JP2610442B2 - X-ray CT system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an X-ray for obtaining an X-ray tomographic image of an examination part of a subject.
Regarding a CT apparatus, in particular, in X-ray tomography, an effective visual field (hereinafter, referred to as FOV: Field Of View) information is displayed on an X-ray fluoroscopic image (hereinafter, referred to as a scanogram image) for positioning a tomographic plane. The present invention relates to an X-ray CT apparatus as described above.

[Background of the Invention]

A conventional X-ray CT apparatus usually first performs scanning positioning, FOV setting, and the like using a scanogram image of a subject. In the positioning and FOV settings, information about the FOV is obtained from the FOV of the scanogram image itself.
And the standard FO for each tomographic imaging site that is empirically known
V only.

Here, positioning of conventional tomographic image scanning will be described.

As shown in FIGS. 9 to 11, when the subject 5 is to be examined, first, a scanogram image 7 is measured for the portion to be examined (the dashed line A in FIG. 11). In the scanogram measurement, the X-ray tube 3 in the measuring device 2 and the X-ray detector 4 arranged opposite thereto are fixed to a predetermined position without rotating around the subject 5 while irradiating the X-ray. The bed 1 on which the subject 5 is placed is placed in the longitudinal direction (10th
(See arrow b in the figure) to take measurement data along the body axis of the subject 5. When it is desired to obtain a tomographic image of the portion indicated by the dashed line a in FIG. 11, the scanogram image 7 is measured, and the measurement device is controlled via the information input device so as to scan the position of the dashed line a based on the information. The bed 1 is moved to obtain a tomographic image 6.

Next, the relationship between the FOV and the scanogram image will be described.

As shown in FIG. 12, the scanogram image is generally
It is given by the measurement width 8 and the measurement length 9. Generally, the measurement width 8 is fixed, and the measurement length 9 is determined by the sliding amount of the bed in the longitudinal direction. The center axis of this measurement width (dot-dashed line C in the figure) indicates the position of the center 10 of the tomographic image (from the scanogram image to the tomographic image, when the bed was not moved up and down) and the diameter of the FOV of the tomographic image In 11, the size of the scanogram image changes only in the measurement width 8 directions.

[Problems to be solved by the invention]

However, in the conventional series of scanning methods described above, in order to obtain a tomographic image of the subject 5, an optimal FOV
The setting of the subject and the position of the subject are performed using the scanogram image 7 in FIG.
And the scanogram image in which there is little information such as the scanogram image in Fig. 12 (there is no display of the central axis or dash-dot line). There is a problem that a missing tomographic image may be obtained.

The present invention has been made to solve the above problems.

An object of the present invention is to provide a technique capable of reliably setting an optimal FOV and an object position in tomography.

The above and other objects and novel features of the present invention are as follows.
It will become apparent from the description of the present specification and the accompanying drawings.

[Means for solving the problem]

The outline of a typical invention disclosed in the present application is briefly described as follows.

That is, a measuring device that irradiates the subject with X-rays and measures transmitted X-rays as data, an image processing device that generates an X-ray fluoroscopic image of the subject from the data, and displays the X-ray fluoroscopic image X-ray CT for use in scanning positioning for obtaining a tomographic image using the X-ray fluoroscopic image
In the apparatus, means for displaying an X-ray fluoroscopic image of the subject and a provisional effective visual field region on the display device, and when the fluoroscopic image of the subject protrudes from the provisional effective visual field region, An input device for inputting a correction command for a target effective visual field region, a calculation device for obtaining a real effective visual field region larger than the temporary effective visual field region based on the correction command, and an X-ray fluoroscopic image and the real It is characterized by comprising means for displaying the field of view together.

A measuring device for irradiating an X-ray from an X-ray source included in the scanner to a subject placed on a bed and measuring transmitted X-rays as data;
An image processing apparatus that generates a fluoroscopic image, and a display device that displays the X-ray fluoroscopic image, an X-ray CT apparatus that uses the X-ray fluoroscopic image for scanning positioning for tomographic image acquisition, wherein the display device Means for displaying the X-ray fluoroscopic image and the real effective visual field area, and, when the X-ray fluoroscopic image of the subject is protruding from the real effective visual field area, positioning the subject in the real effective visual field area. An arithmetic processing unit for calculating the amount, a control unit for adjusting the position of the subject with respect to the real effective visual field based on the output of the arithmetic processing unit, and the X-ray fluoroscopic image and the real effective It is characterized by comprising means for displaying the field of view together.

A measuring device for irradiating an X-ray from an X-ray source included in the scanner to a subject placed on a bed and measuring transmitted X-rays as data;
An image processing apparatus that generates a fluoroscopic image, and a display device that displays the X-ray fluoroscopic image, an X-ray CT apparatus that uses the X-ray fluoroscopic image for scanning positioning for tomographic image acquisition, wherein the display device Means for displaying the X-ray fluoroscopic image, an input device for inputting a temporary effective visual field, an angle between the body axis of the subject and the tilt center axis of the scanner after tilting the scanner, and the provisional angle. An arithmetic processing device for calculating an actual effective visual field area from an effective visual field area, and means for displaying the X-ray fluoroscopic image and the actual effective visual field together on the display device are provided.

Furthermore, as an addition to each of the above feature points,
The provisional effective visual field area or the actual effective visual field area is displayed as two straight lines along the body axis direction of the subject image in the X-ray fluoroscopic image.

[Action]

According to the above-described means, an input device for inputting information of the scanning FOV, an information processing device for creating a signal based on the information of the scanning FOV, and a display device for displaying an output of the information processing device are provided. This allows the scanogram image of the subject to calculate suitable information such as the center axis and a line corresponding to the FOV of the tomographic image (hereinafter referred to as the FOV line) and display the calculated information on the display device. Can be set.

(Example of the invention)

Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings.

In all the drawings for describing the embodiments, components having the same function are denoted by the same reference numerals, and their repeated description will be omitted.

〔Example〕

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of the X-ray CT apparatus according to the present invention.

When the X-ray CT apparatus of the present embodiment captures a scanogram image 12 in order to obtain a tomographic image of a portion to be inspected of the subject 13, first, an FOV known empirically is input to the condition input device 14. The input FOV information is sent to the information processing device 18 and also to the FOV calculation device 16. The FOV calculator 16 is
Processes information such as magnification and shooting position for scanogram images and tomographic images, and converts the input FOV information to the image processing device 1
The image is displayed on the image display device 19 via the.

In the case of the present embodiment, as shown in FIG. 2, the width FOV1 or FOV2 of the FOV line 25 or 26 displayed on the scanogram image 12.
Is calculated from the value of the measurement width L of the scanogram image 12 displayed on the image display device 19 by the following equation (1).

The FOV information processed by the FOV calculation device 16 is stored in an image processing device.
The FOV line 21 is displayed by the image display device 17 and the image display device 19. If the set FOV is suitable for tomographic imaging, that FOV
Are set, and the tomography is performed by the measurement device 20 via the measurement control device 22.

The FOV calculation device 16 is composed of, for example, a microcomputer, and performs processing as shown in FIG.

That is, in step 101, FOV information (value) is input. In step 102, the above formula is calculated, and then, the position on the scanogram image at which the FOV line is drawn is calculated (step 103). An instruction to the image processing apparatus is created based on the result of the calculation. (Step 104) Hereinafter, an operation example when the initially set FOV information is not suitable for tomography will be described.

(A). FIG. 4 is a diagram for explaining an operation when the initially set FOV information is smaller than the portion to be inspected.

The FOV line 25 on the scanogram image 23 based on the initially set FOV information is not suitable for tomographic imaging because it is smaller than the portion to be inspected. Therefore, a larger FOV line 26 is input from the condition input device 14 again. As described above, the width of the FOV line 25 on the scanogram image 23 of the image display device 19 (FIG. 1) is calculated by the FOV calculation device 16 according to the above equation, and the FOV line 26 on the scanogram image 24 of the image display device 19 is calculated. Is displayed as follows. Since this setting can be determined to be suitable for tomographic imaging, tomographic imaging is performed with this FOV setting. Second
The figure shows just before and after correction of the FOV setting of this embodiment on one scanogram image.

(B). FIG. 5 and FIG. 6 are diagrams for explaining an operation of performing a position change setting of a subject (bed).

In this example, in the case where the position of the subject is moved after the scanogram measurement and tomographic imaging is performed thereafter, suitable tomographic imaging can be performed without the need to perform the scanogram measurement again after the movement of the subject position.

That is, as shown in the scanogram image of FIG.
When 13 is shot from the top of the image display, the central axis 27
Is taken as a scanogram image 31
It is necessary to set a large FOV such that the test portion protrudes from V or includes the test portion, and an inefficient tomographic image is obtained. Therefore, in order to obtain an efficient tomographic image, the position of the subject (bed) 13 must be changed and the subject (bed) 13 must be lowered. Then, the lowering width of the subject (bed) 13 is again input to the FOV calculator 16 by the condition input device 14,
Movement amount T of the central axis corresponding to the lowered width of the subject (bed) 13
(FIG. 6) is calculated by the following equation (2).

The FOV line 29 is calculated so as to be shifted upward by the calculated movement amount T, and information is sent to the image processing device 17 so as to be displayed as the central axis 28 of the scanogram image 32 and the FOV line 30. As described above, the position change setting of the subject (bed) 13 is simulated and the FOV bed is obtained. When imaging conditions suitable for tomographic imaging are obtained, information on the bed on which the subject 13 is placed is obtained. Input to the information processing device 18 and output to the measurement device 20 through the measurement control device 22 to set the couch (down in this example)
By moving, the tomography is performed such that the FOV information on the scanogram image 32 matches the state of the measurement device 20.

(C). FIG. 7 and FIG. 8 are views for explaining an operation when the X-ray tube and the X-ray detector are tilted back and forth in the measuring device 20 (FIG. 1).

When shooting with the measuring device 20 tilted, setting the FOV is difficult. That is, when the measuring device 20 is tilted by the angle θ,
As shown in FIG. 8, the tomographic plane at FOV1 or FOV2 is apparently displayed on the image display device 19 as FOV1 'or FOV2'. FOV1 'or FOV2' is represented by the following equation (3) or (4).

FOV1 ′ = FOV1 × sinθ (3) FOV2 ′ = FOV2 × sinθ (4) Therefore, as shown in FIG. At the right position (position of the tomographic plane 40 in FIG. 8), all the test parts can be measured, but at the left position (the position of the tomographic plane 41 in FIG. 8), the target part protrudes. Because there is also.

Therefore, the FOV information input to the FOV calculator 16 from the condition input device 14 is calculated by the FOV calculator 16 using the above equation (3),
(4) When the FOV is converted to an apparent FOV and displayed on the image display device 19 by the above-described method as the FOV lines 38 and 39, and the portion to be detected protrudes as in the scanogram image 33 shown in FIG. ,
By setting the lower FOV again and setting so that the subject does not protrude like the scanogram image 34,
It enables tomographic imaging suitable for diagnosis.

As can be seen from the above description, according to the present embodiment, the condition input device 14 for inputting the information of the scanning FOV,
By providing an information processing device 18 that creates a signal based on the information of the scanning FOV and an image display device 19 that displays the output of the information processing device 18, a
When setting the FOV and the position of the subject, a line corresponding to the center axis and the FOV of the tomographic image (FOV line) on the scanogram image of the subject
It calculates and displays suitable information such as
FOV can be set accurately. In other words, to display the FOV of the tomographic image on the scanogram image,
The optimum FOV can be known in advance, and a tomographic image suitable for inspection can be obtained.

As a result, it is possible to prevent a FOV setting error in tomography and improve the efficiency of X-ray tomography.

As mentioned above, although the present invention was explained concretely based on an example, the present invention is not limited to the above-mentioned example.
It goes without saying that various changes can be made without departing from the scope of the invention.

〔The invention's effect〕

As described above, according to the present invention, the positioning and FO of the tomographic image by the scanogram image by the X-ray CT apparatus are performed.
In the V setting, since the FOV of the tomographic image is simulated on the scanogram image, the optimum FOV can be known in advance, and a tomographic image suitable for inspection can be obtained. In addition, mistakes in tomography can be reduced, and the target portion can be prevented from coming off the FOV.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of an X-ray CT apparatus according to the present invention. FIG. 2 is an explanatory diagram showing a relationship between a scanogram image and a tomographic image of the embodiment shown in FIG. FIG. 3 is a flowchart for explaining the processing flow of the FOV calculation apparatus of the present embodiment shown in FIG. 1, and FIG. FIGS. 5 and 6 are diagrams for describing an operation of performing a position change setting of a subject (bed), and FIGS. Wire tube and X
FIGS. 9 to 12 are views for explaining an operation in a case where a line detector is tilted back and forth for imaging, and FIGS. 9 to 12 are views for explaining problems of a conventional X-ray CT apparatus. In the figure, 1 ... bed, 2 ... measuring device, 3 ... X-ray tube, 4
... X-ray detector, 5 ... subject, 6 ... tomographic image, 7 ...
Scanogram image, 8: Measurement width, 9: Measurement length, 10
...... Center on the fault, 11 ... FOV diameter, 12 ... Scanogram image, 13 ... Subject, 14 ... Condition input device, 15 ... Center axis, 16 ... FOV calculation device, 17 ... Image processing Equipment, 18 ……
Information processing device, 19 ... Image display device, 20 ... Measuring device,
21 …… FOV line, 22 …… Measurement control device, 23,24,31,32,33,34
…… scanogram image, 25,26,29,30,38,39 …… FOV line,
27,28,37 …… The center line.

Claims (6)

(57) [Claims] A measuring device configured to irradiate the subject with X-rays and measure transmitted X-rays as data; an image processing device configured to generate an X-ray fluoroscopic image of the subject from the data; X-ray CT comprising a display device for displaying an image, and using the X-ray fluoroscopic image for scanning positioning for obtaining a tomographic image
In the apparatus, means for displaying an X-ray fluoroscopic image of the subject and a temporary effective visual field region on the display device, and when the X-ray fluoroscopic image of the subject protrudes from the temporary effective visual field region, An input device for inputting a correction command for a target effective visual field region, a calculation device for obtaining a real effective visual field region larger than the temporary effective visual field region based on the correction command, and an X-ray fluoroscopic image and the real An X-ray CT apparatus comprising means for displaying a field of view together with a visual field area. 2. The patent according to claim 1, wherein the provisional effective visual field area or the actual effective visual field area is displayed as two straight lines along the body axis direction of the subject image in the X-ray fluoroscopic image. The X-ray CT apparatus according to claim 1. 3. A measuring device for irradiating an X-ray from an X-ray source included in a scanner to a subject placed on a bed and measuring transmitted X-rays as data, and obtaining an X-ray of the subject from the data. An image processing apparatus that generates a fluoroscopic image, and a display device that displays the X-ray fluoroscopic image, an X-ray CT apparatus that uses the X-ray fluoroscopic image for scanning positioning for tomographic image acquisition, wherein the display device Means for displaying the X-ray fluoroscopic image and the real effective visual field area, and, when the X-ray fluoroscopic image of the subject is protruding from the real effective visual field area, positioning the subject in the real effective visual field area. An arithmetic processing unit for calculating the amount, a control unit for adjusting the position of the subject with respect to the real effective visual field based on the output of the arithmetic processing unit, and the X-ray fluoroscopic image and the real effective Field of view and In addition the X-ray CT apparatus characterized by comprising means for displaying. 4. The patent, wherein the provisional effective visual field area or the actual effective visual field area is displayed as two straight lines along the body axis direction of the subject image in the X-ray fluoroscopic image. The X-ray CT apparatus according to claim 3. 5. A measuring device for irradiating an X-ray from an X-ray source included in a scanner to a subject placed on a bed and measuring transmitted X-rays as data, and obtaining an X-ray of the subject from the data. An image processing apparatus that generates a fluoroscopic image, and a display device that displays the X-ray fluoroscopic image, an X-ray CT apparatus that uses the X-ray fluoroscopic image for scanning positioning for tomographic image acquisition, wherein the display device Means for displaying the X-ray fluoroscopic image, an input device for inputting a temporary effective visual field, an angle between the body axis of the subject and the tilt center axis of the scanner after tilting the scanner, and the provisional angle. An X-ray CT apparatus comprising: an arithmetic processing device that calculates an actual effective visual field area from an effective visual field area; and a unit that causes the display device to display the X-ray fluoroscopic image and the actual effective visual field together. . 6. The patent, wherein the provisional effective visual field area or the actual effective visual field area is displayed as two straight lines along the body axis direction of the subject image in the X-ray fluoroscopic image. The X-ray CT apparatus according to claim 5.