JP4211098B2 - X-ray tomography equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a non-CT (non-computer tomography) X-ray tomography apparatus for obtaining an X-ray tomographic image of a tomographic plane in a subject, and in particular, imaging objects at various depth positions. The present invention relates to an improved technique for obtaining an X-ray tomographic image of a tomographic plane.
[0002]
[Prior art]
As shown in FIG. 9, the non-CT X-ray tomographic imaging apparatus installed in a medical institution such as a hospital has an X for an imaging target tomographic plane Ma in a subject M placed and supported on the top 1. While the X-ray incident direction from the X-ray tube 2 is sequentially changed, the subject M is irradiated with X-rays, and the transmitted X-ray image of the imaging target tomographic plane Ma in the subject M is always an image intensifier. Change of the incident direction of X-rays on the tomographic plane Ma to be imaged (on the X-ray tube 2 side) so as to be projected on the same position on the image receiving surface 3a of the imaging unit 3 such as an X-ray detector such as a film or a photographing material such as film The position of the image receiving surface 3a of the imaging unit 3 is changed in conjunction with the operation) to obtain an X-ray tomographic image of the imaging target tomographic surface Ma.
[0003]
The principle of X-ray tomography using this X-ray tomographic imaging apparatus will now be described in some detail. That is, as shown in FIG. 9, for example, by changing the position of the X-ray tube 2 or the irradiation angle of the X-rays irradiated from the X-ray tube 2, the X with respect to the imaging target tomographic plane Ma in the subject M is changed. Even when the incident direction of the X-ray from the ray tube 2 is changed, the points A and B located in the tomographic plane Ma to be imaged are always projected on the same points a and b on the image receiving surface 3a of the imaging unit 3. As described above, the position of the image receiving surface 3a of the image receiving unit 3 is changed in conjunction with the change in the X-ray incident direction with respect to the imaging target tomographic plane Ma. Then, the projection position on the image receiving surface 3a changes more and more at the point C located outside the imaging target tomographic plane Ma as the X-ray incident direction changes with respect to the imaging target tomographic plane Ma. For example, with respect to the X-ray incidence direction with respect to the imaging target tomographic plane Ma when the X-ray tube 1 is at the position P1, the point C is projected onto the point c1 on the image receiving surface 3a, but at a position P2 different from the position P1. The point C is projected onto the point c2 on the image receiving surface 3a with respect to the X-ray incidence direction with respect to the tomographic plane Ma to be imaged when the X-ray tube 1 moves.
[0004]
When the transmitted X-ray images received on the image receiving surface 3a of the imaging unit 3 are superposed in a state where the X-ray incident direction with respect to the tomographic plane Ma to be imaged is changed in this way, a point C is obtained in the image after superposition. The transmitted X-ray image is scattered (distributed) over the entire image, and the point C appears as an unclear blurred point. The degree of blur at the point C increases as the distance from the tomographic plane Ma to be imaged increases. On the other hand, the transmitted X-ray images of the points A and B are kept (concentrated) at one point of the image, and the points A and B appear as clear points in the superimposed image. Therefore, only the imaging target tomographic plane Ma is clear by superimposing a large number of transmitted X-ray images received on the image receiving surface 3a of the imaging unit 3 by variously changing the X-ray incident direction with respect to the imaging target tomographic plane Ma. , That is, an X-ray tomographic image obtained by extracting the tomographic plane Ma to be imaged in the subject M can be obtained.
[0005]
When the imaging unit 3 is configured by an X-ray detector such as an image intensifier, X-rays for the imaging target tomographic plane Ma sampled during the imaging operation of the X-ray tube 2 or the imaging unit 3 are used. X-ray tomographic images are obtained by converting a large number of transmitted X-ray images having different incident directions into digital images and integrating the images by digital image processing. Further, when the imaging unit 3 is configured by a photographing material such as a film, a large number of transmissions with different X-ray incident directions with respect to the imaging target tomographic plane Ma during the imaging operation of the X-ray tube 2 or the imaging unit 3 are performed. The X-ray image is multiply exposed on the imaging material 3 to obtain an X-ray tomographic image.
[0006]
A drive control system of an X-ray tomography apparatus that obtains an X-ray tomography image of the tomographic plane Ma to be imaged based on the above principle is conventionally configured as follows.
[0007]
[First Conventional Example]
Please refer to FIG. In the first conventional example, the X-ray tube 2 is held by an X-ray tube holding member 22 that is moved horizontally along a rail 21 laid on the ceiling, for example, by an X-ray tube drive mechanism 11 such as a motor. The tube 2 is moved horizontally. An X-ray irradiation driving unit 12 including a high voltage generator is connected to the X-ray tube 2, and X-ray irradiation driving from the X-ray tube 2 is performed by the X-ray irradiation driving unit 12. In addition, the irradiation angle driving mechanism 13 such as a motor changes the X-ray irradiation angle irradiated from the X-ray tube 2 by rotating the X-ray tube 2 with respect to the X-ray tube holding member 22, for example. It is configured.
[0008]
Drive control of imaging drive systems such as the X-ray tube drive mechanism 11, the X-ray irradiation drive unit 12, and the irradiation angle drive mechanism 13 is performed by the control unit 10P1. The control unit 10P1 drives and controls these imaging drive systems 11, 12, and 13 to change the X-ray irradiation angle as described below from the X-ray tube 2 to the X-ray tube 2 while moving the X-ray tube 2 horizontally. Operate to irradiate a line. The X-ray irradiation angle is such that the central axis XJ of the X-ray bundle irradiated from the X-ray tube 2 is always imaged in the imaging target tomographic plane Ma in the subject M at each position during horizontal movement of the X-ray tube 2. It changes so that it may pass through center GC. Thereby, the incident direction of the X-ray with respect to the imaging target tomographic plane Ma (inside the imaging center GC) in the subject M placed and supported on the top board 1 is changed in various directions.
[0009]
The imaging unit 3 disposed on the opposite side of the X-ray tube 2 across the top plate 1 on which the subject M is placed and supported can be horizontally moved integrally with the X-ray tube 2 by an extendable connecting member 100. It is connected to the wire tube 2. The connecting member 100 is provided with a fulcrum 101. Accordingly, when the X-ray tube 2 is moved horizontally, the connecting member 100 is swung around the fulcrum 101, and accordingly, a transmission X-ray image of the imaging target tomographic plane Ma in the subject M is always captured by the imaging unit. The position of the image receiving surface 3a of the imaging unit 3 is changed in conjunction with the operation on the X-ray tube 2 side so as to be projected onto the same position on the third image receiving surface 3a. The position of the fulcrum 101 can be changed.
[0010]
With the above configuration, an X-ray tomographic image of a predetermined imaging range GH centered on the imaging center GC can be obtained from the imaging target tomographic plane Ma shown in FIG.
[0011]
By the way, in this first conventional example, the control unit 10P1 has only one type of drive data corresponding to one to-be-photographed tomographic plane Ma at a predetermined depth position as drive data for driving the imaging drive system. have. Then, when imaging is performed by changing the depth position of the imaging target tomographic plane Ma, the position of the fulcrum 101 is changed to a position corresponding to the depth position of the imaging target tomographic plane Ma to be imaged. The interlocking operation between the tube 2 side and the imaging unit 3 side is changed so that an operation corresponding to the depth position of the imaging target tomographic plane Ma to be imaged can be performed.
[0012]
[Second Conventional Example]
Please refer to FIG. In the first conventional example described above, the interlocking operation between the X-ray tube 2 side and the imaging unit 3 side necessary for obtaining an X-ray tomographic image of the tomographic plane Ma to be imaged is performed between the X-ray tube 2 and the imaging unit 3. The second conventional example is realized with the X-ray tube driving mechanism 11 that horizontally moves the X-ray tube 2 without connecting the X-ray tube 2 and the imaging unit 3. Separately, an imaging unit driving mechanism 14 such as a motor for horizontally moving the imaging unit 3 is provided, and the X-ray tube 2 and the imaging unit 3 are made independent and can be moved horizontally. Then, the X-ray tube driving mechanism 11 and the control unit 10P2 perform an interlocking operation between the X-ray tube 2 side and the imaging unit 3 side necessary for obtaining an X-ray tomographic image of the tomographic plane Ma to be imaged. The imaging unit drive mechanism 14 is driven and controlled. Other X-ray irradiation angle change control and X-ray irradiation drive control from the X-ray tube 2 are the same as in the first embodiment.
[0013]
Also in the second conventional example, the control unit 10P2 has only one type of drive data corresponding to one imaging target tomographic plane Ma at a predetermined depth position as drive data for driving the imaging drive system. ing. When imaging is performed by changing the depth position of the imaging target tomographic plane Ma, the top plate 1 is moved up and down by the top plate driving mechanism 15 that moves the top plate 1 up and down, and the subject M is moved to the X-ray tube 2. Accordingly, the positional relationship of the one to-be-photographed tomographic plane Ma in the subject M is changed in the depth direction.
[0014]
[Problems to be solved by the invention]
However, the conventional example having such a configuration has the following problems.
Usually, in a series of tomographic examinations, in order to specify the position of a lesioned part, imaging is performed by changing the depth position of the imaging target tomographic surface Ma by several points. It is necessary to change the position of the fulcrum 101 of the connecting member 100 every time imaging is performed while changing the depth position of the tomographic plane Ma. Since the changing operation of the fulcrum 101 of the connecting member 100 includes an operator's manual operation, there is a problem that the changing operation of the supporting point 101 of the connecting member 100 is laborious and a heavy burden on the operator.
[0015]
In the second conventional example, it is possible to perform imaging by changing the depth position of the imaging target tomographic plane Ma just by moving the top plate 1 up and down, and the top plate 1 can usually be moved up and down by a button operation or the like. The problem of the first conventional example is solved. However, as the table 1 is moved up and down, body movement of the subject M easily occurs on the table 1, and as a result, an X-ray tomographic image with respect to the imaging target tomographic plane Ma at a desired depth position can be accurately obtained. You may not be able to get to. In particular, in order to specify the position of the lesion, the depth position of the tomographic surface Ma to be imaged may be changed in units of (mm), and the depth position of the tomographic surface Ma to be imaged by the body movement of the subject M. Due to this deviation, the X-ray tomographic images of the tomographic surface Ma to be imaged at the respective depth positions changed in units of (mm) may not be obtained accurately, which may hinder a series of tomographic examinations. In addition, there is also a problem that psychological anxiety is given to the subject M when the top board 1 is frequently lifted and lowered during the tomographic examination.
[0016]
The present invention has been made in view of such circumstances, and can solve the drawbacks of the prior art and easily obtain X-ray tomographic images of imaging tomographic planes at various depth positions. An object is to provide an X-ray tomography apparatus.
[0017]
[Means for Solving the Problems]
In order to achieve such an object, the present invention has the following configuration. That is, the present invention is an X-ray tomography apparatus for obtaining an X-ray tomographic image of a tomographic plane to be imaged in a subject, comprising: (a) a supporting means for supporting the subject; and (b) the supporting means. X-ray irradiating means for irradiating the object to be supported with X-rays, and (c) X arranged on the opposite side of the X-ray irradiating means across the object supported by the supporting means and transmitted through the object An imaging means for receiving and picking up a line transmission image on an image receiving surface; and (d) driving for changing the incident direction of X-rays from the X-ray irradiation means to the tomographic surface to be imaged in the subject supported by the support means. X-ray incident direction changing driving means, X-ray irradiation driving means for performing X-ray irradiation driving from the X-ray irradiating means, and image receiving position changing driving means for changing and driving the position of the image receiving surface of the imaging means. Imaging drive means including: (e) inside the subject supported by the support means While irradiating the subject with X-rays while sequentially changing the incident direction of the X-rays from the X-ray irradiating unit to the imaging target tomographic plane, a transmitted X-ray image of the imaging target tomographic plane is always in the imaging unit. Drive control of the imaging drive means according to the drive data so as to change the position of the image receiving surface of the imaging means in conjunction with the change of the incident direction of the X-ray with respect to the tomographic plane to be imaged so as to be projected at the same position on the image receiving surface. Control means for changing the depth position of the to-be-photographed tomographic plane, and taking the image at the depth position according to the depth position of the to-be-photographed tomographic plane to be imaged. The imaging according to the depth position of the imaging target tomographic plane determined by the positional relationship between the target tomographic plane and the X-ray irradiation means and the positional relationship between the imaging target tomographic plane at the depth position and the image receiving plane of the imaging means. Driving The drive data of the means Under the condition that the moving range of the X-ray irradiation means is the same before and after changing the depth position of the tomographic plane to be imaged The calculation is performed according to the depth position of the tomographic plane to be imaged, and the imaging drive means is driven and controlled accordingly.
[0018]
[Action]
The operation of the present invention is as follows.
When the subject is supported by the support unit and the subject is positioned at a predetermined imaging position between the X-ray irradiation unit and the imaging unit, the control unit is configured to capture the imaging target in the subject supported by the support unit. X-rays are irradiated while sequentially changing the incident direction of the X-rays from the X-ray irradiation unit to the tomographic plane, and the transmitted X-ray image of the imaging target tomographic plane is always projected at the same position on the image receiving plane of the imaging unit. As described above, the X-ray incident direction changing driving means, the X-ray irradiation driving means, and the image receiving position changing driving means are changed so as to change the position of the image receiving surface of the imaging means in conjunction with the change of the X-ray incident direction with respect to the tomographic plane. The X-ray tomographic image of the imaging target tomographic plane is obtained by controlling the imaging driving means including
[0019]
Then, when imaging is performed by changing the depth position of the imaging target tomographic plane, the control means determines the imaging target tomographic plane at the depth position and the X-ray according to the depth position of the imaging target tomographic plane to be imaged. Driving data of the imaging driving means corresponding to the depth position of the imaging target tomographic plane determined by the positional relationship with the irradiation means and the positional relationship between the imaging target tomographic plane at the depth position and the image receiving plane of the imaging means Is calculated according to the depth position of the tomographic plane The X-ray tomographic image of the imaging target tomographic plane at the depth position is obtained by controlling the imaging driving means according to the above.
[0020]
The positional relationship between the imaging target tomographic plane and the X-ray irradiation unit and the positional relationship between the imaging target tomographic plane and the image receiving plane of the imaging unit can be replaced with a geometrical positional relationship.
[0021]
Further, changing the depth position of the imaging target tomographic plane is to make the imaging target tomographic plane near and far from the X-ray irradiation means (close to the image receiving surface of the imaging means).
[0022]
Therefore, the positional relationship between the imaging target tomographic plane at the depth position to be imaged and the X-ray irradiation means, and the positional relationship between the imaging target tomographic plane at the depth position and the image receiving surface of the imaging means are geometrically determined. I can grasp it.
[0023]
Based on this, in order to obtain an X-ray tomographic image on the tomographic plane to be imaged at the depth position, an operation range on the X-ray irradiation means side for changing the X-ray incident direction on the tomographic plane to be imaged Geometric calculation of drive data for the X-ray incident direction change drive means such as operation speed, and drive data for the image receiving position change drive means such as operation range and operation speed for changing the position of the image receiving surface of the imaging means in conjunction with the drive data Etc. In addition, if the operation range and operation speed on the X-ray irradiation means side, the operation range and operation speed for changing the position of the image receiving surface of the image pickup means, etc. are determined, it is also determined at what timing X-rays should be irradiated. The drive data of the line irradiation drive means is also determined. In this way, if the imaging drive means is driven and controlled according to the drive data determined for each imaging target tomographic plane at the depth position, X-ray tomographic images for the imaging target tomographic planes at various depth positions can be automatically obtained. it can.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic configuration diagram of an X-ray tomography apparatus according to an embodiment of the present invention.
In the following embodiments, in order to simplify the description, the X-ray tube 2 is moved horizontally, and the X-ray irradiation angle from the X-ray tube 2 is changed to change the imaging target tomographic plane in the subject M. An example of an apparatus that obtains an X-ray tomographic image of the imaging target tomographic plane Ma by changing the incident direction of the X-ray from the X-ray tube 2 with respect to Ma and moving the X-ray incident surface 3a of the imaging unit 3 horizontally according to the change. To explain. Further, in the embodiments, the portions denoted by the same reference numerals as those used in the description of the prior art are basically the same as those in the prior art, and therefore unnecessary redundant description is omitted.
[0025]
The imaging drive system of the X-ray tomography apparatus according to this embodiment is basically the same as that of the second conventional example. That is, the X-ray tube drive mechanism 11 holds the X-ray tube 2 on the X-ray tube holding member 22 that is horizontally moved along the rail 21 laid on the ceiling, for example, and the X-ray tube 2 is horizontally moved. It is like that. An X-ray irradiation driving unit 12 including a high voltage generator is connected to the X-ray tube 2, and X-ray irradiation driving from the X-ray tube 2 is performed by the X-ray irradiation driving unit 12. In addition, the irradiation angle driving mechanism 13 such as a motor changes the X-ray irradiation angle irradiated from the X-ray tube 2 by rotating the X-ray tube 2 with respect to the X-ray tube holding member 22, for example. It is configured.
[0026]
On the other hand, the image receiving surface 3a of the imaging unit 3 disposed on the opposite side of the X-ray tube 2 across the top plate 1 on which the subject M is placed and supported is horizontally moved by the imaging unit drive mechanism 14. Yes.
[0027]
In this embodiment, the top plate 1 is the support means, the X-ray tube 2 is the X-ray irradiation means, the imaging unit 3 is the imaging means, and the X-ray tube drive mechanism 11 and the irradiation angle drive mechanism 13 are X-ray incident. The X-ray irradiation driving unit 12 is the X-ray irradiation driving unit, the imaging unit driving mechanism 14 is the image receiving position changing driving unit, the X-ray tube driving mechanism 11, the X-ray irradiation driving unit 12, and the irradiation angle driving. An imaging drive system including the mechanism 13 and the imaging unit drive mechanism 14 corresponds to an imaging drive unit.
[0028]
Drive control of the imaging drive system including the X-ray tube drive mechanism 11, the X-ray irradiation drive unit 12, the irradiation angle drive mechanism 13, and the imaging unit drive mechanism 14 is performed by the control unit 10 corresponding to a control unit. The control unit 10 drives and controls the imaging drive systems 11, 12, 13, and 14 according to the drive data stored in the non-volatile memory 30, and the X-ray tomographic image of the imaging target tomographic plane Ma in the subject M is controlled. Take a picture.
[0029]
The memory 30 stores in advance a plurality of drive data corresponding to the imaging target tomographic plane Ma at various depth positions determined by a determination method as will be described later. When the operator sets the depth position of the imaging target tomographic plane Ma to be imaged from the setting panel 31, the control unit 10 drives the drive data according to the set depth position of the imaging target tomographic plane Ma. Is read from the memory 30, and the X-ray tomographic image is taken on the tomographic plane Ma to be imaged at the depth position set by driving the imaging driving systems 11 to 14 according to the drive data.
[0030]
Therefore, according to the configuration of this embodiment, the fulcrum 101 of the connecting member 100 connecting the X-ray tube 2 and the imaging unit 3 is changed as in the first conventional example, or as in the second conventional example. An X-ray tomographic image in which the depth position of the imaging target tomographic plane Ma has been changed can be taken simply by changing the drive of the imaging drive systems 11 to 14 without raising or lowering the top plate 1. Therefore, it is possible to accurately obtain X-ray tomographic images for the tomographic planes at various depth positions by reducing the movement of the subject M during imaging without burdening the operator and the operator. In addition, it is possible to eliminate the disadvantages of the first and second conventional examples, such as reducing psychological anxiety about the subject M during imaging.
[0031]
Further, the photographing drive system of the apparatus is basically the same as that of the second conventional example, and only the drive control content of the photographing drive system is changed. Therefore, the program of the microcomputer constituting the control unit 10 By simply rewriting the contents of the PROM that stores data and data so as to include drive data corresponding to the tomographic plane Ma to be imaged at various depth positions and to drive and control the imaging drive system using the drive data properly, The device assets of the second conventional example can be used without any remodeling. Therefore, when the device of the second conventional example is already installed in a medical institution or the like, it can be effectively used without wasting its assets.
[0032]
In the above embodiment, the top plate 1 is provided with a top plate driving mechanism for moving the top plate 1 in the horizontal direction such as front and rear, left and right, and moving up and down, and photographing by changing the depth position of the tomographic plane Ma to be imaged. Other than the purpose, for example, the top 1 (subject M) is moved between a position where the subject M gets on and off the top 1 and an imaging position between the X-ray tube 2 and the imaging unit 3. Therefore, the top plate 1 may be configured to be movable.
[0033]
Further, as will be described in detail in a drive data determination method to be described later, an imaging target tomographic plane Ma at a certain depth position is set as a reference imaging target tomographic plane MaS, and imaging driving corresponding to the reference imaging target tomographic plane MaS is performed. If the drive data of the systems 11 to 14 is set as the reference drive data, the drive data corresponding to the imaging target tomographic plane MaN at a depth position different from the depth position of the reference imaging target tomographic plane MaS is at the depth position. In some cases, it is only necessary to multiply the reference drive data by a coefficient corresponding to the tomographic plane MaN. In such a case, the drive data corresponding to the imaging target tomographic plane Ma at each depth position is not stored in the memory 30, but the reference driving data and the imaging target tomographic plane MaN at each depth position are stored. Are stored in the memory 30, and when an X-ray tomographic image of the imaging target tomographic plane MaN at each depth position is taken, the imaging target tomographic plane MaN at that depth position is used as reference drive data. The driving data corresponding to the tomographic surface MaN to be imaged at the depth position may be obtained by multiplying the coefficient according to. If comprised in this way, the memory | storage amount to the memory 30 can be reduced.
[0034]
Further, drive data corresponding to the imaging target tomographic plane Ma at each depth position, reference driving data, coefficients corresponding to the imaging target tomographic plane MaN at each depth position, and the like are stored in the memory 30. Instead, the control unit 10 is set every time a method for determining drive data, which will be described later, is programmed and the depth position of the tomographic plane Ma to be imaged from the setting panel 31 is set. The driving position corresponding to the depth position of the tomographic plane Ma to be imaged is calculated before the imaging, and the depth position set by driving the imaging driving systems 11 to 14 according to the driving data obtained as a result of the calculation. An X-ray tomographic image may be captured with respect to the imaging target tomographic plane Ma.
[0035]
Next, a method for determining drive data according to the to-be-photographed tomographic plane Ma at different depth positions will be described.
[0036]
<First determination method>
Please refer to FIG. As shown in FIG. 2, the positional relationship between the imaging target tomographic planes MaS and MaN and the X-ray tube 2 and the positional relationship between the imaging target tomographic planes MaS and MaN and the image receiving surface 3a of the imaging unit 3 are geometrical. It can be replaced with a positional relationship.
[0037]
In FIG. 2, one predetermined imaging target tomographic plane is set as a reference imaging target tomographic plane MaS, and the imaging target tomographic plane MaN has a depth position different from the depth position of the reference imaging target tomographic plane MaS. The tomographic plane to be imaged is shown. A point GCS in FIG. 2 is an imaging center when an X-ray tomographic image is taken in the reference tomographic plane MaS, and GCN is an X-ray tomographic image in the imaging target tomographic plane MaN. Shown as the center of shooting.
[0038]
Here, the imaging in which the depth position of the imaging target tomographic plane is changed basically means that when an X-ray tomographic image is acquired with the point GCS in the imaging target tomographic plane MaS as the imaging center, a different depth is obtained. The depth of the imaging center GCS of the imaging target tomographic plane MaS without changing the position in the horizontal direction (the left-right direction in FIG. 2 and the direction perpendicular to the paper surface in FIG. 2) in the imaging target tomographic plane MaN. This means that an X-ray tomographic image is taken with the point GCN shifted in the direction (vertical direction in FIG. 2) as the imaging center. That is, in FIG. 2, the respective photographing centers GNS and GCN are plotted on the photographing center axis CJ extending in the depth direction.
[0039]
In FIG. 2, a point XF indicates the focal position of the X-ray tube 2, and a point IF indicates the center position of the image receiving surface 3 a of the imaging unit 3. Point XC is the reference position of the focal point XF of the X-ray tube 2, while point IC is the reference position of the image receiving surface 3a. The above-described photographing center axis CJ is an axis connecting these reference positions XC and IC.
[0040]
That is, when X-ray tomographic images of the imaging target tomographic planes MaS and MaN are taken with the point GCS or GCN as the imaging center, the top plate is set so that the imaging centers GCS and GCN coincide with the imaging center axis CJ. 1 and the subject M are positioned.
[0041]
Further, the depth position of the reference imaging target tomographic plane MaS is determined by, for example, a distance XHS from the reference position XC of the focal point XF of the X-ray tube 2. That is, when the X-ray tomographic images of the imaging target tomographic planes MaS and MaN are acquired with the points GCS and GCN as the imaging center, the reference imaging target tomographic plane MaS is the reference of the focal point XF of the X-ray tube 2. The imaging center CGS, CGN is located on the imaging center axis CJ and is located at a position separated from the position XC by the distance XHS, and the top 1 and the subject M are positioned at such imaging positions. In this state, imaging is performed by changing the depth position of the imaging tomographic plane.
[0042]
Now, one imaging target tomographic plane Ma imaged by the driving data of the imaging drive systems 11 to 14 which the control unit 10P2 of the conventional example 2 has is set as a reference imaging target tomographic plane MaS, and using the driving data, Assume that imaging of the reference imaging target tomographic plane MaS is performed.
[0043]
In this imaging data, the reference position XC of the focal point XF of the X-ray tube 2 is set as the center of the movement range of the focal point XF of the X-ray tube 2 at the time of imaging. That is, in the imaging of the reference imaging target tomographic plane MaS, a position away from the reference position XC by a predetermined distance XWS in the left direction in FIG. 2 is set as the movement start position XSS of the focal point XF of the X-ray tube 2, and from the reference position XC. 2, the position separated by the same distance XWS in the right direction in FIG. 2 is set as a movement end position XES of the focal point XF of the X-ray tube 2, and a movement range (2 × XWS) between the movement start position XSS and the movement end position XES is defined. The X-ray tube 2 is horizontally moved so that the focal point XF of the X-ray tube 2 horizontally moves from left to right in FIG.
[0044]
The X-ray irradiation angle from the X-ray tube 2 during movement of the X-ray tube 2 within the moving range is the X-ray flux irradiated from the X-ray tube 2 at each position during horizontal movement of the X-ray tube 2. The central axis XJ is always changed so as to pass the imaging center GCS in the reference imaging target tomographic plane MaS. That is, the rotation range from a state where the angle is tilted by θS to the right with respect to the depth direction to a state where the angle is tilted by θS to the left with respect to the depth direction is adjusted to the horizontal movement of the X-ray tube 2. Then, the X-ray tube 2 is rotated clockwise around the horizontal axis with respect to the X-ray tube holding member 22.
[0045]
By performing the horizontal movement of the X-ray tube 2 and the change of the X-ray irradiation angle as described above, the reference imaging target tomographic plane MaS (inside the imaging center in the subject M) placed and supported on the top board 1 is obtained. The incident direction of X-rays to GCS) is changed in various directions.
[0046]
On the other hand, on the image receiving surface 3a of the imaging unit 3, the central axis XJ of the X-ray bundle irradiated from the X-ray tube 2 is always incident on the center IF of the image receiving surface 3a at each position during the horizontal movement of the X-ray tube 2. Thus, the X-ray tube 2 is moved horizontally in the opposite direction (from right to left in FIG. 2). As a result, the transmitted X-ray image of the reference imaging target tomographic plane MaS is always projected onto the same position of the image receiving surface 3a of the imaging unit 3 with respect to the reference imaging target tomographic plane MaS (inside imaging center GCS). The position of the image receiving surface 3a of the imaging unit 3 can be changed in conjunction with a change in the incident direction of the line (operation on the X-ray tube 2 side).
[0047]
In FIG. 2, the movement start position of the horizontal movement of the image receiving surface 3a of the imaging unit 3 is ISS, the movement end position is IES, the distance between the reference position IC of the image receiving surface 3a and the movement start position ISS, and the image receiving surface. The distance between the reference position IC 3a and the movement end position IES is indicated by IWS. Further, the distance XIH between the reference position XC of the focal point XF of the X-ray tube 2 and the reference position IC of the image receiving surface 3a is determined when the X-ray tube 2 and the imaging unit 3 are installed. If the distance XHS between the reference position XC of the focal point XF and the reference imaging target tomographic plane MaS is determined, the distance IHS between the reference position IC of the image receiving surface 3a and the reference imaging target tomographic plane MaS is determined.
[0048]
The drive data of the X-ray tube drive mechanism 11 that horizontally moves the X-ray tube 2 includes the moving speed of the X-ray tube 2 in addition to the moving range of the X-ray tube 2. Further, the drive data of the irradiation angle drive mechanism 13 for changing and driving the X-ray irradiation angle includes the rotation speed when the X-ray tube 2 is rotated in addition to the rotation range of the X-ray tube 2 described above. Furthermore, the drive data of the imaging unit drive mechanism 14 that horizontally moves the image receiving surface 3a of the imaging unit 3 includes the moving speed of the image receiving surface 3a of the imaging unit 3 in addition to the moving range of the image receiving surface 3a of the imaging unit 3. .
[0049]
An example of the moving speed VXS (t) and the rotating speed WXS (t) of the X-ray tube 2 and the moving speed VIS (t) of the image receiving surface 3a of the imaging unit 3 are shown by solid lines in FIGS. . In this example, the moving speed VXS (t) of the X-ray tube 2 is accelerated from the start of imaging t0 to t1, and when reaching the predetermined speed VX1, is made constant speed VX1 from t1 to t2, decelerated from t2, and then X at t3. The movement of the tube 2 is stopped and photographing is performed at time tS. The time between t0 and t1 and the time between t2 and t3 are set to be the same, for example. The rotation speed WXS (t) of the X-ray tube 2 and the moving speed XIS (t) of the image receiving surface 3a of the imaging unit 3 are set from the imaging start t0 to t1 in accordance with the moving speed VXS (t) of the X-ray tube 2. Is accelerated at a constant speed from t1 to t2, decelerated from t2, and at t3, the rotation of the X-ray tube 2 and the movement of the image receiving surface 3a of the imaging unit 3 are stopped, and imaging is completed at time tS. ing.
[0050]
In addition, the X-ray irradiation driving unit 2 is provided from the X-ray tube 2 between t0 and t3 (may be between t1 and t2 as necessary) as shown in FIGS. 3D and 3E, for example. Drive control is performed so that X-rays are always emitted or pulsed at regular intervals.
[0051]
Next, consider a case where an imaging target tomographic plane MaN having a depth position different from the depth position of the reference imaging target tomographic plane MaS is imaged.
[0052]
Here, the X-ray irradiation angle change range (change range of the X-ray incident direction with respect to the imaging target tomographic planes MaS and MaN), the rotation range of the X-ray tube 2 being used as a reference when imaging the imaging target tomographic plane MaS Consider the case of the same (2 × θS).
[0053]
In order to image the imaging target tomographic plane MaN by setting the rotation range of the X-ray tube 2 to be the same as that of imaging of the imaging target tomographic plane MaS (2 × θS), as shown in FIG. The range of (2 × XWN) where the start position is XSN and the movement end position is XEN is the movement range of the X-ray tube 2. On the other hand, the movement start position of the image receiving surface 3a of the imaging unit 3 is ISN, and the movement end position is It can be geometrically derived that the range of (2 × IWN) as IEN must be the moving range of the image receiving surface 3a of the imaging unit 3. Further, according to the distances XHS, IHS and SNH (all known) in FIG. 2, the distance XHN between the reference position XC of the focal point XF of the X-ray tube 2 and the depth position of the imaging target tomographic plane MaN, and the imaging unit The distance IHN between the reference position IC of the third image receiving surface 3a and the depth position of the imaging target tomographic plane MaN is obtained.
[0054]
The point at which the focal point XF of the X-ray tube 2 is located at the movement start position XSS when photographing the reference tomographic object tomographic surface MaS, the point at which the focal point XF of the X-ray tube 2 is located at the reference position XC, and the reference photographing object A triangle whose apex is the three points with the imaging center GCS of the tomographic plane MaS, a point at which the focal point XF of the X-ray tube 2 is located at the movement start position XSN at the time of imaging of the imaging target tomographic plane MaN, A triangle having apexes at the three points of the point where the focal point XF is located at the reference position XC and the imaging center GCN of the imaging target tomographic plane MaN is similar. In addition, the image receiving surface 3a of the imaging unit 3 is positioned at the movement start position ISS at the time of imaging the reference imaging target tomographic surface MaS, the point where the image receiving surface 3a of the imaging unit 3 is positioned at the reference position IC, and the reference A triangle having the three points of the photographing center GCSN of the photographing target tomographic plane MaS as vertices, a point where the image receiving surface 3a of the imaging unit 3 is located at the movement start position ISN at the time of photographing of the photographing target tomographic plane MaN, A triangle having apexes at the three points of the point where the image receiving surface 3a is located at the reference position IC and the photographing center GCN of the photographing target tomographic surface MaN is similar.
[0055]
Therefore, the distance XWN that determines the moving range of the X-ray tube 2 at the time of imaging the imaging target tomographic plane MaN and the distance IWN that determines the moving range of the image receiving surface 3a at the time of imaging of the imaging target tomographic plane MaN are known values. Using certain XWS, XHS, and XHN and IWS, IHS, and IHN, the following equations (1) and (2) can be used.
[0056]
XWN = KXN × XWS (1)
However, KXN = XHN / XHS
IWN = KIN × XIS (2)
However, KIN = IHN / IHS
[0057]
From the similar relationship, as indicated by the following formulas (3) and (4) and the two-dot chain lines in FIGS. 3A and 3B, the X-ray tube 2 at the time of imaging the tomographic plane MaN to be imaged Is set to a speed obtained by multiplying the moving speed VXS (t) of the X-ray tube 2 at the time of imaging of the reference imaging target tomographic plane MaS by the coefficient KXN of the above equation (1). The moving speed VIN (t) of the image receiving surface 3a of the imaging unit 3 at the time of imaging the imaging target tomographic plane MaN is set as the moving speed VIS (t) of the image receiving surface 3a of the imaging unit 3 at the time of imaging of the reference imaging target tomographic plane MaS. In addition, when driving at a speed multiplied by the coefficient KIN of the above equation (2), in the imaging of the imaging target tomographic plane MaN, the X-ray irradiation angle (at the same time t during imaging of the reference imaging target tomographic plane MaS) ( (An angle in the X-ray incident direction with respect to the tomographic planes MaS and MaN) It is possible to always be the same. Accordingly, the rotational speed of the X-ray tube 2 can be driven with the same drive data as the rotational speed WXS (t) (FIG. 3C) of the X-ray tube 2 at the time of imaging the reference tomographic plane MaS.
[0058]
VXN (t) = KXN × VXS (t) (3)
VIN (t) = KIN × VIS (t) (4)
[0059]
Further, when the horizontal movement of the X-ray tube 2 and the irradiation angle of the X-ray and the horizontal movement of the image receiving surface 3a of the imaging unit 3 are driven and controlled by the drive data described above, the imaging of the imaging target tomographic surface MaN is completed in time tS. Will do. Therefore, the X-ray irradiation drive can be performed with the same drive data (FIGS. 3D and 3E) as that at the time of imaging the reference imaging target tomographic plane MaS.
[0060]
The coefficients KXN and KIN are obtained when the imaging target tomographic plane MaN is further away from the X-ray tube 2 than the reference imaging target tomographic plane MaS as shown in FIG. 2 (closer to the image receiving surface 3a of the imaging unit 3). KXN> 1, 0 <KIN <1, and conversely, if the imaging target tomographic surface MaN is closer to the X-ray tube 2 than the reference imaging target tomographic surface MaS (away from the image receiving surface 3a of the imaging unit 3), 0 < The coefficients are KXN <1, KIN> 1.
[0061]
Further, in order to make it easy to understand the movement state of the image receiving surface 3a between the imaging of the reference imaging target tomographic plane MaS and the imaging of the imaging target tomographic plane MaN, FIG. Although the image receiving surface 3a and the image receiving surface 3a at the time of imaging the imaging target tomographic surface MaN are drawn slightly shifted up and down, they are actually moved on the same axis. Similarly, in the figures and graphs in FIG. 4 and subsequent figures, even when the overlapping portion is actually overlapped, the one at the time of photographing the reference photographing target tomographic plane MaS and the one at the time of photographing the photographing target tomographic surface MaN are distinguished. Sometimes it is drawn slightly shifted.
[0062]
<Second determination method>
First, the movement range of the X-ray tube 2 and the movement range of the image receiving surface 3a of the imaging unit 3 are determined by the same determination method as the first determination method (see FIG. 2). That is, the movement range of the X-ray tube 2 at the time of imaging of the imaging target tomographic plane MaN is set to a range of (2 × XWN) from the movement start position XSN to the movement end position XEN, and the movement range of the image receiving surface 3a of the imaging unit 3 is The range is (2 × IWN) from the movement start position ISN to the movement end position IEN.
[0063]
Next, the moving speed VXN (t) of the X-ray tube 2 is determined so that the speed when moving at a constant speed becomes the same VX1 as that at the time of imaging of the reference imaging target tomographic plane MaS. That is, as shown by the two-dot chain line in FIG. 4A, the imaging is accelerated from the start t0 to t1, and when reaching the predetermined speed VX1, the constant speed VX1 is reached from t1 to t4, and the speed is decelerated from t4 and X-rays at t5. The movement of the tube 2 is stopped and photographing is performed at time tN. The time between t4 and t5 is the same as the time between t2 and t3, for example. The moving speed VXS (t) of the X-ray tube 2 at the time of imaging the reference tomographic plane MaS is shown by a solid line in FIG.
[0064]
In order to match the moving speed VXN (t) of the X-ray tube 2, the moving speed VIN (t) of the image receiving surface 3a of the imaging unit 3 is as indicated by a two-dot chain line in FIG. The moving speed VIS (t) of the image receiving surface 3a of the imaging unit 3 at the time of photographing the reference tomographic plane MaS is shown by a solid line in FIG. 4B.
[0065]
As shown in FIGS. 4A and 4B, in this case, the time tN required for imaging the imaging target tomographic plane MaN is longer than the time tS required for imaging the reference imaging target tomographic plane MaS. In contrast to FIG. 2, when the imaging target tomographic plane MaN is closer to the X-ray tube 2 than the reference imaging target tomographic plane MaS (away from the image receiving surface 3 a of the imaging unit 3), the imaging target tomographic plane MaN is used. The time tN required for the imaging is shorter than the time tS required for the imaging of the reference imaging target tomographic plane MaS.
[0066]
In any case, since the imaging time varies, it is necessary to newly determine the X-ray irradiation angle changing speed (the rotational speed of the X-ray tube 2) accordingly. That is, in order to match the moving speed of the X-ray tube 2, the rotational speed WXN (t) of the X-ray tube 2 is as shown by a two-dot chain line in FIG. The rotational speed WXS (t) of the X-ray tube 2 at the time of imaging the reference tomographic plane MaS is shown by a solid line in FIG.
[0067]
Here, the constant speed WX2 in FIG. 4C is an unknown number, but this speed WX2 can be determined as follows, for example. First, as shown in FIG. 5, assuming that the position where the focal point XF of the X-ray tube 2 arrives after a predetermined time (for example, 1 second) from the reference position XC is XC1, the distance (movement) from the reference position XC to the position XC1 The quantity WC1 can be obtained from the moving speed VXN (t) (VX1) of the X-ray tube 2. This position XC1 is plotted on the movement locus of the focal point XF of the X-ray tube 2. At this time, the change angle per unit time of the X-ray irradiation angle at the constant speed WX2 is θ1 in FIG. In FIG. 5, there are three points: a point where the focal point XF of the X-ray tube 2 is located at the reference position XC, a point where the focal point XF of the X-ray tube 2 is located at the position XC1, and the photographing center GCN of the photographing target tomographic plane MaN. When attention is paid to the triangle as the vertex, θ1 can be obtained from the known distances XHN and XC1 by a trigonometric function. Accordingly, if the change angle θ1 per unit time of the X-ray irradiation angle at the constant speed WX2 is obtained, the constant speed WX2 is obtained.
[0068]
Further, if the above-mentioned constant speed WX2 is obtained, acceleration may be performed so that the speed is set to “0” to WX2 in a time (known) between t0 and t1, so that WXN (t) is accelerated from t0 to t1. The speed gradient at the time is determined, and similarly, the speed gradient at the time of deceleration from t4 to t5 is also determined.
[0069]
As described above, the rotation speed WXN (t) of the X-ray tube 2 at the time of imaging of the imaging target tomographic plane MaN can be determined. The rotation range of the X-ray tube 2 is the same (2 × θS) as in the first determination method. Therefore, drive data for the irradiation angle drive mechanism 13 can also be determined.
[0070]
Further, as the imaging time varies, the X-ray irradiation may be performed in the same manner as in FIGS. 3D and 3E between t0 and t5 (between t1 and t4 as necessary). .
[0071]
<Third determination method>
Here, as shown in FIG. 6, a case is considered in which the movement range of the X-ray tube 2 is the same during imaging of each imaging target tomographic plane MaS, MaN.
[0072]
At this time, the moving speed of the X-ray tube 2 can be made the same at the time of imaging of each imaging target tomographic plane MaS, MaN. That is, the drive data of the X-ray tube drive mechanism 11 can be made the same at the time of imaging of each imaging target tomographic plane MaS, MaN. Further, as a result, since the time required for imaging each of the imaging target tomographic planes MaS and MaN is the same, the drive data of the X-ray irradiation drive unit 12 is also set to be the same when imaging each of the imaging target tomographic planes MaS and MaN. Can do.
[0073]
However, as shown in FIG. 6, in this drive control, the rotation range of the X-ray tube 2, which is the change range of the X-ray irradiation angle (change range of the X-ray incident direction with respect to the tomographic planes MaS and MaN). Therefore, there is a difference between the time of photographing the tomographic surface MaS (2 × θS) and the time of photographing the tomographic surface MaN (2 × θN).
[0074]
This θN is a point where the focal point XF of the X-ray tube 2 is located at the movement start position XSS at the time of photographing the respective tomographic planes MaS and MaN, and a point where the focal point XF of the X-ray tube 2 is located at the reference position XC. If attention is paid to a triangle having apexes at three points with the imaging center GCN of the imaging target tomographic plane MaN, it can be obtained from the known distances XWS and XHN by a trigonometric function.
[0075]
Further, in the imaging of each imaging target tomographic plane MaS, MaN, the imaging time is the same (tS), and the X-ray irradiation angle changing speed ( It is necessary to newly determine the rotational speed of the X-ray tube 2. In order to match the movement of the X-ray tube 2, the rotational speed WXN (t) of the X-ray tube 2 is as shown by the two-dot chain line in FIG. The rotational speed WXS (t) of the X-ray tube 2 at the time of imaging of the reference imaging target tomographic plane MaS is shown by a solid line in FIG.
[0076]
The constant speed WX3 in FIG. 7A can be obtained by the same determination method as the WX2 determination method described in the second determination method described above. Therefore, the drive data of the irradiation angle drive mechanism 13 can be determined.
[0077]
In addition, as shown in FIG. 6, the imaging unit is associated with the same moving range of the X-ray tube 2 when imaging the tomographic planes MaS and MaN to be imaged (the rotation angle of the X-ray tube 2 has been changed). The moving range of the third image receiving surface 3a is changed. The distance IWN2 that determines the moving range of the image receiving surface 3a of the imaging unit 3 at the time of photographing the tomographic surface MaN to be photographed can be obtained as follows. That is, in FIG. 6, the image receiving surface 3a of the imaging unit 3 is located at the movement start position ISN at the time of imaging the imaging target tomographic plane MaN, the point where the image receiving surface 3a of the imaging unit 3 is located at the reference position IC, When attention is paid to a triangle having apexes at three points with the imaging center GCN of the imaging target tomographic plane MaN, a distance IWN2 is obtained by a trigonometric function from the distance IHN and the angle θN which are known values.
[0078]
In the imaging of the tomographic surfaces MaS and MaN to be imaged, the imaging time is the same (tS), and the image receiving surface of the imaging unit 3 is changed as the moving range of the image receiving surface 3a of the imaging unit 3 is changed. It is necessary to newly determine the moving speed of 3a. In order to match the movement of the X-ray tube 2, the moving speed VIN (t) of the image receiving surface 3 a of the imaging unit 3 is as shown by a two-dot chain line in FIG. A moving speed VIS (t) of the image receiving surface 3a of the imaging unit 3 at the time of photographing the reference tomographic plane MaS is shown by a solid line in FIG. 7B.
[0079]
Here, the constant speed VI2 in FIG. 7B is an unknown number, but this speed VI2 can be determined as follows, for example. That is, the third method is the same as the method for obtaining the change angle per unit time of the X-ray irradiation angle at a constant speed among the rotational speeds of the X-ray tube 2 described in the second determination method. The change angle θ2 per unit time of the X-ray irradiation angle at a constant speed WX3 in the rotational speed of the X-ray tube 2 in the case of the determination method is plotted including the image receiving surface 3a of the imaging unit 3 As shown in FIG. A position XC2 in FIG. 8 indicates a position at which the focal point XF of the X-ray tube 2 arrives after a predetermined time (for example, 1 second) from the reference position XC in the third determination method, and the distance WC2 is the reference WC2 The amount of movement from the position XC to the position XC2 is shown. As is apparent from FIG. 8, the moving amount WC3 of the image receiving surface 3a per unit time at a constant speed VI2 of the moving speed VIN (t) of the image receiving surface 3 of the imaging unit 3 is a known distance IHN and an angle θ2. And a trigonometric function, and a constant speed VI2 of the moving speed VIN (t) of the image receiving surface 3 of the imaging unit 3 is obtained. Accordingly, the moving speed VIN (t) of the image receiving surface 3 of the imaging unit 3 is determined, and the drive data of the imaging unit drive mechanism 14 is determined.
[0080]
In addition, the drive data of the imaging drive systems 11 to 14 can also be determined so that the movement range and movement speed of the image receiving surface 3a of the imaging unit 3 are the same during imaging of the imaging target tomographic planes MaS and MaN. In this case, it is necessary to newly determine the movement range, movement speed, rotation range, and rotation speed of the X-ray tube 2 at the time of imaging of the imaging target tomographic plane MaN, but these drive data are also as described above. It can be obtained geometrically.
[0081]
In the first to third determination methods, the driving data of the imaging drive systems 11 to 14 at the time of imaging the imaging target tomographic plane MaN has been described as an example. However, the imaging target tomographic planes at other depth positions are described. The drive data of the imaging drive systems 11 to 14 at the time of Ma imaging can also be determined by the same method.
[0082]
In the first to third determination methods, the driving data of the imaging drive systems 11 to 14 at the time of imaging the reference imaging target tomographic plane MaS is obtained using one predetermined imaging target tomographic plane MaS as a reference. The driving data of the imaging drive systems 11 to 14 at the time of imaging the imaging target tomographic plane MaN at other depth positions is determined, but the present invention is not limited to this, and the imaging target tomography at an arbitrary depth position is used. The drive data of the imaging drive systems 11 to 14 at the time of imaging the surface Ma can also be determined individually.
[0083]
That is, as is clear from the above description, when imaging the imaging target tomographic surface Ma at a certain depth position, the movement range of the X-ray tube 2, the rotation range of the X-ray tube 2, and the image receiving surface of the imaging unit 3. If any one of the moving ranges 3a is determined, the rest is also determined. If any one of the moving speed of the X-ray tube 2, the rotating speed of the X-ray tube 2, and the moving speed of the image receiving surface 3a of the imaging unit 3 is determined, the rest is also determined. Accordingly, the drive data of the X-ray tube drive mechanism 11, the irradiation angle drive mechanism 13, and the imaging unit drive mechanism 14 can be determined. Further, when the driving data of the X-ray tube driving mechanism 11, the irradiation angle driving mechanism 13, and the imaging unit driving mechanism 14 is determined, the imaging time is determined. Therefore, it is determined at what timing X-ray irradiation should be performed. The drive data of the unit 12 is also determined. Since the method for determining the drive data of the imaging drive systems 11 to 14 is the same even if the depth position of the imaging target tomographic plane Ma changes, imaging is performed for each imaging target tomographic plane Ma at an arbitrary depth position. The driving data of the photographing drive systems 11 to 14 at the time can also be determined individually.
[0084]
By the way, when X-rays are always irradiated during imaging, or when X-rays are always irradiated in the form of pulses at the same cycle, if the imaging time varies for each imaging of the imaging target tomographic plane Ma, each imaging of the imaging target tomographic plane Ma is performed. In addition, the amount of X-ray exposure to the subject M is not preferable. Therefore, it is preferable to determine the drive data of the imaging drive systems 11 to 14 so that the imaging time for each imaging of the imaging target tomographic plane Ma is always the same, but the imaging time for each imaging of the imaging target tomographic plane Ma varies. Even when determining the drive data of the imaging drive systems 11 to 14 as described above, for example, the X-rays are irradiated in a pulse shape, and the pulse cycle changes according to the imaging time for each imaging of the imaging target tomographic plane Ma. You may make it make it.
[0085]
Further, when changing the imaging center (imaging range) within the imaging target tomographic plane Ma at the same depth position, the subject M is moved in the horizontal direction on the top board 1 or the subject M is placed and supported. The top plate 1 may be moved in the horizontal direction, but may be configured as follows.
[0086]
The maximum movable range of each horizontal movement of the X-ray tube 2 and the image receiving surface 3a of the image pickup unit 3 is made sufficiently long so that the reference position XC of the focal point XF of the X-ray tube 2 and the reference of the image receiving surface 3a of the image pickup unit 3 If the position IC (imaging center axis CJ) is moved in the longitudinal direction of the top plate 1 (the body axis direction of the subject M), the imaging center (imaging range) is set within the imaging target tomographic plane Ma at the same depth position. The longitudinal direction of the plate 1 (the body axis direction of the subject M) can be changed. In addition, a drive mechanism for moving the entire unit for horizontally moving the X-ray tube 2 including the rails 21 in the lateral direction of the top board 1 (horizontal direction perpendicular to the body axis direction of the subject M) is provided. If the entire unit for horizontally moving the image receiving surface 3a of the image pickup unit 3 is also provided with a drive mechanism that moves in the same horizontal direction, and each unit is horizontally moved in the short direction of the top plate 1, the same depth is obtained. The imaging center (imaging range) can be changed in the lateral direction of the top board 1 (horizontal direction orthogonal to the body axis direction of the subject M) in the tomographic target tomographic plane Ma. If comprised in this way, the X-ray tomography image which changed the imaging | photography center (imaging | capture range) within the imaging | photography tomographic plane Ma of the same depth position will be image | photographed, without moving the top plate 1 or the subject M. You can also.
[0087]
In the above-described embodiment, the case where the X-ray tube 2 and the image receiving surface 3a of the imaging unit 3 are moved only in the horizontal one-axis direction to perform imaging of the imaging target tomographic surface Ma has been described. And the image receiving surface 3a of the imaging unit 3 are moved in a circular arc shape, or moved along a circular or elliptical orbit, a radial or spiral, a spiral orbit, a hypocycloid orbit, etc. in a horizontal plane. The present invention can be similarly applied to a configuration that takes a form and performs imaging of the tomographic plane Ma to be imaged. Note that, for example, an X-ray tube 2 or an image receiving surface 3a of the imaging unit 3 that moves along a circular trajectory in a horizontal plane and performs imaging of the imaging target tomographic surface Ma is usually an X-ray. Since the irradiation angle is fixed, in such a configuration, the driving mechanism for moving the X-ray tube 2 along one circular orbit in the horizontal plane corresponds to the X-ray incident direction changing driving means in the present invention. become.
[0088]
Further, the present invention is not limited to the case where an X-ray tomographic image of the tomographic plane Ma to be imaged is taken while the subject M is laid down, and in a state where the subject M is supported in an oblique state or supported in an upright state, The present invention can be similarly applied to the case where the X-ray tube 2 and the image receiving surface 3a of the imaging unit 3 are disposed with the subject M interposed therebetween and an X-ray tomographic image of the imaging target tomographic surface Ma is captured.
[0089]
【The invention's effect】
As is apparent from the above description, according to the present invention, X-ray tomographic images with respect to the imaging target tomographic planes at various depth positions are imaged only by changing the drive data for driving the imaging driving means. Therefore, it is possible to perform imaging while changing the depth position of the imaging target tomographic plane without burdening the operator and the operator. Further, the depth of the tomographic plane to be imaged without raising and lowering the support means (subject) such as the top plate to bring the subject into perspective with respect to the X-ray irradiation means (close to the image receiving surface of the imaging means). Since the imaging can be performed with the position changed, the body movement of the subject during imaging can be reduced, each X-ray tomographic image can be accurately obtained for the tomographic plane of the imaging at various depth positions, and the subject under imaging Can reduce psychological anxiety.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an X-ray tomography apparatus according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram when driving data of an imaging drive system when imaging is performed by changing the depth direction of an imaging target tomographic plane by the first and second determination methods.
FIG. 3 shows a moving speed of an X-ray tube and an image receiving surface of an imaging unit when driving data of an imaging drive system when imaging is performed by changing the depth direction of a tomographic plane to be imaged. It is a figure which shows a moving speed, the rotational speed of an X-ray tube, etc.
FIG. 4 shows the moving speed of the X-ray tube and the image receiving surface of the imaging unit when driving data of the imaging drive system when imaging is performed by changing the depth direction of the tomographic plane to be imaged. It is a figure which shows a moving speed and the rotational speed of an X-ray tube.
FIG. 5 is a diagram for explaining a method for determining the rotational speed of an X-ray tube when driving data of an imaging drive system when imaging is performed by changing the depth direction of an imaging target tomographic plane by the second determination method; FIG.
FIG. 6 is an explanatory diagram in a case where drive data of an imaging drive system at the time of imaging by changing the depth direction of an imaging target tomographic plane is determined by a third determination method.
FIG. 7 shows the rotational speed of the X-ray tube and the image receiving surface of the imaging unit when determining the drive data of the imaging drive system when imaging is performed by changing the depth direction of the tomographic plane to be imaged. It is a figure which shows a moving speed.
FIG. 8 illustrates a method for determining a moving speed of an image receiving surface of an imaging unit when driving data of an imaging drive system when imaging is performed by changing the depth direction of an imaging target tomographic plane using the third determination method. It is a figure for doing.
FIG. 9 is a diagram for explaining an imaging principle of an X-ray tomographic image of an imaging target tomographic plane.
FIG. 10 is a schematic configuration diagram of a drive control system of an X-ray tomography apparatus according to a first conventional example.
FIG. 11 is a schematic configuration diagram of a drive control system of an X-ray tomography apparatus according to a second conventional example.
[Explanation of symbols]
1: Top plate
2: X-ray tube
3: Imaging unit
3a: Image receiving surface of the imaging unit
10: Control unit
11: X-ray tube drive mechanism
12: X-ray irradiation drive unit
13: Irradiation angle drive mechanism
14: Imaging unit drive mechanism
M: Subject
Ma, MaS, MaN: imaging tomographic plane

Claims (1)

An X-ray tomography apparatus for obtaining an X-ray tomographic image of a tomographic plane in a subject, comprising: (a) a supporting means for supporting the subject; and (b) a subject supported by the supporting means. X-ray irradiating means for irradiating X-rays, and (c) an X-ray transmission image that is disposed on the opposite side of the X-ray irradiating means with the subject supported by the supporting means sandwiched therebetween, And (d) an X-ray incident direction change for driving to change the incident direction of the X-rays from the X-ray irradiating means to the imaging target tomographic plane in the subject supported by the supporting means. An imaging drive unit including a drive unit, an X-ray irradiation drive unit that performs X-ray irradiation drive from the X-ray irradiation unit, and an image receiving position change driving unit that drives to change the position of the image receiving surface of the imaging unit; (E) For the tomographic plane to be imaged in the subject supported by the support means While irradiating the subject with X-rays while sequentially changing the incident direction of the X-rays from the X-ray irradiation means, the transmitted X-ray image of the imaging target tomographic plane is always at the same position on the image receiving surface of the imaging means Control means for driving and controlling the imaging drive means according to the drive data so as to change the position of the image receiving surface of the imaging means in conjunction with the change of the X-ray incident direction with respect to the tomographic plane to be imaged. And when taking an image by changing the depth position of the imaging target tomographic plane, the control means, depending on the depth position of the imaging target tomographic plane to be imaged, and the imaging target tomographic plane at the depth position Driving data of the imaging drive means corresponding to the depth position of the imaging target tomographic plane determined by the positional relationship with the X-ray irradiation means and the positional relationship between the imaging target tomographic plane at the depth position and the image receiving surface of the imaging means. the, Calculated according to the depth position of the imaging target fault plane the moving range under the conditions the same of the X-ray irradiation unit before and after changing the depth position of the imaging target fault plane, the imaging drive means accordingly An X-ray tomography apparatus characterized by controlling driving.

Images