JP2002209880A - X-ray ct system, operation console, and its control method, and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To permit relation between the image quality of a re-constituted and outputted X-ray tomographic image and a slice thickness or magnification to be intuitively and easily recognized. SOLUTION: In an X-ray CT system, the X-ray tomographic image is re-constituted based on data which is transferred from a gantry unit (S4). A shadow image is generated, which is provided with the width corresponding to the slice thickness of the re-constituted X-ray tomographic image (S5). Then the X-ray tomographic image to which the generated shadow image is added is displayed (S6).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray CT system for obtaining an X-ray tomographic image of a subject by X-ray irradiation, an operation console, a control method thereof, and a storage medium.

[0002]

2. Description of the Related Art X-ray CT (Computerized Tomography) systems and apparatuses are roughly classified into an apparatus having a donut-shaped cavity (generally called a gantry apparatus),
An operation console for providing various control signals to the gantry device, reconstructing and displaying an X-ray tomographic image based on the signal (data) obtained from the gantry device, and
It is configured with a transport device for fixedly supporting the subject (subject) in the cavity of the gantry device and for transporting the subject toward the cavity (the axis in the transport direction is generally referred to as the Z axis). You.

A gantry apparatus is a rotating body having a built-in X-ray source (X-ray tube) provided with the above-mentioned cavity interposed therebetween and an X-ray detector for detecting X-rays emitted from the X-ray source. Is provided. The X-ray detection unit includes one including an X-ray detection array in which a large number of X-ray detection elements are arranged in one row, and one including a plurality of X-ray detection arrays. X equipped with the former gantry device
The X-ray CT system is called a single slice X-ray CT system, and the latter is called a multi-slice X-ray CT system.

In actual scanning, the subject is laid on the above-mentioned transport device and transported to the gantry device. After aligning the subject and the gantry device, the technician operates the operation console to make a scan plan and gives a scan start instruction.
As a result, while rotating the X-ray tube, the rotating body (X-ray tube and X-ray detector) of the gantry device is rotationally driven (this operation is generally called scanning), and X-rays are directed toward the subject from different angles. The X-rays irradiated and transmitted through the subject at each angle are detected. Then, the operation console receives the detected data, and reconstructs an X-ray tomographic image by arithmetic operation.
That is the step.

[0005]

Now, consider a single-slice X-ray CT system in which the width of the X-ray detection array along the Z-axis (transfer direction of the subject) is 1 mm. In this system, of course, a 1 mm thick slice X
A line tomogram can be reconstructed. Then, depending on the scan plan, X-ray tomographic images of 2 mm, 3 mm, etc. can be reconstructed. In order to reconstruct an X-ray tomographic image having a slice thickness of 2 mm or more, the subject is repeatedly moved by 1 mm in the Z-axis each time the rotating body of the gantry device rotates once. As a result, continuous X-ray transmission data in the Z-axis direction can be obtained. For example, by averaging data for two consecutive scans and performing reconstruction based on the data, an X-ray tomogram having a thickness of 2 mm can be obtained. Similarly, if a process of reconstructing from data for three scans is performed, an X-ray tomographic image having a thickness of 3 mm can be obtained.

Although the above is an example of a single-slice X-ray CT system, in the case of a multi-slice X-ray CT system, processing can be performed more efficiently. Because
In the case of the multi-slice X-ray CT system, since the X-ray detection unit of the gantry device is originally provided with a plurality of rows of X-ray detection arrays, the rotation of the gantry device by one rotation only allows different positions in the Z-axis direction. This is because X-ray transmission data can be obtained.

As described above, Z of one X-ray detection array
Reconstructing an X-ray tomographic image having a width (thickness) larger than the axial width is, after all, an image equivalent to a synthesized X-ray tomographic image in a different Z-axis direction. Therefore, the displayed image is blurred. However,
The affected part in the Z-axis direction of the subject can be diagnosed with a small number of X-ray tomographic images, which is suitable for searching for the affected part at an early stage. In particular, multi-slice X-ray CT
This is a scan mode that is relatively frequently used in the system.

As described above, the operation console reconstructs an X-ray tomographic image based on the data transferred from the gantry device and displays it. At this time, when the displayed X-ray tomographic image is 1 mm thick,
When compared with an X-ray tomographic image having a mm slice thickness, an image of an X-ray tomographic image having a 1 mm slice thickness has higher resolution and looks sharper for the above-described reason. In other words, 4mm
An X-ray tomographic image having a slice thickness looks more blurred than an X-ray tomographic image having a slice thickness of 1 mm.

[0009] However, it is difficult for an operator (technologist or doctor) to understand what accuracy the displayed X-ray tomographic image has. Even if a message indicating that the slice thickness is 1 mm slice thickness or 4 mm slice thickness is displayed as an annotation near the displayed X-ray tomographic image, it is not easy to intuitively grasp the meaning.

The resolution of a plane (XY plane) perpendicular to the Z-axis direction is determined by an interval in the direction in which the X-ray detection element groups of the gantry apparatus are arranged (an interval between the detection elements). However,
If you select a thick slice thickness in the Z-axis direction,
Even if the resolution of the plane is good, only the information averaged by the thickness in the Z-axis direction can be obtained, and as a result, the fine structure of the human body cannot be extracted. The operator can also instruct to reconstruct and enlarge an area (Field of View; hereinafter, FOV) centered on a certain part of the affected part. It is often the case that an FOV that is extremely small with respect to the thickness in the axial direction is specified, or the enlargement ratio is made unnecessarily large. As a result, the image becomes Z
This means that what is blurred in the axial direction is displayed, confusion,
Misleading.

The present invention has been made in view of such a problem, and makes it possible to intuitively understand the relationship between the image quality of a reconstructed and output X-ray tomographic image and slice thickness or magnification. An object of the present invention is to provide a distribution device for an X-ray CT system and a control method thereof, and an X-ray CT system and a storage medium.

[0012]

In order to solve such a problem, for example, an X-ray CT system of the present invention has the following configuration. That is, while controlling the gantry device and the gantry device, an X-ray tomographic image is reconstructed based on the transmitted X-ray data of the subject transferred from the gantry device,
In an X-ray CT system including an operation console for outputting, the operation console is configured by a reconstructing unit configured to reconstruct an X-ray tomographic image based on data transferred from the gantry device, and reconstructed by the reconstructing unit. Generating a shadow image having a width corresponding to the slice thickness of the X-ray tomographic image;
And a shaded X-ray tomographic image output means for adding to and outputting a tomographic image.

[0013]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

In the embodiment, the multi-slice X-ray C
An example in which the present invention is applied to a T system will be described. However, those skilled in the art will be able to apply the present invention to a single slice X-ray CT system from the following description.

FIG. 1 is a block diagram of an X-ray CT system according to the embodiment. In the figure, 100 indicates a gantry device, and 200 indicates an operation console. The table device for transporting the subject is a portion indicated by reference numerals 12 to 14 in the drawing.

The gantry device 100 has the following configuration, including the main controller 1 that controls the entire system.

Reference numeral 2 denotes an interface for performing communication with the operation console 200. Reference numeral 3 denotes a transport of a subject (subject) lying on the table 12 (hereinafter referred to as Z in a direction perpendicular to the drawing).
An X-ray tube 4 (X-ray tube controller 5) which is an X-ray generation source and is internally driven and controlled by an X-ray tube controller 5 ), A collimator 6 having a slit for defining an X-ray irradiation range, and a motor 7a for adjusting the X-ray irradiation range of the collimator 6 are provided (details will be described later). The driving of the motor 7a is controlled by the collimator controller 7.

The rotating body 3 has X transmitted through the subject.
A detection unit 8 for detecting a line and a data collection unit 9 for collecting data obtained by the detection unit 8 are also provided. The X-ray tube 4, the collimator 6, and the detection unit 8 are provided at positions opposing each other across the hollow portion, that is, across the subject, and in the circumferential direction together with the rotating body 3 in a state where the relationship is maintained. It is designed to rotate. This rotation is performed by a rotation motor 10 driven by a drive signal from a motor controller 11.
Done by

Reference numerals 12 to 14 denote elements constituting a table device, 12 is a table on which a subject is placed, 13 is a motor for transporting the table 12 in the Z-axis direction, and 14 is a motor. This is a table motor controller for driving the motor 13 in accordance with an instruction from the main controller 1.

The main controller 1 analyzes various commands received via the I / F 2, and based on the analysis, the X-ray tube controller 5, the collimator controller 7, the motor controller 11, the table motor controller 14, and the data Various control signals are output to the collection unit 9. Also, the main controller 1
Also performs a process of transmitting the data collected by the data collection unit 9 to the operation console 200 via the I / F 2.

The operation console 200 is a gantry device 1
In addition to performing various operation settings for 00, an X-ray tomographic image is reconstructed based on data output from the gantry apparatus 100, and is displayed or printed out. The operation console 200 is a so-called workstation, and includes a CPU 51 that controls the entire apparatus, a ROM 52 that stores a boot program and a BIOS, and a RAM 53 that functions as a main storage device, as shown in FIG. Prepare.

The HDD 54 is a hard disk drive, and stores therein an OS, a diagnostic program for giving various instructions to the gantry apparatus 100, and reconstructing an X-ray tomographic image based on data received from the gantry apparatus 100. Have been. The VRAM 55 is a memory for expanding the image data to be displayed. The image data and the like can be displayed on the CRT 56 by expanding the image data and the like. 57 and 58 are a keyboard and a mouse for performing various settings. 59 is a gantry device 1
This is an interface for communicating with 00.

The configuration of the X-ray CT system in the embodiment is generally as described above. Next, the structure and operation of the X-ray tube 4, collimator 6, and detector 8 will be described in more detail with reference to FIGS. explain.

FIG. 2 is a configuration diagram of the main parts of the X-ray tube 4, the collimator 6, and the detection unit 8 housed in the rotating body 3.

In the drawing, the X-ray tube 4 is provided with a housing 41.
In addition, it has a structure in which a cathode sleeve 42 containing a focusing electrode and a filament and a rotating target 43 are incorporated, and emits X-rays Xa from a focal point f.

Further, the detecting section 8 in the embodiment is composed of eight detecting arrays 81 to 88 as shown in the figure, and the width of the detecting array in the Z-axis direction is 1 mm for simplicity of explanation.
It is assumed that Of course, the present invention is not limited by the number and the width.

The collimator 6 is made of a member made of an X-ray shielding material (such as lead or tungsten). As shown in the drawing, the collimator 6a defines an X-ray irradiation range of the X-ray emitted from the X-ray tube 4 in the Z-axis direction. And a collimator 6b composed of two fixed shielding plates that define an irradiation range (fan angle) in the longitudinal direction of the detection unit 8.

In the above configuration, the collimators 6a and 6b
The width of the slit 15 in the Z-axis direction (hereinafter, simply referred to as the slit width) is made variable by performing mechanical operation of the collimator 6a. This operation is realized by the motor 7a, and its specific structure will be described with reference to FIG.

FIG. 3A is a top view of the collimator 6a (view when viewed from the direction of the X-ray tube 4).

The collimator 6a includes two shielding plates 60, 6
1 and connecting rods 63 and 64 for connecting their ends. The connecting portion between the connecting rod and the shielding plate is rotatably supported on each other. Further, the connecting rods 63 and 64 have the same length, and this configuration enables the shielding plates 60 and 61 to be kept parallel to each other. In addition, connecting rods 63, 6
Shafts 62a and 62b are provided at the center position of 4, and the shafts 62a and 62b are adapted to rotate about the fulcrum by driving by the motor 7a.

Therefore, the motor 7a is driven and the shaft 6
When 2a and 63b are rotated clockwise, FIG.
It can be understood that the shield plates 60 and 61 can be gradually approached while maintaining their parallelism. In other words, the gap formed by the shielding plates 60 and 61 defines the slit width of the slit 15, and the width can be adjusted.

Therefore, when X-rays are detected by using the four central detection arrays in the plurality of detection arrays in FIG. 2, the slits are set so that only the four detection arrays are irradiated with X-rays. By adjusting the width so that the two detection arrays at both ends are not irradiated with X-rays, it is possible to avoid unnecessary exposure of the subject.

Now, in the above configuration, it is assumed that the slit width of the collimator 6 is maximized and the X-ray tube 4 is driven to rotate (rotate) the rotating body 31 one time. Operation console 20
0 is each X-ray detection array 81 sent from the gantry device.
X-ray tomographic images are reconstructed on the basis of the data obtained in
Up to 8 X-ray tomographic images and up to 4 X-ray tomographic images of 2 mm thickness
It is possible to reconstruct up to two X-ray tomographic images having a thickness of 4 mm and at most one X-ray tomographic image having a thickness of 8 mm. Further, if the table 12 is conveyed by 8 mm in the Z-axis direction for each scan, it is theoretically possible to reconstruct an X-ray tomographic image having a slice thickness exceeding 8 mm.

At present, due to the limitation of the band and the data channel of the interface between the gantry device 100 and the operation console 200, the number of data that can be transferred at one time is limited to a maximum of four channels. Therefore, the maximum number of slices that can be reconstructed by one scan is four. 2mm
When reconstructing four slice-thickness X-ray tomographic images,
Command information is transmitted from the operation console 200 to the gantry device 100 in advance, and the data collection unit 9 is instructed to synthesize data of two adjacent detection arrays. As a result, four pieces of transmission X-ray data are generated and transferred to the operation console 200 via the interface 2. In this case, one piece of transmitted X-ray data has a meaning equivalent to that detected by an X-ray detection array having a width of 2 mm in the Z-axis direction.

In any case, the operation console 200
(Accurately, an application in the operation console 200) includes the number of data transferred from the gantry device 100 (how many data out of the four channels are valid), and each is detected by a detection array having a width of several mm. You will know in advance if it is. In the operation console 200, based on the received data,
An X-ray tomographic image is reconstructed and displayed.

One of the factors determining the sharpness of a displayed X-ray tomographic image is the slice thickness, as described above.

The slice thickness can be set by a scan plan established before actual scanning or an addition operation after scanning (however, in the addition, the resolution in the Z-axis direction exceeds the actually scanned data). Cannot be requested).

However, actually reconstructing an X-ray tomographic image,
When it is displayed, the operator (technologist or doctor)
It is difficult to know for some reason whether the sharpness of the image is high or low. Therefore, in the present embodiment, when displaying a reconstructed X-ray tomographic image, the point at which the difference in sharpness depends on the slice thickness depends on the slice thickness. A shadow corresponding to the slice thickness is added and displayed.

FIG. 4A shows an X-ray tomographic image when the slice thickness is 1 mm, and FIG. 4B shows an X-ray tomographic image when the slice thickness is 4 mm. As shown in the figure, a shadow having a thickness D depending on the slice thickness of the reconstructed X-ray tomographic image is added to the X-ray tomographic image and displayed.

Although the sizes of these images are the same, the shadow widths D are different from each other, so that it is as if a composite result of a plurality of images having a thickness in the Z-axis is being displayed. It becomes obvious at a glance why the sharpness of the image is high or low.

For the sake of simplicity, a case will be described where the size of an image obtained by reconstructing is 512 × 512 pixels and the image is displayed as 512 × 512 display pixels when displaying.

In this case, the thickness (the number of display pixels) D of the shadow portion added to the X-ray tomographic image was calculated and determined as follows.

D = α × slice thickness (1) Here, α is a coefficient, and α = 1 when one calculated pixel (one pixel obtained by the reconstruction process) = 1 display pixel. However, as far as human vision is viewed at a normal distance (approximately 40 to 70 cm) from the display screen, the accuracy is not necessarily high enough to allow one display pixel to be resolved.
When the display screen of the CRT 56 is large and the display resolution is high, even if one calculation pixel = 1 display pixel, CR
Since the display image on T becomes small, α
There is no visual problem even if = 2 etc. Therefore, it is desired that the coefficient α can be appropriately adjusted according to the environment of the user such as the performance of the CRT in the system. In this case, the above α
May be set, and the set contents may be registered (stored) in the HDD 54.

A specific area (Field Of View = FO)
Of course, there is a case where it is desired to display V) in an enlarged manner.

The size of this FOV is m × m in 512 × 512, and the FOV
Is displayed as a size of 512 × 512 on the CRT, one calculated pixel (one pixel constituting the image data obtained by the reconstruction process) is enlarged to 512 / m both horizontally and vertically.

For example, FOV in an image obtained by reconstructing
Is 64 × 64 pixel size, and it is 512 × 512.
Consider a case in which the image is enlarged and displayed up to the area of the display pixel. In this case, one calculated pixel will be displayed as 8 × 8 pixels on the display screen, and it will be enlarged and displayed in appearance, so that an environment that is easy to see can be provided to the operator. The details are rather obscure (more blurred). That is, it can be said that enlargement and sharpness have a trade-off relationship.

Therefore, also at the time of enlargement processing, to clearly show that the sharpness of the displayed image is reduced,
As shown in FIG. 5, a shadow is added to an image displayed in the same manner as described above, and the image is expressed by the thickness D of the shadow.

That is, the FOV for the enlarged display is a square, and one side of the square is m pixels.
Assuming that the display area at the time of displaying the image No. 6 is a square and one side is M pixels, the shadow thickness D is calculated as D = β × M / m (2). Here, β is a coefficient.

Therefore, by combining the expression (1) for the slice thickness with the expression (2) in the enlarged display, a general expression such as D = γ × slice thickness × M / m (3) can be obtained. Here, γ is a coefficient, which may be appropriately set and stored and registered according to the usage environment, as described above. When γ = 1, the shadow thickness D = 1 when the slice thickness is 1 mm and displayed at the same magnification. That is, one display dot of shadow thickness 1 m
This corresponds to m slice thickness. If γ = 2, a shadow having a width of two display dots is added even if the slice thickness is 1 mm and the display is the same size.

In some cases, each calculated X-ray tomographic image must be displayed in a reduced scale (M / m <1), such as displaying many X-ray tomographic images on one display device. In such a case, if the value D calculated by the equation (3) is less than “1”, no shadowing is performed. In addition, since the display is performed on a pixel-by-pixel basis, the decimal portion of the calculated value D is discarded.

FIG. 6 is a flowchart showing a processing procedure in the operation console 200 in the embodiment, and a program for executing the procedure is stored in the HDD 54.

The operation procedure of the operation console 200 according to the embodiment will be described below with reference to FIG.

First, in step S1, a scan plan is set. Although the setting confidence is known, the setting of the scan range, slice thickness, FOV, etc. of the subject in the Z-axis direction is performed. Next, in step S2, various instructions are given to the gantry device 100 according to the set plan, and the operations of the gantry device 100 and the table device are started.

As a result, the data collected by the data collection unit 9 of the gantry device 100 is transferred to the operation console 100. The data is received and stored in the HDD 54 in step S3.

Then, the process proceeds to a step S4, wherein the HDD 54
The reconstruction processing of the X-ray tomographic image is performed based on the data accumulated in the.

In the next step S5, X in step S4
The number of slices is determined based on the number of channels used for reconstructing the line tomographic image and the number of detection arrays obtained by combining the data of each channel. Then, based on the slice thickness and the FOV (if set), the width D of the shadow to be added is calculated using Expression 3 described above.

In step S6, a shadow image based on the width D of the shadow calculated in step S5 is generated, and is generated in step S5.
The image is displayed in addition to the X-ray tomographic image reconstructed in step 4.

In step S7, the process returns to step S4, if any, in accordance with the instruction as to whether or not to perform the addition, and repeats the above processing. In this addition, since data obtained by scanning is already stored in the HDD 54, the data is reused to set another FOV (size and position) or to set another slice. This is to deal with setting the thickness. The setting of a new FOV and the like can be performed by specifying a desired area in the displayed X-ray tomographic image using the mouse 58. The slice thickness may be separately set in units of millimeters. Is omitted.

As described above, according to the present embodiment,
It is possible to provide an operator with an environment in which the accuracy such as the sharpness of the reconstructed X-ray tomographic image is intuitive and easy to understand. Therefore, it is possible to provide a useful user interface for learning mistakes in a scan plan or an addition operation and for making a meaningful plan.

<Modification> In the above embodiment, the X of the subject on the rotating surface of the rotating body 3 in the gantry apparatus 100 is changed.
Although an example of the X-ray tomographic image has been described, there is an MPR (Multiple Planar Reconstruction) as one of the techniques for reconstructing the X-ray tomographic image.

Since the MPR itself is publicly known, a detailed description thereof will be omitted, and a brief description will be given as follows.

Now, assume that a 1 mm thick X-ray tomographic image is reconstructed at 1 mm intervals in the Z-axis direction. Reference numeral 70 in FIG. 7 indicates that a plurality of X tomographic images are continuous. Each X-ray tomographic image is a plane parallel to the rotation plane of the rotating body 3.

In the MPR, when a plurality of X-ray tomographic images are continuous as described above, a plane 71 crossing the plurality of X-ray tomographic images is set as shown in FIG.
This is for reconstructing an X-ray tomographic image when cut by one.

Normally, when performing the MPR, the setting of what plane is used to cut the X-ray tomographic image group 70 and the slice thickness T thereof are set.

Therefore, in this modification, the shadow width D of the X-ray tomographic image 72 reconstructed by MPR is determined using the slice thickness T as a parameter. However, a VOF may be set in an X-ray tomographic image reconstructed by MPR and may be enlarged, so that it is also treated as one of the parameters. The arithmetic expression in this case may be the same as Expression 3.

<Second Embodiment> In the above embodiment, a shadow image having a width D is generated and added to an X-ray tomographic image. However, in the second embodiment, a shadow image is added to the shadow image. It adds further added value.

As described above, the detection unit 8 of the gantry device 100 in the embodiment has eight detection arrays 81.
To 88. When the collimator 6 is controlled to irradiate all the detection arrays with X-rays, all these X-ray detection arrays can detect X-rays transmitted through the subject.

In the embodiment, the width of each detection array in the Z-axis direction is 1 mm.
An X-ray tomographic image having a slice thickness of 8 mm can be reconstructed only by rotating the rotator 3 of 0 once. In the second embodiment, a case will be described in which an X-ray tomographic image having a slice thickness of 8 mm is reconstructed.

Since the maximum number of channels for data transfer between the gantry device 100 and the operation console 200 is four, the data detected by the eight detection arrays cannot be transferred as it is (if the transfer band becomes wider, Data transfer of eight channels becomes possible). Therefore, the data collection unit 9 is controlled to combine (add) the data obtained by the two adjacent detection arrays, generate four combined data, and transfer them. Alternatively, the setting may be such that data of four consecutive detection arrays are combined to generate and transfer two data.

For the sake of simplicity, the data collection unit
One of the data after the synthesis of the data obtained from the detector array adjacent are the equivalent to that detected by a single detector array having a width of substantially 2mm in the Z-axis direction is expressed as D _2. For the same reason, the data detected by the four detector array adjacent can be defined as D _4.

Therefore, when reconstructing an X-ray tomographic image having an 8 mm slice thickness, Reconstituted with four data D _2. 2. Reconstituted with two data D _4.

Either one of them may be used. After calculating the average of the data, the X-ray tomographic image may be reconstructed or the weighted average may be calculated.

In the second embodiment, the operator is clarified in which of the above 1 and 2 the X-ray tomographic image has been reconstructed.

FIG. 8A shows an example in which an X-ray tomographic image having a slice thickness of 8 mm is reconstructed and displayed based on the data of D ₄ × 2. To clearly show that two data were used, the shadows were displayed in two layers. FIG. 2B shows D ₂ × 4.
Shows a display example of an X-ray tomographic image having a slice thickness of 8 mm, and is expressed by shadows in four layers to show that four data are used.

From the viewpoint of the operator, it is understood that, for example, in the case of FIG. 9A, two X-ray tomographic images having a slice thickness of 4 mm can be reconstructed. Therefore, in the addition operation,
By giving an instruction to reconstruct an X-ray tomographic image having a slice thickness of 4 mm, an X-ray tomographic image whose resolution in the Z-axis direction is doubled is reconstructed using data already stored in the HDD 54 (without scanning). It can be seen that a configuration is also possible.

On the other hand, in the case of FIG. 9B, since it can be seen that four layers of shadows are added, only the combination can be reconstructed by the addition operation. For example,
It is also possible to reconstruct four X-ray tomographic images having a slice thickness of 2 mm (the resolution in the Z-axis direction in this case is shown in FIG.
The X-ray tomographic image is twice as large as the X-ray tomographic image reconstructed by the addition, and an X-ray step image with higher sharpness can be reconstructed. Further, two X-ray tomographic images having a slice thickness of 2 mm × 2 = 4 mm can be reconstructed, and 2 mm × 3 = 6 m
It is also possible to reconstruct an X-ray tomographic image of m slice thickness and an X-ray step image of different slice thickness of 2 mm slice thickness.

As described above, by adding a shadow indicating how many (how many channels) data was used in calculating the displayed X-ray tomographic image to the displayed X-ray tomographic image, the Z-axis position can be increased by the subsequent addition operation. It becomes possible to know beforehand whether or not an image with a higher resolution in the direction can be reconstructed, and a better operating environment can be provided.

In the first and second embodiments, the example in which the scanning method of the gantry apparatus 100 is an axial scan has been described. That is, after the top 12 is moved along the Z-axis by a predetermined distance, scanning is performed by rotating the rotating body 3 of the gantry apparatus 100 once, and then the top 12 is moved a predetermined distance. Is a scanning method of rotating.

As a scanning method, there is a helical scanning method other than the above-described axial scanning method. Briefly explaining helical scanning,
The movement of the top board 12 and the rotation of the rotating body 3 of the gantry device are simultaneously executed. When displaying a reconstructed X-ray tomographic image, it is more convenient to be able to distinguish between them.

In order to show that the data obtained by “helical”, that is, the data obtained by the spiral scan, is used for the shadow portion for indicating the slice thickness, FIG.
As shown in (1), a diagonal line of a surface forming a shadow is added and displayed.

In the drawing, the width D of the shadow portion is a helical scan, so that when reconstructing a tomographic image,
The determination is made by using data from where to in the Z-axis direction of the subject. Therefore, the formula 3 described above can be used as it is as the formula for calculating the shadow width D.

As described above, according to the second embodiment, the relationship between the sharpness and the slice thickness of the reconstructed and displayed X-ray tomographic image becomes clear at a glance.
When reconstructing by addition, it is also possible to intuitively grasp how many mm thick slice X-ray tomographic images can be reconstructed. Further, it is also possible to easily grasp whether the reconstructed X-ray tomographic image is an axial scan or a helical scan.

Although the multi-slice X-ray CT system has been described as an example in the embodiment, it may be applied to a single-slice X-ray CT system. If you can easily understand. In the embodiment, the width of one detection array in the Z-axis direction is set to 1 mm. However, this is, of course, for convenience.
Any width is acceptable. For example, if the width is 0.5 mm, when γ = 1 in Expression 3, one dot of the shadow width corresponds to 0.5 mm.

In the embodiment, the output destination of the X-ray tomographic image with shadow image is described as a display device such as a CRT, but may be a printer.

Further, when realizing the functions of the first and second embodiments, an existing system can be directly used in terms of hardware. That is, a characteristic part of the present application is processing in the operation console 200. As described above, the operation console 200 is a general-purpose information processing device such as a workstation, and the above functions can be realized by an application program.

Therefore, it is obvious that the present invention can be applied to a case where a program code is supplied to a computer from the outside. In this case, the program code itself constitutes the present invention. There are various types of media for supplying the program. For example, removable media such as a floppy (registered trademark) disk and CDROM are available.

[0087]

As described above, according to the present invention, the image quality and slice thickness of the reconstructed and output X-ray tomographic image,
Alternatively, it is possible to intuitively understand the relationship with the enlargement ratio. Therefore, from the viewpoint of the operator, even if the quality of the output X-ray tomographic image is not intended, the reason can be easily grasped, and the learning concerning the operation of the X-ray CT can be easily performed. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a block diagram of an X-ray CT system according to an embodiment.

FIG. 2 is a main part configuration diagram of an X-ray tube 4, a collimator 6, and a detection unit 8 in the embodiment.

FIG. 3 is a configuration diagram of a collimator in the embodiment.

FIG. 4 is a diagram illustrating a display example of an X-ray tomographic image according to a difference in slice thickness according to the first embodiment.

FIG. 5 is a diagram illustrating a display example of an X-ray tomographic image in an enlargement process according to the first embodiment.

FIG. 6 is a flowchart illustrating an operation processing procedure of the operation console according to the first embodiment.

FIG. 7 is a diagram illustrating an X-ray tomographic image by MPR and a display example according to the embodiment.

FIG. 8 is a diagram illustrating a display example of an X-ray tomographic image according to the second embodiment.

FIG. 9 is a diagram illustrating a display example of an X-ray tomographic image by helical scan according to the second embodiment.

Continued on the front page (72) Inventor Makoto Gono 127 Gee Yokogawa Medical System Co., Ltd., 4-7 Asahigaoka, Hino-shi, Tokyo F-term (reference) 4C093 AA22 BA03 CA21 FF41 FG11

Claims (18)

[Claims] 1. An X-ray apparatus comprising: a gantry device; and an operation console for controlling the gantry device and reconstructing and outputting an X-ray tomographic image based on transmitted X-ray data of a subject transferred from the gantry device. In the X-ray CT system, the operation console includes: reconstruction means for reconstructing an X-ray tomographic image based on data transferred from the gantry device; and slice thickness of the X-ray tomographic image reconstructed by the reconstruction means. An X-ray CT system comprising: a shadow X-ray tomographic image output unit that generates a shadow image having a width corresponding to the above, and outputs the generated shadow image in addition to the X-ray tomographic image. 2. The method according to claim 1, further comprising the steps of:
2. The apparatus according to claim 1, further comprising a second X-ray tomographic image output unit that adds and outputs a shadow image having a thickness corresponding to the input slice thickness when displaying the tomographic X-ray image. X-ray CT system. 3. When reconstructing an X-ray tomographic image based on data obtained by an axial scan, when data of a plurality of slices is used, a number of lines corresponding to the number of slice data used are used. 2. The X-ray CT system according to claim 1, further comprising means for drawing a minute on the shadow image. 4. A shadow image to be added to an X-ray tomographic image reconstructed by helical scanning, further comprising means for drawing a line segment on a diagonal line of each surface of the shadow image. An X-ray CT system according to item 3. 5. When the X-ray tomographic image is reconstructed by enlarging a desired region, the ratio of the output size corresponding to one calculation pixel obtained by the reconstruction process is determined by the width of the shadow image. The X-ray CT system according to claim 1, wherein the X-ray CT system is used as a parameter to be determined. 6. The X-ray CT according to claim 1, wherein the width of the shadow image is determined by multiplying a slice thickness by a predetermined coefficient, and the coefficient can be appropriately changed.
system. 7. An X-ray apparatus comprising: a gantry device; and an operation console for controlling the gantry device and reconstructing and outputting an X-ray tomographic image based on transmitted X-ray data of the subject transferred from the gantry device. In the control method of the X-ray CT system, the operation console includes: a reconstructing step of reconstructing an X-ray tomographic image based on data transferred from the gantry device; and an X-ray tomographic image reconstructed in the reconstructing step. And generating a shadow image having a width corresponding to the slice thickness of the X-ray tomographic image and adding the shadow image to the X-ray tomographic image and outputting the shadow image. 8. An operation console for controlling a gantry device in an X-ray CT system, reconstructing and outputting an X-ray tomographic image based on transmitted X-ray data of a subject transferred from the gantry device. Reconstructing means for reconstructing an X-ray tomographic image based on data transferred from the gantry apparatus; and a shadow image having a width corresponding to a slice thickness of the X-ray tomographic image reconstructed by the reconstructing means. And a shadowed X-ray tomographic image output means for generating the image data and adding the generated X-ray image to the X-ray tomographic image. 9. A control of an operation console for controlling a gantry device in an X-ray CT system and reconstructing and outputting an X-ray tomographic image based on transmitted X-ray data of a subject transferred from the gantry device. A reconstruction step of reconstructing an X-ray tomographic image based on data transferred from the gantry apparatus, and a width corresponding to a slice thickness of the X-ray tomographic image reconstructed in the reconstruction step. And a shadow X-ray tomographic image output step of generating a shadow image having the shadow image and adding the shadow image to the X-ray tomographic image and outputting the resulting image. 10. An operation console for controlling a gantry device in an X-ray CT system and reconstructing and outputting an X-ray tomographic image based on transmitted X-ray data of a subject transferred from the gantry device. A storage medium for storing a program code, comprising: a program code for a reconstruction step of reconstructing an X-ray tomographic image based on data transferred from the gantry device; and an X-ray tomogram reconstructed in the reconstruction step. A storage medium for generating a shadow image having a width corresponding to the slice thickness of an image, and storing a program code of a shadowed X-ray tomographic image output step of adding the X-ray tomographic image to output. 11. A gantry device and controlling the gantry device, reconstructing an X-ray tomographic image based on transmitted X-ray data of the subject transferred from the gantry device,
In an X-ray CT system including an operation console for outputting, the operation console includes: a reconstruction unit configured to reconstruct an X-ray tomographic image based on data transferred from the gantry device; X-ray tomographic image output means for generating a shadow image having a width corresponding to the enlargement ratio at the time of enlarged display and adding the generated shadow image to the X-ray tomographic image and outputting the resulting image. CT system. 12. When reconstructing an X-ray tomographic image based on data obtained by an axial scan, when data of a plurality of slices is used, a number of lines corresponding to the number of slice data used are used. 12. The X-ray CT according to claim 11, further comprising: means for drawing a minute on the shadow image.
system. 13. A shadow image to be added to an X-ray tomographic image reconstructed by helical scanning, further comprising means for drawing a line segment on a diagonal line of each surface of the shadow image. Item 13. An X-ray CT system according to Item 12. 14. The X-ray CT according to claim 11, wherein the width of the shadow image is determined by multiplying an enlargement ratio by a predetermined coefficient, and the coefficient can be appropriately changed.
system. 15. A gantry device and controlling the gantry device, reconstructing an X-ray tomographic image based on transmitted X-ray data of the subject transferred from the gantry device,
In a control method of an X-ray CT system including an operation console for outputting, the operation console includes: a reconstruction step of reconstructing an X-ray tomographic image based on data transferred from the gantry apparatus; When displaying the tomographic image in an enlarged manner, a shadowed X-ray tomographic image output step of generating a shadow image having a width corresponding to the magnification and adding the shadow image to the X-ray tomographic image and outputting the added image is provided. X-ray CT system control method. 16. An operation console for controlling a gantry device in an X-ray CT system, reconstructing and outputting an X-ray tomographic image based on transmitted X-ray data of a subject transferred from the gantry device. A reconstructing means for reconstructing an X-ray tomographic image based on the data transferred from the gantry device, and having a width corresponding to the magnification when displaying the reconstructed X-ray tomographic image in an enlarged manner. An X-ray CT system operation console, comprising: a shadowed X-ray tomographic image output unit that generates a shadow image and adds the X-ray tomographic image to output. 17. A control of an operation console for controlling a gantry device in an X-ray CT system and reconstructing and outputting an X-ray tomographic image based on transmitted X-ray data of a subject transferred from the gantry device. A reconstructing step of reconstructing an X-ray tomographic image based on the data transferred from the gantry apparatus, and displaying the reconstructed X-ray tomographic image in an enlarged manner according to the magnification. A shadow X-ray tomographic image output step of generating a shadow image having a width, adding the generated shadow image to the X-ray tomographic image, and outputting the resulting image. 18. An operation console for controlling a gantry device in an X-ray CT system and reconstructing and outputting an X-ray tomographic image based on transmitted X-ray data of a subject transferred from the gantry device. A storage medium for storing a program code, wherein a program code of a reconstruction step of reconstructing an X-ray tomographic image based on data transferred from the gantry device and a reconstructed X-ray tomographic image are enlarged and displayed. In this case, a shadow image having a width corresponding to the enlargement ratio is generated, and a program code of a shadowed X-ray tomographic image output step to be added to the X-ray tomographic image and output is stored. Medium.