JP5435860B2 - X-ray diagnostic imaging equipment - Google Patents

Description

  The present invention relates to an X-ray diagnostic imaging apparatus using an X-ray flat panel detector as an X-ray detector, and more particularly to a method for setting an X-ray irradiation region for a subject.

  In recent years, X-ray diagnostic imaging devices such as X-ray devices dedicated to radiography, X-ray fluoroscopic imaging tables, cardiovascular X-ray inspection systems, mammography units, etc., use semiconductor digital as a means to detect X-rays that have passed through the subject X-ray detectors have been used. This semiconductor digital X-ray detector is generally called an X-ray flat panel detector, and there are various types of X-ray flat panel detectors. However, compared to conventional image intensifiers and other X-ray detectors, it is characterized by being thinner and lighter.

Among X-ray diagnostic imaging devices that use this X-ray flat panel detector, especially X-ray devices dedicated to radiography are provided in the vicinity of the X-ray source when the X-ray irradiation area is set to an appropriate range. The light irradiation means for irradiating light to the same region as the region irradiated with X-rays is used, and the position of the X-ray movable diaphragm is adjusted so that the region irradiated with the light falls within an appropriate range. (For example, see Patent Document 1.)
The reason why the X-ray irradiation area is adjusted to an appropriate range and the light irradiation means is used for adjusting the X-ray irradiation area is to reduce the ineffective exposure to the subject.

JP 2006-255216 A.

  In the conventional technique, in order to set the X-ray irradiation region to an appropriate range, a light irradiation unit that irradiates light to the same region as the region irradiated with X-rays is used. The light irradiation means generally uses an incandescent lamp as its light source, and has the following problems.

First, a series of operations such as lamp lighting operation, visual recognition of the light irradiation area, and adjustment of the position of the blades of the X-ray movable diaphragm are complicated.
Second, it is difficult to visually recognize the light irradiation area by the incandescent lamp in a bright environment.
Third, the incandescent lamp has a short life span and needs to be replaced regularly. Fourth, the optical irradiation area and the X-ray irradiation area may cause a difference between the light irradiation area and the X-ray irradiation area. .

The object of the present invention has been made in view of the above circumstances, and the object of the present invention is to provide an X-ray diagnostic imaging apparatus capable of easily and accurately setting an appropriate X-ray region. It is in.

According to the present invention,
An X-ray source that irradiates a subject with X-rays, an X-ray movable diaphragm that has blades that limit an X-ray irradiation region irradiated from the X-ray source, and the X-ray source disposed opposite to the X-ray movable diaphragm An X-ray image diagnostic apparatus comprising: an X-ray flat panel detector for detecting transmitted X-rays of a subject; and a blade of the X-ray movable diaphragm on a side different from the X-ray incident surface of the X-ray flat panel detector An X-ray movable diaphragm range setting means for setting a movement range; and a control unit for controlling movement of the blades of the X-ray movable diaphragm based on information set by the X-ray movable diaphragm range setting means, The control unit is set so that the X-ray irradiation region set by the operator using the X-ray movable aperture range setting unit is a region on the body surface of the subject on the X-ray irradiation surface side. Each of the X-ray irradiation area, the X-ray source, the X-ray movable diaphragm, and the X-ray flat panel detector And septum value, the value of the body thickness of the subject, X-ray image diagnostic apparatus, characterized by movement control vane of the aperture the X-ray movable based on is provided.

Further, according to the present invention, the X-ray movable aperture range setting means includes a display unit for displaying an X-ray irradiation area set by an operator using the X-ray movable aperture range setting means. An X-ray diagnostic imaging apparatus is provided.

According to the present invention, it is possible to set the position of the blade of the X-ray movable diaphragm by the X-ray movable diaphragm range setting means arranged on the side opposite to the X-ray incident surface of the X-ray flat panel detector. X-ray irradiation area can be set with a simple operation. Furthermore, the operability is not affected by the external environment such as the brightness of the room, and if it is within the general life of the equipment, it is not necessary to periodically replace the parts related to the setting of the X-ray irradiation area. There are also effects such as. Furthermore, it becomes possible to delete the light irradiation means from the X-ray movable diaphragm, and the X-ray movable diaphragm can be made thin.

An embodiment of the X-ray image diagnostic apparatus of the present invention will be described below with reference to the drawings.
The X-ray image diagnostic apparatus according to the first embodiment shown in FIG. 1 of the present invention includes an X-ray source that irradiates a subject with X-rays, an X-ray movable diaphragm that restricts an X-ray irradiation area, and an X-ray An X-ray flat panel detector for detecting transmitted X-rays of a subject arranged opposite to the source, an X-ray movable aperture range setting means arranged on the opposite side of the X-ray incident surface of the X-ray flat panel detector, and an X-ray A control device is provided that performs various controls by performing wired or wireless communication with the movable aperture range setting means and the X-ray movable aperture.

  An X-ray source is an apparatus that irradiates a subject with X-rays, and accelerates thermoelectrons emitted from a cathode in a vacuum at a high voltage of about several tens to hundreds of kV, and is an anode made of tungsten or the like. An X-ray tube apparatus that generates X-rays by colliding with a carbon nanotube is common, but in recent years, an apparatus using carbon nanotubes has also been studied.

  The X-ray movable diaphragm restricts the irradiation area (X-ray irradiation region) of X-rays irradiated to the subject. A conceptual view of the X-ray movable diaphragm viewed from the X-ray source side is shown in FIG. As shown in the figure, the X-ray movable diaphragm is equipped with four independent blades made of a material with a high X-ray absorption coefficient, such as lead, which can move in the vertical and horizontal directions and in the rotational direction. Limit the X-ray irradiation area to the subject. For example, if the inside of the circle surrounded by the dotted line is an area irradiated with X-rays from the X-ray source, the blade part does not transmit X-rays, resulting in points a, b, c, and d. X-rays of only the rectangular area surrounded by the permeation are transmitted, and the subject is irradiated.

  Here, the number of the blades is not necessarily four, and for example, it is possible to adopt a configuration of eight blades as shown in FIG. 3, and furthermore, it is necessary that each blade has the same X-ray absorption coefficient. Instead, the blades (oblique blades) shown obliquely in the figure may have a low X-ray absorption coefficient compared to other blades. In general, blades made of lead having a high X-ray absorption coefficient are called lead blades, and blades made of X-ray absorption lower than lead are called filters. In this specification, all blades are expressed as blades. The configuration is the four-sheet configuration shown in FIG.

  There are various types of X-ray flat panel detectors. For example, it consists of a scintillator that converts X-rays that have passed through the subject into light, and a photodiode that converts light output from the scintillator into electric charge, generally called an indirect X-ray flat panel detector, etc. Yes, it is thin and lightweight.

  The X-ray movable aperture range setting means is constituted by what is called a matrix switch, for example. A matrix switch is a two-dimensional representation of X-axis and Y-axis at the place touched by the operator, as shown in Fig. 4, where a number of switches are arranged in a plane like a grid. It is possible to obtain position information. The switch structure is short-circuited by a thin electrode consisting of a two-layer structure with a gap when the operator touches the switch to detect optical changes and capacitance changes. There are various methods such as a method of detecting the position.

  In addition to the matrix switch, there are a variety of methods for detecting the position touched by the operator, such as a resistive film method and a surface acoustic wave method, and these can also be used for the X-ray movable aperture range setting means. Of course.

  The operation of the X-ray image diagnostic apparatus according to the first embodiment of the present invention shown in FIG. 1 will be described. Prior to imaging, the operator places an X-ray flat panel detector in the vicinity of a region (region of interest) where the subject is desired to be imaged.

  This X-ray flat panel detector is supported by a support device (not shown), and its position can be freely set. If the X-ray flat panel detector becomes thinner and lighter, the subject itself will be able to support the X-ray flat panel detector.

  The X-ray source and X-ray movable diaphragm in the figure are always supported by a support device (not shown), and its position can be freely set.When the X-ray flat panel detector is placed near the region of interest, Positioned so that the center of the field of view of the X-ray flat panel detector coincides with the center point of the X-ray source and the X-ray movable diaphragm by automatic tracking by a mechanism (not shown) or manual operation by the operator. Shall.

  Note that the distance d1 between the X-ray source and the X-ray movable diaphragm is a constant determined by the apparatus structure and is known. Also, the distance d2 between the X-ray source and the X-ray flat panel detector is assumed to be a value set in advance by an operation input means (not shown) when the X-ray source is moved by the automatic tracking described above. Known. When the X-ray source is moved by a manual operation by the operator, the distance d2 is a distance arbitrarily moved by the operator, but is measured by a distance measuring mechanism (not shown) and becomes known. That is, in any case, the distances d1 and d2 are known values.

  Next, the operator sets the X-ray irradiation area by the X-ray movable diaphragm range setting means arranged on the side opposite to the X-ray incident surface. FIG. 5 shows an X-ray flat panel detector, an X-ray movable aperture range setting means, and a subject illustrated from the opposite side to the X-ray incident direction. This X-ray movable aperture range setting means is composed of the matrix sensor described above, and its detection range is the same as the maximum field size of the X-ray flat panel detector.

  The operator touches the four points of the X-ray movable aperture range setting means so as to surround the region of interest. In the figure, the four points A to D are the four points touched by the operator. The X-ray movable aperture range setting means transmits the position information expressed by the two axes X and Y touched by the operator to the control device by wire or wirelessly. In this specification, the center of the field of view of the X-ray flat panel detector is the origin, the horizontal direction with respect to the ground is expressed as the X axis, and the vertical direction is expressed as the Y axis.

  The control device determines a region to be irradiated with X-rays from four points touched by the operator, and calculates position information of the blades of the X-ray movable diaphragm. For example, as shown in FIG. 6, the coordinates of the four points touched by the operator are A (x1, y1), B (x2, y2), C (x3, y3), and D (x4, y4), respectively. Assume that a quadrangular region where is a vertex is an X-ray irradiation region. Here, the region of interest range is set by touching the four points of the X-ray movable aperture position setting means. However, the present invention is not necessarily limited to this. For example, the operator surrounds the region of interest. In this way, it is possible to easily set the X-ray irradiation area by tracing with a finger, and even if the area of interest is specified halfway, the operator would have desired it Estimating the area and setting the X-ray irradiation area can be easily realized.

  Since the coordinates of the X-ray irradiation area and the position of the X-ray movable diaphragm blade are similar to each other as shown in FIG. 7, the X-ray movable diaphragm satisfying the X-ray irradiation area specified by the operator, The shift amount from the center point of the blade is expressed by the following equations (1) to (4). Note that the shift amount from the center point of each blade is defined as shown in FIG. 8, and always takes a value of zero or more.

d1: WUps = d2: | y1 | (1)
d1: WDns = d2: | y3 | (2)
d1: WRts = d2: | x2 | (3)
d1: WLts = d2: | x1 | (4)

By arranging the above equations, the following equations (5) to (8) are obtained.

WUps = k ・ | y1 | ・ ・ ・ (5)
WDns = k ・ | y3 | ・ ・ ・ (6)
WRts = k ・ | x2 | (7)
WLts = k ・ | x1 | (8)
However, k = d1 / d2 (9)
At this time, the distance d1 and the distance d2 in FIG. 7 are known values as described above, and the shift amount from the center point of each blade can be calculated.

  The control device transmits the shift amount from the center point of each blade calculated by the above formulas (5) to (8) and (9) to the X-ray movable aperture device by wire or wirelessly.

  Although the case where the X-ray irradiation region is set at a position rotated around the center of the visual field has not been described so far, even if the X-ray irradiation region is set at a position rotated around the visual field center, This can be easily realized by rotating the blades of the X-ray movable diaphragm at the same angle.

  In the X-ray movable diaphragm, each blade is moved according to the shift amount from the central point received from the control device, and the X-ray irradiation area is determined.

With the above operation, the X-ray irradiation area can be set easily and intuitively by touching the matrix switch which is the X-ray movable aperture position setting means.
The X-ray diagnostic imaging apparatus of the present invention shown in FIG. 1 does not require an examination table on which a subject is placed, for example, chest imaging has been described, but the present invention is not limited to this.

  In the present embodiment, the control device is shown for ease of explanation, but it does not necessarily have to exist as a unit, and its function is not limited to the X-ray movable diaphragm range detecting means or the X-ray movable diaphragm. It can also be given.

  According to the above-described embodiment, the X-ray source for irradiating the subject with X-rays, the X-ray movable diaphragm including the blades for limiting the X-ray irradiation area, and the X-ray source are disposed opposite to each other. In an X-ray diagnostic imaging apparatus comprising an X-ray flat panel detector for detecting transmitted X-rays of a subject, an X-ray movable diaphragm range setting means is disposed on the opposite side of the X-ray incident surface of the X-ray flat panel detector, An X-ray movable diaphragm range setting means and a control device for performing various controls by communicating with the X-ray movable diaphragm in a wired or wireless manner are provided, and the X-ray movable diaphragm range setting means is at least two places touched by an operator. Provided is an X-ray diagnostic imaging apparatus that obtains three-dimensional position information, controls the position of the blade of the X-ray movable diaphragm based on the position information, and sets an appropriate X-ray irradiation area. .

FIG. 9 is a schematic diagram showing a configuration of Example 2 in the X-ray image diagnostic apparatus of the present invention.
In the figure, components having functions similar to those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
The X-ray image diagnostic apparatus according to the second embodiment of the present invention shown in FIG. 9 is different from the X-ray image diagnostic apparatus according to the first embodiment shown in FIG. 1 according to the distance between the X-ray source and the X-ray flat panel detector. A function for correcting the blade position of the movable diaphragm is added. Here, the distance between the X-ray source and the X-ray flat detector is generally called SID (Source Image Distance). In this specification, this name will be used hereinafter, and the unit having the correction function is referred to as the SID correction mechanism. Call it.

  The X-rays used in the X-ray diagnostic imaging apparatus are not parallel X-rays, but X-rays that are irradiated in a conical shape with an X-ray source having a certain small area as a vertex and have a spread. Therefore, if the X-ray irradiation area for imaging the region of interest is to be specified strictly, the operator needs to specify the area by the X-ray movable aperture range setting means in consideration of the X-ray spread. . For example, in Fig. 10, if the region painted with gradation is the region of interest, the operator is aware of the spread of the X-ray, and the four points that specify the X-ray irradiation region are E, F, G, and H. There is a need.

  However, it is difficult for a normal operator to set points E to H in consideration of the spread of X-rays, and a region wider than the true region of interest is designated as the X-ray irradiation region, and the subject is invalidated. The exposure may increase, or the X-ray irradiation area may be narrower than the true area of interest, leading to loss of diagnostic information.

  When an operator designates an X-ray irradiation region, an intuitive operation is possible when the region of interest is planarly viewed from the front of the X-ray flat detector and the depth direction is not conscious. In this way, the four points when the region of interest is set are designated as E ′, F ′, G ′, and H ′, and are shown in FIG. 11 together with the points E to H described above. The SID correction mechanism automatically calculates E to H points that are appropriate X-ray irradiation areas in consideration of the X-ray spread, from E 'to H' points that the operator intuitively specifies.

  First, a method for calculating the Y coordinate among the coordinates (x5, y5) of the point E will be described. From FIG. 11, it is clear that the following equation (10) holds.

y5 = y9 + L2 (10)
Here, since the triangle connected by the M point, the N point, and the P point and the triangle connected by the P point, the Q point, and the R point have a similar relationship, L2 is expressed by the following equation (11). Be
L2 = tanθ ・ L1 = (y9 / (d2-L1)) ・ L1 (11)
Therefore, by substituting equation (11) into equation (10), the Y coordinate of point E is expressed by equation (12) below.

y5 = y9 + (y9 / (d2-L1)) ・ L1 (12)
The X coordinate of point E and the X and Y coordinates of points F to H can be calculated in the same way, and are expressed by the following equations (13) to (19).

x5 = x9 + (x9 / (d2-L1)) ・ L1 ... (13)
y6 = y10 + (y10 / (d2-L1)) ・ L1 ... (14)
x6 = x10 + (x10 / (d2-L1)) ・ L1 ... (15)
y7 = y11 + (y11 / (d2-L1)) ・ L1 ... (16)
x7 = x11 + (x11 / (d2-L1)) ・ L1 ... (17)
y8 = y12 + (y12 / (d2-L1)) ・ L1 ... (18)
x8 = x12 + (x12 / (d2-L1)) ・ L1 ... (19)
Here, in the formulas (12) to (19), the thickness L1 of the region of interest varies depending on the region to be examined and the individual difference of the subject. The thickness is input to a known value in advance.

  Similarly to the first embodiment, the X-ray source and the X-ray movable diaphragm are positioned before the X-ray irradiation area is designated by automatic tracking of the movement of the X-ray flat panel detector or by manual operation by the operator. Is already determined, and SID in equations (12) to (19), that is, d2 is a known value. Thereby, if the points E ′ to H ′ are designated, the points E to H can be calculated.

  In the SID correction mechanism, after performing the correction calculation according to the equations (12) to (19), the position information is transmitted to the control device by wire or wirelessly. The subsequent processing is the same as in the first embodiment.

  In the present embodiment, the control device and the SID correction mechanism are shown for ease of explanation, but they do not necessarily exist independently as a unit, and their functions are not limited to the X-ray movable aperture range detecting means or X It is also possible to put it on a line movable diaphragm.

  According to the above-described embodiment, the correction means for correcting the position of the blade of the X-ray movable diaphragm is provided based on the spread of the X-ray and the geometric arrangement of the X-ray diagnostic imaging apparatus and the subject. An X-ray diagnostic imaging apparatus is provided.

  FIG. 12 is a schematic diagram showing a configuration of Example 3 in the X-ray image diagnostic apparatus of the present invention. In the figure, components having the same functions as those in the first or second embodiment are denoted by the same reference numerals, and the description thereof is omitted. The X-ray diagnostic imaging apparatus of Embodiment 3 of the present invention shown in FIG. 12 is the X-ray diagnostic imaging apparatus of the first or second embodiment, the X-ray movable aperture range setting means has a display function, and Like the matrix sensor, a sensor capable of obtaining position information of a place touched by an operator is used. In FIG. 12, the SID correction mechanism in the second embodiment is not shown.

  In Example 1 or Example 2, since the X-ray movable aperture range setting means does not have a display function, the operator does not have means for recognizing the designated X-ray irradiation area. The point can be improved.

  Assume that an X-ray irradiation area is designated by the operator as shown in FIG. The X-ray movable aperture range designation means draws four line segments connecting the S and T points, the T and U points, the U and V points, and the V and S points. Display to the operator. It is also effective to color the area surrounded by the line segment.

  It goes without saying that by adding a display function to the X-ray movable aperture range specifying means, it is possible to easily add a simple display function for captured images and a setting mechanism for SID and various imaging conditions. .

  According to the above-described embodiment, there is provided an X-ray image diagnostic apparatus comprising a display unit that displays the position information.

Schematic diagram showing the configuration of Example 1 in the X-ray diagnostic imaging apparatus of the present invention Schematic diagram of an X-ray movable diaphragm composed of four blades Schematic diagram of an X-ray movable diaphragm composed of 8 blades Conceptual diagram of matrix switch used in X-ray movable aperture range setting means Schematic diagram showing the operator touching 4 points with the X-ray movable aperture range setting means Schematic diagram showing that the X-ray movable area setting means determines the X-ray irradiation area from the four points touched by the operator Schematic diagram showing the positional relationship between the X-ray irradiation area and the X-ray movable diaphragm in the first embodiment. Schematic diagram showing the definition of the shift amount from the center point of an X-ray movable diaphragm composed of four blades Schematic diagram showing the configuration of Example 2 in the X-ray diagnostic imaging apparatus of the present invention Schematic diagram showing the positional relationship between the X-ray irradiation area and the X-ray movable diaphragm in the second embodiment (1) Schematic diagram showing the positional relationship between the X-ray irradiation area and the X-ray movable diaphragm in the second embodiment (2) Schematic diagram showing the configuration of Example 3 in the X-ray diagnostic imaging apparatus of the present invention

Explanation of symbols

  1 X-ray source, 2 X-ray movable aperture, 3 blades, 4 control device, 5 subject, 6 X-ray movable aperture range setting means, 7 X-ray flat panel detector, 8 switch, 9 SID correction function, 10 display function X-ray movable aperture range setting means

Claims (2)

An X-ray source that irradiates a subject with X-rays, an X-ray movable diaphragm that has blades that limit an X-ray irradiation region irradiated from the X-ray source, and the X-ray source disposed opposite to the X-ray movable diaphragm In an X-ray diagnostic imaging apparatus comprising: an X-ray flat panel detector that detects transmitted X-rays of a subject;
X-ray movable diaphragm range setting means for setting the movement range of the blades of the X-ray movable diaphragm on the side different from the X-ray incident surface of the X-ray flat panel detector, and the X-ray movable diaphragm range setting means. A control unit that controls movement of the blades of the X-ray movable diaphragm based on the information,
The control unit places an X-ray irradiation region set by an operator using the X-ray movable diaphragm range setting unit in the subject arranged between the X-ray source and the X-ray flat panel detector. Each of the set X-ray irradiation area, the X-ray source, the X-ray movable diaphragm, and the X-ray flat panel detector so as to be an area on the body surface of the X-ray irradiation surface on the X-ray source side . An X-ray diagnostic imaging apparatus, wherein movement of the blades of the X-ray movable diaphragm is controlled based on an interval value and a body thickness value of the subject.   The X-ray movable aperture range setting means includes a display unit that displays an X-ray irradiation area set by an operator using the X-ray movable aperture range setting means. Line image diagnostic device.

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