JPS6272326A - X-ray 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] [Technical field of invention] The present invention relates to an X-ray CT apparatus.

[Problems with technical limitations of the invention] When attempting to observe changes over time in a certain part of a subject using an X-ray C1-device, a conventional device that does not have a slip ring mechanism requires a very short gap V as possible. The object is scanned during the scan time, and then the object is scanned again after a pause period between scans. With this conventional device, after performing one scan, the gantry is usually decelerated, stopped, and accelerated in the reverse rotation direction to perform the next scan, and this requires no slip ring mechanism and a cable handling mechanism. It is based on having.

Such conventional apparatuses have a problem in that scan pause times are long and it is often impossible to obtain image data sufficient to reconstruct a tomographic image of a subject at an arbitrary point in time.

In addition, in the conventional apparatus described above, the inter-scan pause time is variable, and the time at which the temporal change of the phenomenon occurring in a specific part of the subject to be observed becomes slow is usually reached at the third point.
As shown in the figure, an attempt is made to lengthen the pause time between scans and avoid unnecessary scans depending on the temporal changes.

Furthermore, as shown in Figure 4, projection data from 360° directions on the subject is obtained in one scan, but images of a specific region can also be reconstructed from 360° unvortexed projection data (180° plus beam angle of the X-ray source), so
As shown in FIG. 4, it is possible to reconstruct three images taken at different times in one scan.

There is a method of sequentially updating and displaying a series of images obtained at the timings shown in FIGS. 3 and 4 on a display means such as a TV monitor in the order in which these images were obtained. This is called cine display.

By the way, in conventional cine display, the update time interval of images is set to be constant, and no consideration is given to the fact that the time interval at which a large number of images to be updated and displayed are obtained is not necessarily constant but variable.

As a result, when observing a displayed image using a display means, a significant distortion in the sense of time occurs between the image obtained by actually scanning and the displayed image.

In other words, considering the reconstruction timing and the display timing of an image as shown in FIG. Although it is possible to almost match the timing and display timing, the reconstruction timing and display timing are different for the third reconstructed image of the first scan and the first reconstructed image of the second scan. This is a significant problem and results in the display being displayed at a much faster timing than the actual timing of reconfiguration.

[Object of the Invention] The present invention has been made in view of the above-mentioned circumstances, and it is possible to obtain a tomographic image of a subject at a desired time, and also to match the timing of image reconstruction and the timing of display, so that both images can be obtained. It is an object of the present invention to provide an X-ray CT apparatus that does not cause distortion in the sense of time.

[Summary of the Invention] The outline for achieving the above object is to irradiate the subject with X-rays from an X-ray source that can continuously rotate around the subject, and to collect information on the transmission of X-rays transmitted through the subject. In an X-ray CT apparatus that obtains a tomographic image of a subject based on the X-ray CT apparatus, there is provided a storage section that continuously stores the X-ray transmission information, and an arbitrary rotation angle of the X-ray source based on the X-ray transmission information stored in this storage section. an image reconstruction unit that cuts out information sufficient to reconstruct one image each based on the point in time and performs reconstruction processing on each of them to obtain a series of reconstructed images, and continuously moves around the subject. In an X-ray CT apparatus that irradiates a subject with X-rays from a rotatable X-ray source and obtains a tomographic image of the subject based on information on the transmission of X-rays transmitted through the subject, the X-ray transmission information is continuously transmitted. A storage unit stores data in the storage unit, and from the X-ray transmission information stored in this storage unit, information sufficient to reconstruct one image each is cut out based on an arbitrary point in the rotation angle of the X-ray source, and each of these is reconstructed. an imaging memory that stores the reconstructed image data for each piece of reconstructed image data at a predetermined address together with original time information without indicating when each piece of reconstructed image data was reconstructed, and the original time information. A display control means that updates and overrides the display of the reconstructed image at time intervals corresponding to the original time information is set based on the information and the address on the image memory! I) It is a sign.

[Embodiments of the invention] An embodiment of the present invention will be described below with reference to FIG.

The embodiment shown in FIG. 1 has an X-ray detector 3 and an X-ray detector 3 disposed facing each other with the subject M in the center in a country having a slip ring 1 and configured for rotation.
It is equipped with a data collection section 4 that collects X-ray transmission information ((transmission X-ray section, transmission X-ray data) detected by the ray detector 3, and includes a slip ring 1 from a high-pressure generator 5 to the front X-ray tube 2.
It is designed to supply high pressure for the X-ray beam through the

Additionally, this device includes a storage section 6 that captures the output of the data collection section 4 via the slip ring 1, and
an image reconstruction unit 7 that performs tomographic image reconstruction processing of the subject M based on the X-fight transmission information stored in the image reconstruction unit 7;
A magnetic disk 8 stores the tomographic data output from the magnetic disk 8 along with original time information indicating which time the data was used, a large-capacity image memory 9 stores the tomographic data stored in the magnetic disk 8, memory 9
a display control means 11 that takes in tomographic image data from a computer and sends it to a display means 10 such as a TV monitor at a predetermined timing; and an input means 12 such as a keyboard that sends predetermined human input information to the display control means 11; A CPU (Central Proc) controls each part of this device described above.
cssingUnit>13.

The display control means 11 is configured to provide an address for storing the original time information stored in the magnetic disk 8 and the address of each reconstructed image data on the image memory 9 via the CPU 13.
a time storage unit 14; an update time generation unit 15 that generates an update time Ti of the display image on the base display unit 10 based on the input information from the input unit 12; and the address/time storage unit 14 and the update port). an address generator 16 that controls the image memory 9 to sequentially send out reconstructed image data corresponding to each tomographic image based on the output of the image memory 9 in accordance with the update time Ti; It has a display controller 17 that converts constituent image data into an image signal and sends it to the display means 10.

Next, the operation of the above-mentioned apparatus will be explained by taking as an example a case where a tomographic image of the subject M at a desired time point is obtained.

X-ray source 2. The X-ray detector 3 and data collection unit 4 are connected to the subject M.
High pressure is applied from the high pressure generator 5 to the X-ray source 2 through the slip ring 1 while continuously rotating
X-rays are continuously exposed at .

The rotation period at this time is defined as a king as shown in FIG.

The X-ray transmission information obtained by passing through the subject M through the continuous irradiation described above is detected by the X-ray detector 3, further collected by the data collection section 4, and then distributed to the storage section 6 via the slip ring 1. be included.

After completing the scan on the subject M, the image reconstruction unit 7
Controlled by the PU, one rotation (2π
) are cut out, and image reconstruction processing is performed on each of them. In this case, the X-ray transmission information for reconstructing one tomographic image is not necessarily limited to the rotation angle of 2π of the X-ray source 2, etc.;
(fan angle of X-ray source 2).

Furthermore, the X-ray transmission information may be the output of the data acquisition section 4 as it is, and in this case, the image reconstruction section 7 may be equipped with various preprocessing functions in advance. Furthermore, by providing a sufficiently high-speed preprocessing function, it is possible to
Preprocessing may be performed on the data sent from the data collection section 4 during the scanning, and the processing results may be stored in the magnetic disk 8 as projection data.

The reconstructed image data that has been reconstructed for each image in the image reconstruction section 7 in this manner is written to the magnetic disk 8. The CPU 13 reads reconstructed image data for one rotation from the magnetic disk 8 with reference to an arbitrary point in time, and writes it to the image medium 9. The reconstructed image data is then sent to a display controller 17, where it is converted into an image signal and sent to the display means 10. Display means 1
0 uses this image signal to display each tomographic image for diagnosis.

Through the above-described series of operations of this apparatus, it is possible to obtain a tomographic image of the subject M at a desired time.

Next, an explanation will be given of the operation when this device creates a proportional relationship between the timing of image reconstruction and the timing of display on the display means 10. Incidentally, the procedure up to the time when the X-ray transmission information is taken into the image reconstruction section 7 is the same as that described above, so a detailed explanation thereof will be omitted.

A series of reconstructed image data processed by the image reconstruction unit 7 is stored in the magnetic ice cream 8 together with original time information indicating at what point in time collected data was used, and furthermore, these reconstructed image data are stored at the original time. The information is stored one after another at a predetermined address in the image memory 9.

The number of each reconstructed image corresponding to each of these reconstructed image data is i (i is a positive integer), and the reconstructed image data from the time when the reconstructed image data immediately before the certain reconstructed image data is obtained) q The following explanation will be given assuming that the elapsed time up to the point in time is ti.

The address/time storage section 14 of the display control means 11 is a CPU.
The elapsed time ti of the reconstructed image data corresponding to the image number Qi on the image memory 9 and the address on the image memory 9 are stored in the address/time storage section 14.

At this time, it is assumed that the reconstructed image with image number i is being displayed on the display means 10.

The operator operates the input means 12 to send information K (K is a constant that can be changed as appropriate) for updating the display image to the update time generating section 15. The update time generating section 15 is connected to the input means 12
An update time Ti (-Kti) for updating the display on the display means 10 is calculated based on the information K from , and is sent to the address generator 16.

The address generator 16 inputs the elapsed time t1 of the image of the first night and its address to the address/time storage unit 14.
At the same time, the update time Ti from the update time generator 15 is also fetched, and based on these, the address of the (i+1)th reconstructed image data is calculated, and this address is sent to the image memory 9 after the update time Ti has elapsed. This results in (
i+1) No. H reconstructed image data is displayed] Controller 1
7 and the display image on the result display means 10 is (i+
1) Updated to the th reconstructed image.

In this way, the reconstructed images on the display means 10 can be updated one after another at arbitrary intervals using the information k from the input means 12, and if the value of K is set to 1, the reconstructed images f - evening. A 1:1 correspondence can be established between the obtained timing and the update timing of the displayed image.

In this case, even if the update time Ti is set to 13 hours, which is quite short, in this device, the magnetic disk 8
Since there is no need to send the reconstructed image data from to the display control means 11 each time, and it is only necessary to change the address range of the image memory 9, it is possible to quickly update the display image.

The present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the invention.

For example, the CPU 13 saves the address and elapsed time ti of reconstructed image data corresponding to each image number i, calculates the update time Ti based on these, and after a predetermined elapsed time Ti elapses, the image memory 9 Alternatively, the access may be made to send reconstructed image data to be displayed.

In addition, if the elapsed time T: is extremely long, the CPU
13 control to create and display an interpolated image on the time axis from the i-th to (i+1)-th without waiting until the update time of the (i+1)-th display image can also reduce the sense of discontinuity. This is a useful variation for unaccompanied image display.

Roughly speaking, first a series of reconstructed image data is
It is also possible to create interpolated image data when storing it on the screen 9 and display it.

Further, as a useful modification of the present invention, there may be mentioned a gated image such as a heart rate synchronized image of the heart of the subject M.

Is this a combination of electrocardiogram waveforms and multiple X-ray CT scans? 1
After completing the scan, the CT scan data for a specific phase of the electrocardiogram is collected and reconstructed to obtain a series of CT images corresponding to each phase of the electrocardiogram. . In this case, images can be created at relatively narrow time intervals in the vicinity where the heart shape changes rapidly.

When displaying such images, images created at narrow time intervals by applying the present invention will be updated rapidly correspondingly, and images created at coarse intervals and at 5-interval intervals will be updated accordingly. If the displayed image is updated at long time intervals, it becomes possible to display the gate image without distortion of the sense of time.

= 15- What should be noted about this application example is that the update interval of the displayed image is not controlled depending on when the projection gator used to create the image is taken, but rather when the image is This is to control the update time interval of the displayed image depending on which time phase is meant.

Further, in the above-described embodiments, a case has been described in which a tomographic image is displayed by an X-ray CT apparatus, but the present invention is also applicable to other radiation CT apparatuses, ultrasonic CT apparatuses, and the like.

[Effects of the Invention] According to the present invention described in detail above, it is possible to obtain a tomographic image of a subject at a desired time, contributing to improvement in diagnostic ability, and also to detect changes in a specific region of a subject. X-ray C has great clinical significance as it can be displayed as an image without distorting the sense of time.
T device can be provided.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an example device of the present invention, Fig. 2 is an explanatory diagram showing the rotation period of the X-ray source, etc. in the same device, and the cutout timing of reconstructed image data, and Fig. 3 is a conventional diagram. FIG. 4 is an explanatory diagram showing scan timing in the apparatus. FIG. 4 is an explanatory diagram showing scan timing and composition timing of a reconstructed image in a conventional apparatus. 1...Slip ring, 2...X-ray tube, 3...X
Ray detector, 4... Data acquisition section, 5... High pressure generator, 6... Storage section, 7... Image reconstruction section, 8... Magnetic disk, 9... Image memory, 10... Display means, 11... Display control means, 12... Input means.

Claims (5)

[Claims] (1) X-ray CT, in which X-rays are emitted onto the subject from an X-ray source that can continuously rotate around the subject, and a tomographic image of the subject is obtained based on information on the transmission of X-rays that have passed through the subject. The device includes a storage unit that continuously stores the X-ray transmission information, and a storage unit that reproduces one image from the X-ray transmission information stored in the storage unit, with reference to an arbitrary point in the rotation angle of the X-ray source. An X-ray CT apparatus characterized by comprising an image reconstruction unit that extracts information sufficient for configuration and reconstructs each of these pieces of information to obtain a series of reconstructed images. (2) The X-ray transmission information is the amount of transmitted X-rays or the transmitted
The X-ray CT apparatus according to claim 1, which is ray data. (3) The transmitted X-ray information is the transmitted X-ray amount or transmitted X-ray information.
The X-ray CT apparatus according to claim 1, wherein line data is converted into projection data. (4) X-ray CT, in which an X-ray source that can continuously rotate around the subject irradiates the subject with X-rays, and a tomographic image of the subject is obtained based on information on the transmission of X-rays that have passed through the subject. The device includes a storage unit that continuously stores the X-ray transmission information, and a storage unit that reproduces one image from the X-ray transmission information stored in the storage unit, with reference to an arbitrary point in the rotation angle of the X-ray source. An image reconstruction unit that cuts out information sufficient for composition and reconstructs each of them, and a predetermined address along with original time information indicating when each piece of reconstructed image data was obtained. and a display control means for updating the display of the reconstructed image at time intervals corresponding to the original time information based on the original time information and the address on the image memory.
Ray CT device. (5) The X-ray CT apparatus according to claim 4, wherein the display control means has a function of creating an interpolated image based on reconstructed image data when updating the reconstructed image.