the X-ray tube 1 drawn with a solid line in FIG. 2 shows a state inclined with respect to the X-ray detector 3, and the other X-ray tube 1 drawn with a two-dot chain line shows the X-ray tube The state which is not inclined with respect to the detector 3 is shown. First, a state where the X-ray tube 1 drawn with a solid line is inclined (2 °) with respect to the X-ray detector will be described. This state is a state of the collimator leaf 35 of the collimator 2 in X-ray imaging when the instruction unit 21 instructs that the X-ray irradiation field is large (17 inches), and the X-ray irradiation field is small (9 inches). ) It is narrowed down by the opening K of the collimator 2 that is larger than the case and output to the X-ray detector 3 side. Specifically, the X-rays output from the X-ray tube 1 are output in the range of the X-ray directions a to e shown in FIG. Further, the X-rays are narrowed down to a range from the X-ray direction a to d by the collimator leaf 35 of the collimator 2 and output. The X-ray detector 3 detects X-rays in the range from the X-ray direction a to d. Here, X-rays in a range where the X-ray intensity in the X-ray direction a to b is strong are detected, and an X-ray image in which deterioration in image quality is reduced is obtained.

  Next, based on the instruction unit 21 instructing that the X-ray irradiation field is small (9 inches), the tilt control unit 43 moves the X-ray tube 1 to the X-ray focal point XS of the target 33 of the X-ray tube 1. As a reference, the tilt drive motor 47 is controlled so as to move from the tilt of 2 ° to 0 ° (the state of not tilting), and the state depicted by the two-dot chain line in FIG. Further, the aperture control unit 41 controls the driving of the collimator leaf drive motor 45, the aperture K formed by the collimator leaf 35 is throttled, and the X-ray output from the X-ray tube 1 is the X-ray detector 3 side. It will be in the state output to. Specifically, the X-rays output from the X-ray tube 1 are narrowed down and output by the collimator 2 in the X-ray direction a to c (see FIG. 6). Further, the X-ray detector 3 detects X-rays in the range from the X-ray direction a to c. Here, X-rays in a range where the X-ray intensity in the X-ray direction a to b is strong are detected, and an X-ray image in which deterioration in image quality is reduced is obtained.

  As described above, according to the X-ray diagnostic apparatus, the tilt control unit 43 has the instruction unit stored in the tilt storage unit 25 based on an instruction from the instruction unit 21 that the X-ray irradiation field is large. The drive of the tilt drive motor 47 is controlled so that the X-ray tube 1 tilts at an angle (2 °) associated with a large X-ray irradiation field indicated by 21 (17 inch square). Therefore, when X-rays are output from the X-ray tube 1, detection can be performed when the X-ray irradiation field detected by the X-ray detector 3 is large (17 inch square). Further, the tilt control unit 43 determines that the X-ray irradiation field instructed by the instruction unit 21 stored in the tilt storage unit 25 is based on the instruction unit 21 instructing that the X-ray irradiation field is small. The drive of the tilt drive motor 47 is controlled so that the X-ray tube 1 tilts at an angle (0 °) associated with a small (9 inch square). Therefore, when X-rays are output from the X-ray tube 1, detection with a small (9 inch square) X-ray irradiation field detected by the X-ray detector 3 can be performed. Therefore, a complicated configuration is not required, and X-ray imaging can be performed even when the X-ray irradiation field is large. In X-ray imaging when the X-ray irradiation field is small, it is necessary when the X-ray irradiation field is large. X-ray imaging is not performed using X-rays with low X-ray intensity, and deterioration in image quality can be reduced.

  The X-ray tube 1 includes a filament 31 and a target 33. The filament 31 generates thermoelectrons, and the target 33 is provided with an inclined surface on which the thermoelectrons generated by the filament 31 collide. When the thermoelectrons collide with the inclined surface, X-rays are output in a predetermined angle range from the direction along the inclined surface in front of the end portion. Here, the plurality of angles of inclination of the X-ray tube 1 stored in the inclination storage unit 25 are such that the X-ray output from the direction along the inclined surface of the target 33 is detected by the X-ray detector 3. Is irradiated to one end of the X-ray irradiation field, and the other end of the X-ray irradiation field is irradiated with X-rays output at a predetermined angle from the direction along the inclined surface of the target 33. Is the angle to be. That is, the X-ray tube 1 always irradiates one end portion of the X-ray irradiation field with X-rays output from the direction along the inclined surface of the target 33 even when the size of the X-ray irradiation field changes. In addition, the other end of the X-ray irradiation field is irradiated with X-rays output at a predetermined angle from the direction along the inclined surface of the target. Therefore, imaging can always be performed using X-rays with a high X-ray intensity output from a direction along the inclined surface of the target 33, and a reduction in image quality can be reduced.

  Further, the aperture storage unit 26 stores the aperture control unit 41 in the aperture storage unit 26 based on an instruction from the instruction unit 21 indicating that the X-ray irradiation field is large (17 inch square). Variable control is performed so that the size of the opening K of the collimator 2 is associated with a large (17 inch square) X-ray irradiation field instructed by the instruction unit 21. Therefore, when X-rays are output from the X-ray tube 1, the X-rays are focused by the opening K of the collimator 2 when the X-ray irradiation field is large (17 inch square) and detected by the X-ray detector 3. Detection can be performed when the X-ray irradiation field is large (17 inch square). In addition, the aperture control unit 41 is instructed by the instruction unit 21 stored in the aperture storage unit 26 based on an instruction from the instruction unit 21 that the X-ray irradiation field is small (9 inch square). Variable control is performed so that the size of the opening K of the collimator 2 is associated with a small line irradiation field (9 inch square). Therefore, when the X-ray is output from the X-ray tube 1, the X-ray is narrowed by the opening K of the collimator 2 in accordance with the small X-ray irradiation field, and the X-ray detector 3 reduces the X-ray irradiation field. In some cases, detection can be performed. That is, when the X-ray irradiation field detected by the X-ray detector 3 is large or X-ray imaging is performed in any case where the X-ray irradiation field is small, X-rays are irradiated to a range other than the X-ray irradiation field. Without being subjected to secondary irradiation such as out-of-focus X-rays and scattered rays other than X-rays from the X-ray detector 3, and as a result, it is possible to reduce deterioration in image quality, Further, it is possible to reduce the irradiation of the subject with unnecessary X-rays.

  The present invention is not limited to the above-described embodiment, and can be modified as follows.

  (1) In the above-described embodiments, the X-ray irradiation field has been described as having an X-ray irradiation field size of 1 inch in the range from 9 inch square to 17 inch square. The range of the field size may be a range other than this, or may be a size other than one inch.

  (2) In the embodiment described above, the X-ray detector 3 has been described as a direct conversion type flat panel detector (FPD). However, an X-ray may be detected by an indirect conversion type flat panel detector. In addition, I.I. I. (Image intensifier) A tube may be used for detection.

It is a block diagram which shows the whole structure of a X-ray diagnostic apparatus. It is a schematic diagram which shows the state which inclined the X-ray tube with respect to X-ray detector, and the state which is not inclined. It is a schematic diagram which shows the relationship between an X-ray tube, a collimator, and an X-ray detector. It is a perspective view which shows the structure of a collimator leaf. It is the schematic diagram which showed the inclination angle which an X-ray tube inclines with respect to the magnitude | size of an X-ray irradiation field. It is a schematic diagram which shows the state which has not inclined the X-ray tube with respect to the X-ray detector in the past. It is a schematic diagram which shows the state which inclined the X-ray tube with respect to the X-ray detector in the past.

Explanation of symbols

1 X-ray tube (X-ray output means)
2 ... Collimator (X-ray diaphragm means)
3 X-ray detector (X-ray detection means)
21 ... Instruction part (instruction means)
25. Inclination storage unit (inclination storage means)
26: Opening storage unit (opening storage means)
31 ... Filament 33 ... Target 41 ... Aperture control unit (aperture control means)
43: Inclination control unit (inclination control means)
47. Inclination drive motor (inclination drive means)
K ... opening

Claims (2)

(A) X-ray output means for outputting X-rays, (B) X-ray detection means for detecting X-rays output from the X-ray output means, and (C) driving to tilt the X-ray output means. Inclination drive means, (D) Inclination control means for controlling the drive of the inclination drive means, and (E) The X-ray with respect to the sizes of a plurality of X-ray irradiation fields detected by the X-ray detection means Inclination storage means for storing a plurality of angles at which the output means is inclined, and (F) the size of the plurality of X-ray irradiation fields detected by the X-ray detection means. (G) the X-ray output means is provided with a filament that generates thermoelectrons and an inclined surface on which the thermoelectrons generated by the filament collide, Thermionic electrons collide with the inclined surface, so that it is forward of the edge, and A target for outputting X-rays in a range of a predetermined angle from a direction along the inclined surface. ( H ) The inclination control means is a size of any one X-ray irradiation field by the indicating means. The X-ray output means is inclined so that the X-ray output means is inclined at an angle associated with the size of the X-ray irradiation field indicated by the indication means stored in the inclination storage means. The drive of the tilt drive means is controlled . (I) The end of the X-ray output in the direction opposite to the filament side along the tilted surface of the target is indicated by the indicating means. An X-ray diagnostic apparatus characterized in that the angle is applied to the end of the X-ray irradiation field opposite to the filament side . 2. The X-ray diagnostic apparatus according to claim 1 , wherein X-ray diaphragm means for narrowing X-rays output from the X-ray output means by changing the size of the opening, and the opening of the X-ray diaphragm means A plurality of apertures variable by the X-ray diaphragm unit with respect to a plurality of X-ray irradiation fields detected by the X-ray detector; And aperture storage means for storing the information in association with each other, and the aperture control means stores the aperture storage means in response to the instruction means instructing the size of any one X-ray irradiation field. X-rays that perform variable control so as to be the size of the opening of the X-ray diaphragm means associated with the size of the X-ray irradiation field instructed by the indicated instruction means. Diagnostic device.

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