JPH11188032A - Medical diagnostic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect contact between image intensifier of a digital substruction angiography device and a subject with noncontact. SOLUTION: Driving high frequency coil 21 is placed on the opposite side of a subject of image intensifier 3 and driven connected with high frequency generator 22. High frequency search coil 23 is put concentrically inside the driving high frequency coil 21 and connected with Q value measuring device circuit 24. When the image intensifier 3 comes near a subject, the value of Q changes since the human body as a subject is a dielectric, and signal level is lowered which is given by the driving high frequency coil 21 and transmitted and received by the high frequency search coil 23. The Q value measuring device circuit 24 detects the signal level of receiving by the high frequency search coil 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical diagnostic apparatus provided with a movable body that can approach a subject, and more particularly, to a medical diagnostic apparatus attached to the movable body to detect contact or proximity of the movable body to the subject. Safety mechanism.

[0002]

2. Description of the Related Art A medical diagnostic apparatus having a moving body which can approach a subject, for example, an X-ray tube as X-ray generating means, an imaging means comprising an image intensifier and a TV camera, and a DSA (Digital Subtraction Angiography) that includes digital image processing means for digitizing a video signal and extracts only a portion (for example, a blood vessel) where a contrast agent exists by digitally performing subtraction between images. In the apparatus, since the X-ray tube and the imaging means are supported opposite to each other so as to approach the subject, contact detection means for detecting contact with the subject is provided as a safety measure for ensuring safety of the subject. ing.

FIG. 2 is a schematic diagram of a DSA device provided with contact detecting means. In FIG. 2, a subject M is supported on a bed top 1 of a bed, and an X-ray tube 2 and an imaging unit 5 including an image intensifier 3 and a TV camera 4 sandwich the subject M. For example, the object M is supported by the C-arm 6 so as to sandwich the object M therebetween, and is attached to the C-arm holding mechanism 7 so as to be rotatable around the body axis of the object M (direction A in the drawing). The C-arm holding mechanism 7 is attached to the stand 8 so as to be rotatable in the body axis direction of the subject M (direction B in the drawing). The video signal of the X-ray fluoroscopic image from the TV camera 4 is transmitted to the monitor 10 via the digital image processing means 9.
A fluoroscopic image is displayed. The digital image processing means 9
As is well known, an A / D converter for converting a video signal from the TV camera 4 into digital image data stores a mask image (an image before injection of a contrast agent) and a live image (an image after injection of a contrast agent). And an arithmetic unit for obtaining a blood vessel image by performing a subtraction process.

When the C-arm 6 is rotated in directions A and / or B in order to perform angiographic imaging from various directions with the DSA apparatus having the above configuration, the X-ray tube supported by the C-arm 6 2 or the image intensifier 3 of the imaging means 5 comes into contact with the subject M or the top plate 1 supporting the subject M, thereby damaging the subject M or causing the image intensifier 3, X There is a possibility that the wire tube 2 may be damaged. For this purpose, the DSA apparatus is provided with a contact detecting means as a safety device, and the contact detecting means is provided on the image intensifier 3 which is usually a heavy object and which is likely to be close to the subject M during imaging. Have been.

[0005] As shown in FIG. 3, the contact detecting means 11 comprises a movable frame 12 movably supported by a helical spring or the like on a surface of the lower part of the image intensifier 3 facing the subject M,
A microswitch fixed to a lower portion or a side portion of the image intensifier 3 and energized by the movable frame 12
The movable switch 12 is configured to be in contact with the subject M and to be biased regardless of the direction in which the movable frame 12 is displaced upward, laterally, or the like.

Therefore, when the image intensifier 3 is rotated from the position shown in FIG. 2 in the direction a and / or b (see FIG. 2) during diagnosis, the movable frame 12 comes into contact with the subject M, As a result, the movable frame 12 is displaced, for example, in the direction indicated by the dotted arrow C in FIG. 3 (upward), and the micro switch 13 is biased. it can.

[0007]

As described above, since the conventional contact detecting means detects a minute displacement caused by the contact of the moving frame with the subject by the microswitch, the lower end of the moving frame is the subject. It is indispensable that a movable body such as an image intensifier is in a proximity position to come into contact with the subject, or that there is a danger of contact, that is, it is essential that the movable frame contacts the subject, It is unsanitary and may pose some danger to the subject. -There is naturally a limit in positioning the moving body close to the subject. There is a problem.

In view of the above, it is an object of the present invention to detect an approaching state between a moving body and a subject without contact and a danger of contact and to position the moving body as close to the subject as possible. It is an object of the present invention to provide a medical diagnostic apparatus including a contact detecting means.

[0009]

In order to achieve the above object, a medical diagnostic apparatus according to the present invention is provided with a high-frequency excitation coil and a high-frequency search coil on at least a surface of a mobile object facing a subject. And a measurement circuit for detecting a change in the Q value of the high-frequency coil due to the movement of the moving object, or a reception signal level of the high-frequency search coil based on the change in the Q value.

The high frequency coil for excitation is driven by a high frequency generator of several + MHz, and the high frequency signal emitted from the high frequency coil for excitation is received by the high frequency search coil. For the signal received by the high frequency search coil, the measurement circuit measures the Q value of the high frequency coil or the received signal level due to a change in the Q value. Since the human body as the subject is a dielectric, when the high-frequency coil approaches the subject, the Q value of the high-frequency coil deteriorates according to the distance between the two. The deterioration of the Q value is measured as a change in the return loss, and the Q value measured by the measurement circuit, or the received signal level of the high frequency search coil based on the change in the Q value, causes the moving object to approach the subject. Can be detected in a non-contact manner.

Further, since the exciting high-frequency coil and the high-frequency search coil can be formed in a sheet shape by a printing technique, the moving body can be positioned very close to the subject without protruding from the lower surface of the moving body. it can. In addition,
If the change in Q value with respect to the distance between the high-frequency coil and the subject or the change characteristic of the received signal level based on the change in Q value is obtained in advance, and the Q value or the received signal level is converted into the distance, the movement will occur. Positioning the body at a position at a predetermined distance to the subject, or issuing an alarm signal when the moving body is moved to a dangerous proximity position where it contacts the subject, or in the case of an electric drive system In this case, it is possible to stop and avoid contact with the subject.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of a main part. Reference numeral 3 denotes an image intensifier, which is supported by a C-arm (not shown) similarly to the conventional apparatus shown in FIG. Is rotatable in the body axis direction.

Reference numeral 20 denotes a contact detecting means which is a main part of the present invention. Reference numeral 21 denotes a high-frequency excitation coil disposed on the outer peripheral edge of the lower surface of the image intensifier 3 facing the subject.
It is connected to a high frequency generator 22 for generating a sine wave of several + MHz. Reference numeral 23 denotes a high-frequency search coil, which is disposed concentrically inside the excitation high-frequency coil 21 and connected to a Q-value measuring circuit 24 comprising an amplifier and a detector.

Next, the operation of the embodiment apparatus having the above configuration will be described. First, the excitation frequency, circuit constants, and the like are set so that the Q value of the high-frequency coil is good when the image intensifier 3 is at a position farther from the subject and the high-frequency coils 21 and 23 are not affected by the subject. Keep it. In this state, the high frequency search coil 23 efficiently transmits the high frequency signal emitted from the high frequency coil 21 for excitation, and the Q value measurement circuit 24 detects the high signal level as a high signal level.

When the image intensifier 3 rotates around the body axis of the subject and in the body axis direction of the subject and enters the region affected by the conductive body of the subject, the high frequency coil Q value is inferior. The degree of deterioration of this Q value is
In general, it is proportional to the distance between the high-frequency coil and the subject, and deteriorates as the high-frequency coil approaches the subject. Therefore, the signal transmitted to the high frequency search coil 23 decreases as the image intensifier 3 approaches the subject, and this is measured by the Q value measurement circuit 24 as a decrease in the received signal level.

Thus, the approach of the image intensifier 3 to the subject (human body) can be detected in a non-contact manner. Therefore, the image intensifier 3 measures in advance the signal level or Q value that should not approach the subject any more, and uses it as a threshold value. When the threshold value is reached, the Q value measurement circuit 24 outputs If a signal is issued and the alarm is activated by the output signal, the operator can be notified that the image intensifier 3 should not be rotated, or can be stopped in the case of electric drive.

Further, the high-frequency coil disposed on the surface of the image intensifier 3 facing the subject can be formed by a thin film technology in the field of semiconductors, and if it is used, the image intensifier 3 can be positioned closer to the subject. It is possible to do. In the above-described embodiment, the high-frequency coil is provided on the surface of the image intensifier facing the subject. However, the high-frequency coil may be provided on the side peripheral surface of the image intensifier.

In the embodiment, the X-ray tube and the image intensifier are supported by the C-arm so as to sandwich the subject M, but may be supported by another support mechanism. The means can also be attached to an X-ray tube.

Further, in the embodiment, the DSA apparatus has been described as an example. However, the present invention can be applied to contact detection of a medical diagnostic apparatus having a moving body such as a scintillation camera apparatus which may come into contact with a subject. Further, a Q meter can be used as a Q value measuring circuit of the high frequency coil.

[0020]

According to the medical diagnostic apparatus of the present invention, it is possible to detect the approach of a moving body and a subject and the danger of contact without contact, and to arrange the moving body close to the subject. Becomes possible. In addition, since it is non-contact, it is sanitary and safe.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of one embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of a conventional DSA device.

FIG. 3 is a schematic view of an image intensifier provided with a conventional contact detection unit.

[Explanation of symbols]

3: Image intensifier 20: Contact detection means 21: High frequency coil for excitation 22: High frequency generator 23: High frequency search coil 24: Q value measurement circuit

Claims (1)

[Claims] 1. A medical diagnostic apparatus provided with a moving body that can approach a subject, wherein a high-frequency excitation coil and a high-frequency search coil are provided on at least a surface of the moving body facing the subject. A medical diagnostic apparatus comprising: a measurement circuit for detecting a Q value of a high-frequency coil due to movement of a moving body or a reception signal level of the high-frequency search coil based on a change in the Q value.