JP2004180846A - X-ray ct apparatus - Google Patents

X-ray ct apparatus Download PDF

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Publication number
JP2004180846A
JP2004180846A JP2002349998A JP2002349998A JP2004180846A JP 2004180846 A JP2004180846 A JP 2004180846A JP 2002349998 A JP2002349998 A JP 2002349998A JP 2002349998 A JP2002349998 A JP 2002349998A JP 2004180846 A JP2004180846 A JP 2004180846A
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Japan
Prior art keywords
subject
means
scanning
data
image
Prior art date
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Pending
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JP2002349998A
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Japanese (ja)
Inventor
Takeshi Shinokawa
毅 篠川
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Shimadzu Corp
株式会社島津製作所
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Priority to JP2002349998A priority Critical patent/JP2004180846A/en
Publication of JP2004180846A publication Critical patent/JP2004180846A/en
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Abstract

Provided is an X-ray CT apparatus capable of obtaining image data in a state where an imaging position of a subject is stabilized.
A top plate (2) on which a subject (M) is not placed, using correction data detected by a deflection detector (10), which is obtained by comparing reference data before the placement of the subject (M) with actual measurement data after the placement. The relative positions of the couchtop 2, the couch and the gantry 9 are determined by the couch drive control unit 8 and the gantry drive control 16 so that the subject M can be scanned in the initial state, that is, in a state where the influence of the bending of the couchtop 2 is removed. Adjust through.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an X-ray CT apparatus used for nondestructive measurement in the medical field and the industrial field, and particularly to a technique for stabilizing an imaging state of a subject.
[0002]
[Prior art]
Conventionally, this type of X-ray CT apparatus includes an X-ray tube that irradiates an X-ray toward a subject, and an X-ray detector that is arranged to face the X-ray tube with the subject interposed therebetween. In some cases, the tube and the X-ray detector rotate around the subject in synchronization.
[0003]
When a tomographic image of the subject is obtained with this X-ray CT apparatus, the bed having the top on which the subject is placed is moved up and down to adjust the height, and then horizontally moved while sliding the top toward the gantry opening. Then, the subject is inserted into the gantry.
[0004]
[Problems to be solved by the invention]
However, the conventional device having such a configuration has the following problems.
That is, in the conventional X-ray CT apparatus, when the top board moves horizontally while sliding, the top board itself is supported in a cantilever manner, and the top end of the top board itself is bent downward due to the load of the subject.
[0005]
When the subject is scanned in a state in which the top is bent, the top is in a horizontal state, that is, where a predetermined tomographic image of the subject is to be, for example, a plane perpendicular to the body axis, There is a problem that the body axis of the subject is tilted due to the bending of the object, and an accurate tomographic image cannot be obtained. Further, when synthesizing a 3D image, similarly, there is a problem that the accuracy of the synthesized image is deteriorated.
[0006]
Furthermore, since the radiation treatment plan when performing radiation treatment is performed ignoring the bending of the top plate, there is a problem that the accuracy of the actual radiation treatment is reduced.
[0007]
The present invention has been made in view of such circumstances, and a main object of the present invention is to provide an X-ray CT apparatus capable of obtaining a predetermined tomographic image in a state where the position of a subject is stabilized. .
[0008]
[Means for Solving the Problems]
The present invention has the following configuration to achieve such an object.
That is, the invention according to claim 1 includes (a) an X-ray source for irradiating the subject with X-rays, and (b) an X-ray source arranged opposite to the X-ray source with the subject interposed therebetween and transmitted through the subject. (C) scanning means for scanning the X-ray source and the X-ray detector around the body axis of the subject within the aperture; A bed on which a subject can be placed and which can move up and down through the opening of the scanning means; and a bed which can ascend and descend itself; and (e) detection for detecting bending of the top plate when the subject is placed Means, (f) correcting means for correcting the relative position between the top plate on which the subject is placed and the scanning means in accordance with the deflection of the top plate detected by the detecting means, and (g) scanning of the subject. Data collecting means for collecting image data obtained at the position, and (h) forming a predetermined tomographic image from the image data of the data collecting means. An image reconstruction means for reconstructing processing, characterized by comprising an image display means for displaying a tomographic image generated in (i) the image reconstruction means.
[0009]
(Operation / Effect) When the top plate on which the subject is placed is moved toward the opening of the scanning means, the top plate is bent by the weight of the subject. The deflection of the top plate at this time is detected by the detection unit, and the relative position between the top plate on which the subject is placed and the scanning unit is corrected according to the detected deflection. For example, when the subject is scanned by irradiating the table with X-rays from a vertical direction, the influence of the bending of the table is corrected so that the scanning unit is perpendicular to the table, and each scanning of the subject is performed. A tomographic image that is a plane perpendicular to the body axis at the position is obtained. Therefore, the influence of the bending of the top plate due to the weight of the subject is removed, and a highly accurate tomographic image or the like can be obtained.
[0010]
Further, according to a second aspect of the present invention, in the X-ray CT apparatus according to the first aspect, (f1) the correction unit controls at least one of the bed and the scanning unit in accordance with the detected bending of the top plate. It is characterized in that drive control is performed to correct the relative position between the top plate and the scanning means.
[0011]
(Operation / Effect) At least one of the bed and the scanning means is drive-controlled in accordance with the deflection of the top board detected by the detection means, and the relative position between the top board and the scanning means is corrected. For example, the scanning unit is controlled to move up and down so that the scanning unit is perpendicular to the tabletop, or the scanning unit is driven and controlled to have an inclination angle so that the scanning unit is perpendicular to the tabletop. Therefore, the X-ray CT apparatus according to claim 1 can be suitably implemented.
[0012]
According to a third aspect of the present invention, there is provided an X-ray source for irradiating the subject with X-rays, and (B) an X-ray source arranged opposite to the X-ray source with the subject interposed therebetween and transmitted through the subject. (C) scanning means for scanning the X-ray source and the X-ray detector around the body axis of the subject within the aperture; A bed on which the subject can be placed and which can advance and retreat through the opening of the scanning means, and which can be raised and lowered by itself; and (E) detection of bending of the top plate when the subject is placed Detecting means; (F) data collecting means for collecting image data obtained at each position of scanning of the subject; and (G) a top plate and a scanning means in accordance with the bending of the top plate detected by the detecting means. A data extraction unit for extracting image data of a tomographic plane of the subject in a state where the relative position has been corrected, and (H) the data extraction unit. Image reconstruction means for performing image reconstruction processing of a predetermined tomographic image from the extracted image data; and (I) an image display means for displaying a tomographic image generated by the image reconstruction means. I do.
[0013]
(Operation / Effect) When the top plate on which the subject is placed is moved toward the opening of the scanning means, the top plate is bent by the weight of the subject. At this time, the bending of the top plate is detected by the detecting means, and thereafter, the subject is scanned to obtain image data. From the obtained image data, the image data of the tomographic plane of the subject in a state where the relative position between the top plate and the scanning unit has been corrected is extracted by the data extracting unit in accordance with the deflection detected by the detecting unit. For example, when it is originally desired to obtain an image of a tomographic plane perpendicular to the body axis of the subject, an image of a tomographic plane having an inclination with respect to the body axis is obtained at each scanning position due to bending of the top plate. The image data of the tomographic plane perpendicular to the body axis is extracted from the plurality of tomographic image data according to the bending, and the image reconstructing means performs image reconstruction processing and outputs the image data. Therefore, the influence of the bending of the top plate due to the weight of the subject is removed, and a highly accurate tomographic image or the like can be obtained.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
<First embodiment>
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram illustrating a schematic configuration of an X-ray CT apparatus, and FIG. 2 is a side view illustrating a main configuration of a bed.
[0015]
As shown in FIG. 1 and FIG. 2, the X-ray CT apparatus includes a bed 3 having a movable top plate 2 on which a subject M is placed, an X-ray tube 4 that is provided to face the subject M, and an X-ray tube 4. An imaging system 1 having an X-ray detector 5, a correction processing unit 6 for obtaining correction data for correcting the bending of the top 2, and a re-processing using the X-ray detection data output from the imaging system 1. The image processing apparatus includes a data processing unit 7 that outputs a constituent image, and various control units that control each constituent unit. Hereinafter, each configuration will be described.
[0016]
The couch 3 in the imaging system 1 is configured to be able to change the height of the couchtop 2 under the control of the couch drive control unit 8. For example, while the top plate 2 can be moved up and down horizontally, as shown in FIG. 2, the height can be changed to different heights before and after the top plate 2 in the longitudinal direction, and the top plate 2 can have an inclination angle. It has become. The top board 2 is also configured to be able to advance and retreat from the couch 3 into the opening of the gantry 9 under the control of the couch drive control unit 8.
[0017]
Further, on the side surface of the top plate, for example, a deflection detector 10 that outputs the deflection of the top plate 2 detected from a sensor group attached at a predetermined interval in the longitudinal direction of the top plate 2 as coordinate data of the position is provided. Have been. The detection result from the deflection detector 10 is sent to a correction processing unit 6 described later. Note that the deflection detector 10 corresponds to a detecting unit of the present invention.
[0018]
The X-ray tube 4 is configured to irradiate the subject M with fan beam-shaped X-rays according to set irradiation conditions such as a tube voltage and a tube current under the control of an irradiation control unit 11 including a high voltage generation unit and the like. .
[0019]
The X-ray detector 5 is a multi-channel detector in which, for example, about 1000 X-ray detection elements are arranged along the spread of the fan beam. The X-ray detector 5 rotating together with the X-ray tube 4 outputs X-ray detection data in accordance with the irradiation of the fan beam from the X-ray tube 4.
[0020]
Further, the imaging system 1 includes a rotating ring 12 to which the X-ray tube 4 and the X-ray detector 5 are fixed, and a ring rotating mechanism 13 including a pulley 13a and a belt 13b. As the ring rotating mechanism 13 rotates the rotating ring 12, the X-ray tube 4 and the X-ray detector 5 relatively rotate around the body axis of the subject M in the direction indicated by the arrow. . This rotation is controlled by the rotation drive control unit 14 based on an output signal from the imaging control unit 15.
[0021]
The rotating ring 12 and the gantry 9 can have an inclination angle, and the irradiation angle of the fan beam from the X-ray tube 4 for irradiating the subject M and the relative angle of the gantry 9 with respect to the top plate 2 are determined. It is possible to change. The rotation of the rotating ring 12 and the gantry 9 is performed by a gantry drive control unit 16.
[0022]
The correction processing unit 6 includes a reference data memory 17, an actual measurement data memory 18, and a first arithmetic processing unit 19. Note that the correction processing unit 6, the bed drive control unit 8, and the gantry drive control unit 16 constitute a correction unit of the present invention.
[0023]
In the reference data memory 17, the detector 10 detects the bending of each part of the top plate 2 at each movement point while sliding the top plate 2 toward the gantry opening before the subject M is placed. The coordinate data (reference data) of the tabletop 2 detected from a plurality of locations is stored in advance. The reference data may be acquired every time before scanning the subject M, or may be acquired periodically.
[0024]
The measured data memory 18 stores coordinate data (actually measured data) detected from a plurality of locations on the top 2 by the flexure detector 10 when the top 2 is slid toward the gantry opening with the subject M placed thereon. Data).
[0025]
The first arithmetic processing unit 19 uses the coordinate data of each detection point stored in the reference data memory 17 and the actual measurement data memory 18 to obtain a predetermined tomographic image of the subject M, and obtains a top position at the scanning position. The coordinate data (correction data) of the position in the reference state (substantially horizontal state) in which the bending of the plate 2 has been removed is obtained. A specific calculation method will be described below.
[0026]
For example, as shown in a simplified diagram of the table 2 in FIG. 3, the coordinates of two points A and B are set as reference coordinates from the table 2 before the subject is placed on the reference data A (x 1 , y 1 ), B (x 2 , y 2 ) is stored in the reference data memory 17. On the other hand, when the subject M is placed on the top 2 and the top 2 is bent, two points (A, B) are displaced by two points A ′ and B ′ on the top 2 ′. The respective coordinates are stored in the measured data memory 18 as measured data A ′ (x 1 ′, y 1 ′) and B ′ (x 2 ′, y 2 ′).
[0027]
When the subject M is placed on the top 2 and the bending of the top 2 is detected, the position of the point C ′ between the two points A ′ and B ′ on the top of the tomographic plane of the subject M to be acquired is obtained. In this case, the coordinate data of the point C when this point C ′ is at the reference position where the top plate 2 is not bent is obtained.
[0028]
That is, as shown in FIG. 4, which is an enlarged view of FIG. 3, when the reference points A, B, and C are displaced to points A ′, B ′, and C ′ due to the bending of the top plate 2, the relationship is as follows. AA ′ // BB ′ // CC ′. Thus, the relationship between the points can be expressed by the following equation (1).
[0029]
(Equation 1)
[0030]
Further, the unknown coordinates (x 3 , y 3 ) of the point C at a position that internally divides the points A and B of the top 2 in the reference state are expressed by the following equations (2) and (3). Can be.
[0031]
(Equation 2)
[0032]
[Equation 3]
[0033]
Here, by using the coordinates of the known points A, B, A ', and B', the distance from the displacement points A 'and B' to the displacement point C 'can be obtained. This relationship can be expressed by the following equations (4) to (7).
[0034]
(Equation 4)
[0035]
(Equation 5)
[0036]
(Equation 6)
[0037]
(Equation 7)
[0038]
Therefore, using the results of the above equations (4) to (7), the unknown coordinates (x 3 , y 3 ) of the point C in the reference state can be obtained by the following equations (8) and (9). .
[0039]
(Equation 8)
[0040]
(Equation 9)
[0041]
The coordinate data of the point C obtained by the correction processing unit 6 is sent to the bed drive control unit 8 and the gantry drive control unit 16. Based on the coordinate data (correction data), the positions of the table 2, the bed 3, and the gantry 9 are adjusted so that each control unit removes the deflection from the position of the table 2, which is the scanning position of the subject M. Correction is performed.
[0042]
Returning to FIG. 1, at the subsequent stage of the X-ray detector 5, a data collection unit 20 (DAS) for collecting transmitted X-ray detection data and the transmitted X-ray detection data collected by the data collection unit 20 are used. The image processing apparatus includes a data processing unit 7 for performing image reconstruction processing and the like, and a monitor 24 for displaying an X-ray CT image or the like subjected to the image reconstruction processing.
[0043]
The data processing unit 7 includes an image data memory 21 that records X-ray detection data, and an image reconstruction unit that performs an image reconstruction process for creating an X-ray CT image based on the image data recorded in the image data memory 21. 22 and a CT tomographic image memory 23 for recording an X-ray CT image of a desired tomographic plane generated by the image reconstruction unit 22.
[0044]
The imaging control unit 15 is connected to the correction processing unit 6, the data processing unit 7, the bed drive control unit 8, the irradiation control unit 11, the rotation drive control unit 14, the gantry drive control unit 16, and the console 25. . The imaging control unit 15 controls each of the connected units as a whole based on the information set and input from the console 25.
[0045]
Next, a procedure from the positioning of the tabletop 2 or the like to the output of a reconstructed image using the apparatus of the first embodiment will be described with reference to the flowchart of FIG.
[0046]
<Step S1> A reference value setting operator moves the table 2 horizontally toward the opening of the gantry 9 without placing the subject M on the table 2, and positions the predetermined table 2 at each moving point. Is detected and set in advance in the reference data memory 17 of the correction processing unit 6.
[0047]
<Step S2> Deflection detection by actual measurement The subject M is placed on the top 2 and the top 2 is slid to the scanning position of the region of interest to be imaged, and a plurality of deflections of the top 2 at this time are performed. Is detected. The detected measurement data is recorded in the measurement data memory 18 of the correction processing unit 6.
[0048]
<Step S3> The correction data calculation first arithmetic processing unit 19 selects the reference data at the same position of the top 2 as when performing the scanning position from the obtained reference data at a plurality of points on the top 2, and sets the reference data The coordinate data (correction data) in the reference state (substantially horizontal state) in which the bending of the top plate 2 at the predetermined scanning position of the subject M is removed from the above-described calculation method using the above and the measurement data.
[0049]
<Step S4> Based on the correction data obtained by the position correction correction processing unit 6, operation signals are sent from the couch drive control unit 8 and the gantry drive control unit 16, respectively, so that the top 2 slides and the couch 3 moves up and down. And tilt, country height, tilt angle, and slide movement are controlled.
[0050]
For example, when the subject M is placed on the top 2, as shown in FIG. 6, the top 2 is deflected by the load, so that the tip is lower than the horizontal axis H of the top 2 before placing the subject. 7, based on the correction data obtained by the correction processing unit 6, as shown in FIG. 7, the head side of the subject M on the bed 3 is raised so that the top 2 is substantially horizontal, The couch drive control unit 8 may control the top plate 2 so that the top plate 2 is slid and the bending at the predetermined scanning position is removed.
[0051]
As shown in FIG. 8, the gantry 9 is inclined to be perpendicular to the top plate 2 without driving the top plate 2 and the bed 3 and the gantry 9 is slid and moved to a predetermined position. The gantry drive control unit 16 may control the bending of the top plate 2 at the scanning position so that the bending is removed.
[0052]
Further, each of the top plate 2, the bed 3, and the gantry 9 may be simultaneously controlled by each control unit, and the bending of the top plate 2 at a predetermined scanning position may be removed.
[0053]
<Step S5> When the top plate 2, the bed 3, and the gantry 9 are operated to correct the positional deviation due to the bending of the top plate 2 in the scanning start step S4, the scanning of the subject M is started.
[0054]
<Step S6> When the image reconstruction / output scanning is completed, an image reconstruction process of a tomographic image of a predetermined region of interest is performed by the image reconstruction unit 22 using the image data recorded in the image data memory 21, and the CT is performed. It is stored in the tomographic image memory 23. The stored reconstructed image is output and displayed on the monitor 24 in a timely manner by the operation of the operator from the console 25.
[0055]
In the above flowchart, the procedure of scanning one tomographic plane of the subject M is shown. However, when scanning a plurality of tomographic planes at a predetermined pitch, correction data at each scanning position is calculated in step S3. The procedure of steps S4 and S5 may be repeated for each scan.
[0056]
As described above, the correction processing unit 6 uses the reference data obtained by measuring the deflection of the top plate 2 before placing the subject (reference state) and the actually measured data obtained after placing the subject. Correction data in the reference state in which the bending of the top plate 2 at each position of the scanning of the sample M is removed is obtained. Based on the obtained correction data, at least one of the top 2, the bed 3, and the gantry 9 is controlled by each control unit, so that an accurate tomographic image or the like in which the influence of the bending of the top 2 is removed is obtained. be able to.
[0057]
<Second embodiment>
An X-ray CT apparatus according to a second embodiment will be described with reference to the drawings.
In the apparatus of the first embodiment, in order to obtain a predetermined tomographic image, reference data and measured data are used to obtain correction data as unknown coordinates of the tabletop 2 at each scanning position. The correction is performed by adjusting the relative position between the top 2 and the gantry 9, that is, by adjusting the hardware based on the data. In the present embodiment, the image data obtained by scanning the subject M is reflected on the bending of the top plate 2 detected by the bending detector 10 to extract image data in a state where the bending is removed, and output the image. The case will be described as an example. Therefore, since the configuration of the device is substantially the same, only the portions different from the first embodiment will be described, and the common portions will be denoted by the same reference numerals and description thereof will be omitted.
[0058]
As shown in FIG. 9, the data processing unit 7 of the X-ray CT apparatus of the present embodiment includes a data extraction unit 26 that extracts image data from which the top plate 2 has been deflected. The data extraction unit 26 includes a reference data memory 17, an actual measurement data memory 18, and a second arithmetic processing unit 27.
[0059]
The reference data memory 17 stores the coordinate data of the top plate 2 before the placement of the subject detected by the deflection detector 10, and the actual measurement data memory 18 stores the top plate after the placement of the subject detected by the deflection detector 10. Record the coordinate data when 2 is bent.
[0060]
The second arithmetic processing unit 27 uses the X-ray detection data obtained by scanning a predetermined region of interest while the top plate 2 is bent by the weight of the subject M, and detects the X-ray detection data with the deflection detector 10. The image data of the tomographic plane of the subject M in a state where the relative position between the table 2 and the gantry 9 is corrected according to the bending of the table 2 thus extracted.
[0061]
For example, in a case where X-rays are emitted from the vertical direction to the top 2, as shown by a two-dot chain line in FIG. When the region of interest D is scanned at a predetermined pitch, image data of a tomographic plane indicated by a chain line is obtained. The image data of the tomographic plane V indicated by the solid line obtained in a state where the bending of the tabletop 2 is removed is extracted from the plurality of image data.
[0062]
That is, similarly to the first embodiment, the coordinate data of each scanning position when the top plate 2 is not bent is obtained using the equations (1) to (9). From the obtained coordinate data, image data on the Y coordinate axis plane may be extracted as shown in the tomographic plane V in FIG. Note that the extracted image data is sent to the image reconstruction unit 22.
[0063]
Next, a procedure up to outputting a reconstructed image using the above-described second embodiment will be described with reference to the flowchart of FIG.
[0064]
<Step S10> The subject M is placed on the top plate 2 for setting the reference value, and the top plate 2 is slid to the scanning position of the region of interest to be imaged. Is detected. The detected measured data is stored in the reference data memory 17 of the data extracting unit 26.
[0065]
<Step S20> The subject M is placed on the deflection measurement top plate 2 by actual measurement, and the top plate 2 is slid to a scanning position having a region of interest to be imaged, and a plurality of deflections of the top plate 2 at this time are performed. Is detected. The detected measurement data is stored in the measurement data memory 18 of the data extraction unit 26.
[0066]
<Step S30> When the acquisition of the scan start measurement data is completed, the scan of the region of interest of the subject M to be imaged is started at the pitch set in advance from the console 25.
[0067]
<Step S40> The data extraction second arithmetic processing unit 27 uses the obtained reference data and measured data to remove the deflection of the top 2 at each scan position of the subject M from the above calculation method. The coordinate data (correction data) in the state (substantially horizontal state) is obtained. For example, image data such as a tomographic plane V on the Y-axis plane shown in FIG. 10 is extracted from each of the obtained coordinate data for each scanning position and sent to the image reconstruction unit 22.
[0068]
<Step S50> The image reconstruction / output image reconstruction processing unit 22 generates a reconstructed image at each scanning position based on the extracted image data, and stores it in the CT tomographic image memory 23. Each of the stored reconstructed images is displayed on the monitor 24 in a timely manner by the operation of the operator from the console 25.
[0069]
As described above, using the correction data obtained from the reference data detected by the deflection detector 10 and the actual measurement data, and the image data at each scanning position stored in the image data memory 21, the deflection of the top plate 2 is obtained. By extracting image data to be obtained when scanning in the absence state and performing reconstructed image processing, it is possible to obtain a highly accurate reconstructed image or the like in which the bending of the top board 2 is removed.
[0070]
The present invention is not limited to the above embodiment, but can be modified as follows.
(1) In each of the above-described embodiments, the correction data for the deflection of the top plate 2 in a predetermined range is used by using the reference data and the actual measurement data detected from the sensor group arranged at predetermined intervals in the longitudinal direction of the top plate 2. Has been obtained by calculation, but correction data may be obtained using optical means such as a CCD camera. For example, a reference image before placing the subject and a real image after placing the subject are acquired, the coordinates of the top plate 2 at the position where a predetermined tomographic image is acquired are compared in pixel units, and the correction data is obtained. The hardware of the top plate 2 or the like may be adjusted accordingly as in the first embodiment, or the image data may be corrected as in the second embodiment.
[0071]
(2) In each of the above-described embodiments, the deflection is measured from one side of the top 2 and the positions of the top 2, the bed 3 and the gantry 9 are adjusted based on the measured values. Of the top plate may be measured from both sides, and the respective positions may be adjusted according to the deviation of the amount of bending on both sides. For example, in the gantry 9 shown in FIG. 8, a configuration may be added in which the gantry 9 can be inclined in the lateral direction, or the couch 3 can be inclined in the width direction and the top plate 2 can be inclined.
[0072]
(3) In each of the above-described embodiments, the deflection of the top 2 before the placement of the subject is detected by the deflection detector 10 and used as reference data. However, it is assumed that the deflection of the top 2 does not occur by its own weight. Alternatively, the correction data may be obtained in accordance with the deflection detected by the deflection detector 10 after the subject M is placed on the top 2.
[0073]
【The invention's effect】
As is apparent from the above description, according to the present invention, it is possible to detect the bending of the top plate, correct the relative position between the top plate and the scanning unit according to the bending, and remove the influence of the bending. Thereby, a high-precision tomographic image and a 3D image of a region of interest can be obtained from image data acquired at each scanning position of the subject, and a highly accurate radiation treatment plan can be established.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating an overall configuration of an X-ray CT apparatus according to a first embodiment.
FIG. 2 is a side view showing a configuration of a main part of the bed.
FIG. 3 is an explanatory diagram for correcting deflection of a top plate.
FIG. 4 is an enlarged view of FIG. 3;
FIG. 5 is a flowchart illustrating a procedure of top plate position correction in the first embodiment apparatus.
FIG. 6 is an explanatory diagram of an operation for correcting a position of a top plate.
FIG. 7 is an explanatory diagram of an operation for correcting a position of a top plate.
FIG. 8 is an explanatory diagram of an operation for performing gantry position correction.
FIG. 9 is a block diagram illustrating an overall configuration of an X-ray CT apparatus according to a second embodiment.
FIG. 10 is a diagram showing a state of correction of image data.
FIG. 11 is a flowchart illustrating a procedure of data correction in the device of the second embodiment.
[Explanation of symbols]
M ... subject 2 ... top plate 3 ... bed 4 ... X-ray tube 5 ... X-ray detector 6 ... correction processing unit 7 ... data processing unit 8 ... bed drive control unit 9 ... gantry 16 ... gantry drive control unit

Claims (3)

  1. (A) an X-ray source that irradiates the subject with X-rays; (b) an X-ray detector that is arranged to face the X-ray source across the subject and detects X-rays transmitted through the subject; c) scanning means for scanning the X-ray source and the X-ray detector around the body axis of the subject in the opening, and (d) placing the subject on the scanning means. A couch having a couchtop capable of moving up and down through the opening and capable of ascending and descending; (e) detection means for detecting bending of the couchtop when a subject is placed; and (f) detection by the detection means. Correction means for correcting the relative position between the scanning means and the top plate on which the subject is placed, in accordance with the obtained bending of the top board, and (g) data for collecting image data obtained at each scanning position of the subject. Collection means; and (h) image reconstruction means for performing image reconstruction processing of a predetermined tomographic image from the image data of the data collection means; i) X-ray CT apparatus characterized by comprising an image display means for displaying the tomographic image generated by the image reconstruction means.
  2. 2. The X-ray CT apparatus according to claim 1, wherein (f1) the correction unit controls the driving of at least one of the bed and the scanning unit in accordance with the detected bending of the top plate, and controls the position of the top plate and the scanning unit. An X-ray CT apparatus for correcting a relative position.
  3. (A) an X-ray source that irradiates the subject with X-rays; (B) an X-ray detector that is arranged opposite to the X-ray source with the subject interposed therebetween and detects X-rays transmitted through the subject; C) scanning means for scanning the X-ray source and the X-ray detector around the body axis of the subject within the opening; A couch having a couchtop capable of moving back and forth through the opening and capable of moving up and down, (E) detection means for detecting bending of the couchtop when the subject is placed, and (F) scanning of the subject Data collection means for collecting image data obtained at each position; and (G) a tomographic image of the subject in a state in which the relative position between the top and the scanning means has been corrected according to the deflection of the top detected by the detection means. Data extraction means for extracting image data of the surface; and An image reconstruction means for image reconstruction processing a tomographic image, (I) X-ray CT apparatus characterized by comprising an image display means for displaying the tomographic image generated by the image reconstruction means.
JP2002349998A 2002-12-02 2002-12-02 X-ray ct apparatus Pending JP2004180846A (en)

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JP2007050244A (en) * 2005-08-18 2007-03-01 Ge Medical Systems Global Technology Co Llc Method for measuring cradle position, method for compensating cradle sag, and x-ray ct apparatus
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US9355437B2 (en) 2013-06-28 2016-05-31 Shenyang Neusoft Medical Systems Co., Ltd. Image position compensation method and apparatus
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