JPS60246738A - Ct apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an improvement in a mechanism for photographing and displaying X-ray fluoroscopic images, which is an auxiliary function of an X-ray CT apparatus.

[Background of the invention]

The X-ray CT apparatus has a structure as shown in the example of FIG.

FIG. 1(a) shows a front view of the scanner section, and FIG. 1(b) shows a side sectional view and a block diagram of the measurement system.

1 is an X-ray tube device, 2 is a collimator for irradiating the X-ray beam only onto the tomographic plane, and 3 is a multi-channel detector. is attached to. The subject 6 is placed on a bed 5 at the center of rotation of the rotatable structure and transported to the measurement site.

In order to obtain an X-ray tomographic image, an X-ray tube device (1), a collimator (2), and a multi-channel detector (3) are placed around the subject (
While rotating in the direction of arrow A), multi-directional data is measured by a multi-channel detector 3, and the obtained data is passed through a preamplifier and an AD converter 7 to a digital image processing circuit 8.
The data is then sent to , where various data processing is performed to obtain the tomographic image. The tomographic image data obtained as a result of the processing is stored in ten storage devices. The display of the obtained tomographic image is 11D
This is performed by a TV monitor device or the like using an A converter. 9 is the central controller that controls these systems, 13
is the operating console for operating these systems. A part of the storage device 10 indicated by 10' is a part for storing related data accompanying images, and indicates an area for storing, for example, the patient's name inputted from the console 13. . Note that a mechanism is also generally used in which the rotating structure is supported in an inclined manner so that an inclined tomographic plane can be obtained as shown by arrow B in FIG.

In order to determine the position from which a tomographic image is to be obtained using a CT apparatus, a function is generally provided to obtain an X-ray fluoroscopic image using the same CT apparatus and then position the part from which the tomographic image is to be obtained on the image.

As shown in Figure 2, the X-ray fluoroscopic image is obtained by moving the bed in the longitudinal direction while irradiating X-rays with the scanner unit not rotating, and simultaneously capturing the X-ray data and the amount of movement in the longitudinal direction of the bed. obtained by.

14 potentiometers and 15 AD converters send the bed position to the image processing circuit 8 as a digital quantity.

The configuration diagram shown in Figure 2 adds the aforementioned 14 potentiometers and 15 AD converters, which are necessary to explain the principle of taking X-ray fluoroscopic images, and are already explained in Figure 1. The same numbers are given to the different components.

Further, the image processing circuit 8 performs data processing for creating an X-ray fluoroscopic image in FIG. Control of switching between processing for creating tomographic images and processing for creating X-ray fluoroscopic images is performed by a central controller 9.

As mentioned above, by combining the longitudinal position data of the bed and the X-ray transmission data obtained from the detector,
The X-ray fluoroscopic images obtained by the image processing circuit are stored in 10 storage devices and displayed on 12 TV monitor display devices as needed.

Observe the X-ray fluoroscopic image displayed on the display device 12 and enter the desired tomographic imaging position from the console 13.
Since the X-ray fluoroscopic image is already stored in the storage device No. 10 along with the longitudinal position data of the bed, it is possible to determine how much the bed should be moved to move the target region to the measurement position. I understand. For example, if the desired measurement position when observing the X-ray fluoroscopic image displayed on the monitor is the position shown by the thick solid line A, as shown by the solid line in Figure 3, then input that position from the console 13. The central processing unit can display the position on the monitor screen and also calculate and display the amount by which the bed should be moved based on the bed position data stored in the storage device 10 or 10'.

Also, specify a sloped fault plane as shown by the solid line A' from the console,
In this case, the angle at which the rotating structure 5 should be tilted can be calculated and displayed.

A typical CT master device has a structure in which the bed and scanner section are automatically or semi-automatically positioned based on the calculation results.

Now, in such a CT apparatus, it may be necessary to readjust the height of the subject based on the results of X-ray fluoroscopic imaging.

This is because the fundamental structure of the CT main device requires that the subject be at the center of measurement.

Therefore, the height of the bed is carefully set before obtaining an X-ray fluoroscopic image, but the setting may be incorrect depending on the patient's body shape and posture. Furthermore, by observing the fluoroscopic image, the tomographic image measurement position, and the inclination angle on a monitor, the exact amount of adjustment of the vertical position of the bed may be determined.

If you change the bed height after obtaining an X-ray fluoroscopic image, the actual position of the subject will be different from the displayed image, as shown by the dotted line in Figure 3, and the image on the monitor will be tilted. When the fault position is set, the actual fault position will be different. - Therefore, in order to perform accurate positioning, it is necessary to re-measure the X-ray fluoroscopic image, causing a loss of time and
Extra exposure and physical to the subject.

The problem was that it added to the psychological burden.

[Purpose of the invention]

An object of the present invention is to solve the above-mentioned problems, and when the bed height is changed after obtaining an X-ray fluoroscopic image, the image position can be accurately adjusted by an amount corresponding to the amount of change without having to adjust the image position. The purpose is to enable the setting of fault planes.

[Key key to the invention]

In the present invention, when measuring an X-ray fluoroscopic image, the height of the bed is simultaneously measured and the height of the bed is adjusted, the amount of adjustment is read, and the display position of the X-ray fluoroscopic image is of,
This is characterized in that accurate positioning can be performed on the image displayed on the monitor by displaying the image shifted to a position corresponding to the actual position of the subject.

[Embodiments of the invention]

The present invention will be explained with reference to FIGS. 4 and 5.

Assuming that the subject is photographed at the position indicated by the solid line 6 in FIG. 4 during X-ray fluoroscopic imaging, the image of the subject is projected onto the range of detectors A1-A2 and stored within the range of ten storage devices ItI2. After taking the X-ray fluoroscopic image, if the height of the bed is changed by ΔX, the subject 6 will be moved to the 1' position and the X-ray fluoroscopic image will be at A.
The relationship between the movement amount ΔX of the bed and the movement ΔX' of the image is as follows.

Here, dlld is the center distance between the X-ray source and the subject, that is, the center distance from the bed, and the distance from the X-ray source to the detector, which is a constant determined by the apparatus.

(1) According to the formula, after taking an X-ray fluoroscopic image at position 6 in Figure 5, Δ
It can be seen that when the height of the X-bed is changed, if the image is translated by ΔX', the N-ray fluoroscopic image can be displayed at the correct position without taking another X-ray fluoroscopic image.

FIG. 5 shows a potentiometer 16 for height reading on the bed of a conventional OCT apparatus, which is used for the above-mentioned function.
An AD converter 17 is added, and the data is read into the image processing device. FIG. 5: Using an OCT device, the height of the bed at the time the X-ray fluoroscopic image was taken is read and memorized, and the image is displayed. If it becomes necessary to change the bed height as a result, the amount of change ΔX shall be
It is only necessary to calculate ΔX' read by the potentiometer, and to translate the image on the storage device by that value using the image processing circuit 8.

〔Effect of the invention〕

As described above, according to the present invention, even when the height of the CT rack or the bed is changed after taking an X-ray fluoroscopic image, it is possible to set a tilted front section without re-measuring the X-ray fluoroscopic image.

[Brief explanation of the drawing]

Figure 1 is a general structural diagram of a CT system, Figure 2 is a diagram showing the principle and structure of how a CT rack takes X-ray fluoroscopic images, and Figure 3 is a diagram showing the display of X-ray fluoroscopic images and the displayed image. FIG. 4 is an explanatory diagram of an embodiment of the present invention, and FIG. 5 is a diagram of the configuration of the present invention. 8... Image processing circuit, 10... Storage device, 12...
・TV monitor display device, 13...operation console, 16.17
...potentiometer. 3rd day

Claims (1)

[Claims] 1. A CT device that has the function of capturing and displaying an X-ray fluoroscopic image for positioning for tomography, and the ability to specify the position of the tomographic plane to be measured and the inclination angle of the gantry on the displayed image; It has a function to read and store the bed height at the time of X-ray fluoroscopic image acquisition, and when the bed height is changed after X-ray fluoroscopic image acquisition, the amount of change from the previously memorized bed height is read and the A DT device characterized by having a function of translating and displaying an X-ray fluoroscopic image by an amount corresponding to the difference.