JPS6066729A - X-ray ct apparatus with body movement monitor - 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 the Invention] The present invention relates to an X-gan CT apparatus, X equipped with a body movement monitor device equipped with a device that automatically detects the body movements of the subject.
It relates to a line CT device.

[Technical background of the invention and its problems]

In conventional X-ray CT systems, the operator either directly observes the movements (body movements) of the patient being examined during X-ray exposure, or
Alternatively, a television camera is used to monitor the situation, and the operator makes a decision to stop the scan (stop X-ray exposure) or retake a specific slice (the slice when the human body succumbs).

This is because patient movement introduces artifacts in the reconstructed image, which significantly degrades the image.

By the way, in conventional monitoring of a patient's body movement by an operator, it is not possible to clearly determine quantitatively how much body movement has occurred before the scan should be stopped, and the decision to stop the scan may be delayed. In such a case, there is a risk that the patient will be exposed to unnecessary X-rays. In addition, the operator must keep a close eye on the patient during the scan, which places a heavy burden on the operator, and there is also a risk that the patient's body movements may be overlooked.

[Purpose of the invention]

The present invention was made in view of the above circumstances, and includes a body movement monitoring device that automatically detects the patient's body movements, reduces the burden on the operator, and prevents unnecessary X-ray exposure to the patient. The purpose is to provide an X-ray CT device.

[Summary of the invention]

The outline of the present invention for achieving the above object is to provide an
In an X-ray CT apparatus, the X-ray CT apparatus includes a radiation controller and a photographing means for photographing the subject, an alarm means for generating an alarm when a body movement of the subject occurs, and a frame for storing an output signal of the photographing means. At least two pieces of image data are compared based on the stored contents of the memory and the frame memory, and based on the comparison result, an alarm generation command signal is output to the alarm means, and an X-ray exposure command signal is output to the X-ray controller. The present invention is characterized by comprising a body movement detecting means capable of outputting a stop command signal.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an X-ray CT apparatus with a body motion monitor according to the present invention, and 2 is a gantry. 4 is the patient who is the subject, and 4 is the patient who is the subject 3.
This is a bed device that moves into an imaging hole (not shown). Reference numeral 1 denotes a photographing means for photographing the subject 3, which is composed of a television camera (ITV) 1a and an A/D converter 1b for converting the output (video signal) of the television camera 1a into a digital signal. , the video signal output from the television camera 1a is displayed on a display means (CRT display) 11.
The signal is displayed on a monitor, and is also input to a frame memory 7 disposed at a subsequent stage via an A/D converter 1b. This frame memory 7 has, for example, a memory capacity for two images (memories 7a, 7b), and its stored contents are transferred to a body movement detecting means (processor) 9 arranged at a subsequent stage. The body movement detection means 9 detects the body movement of the subject 6 based on the image data transferred from the frame memory 7, and the detection result is transmitted to the X-ray controller 5 and the alarm means 12. It's like a trap. The X-ray controller controls the X-ray exposure and the stop of X-ray exposure of the X-ray exposure means (not shown) in the gantry 2, and the alarm means 12 detects the occurrence of body movement of the subject 3, for example. A signal to notify the operator by sound or light. The operator console 10 is used to input various operation commands through operator operations.
The T-scan middle double signal is input to the X-ray controller 5, the A/D converter 1b, and the body movement detecting means 9. Note that the clock generation means 8 includes an A/D converter 1b and a frame memory 7.
and generates a synchronization signal to be input to the body movement detection means 9.

Next, the operation of the device configured as described above will be explained. The operator console 10 allows the operator to
When the start of T-scan is instructed, the frame in the gantry 2 is rotated by a mechanism (not shown), X-rays are emitted by an X-ray emitting means (not shown), and the CT scan is started. A CT scan intermediate signal indicating that the heavy lid is being scanned is inputted to the D converter 1b, the X-ray controller 5, and the body movement detecting means 9. The ITVIa constantly photographs the subject 3, and the video signal is displayed on the CRT display 11 and written into the frame memory 7 as digital image data via the A/D converter 1b.

Here, the data stored in the frame memory 7 is, for example, 128x128 pixels (pixe/) and 0
It is expressed with a brightness level of ~255 8 bits) (bit). In addition, the writing operation of the frame memory 7 starts with a specific time (
For example, i Q m5ec) after a pause, it is now written to the second memory, and then again after a specific time pause, it is written to the first memory.
are written to memory, and so on.

Next, the operation of the body movement detecting means 9 will be explained.

The body movement detecting means 9 uses, for example, the pause time of the writing operation of the frame memory 7 to write the memo U7a.

The data for two images 7b are read out, and the sum of the differences between the corresponding pixels is continuously calculated during scanning, and when the calculated value exceeds a specific value, an alarm generation command signal is output to the alarm means 12. The A/D converter 1b, the frame memory 7, and the body movement detection means 9 operate based on the synchronization signal output from the clock generation means 8, and their respective operations are synchronized in terms of timing. It is being

Next, the body movement detection algorithm of the body movement detection means 9 will be explained. As described above, the memory 7a of the frame memory 7 stores digital image data that is captured first, and the memory 7bK stores digital image data that is captured later. Here, if the image stored in the memory 7a is scene 1 (for example, FIG. 2A), and the image stored in the memory 7bK is scene 2 (for example, FIG. 2B), then the array of scene 1 is 5cx (1
-j) = 0~25 5 -... (S i = 1~128 j = 1~128.Similarly, the arrangement of scene 2 is 5c2(i,
j) ~0~255 -.-(2) i=1~128 j=1~12B. Therefore, the difference scene between scene 1 and scene 2 (Fig. 2 C) is expressed as 5ub(Lj) = 5c2(ilj) -8e, (i
lj)-(3), and furthermore, let be the "amount of variation".

Therefore, when the amount of variation m shown in the above equation (4) exceeds a preset specific value (M), the body movement detection means 9 assumes that a body movement has occurred in the subject 6, and issues an alarm. A command signal and a xis exposure stop command signal are output.

It goes without saying that the present invention is not limited to the embodiments described above, and that modifications can be made as appropriate within the scope of the gist of the present invention.

For example, in the embodiment described above, ITVI & was used, but the present invention is not limited to this, and any device that can photograph the subject 3 can be applied. Further, for example, in the case of a digital camera, the A/D converter 1b is naturally unnecessary.

Although the alarm means 12 in the above embodiment notifies the operator of the occurrence of body movement of the subject 60 by sound or light, the present invention is not limited to this, and may, for example, display the amount of body movement and stop X-ray exposure. It is also possible to leave it up to the operator's discretion as to whether or not this is the case.

In addition, as shown in FIG.
Rotates 60°, but fan beam angle α plus 180°
By rotating, a half-scan reconstructed image can be obtained. Therefore, when the body movement of the subject 30 occurs after scanning for the fan beam angle f9f80°, a reconstructed image may be automatically obtained by noof scanning.

In the embodiment described above, the memory capacity of the frame memory 7 was set to be the capacity for two images, but the memory capacity is not limited to this, and the memory capacity may be further increased. Moreover, the capacity can be set to one sheet. In this case, for example, as shown in FIG.
(capacity for one sheet) 15. Next, the image data of scene 2 is input via the A/D converter 1b, and at the same time,
Read the image data of scene 1 from the frame memory,
It may be configured to compare these in real time.

Furthermore, scene 1 may be updated at specific time intervals. That is, in the case of the above embodiment, even when the subject 3 moves very slowly, the scan is stopped (X-ray exposure is stopped).
Although this may occur, the effect on image quality when the subject 3 moves very slowly is small. In such a case, by updating scene 1 from time to time so that the time interval between scene 1 and scene 2 is, for example, 1 sec, it is possible to detect only sudden body movements that occur within 1000 seconds, and therefore, There is no possibility that the scan will be canceled even if the subject 3 moves very slowly.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to automatically detect the body movement of the subject (patient) and promptly stop X-ray exposure, thereby reducing the burden on the operator and It is possible to provide an X-ray CT apparatus with a body movement monitor that does not expose patients to unnecessary X-rays.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an X-ray CT apparatus with a body movement monitor according to the present invention; FIGS. 2A, B, and C are explanatory diagrams for explaining the operation of the apparatus shown in FIG. 1; 4 are an explanatory diagram and a block diagram, respectively, for explaining a modification of the apparatus shown in FIG. 1. 1... Photographing means, 3... Subject (patient), 5.
・・X-ray controller, 7・・Frame memory, 9・
...Body movement detection means (processor), 12...Alarm means.

Claims (1)

[Claims] In an X-ray CT apparatus, the X-ray CT apparatus includes an X-ray controller capable of controlling exposure and stop of X-rays emitted toward a subject, and a photographing means for photographing the subject. an alarm means that issues an alarm when a motion occurs; a frame memory that stores the output signal of the photographing means; and a comparison result of at least two images based on the stored contents of the frame memory. An alarm generation command signal is output to the alarm means, and X, ! is output to the X-ray controller. i! An X-ray CT with a body movement monitor, characterized by comprising a body movement detection means capable of outputting a radiation stop command signal.
Device,