JPS63313988A - Object to be inspected monitoring device for magnetic resonsnce imaging device - Google Patents

Abstract

PURPOSE:To save labor and to improve the reliability of the monitoring and the objectivity of discrimination reference by monitoring the motion of an object to be inspected by using a video signal from the TV camera of a monitoring device and informing a checker as necessary. CONSTITUTION:A video signal from the TV camera 2 undergoes a switch circuit 3 and is inputted to a line memory 4 and a comparator 9. The memory 4 consists of two banks(4a,4b), and data is written and read in/from the banks 4a, 4b alternately. A timing signal outputted from a circuit 6 controls the timing of a write/read in/from the memory 4, and simultaneously drives a gate circuit 8 to supply an output from the memory 4 to a comparator 9. Accordingly, the comparator 9 compares a signal in the last one field with a current signal in the desired area of the TV screen, and obtains the difference. A resulting difference signal is transmitted to an alarm 10 so that it 10 alarms is the checker a large difference when the magnitude of the difference signal exceeds a prescribed value.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a magnetic resonance imaging apparatus (hereinafter referred to as a magnetic resonance imaging apparatus).

The present invention relates to a device for monitoring the movement of a subject in a laboratory (abbreviated as “M-K”), and particularly relates to a subject monitoring device that automatically notifies when the movement of the subject exceeds a predetermined limit.

[Conventional technology]

In the M-box, a subject enters a gantry with a static magnetic field and undergoes an examination. For this reason, T
The condition of the subject is observed using a monitor device consisting of a V-camera and a monitor TV.

By the way, in MR1, the examination time is generally long.

Since it takes several minutes to several tens of minutes, the subject may move at one o'clock and the reconstructed image may be blurred. For this reason, conventionally, the examiner constantly monitored the movement of the subject on a monitor TV or the like, and when the movement was large, the test was immediately interrupted and the test was re-examined.

[Problem that the invention seeks to solve]

In the conventional technology, the inspector needs to constantly monitor during a long measurement time, which requires manpower, and simple monitoring tasks tend to overlook movement due to lack of concentration.

Furthermore, there are problems in that the criteria for determining where the current region of interest in photographing the subject is located and the degree of movement required to interrupt the examination vary depending on the examiner.

In place of the above-described artificial monitoring method, the present invention electrically monitors the movement of a subject by using a video signal from a TV camera of a monitoring device.

It is an object of the present invention to provide a subject monitoring device for MRI that can save the labor of an examiner and improve the reliability of monitoring and the objectivity of discrimination criteria by notifying the examiner when necessary.

[Means for solving problems]

The present invention sequentially captures a fixed amount of video signals having the same scanning area (in other words, a shooting area) from a TV camera of a monitoring device at predetermined time intervals, and generates two sets of fixed amount videos that are captured sequentially in time. The signals are compared one after another, and when the comparison result shows a mismatch exceeding a predetermined limit of the degree of mismatch, it is notified.

[Effect]

As described above, two sets of fixed amount video signals captured at different times are sequentially compared.

It is possible to follow and observe the presence or absence of movement of the subject. The comparison result will be a match (no signal) if there is no movement of the subject, and a mismatch (signal present) if there is movement. If the comparison result (comparison output signal) mismatches beyond the predetermined mismatch degree limit (
When the comparison output signal exceeds a predetermined threshold value),
By notifying this with a lamp, buzzer, etc., the examiner can know whether the subject is moving beyond a predetermined limit without constantly monitoring the subject, and the above-mentioned purpose is achieved.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an MRI subject monitoring device according to the present invention. In the figure, 1 is an MRI (magnetic resonance imaging apparatus) in which a subject (not shown) is placed in a gantry with a static magnetic field. Enter and undergo an examination. Reference numeral 2 denotes a TV camera of a monitor device, which photographs the subject on the bed in the gantry and converts it into a video signal for each scanning line. This video signal is similar to a video signal from an ordinary video camera, and is obtained by converting two-dimensional grayscale optical information into a time-series electric signal having, for example, 525 scanning lines. This video signal passes through the switch circuit 3 and is applied to the line memory 4 (4a, 4b) and the input of the comparator 8.

The line memory 4 consists of two banks (4a, 4b), and in the first TV field, one bank (for example, 4a) is used for writing, the other (4b) is used for reading, and the next T
In the V field, both sides (4a.

9. Reading and writing in 4b) are swapped. From then on, this is repeated, and so on.

The switch circuit 3 is provided for switching the banks (4a, 4b). 5 is an address generator that generates address signals for writing and reading the line memory 4;
It is reset by the synchronization signal of the TV camera 2 and generates an address signal synchronized with the scanning line. This address generator 5 is controlled by a position setting device 7. That is, the address generator 5.

A noteworthy part (region of interest) within the field of view photographed by the TV camera 2 is determined based on a signal from the part setting device 7.

It operates to generate an address signal corresponding to a scanning line of a video signal. Reference numeral 6 denotes a timing generator that generates write and read timing signals, which is controlled by the 1-position setting device 7 in the same way as the address generator 5, and when the scanning of the TV camera 2 hits a desired area of interest in the field of view. generating the timing signal; This timing signal controls the read/write timing of the line memory 4, drives the gate circuit 8, and connects the output of the line memory 4 to the comparator 9. As a result, the comparator 9 compares the current signal with the signal one field before in the desired region of interest on the TV screen, and calculates the difference. This difference signal is sent to the alarm 10, and when the magnitude of the difference signal exceeds a preset threshold value, a lamp is turned on, a buzzer is sounded, and the examiner is notified of this (when the subject is (i.e. movement exceeding the limit).

As a result of the above, the movement of the subject can be determined by one field on the TV screen (
It is detected every approximately aomsec), and can respond to moment-to-moment changes. This response time is the switch circuit 3
It is possible to provide an arbitrary response characteristic by changing the switching timing. Further, the region of interest of the subject can be set to any region within the field of view of the TV camera 2 using the body part setting device 7.

Note that in the above embodiment, a fixed amount of video signal is captured.

Although the comparison means is constituted by the circuit sections 3 to 9 in the figure, it is not limited thereto.

〔Effect of the invention〕

As described above, according to the present invention, the extent of the movement of the subject can be known through notification means such as an indicator light or a buzzer without the examiner constantly monitoring the movement of the subject. In addition, the area to be examined can be changed freely.

It is possible to grasp the amount of movement relatively quantitatively without overlooking movement or making judgment errors. As a result.

It is effective in saving the labor of the inspector and improving the reliability of monitoring and the objectivity of judgment criteria.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the apparatus of the present invention. 1... Magnetic resonance imaging device (MRI), 2...
・TV left camera 3...switch circuit, 4 (4a, 4
b)...Line memory, 5...Address generator, 6
...Timing generator, 7...Part setting device, 8...
・Gate circuit. 9... Comparator, 10... Notification device (notification means). Agent: Patent Attorney Katsuo Ogawa7・'TE''・【

Claims (1)

[Claims] 1. In a magnetic resonance imaging apparatus equipped with a monitor device that photographs a positioned subject with a TV camera and displays it on a monitor TV for monitoring, a certain amount of video signals with matching scanning areas are sent from the TV camera at predetermined time intervals. a fixed amount video signal capturing and comparing means for sequentially comparing two sets of fixed amount video signals that are sequentially captured and captured temporally before and after each other; 1. A subject monitoring device for a magnetic resonance imaging apparatus, comprising a notification means for notifying when a mismatch occurs.