JPH08280660A - Slip ring type x-ray ct apparatus - Google Patents

Abstract

PURPOSE: To provide a slip ring type X-ray CT apparatus by which a tomogram with less influence of noises can be obtd. CONSTITUTION: A fixed frame 6 forms a U-shaped storing part 20. A slip ring 7 and a brush 8 are stored in this storing part 20. As noises from a contact point between the slip ring 7 and the brush 8 are shielded thereby by the storing part 20 and there exists less possibility of transmitting of the noises to a detecting circuit 3 arranged behind the storing part 20, a signal can be obtd. from the detecting circuit with less noises than the conventional one and thereby a tomogram with less influences of noises can be obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slip ring type X which supplies power to an X-ray generation source and an X-ray detector detection circuit by a slip ring and a brush and takes out a signal from the detection circuit.
Slip ring relating to an X-ray CT apparatus, in particular, a slip ring that supplies power to an X-ray generation source and a slip ring that prevents signal noise (hereinafter, referred to as noise) that mixes in an X-ray detector and a detection circuit, generated from a contact point of a brush. The present invention relates to a formula X-ray CT apparatus.

[0002]

2. Description of the Related Art The structure of a conventional X-ray CT scanner will be described with reference to FIG. 5A is a front view of the scanner (a view of the scanner as seen from the insertion direction of the subject), and FIG. 5B is a sectional view taken along the line AA ′ of FIG. 5A.
A conventional signal transmission system having a scanner structure includes an X-ray tube 1 which is an X-ray generation source, an X-ray detector 2 which detects an X-ray from the X-ray tube 1 and outputs an analog electric signal, and an X-ray detector 2. A detection circuit 3 that amplifies an analog electric signal from the line detector 2 and outputs a digital electric signal, and an image processing apparatus 10 that processes the digital electric signal from the detection circuit 3 to obtain a tomographic image of the subject are provided. Was. Further, the rotating mechanism system of the scanner structure supports a rotating frame 4 supporting an X-ray detecting system including an X-ray tube 1, an X-ray detector 2 and a detecting circuit 3, and the rotating frame 4 via a rotating bearing 5. It had a fixed frame 6 for rotatably supporting it. Here, the rotary bearing 5 had a bearing structure.

By the way, taking out the digital electric signal from the detection circuit 3, the X-ray tube 1 and the X-ray tube.
The slip ring 7 and the brush 8 are used to supply power to the line detector 2 and the detection circuit 3. The slip ring 7 is a channel for extracting a digital electric signal from the detection circuit 3 and a channel for supplying power to the X-ray tube 1, the X-ray detector 2 and the detection circuit 3, respectively. And an insulator that separates each of these channels. Also, the slip ring 7
Was attached to the rotary frame 4 so as to be rotationally interlocked with the rotary frame 4. The brushes 8 corresponded to the respective channels of the slip ring 7. The brush 8 was arranged on the outer circumference of the slip ring 7 and was in contact with the outer diameter portion of the slip ring 7.

Further, the X-ray detection system is arranged so as to rotate outside the slip ring 7 and the brush 8 in contact with the outer circumference of the slip ring 7.

[0005]

In the prior art, the slip ring structure not only takes out the digital signal but also supplies a high voltage to the X-ray tube. Since the rotation trajectory of the slip ring is outside the slip ring structure, the X-ray detection system is provided on the outer periphery of the slip ring that supplies a high voltage to the X-ray tube, Since noise is received, if a digital electrical signal from the detection circuit of the X-ray detection system that has received this noise is subjected to signal processing to obtain a tomographic image of the subject, a tomographic image affected by noise will be obtained. was there. As a countermeasure for the above problem,
As shown in FIG. 5B, the noise shielding plate 11 was arranged in a cylindrical shape outside the slip ring and the brush.
However, since the rotating frame rotates, S in FIG.
As shown in, it was not possible to completely eliminate the gap between the rotating frame and the fixed frame. For this reason, since noise will jump from the slip ring structure to the X-ray detection system through this gap, there is a problem that it is not a fundamental solution to noise countermeasures. Therefore, in addition to the above measures, it is necessary to attach a noise shielding member to each part of the X-ray detection system, especially to the X-ray detector and the detection circuit. There was a problem.

The present invention has been made to solve the above problems, and its purpose is to provide a slip ring type X-ray CT capable of obtaining a tomographic image less affected by the noise.
It is to provide a device.

[0007]

The above object is to provide an X-ray generation source, an X-ray detector arranged to face the X-ray source, and a detection circuit for amplifying a detection signal from the X-ray detector into a digital signal. A rotating frame that supports an X-ray detection system, a fixed frame that rotatably supports the rotating frame via a rotary bearing, the X-ray generation source, the X-ray detector, and the detection circuit on the rotating frame. In a slip ring type X-ray CT apparatus having a slip ring and a brush for supplying each power source or extracting a signal from the detector circuit, the fixed frame forms an accommodating portion, and the slip ring and the slip ring are provided in the accommodating portion. This is achieved by accommodating the brush and installing the X-ray detection system behind the accommodating portion.

[0008]

The fixed frame forms an accommodating portion, the accommodating portion accommodates the slip ring and the brush, and the X-ray detection system is installed at the rear of the accommodating portion. Since noise from the contact points of the slip ring and the brush, which supplies power, is shielded by the accommodating portion, a signal from a detection circuit that is less affected by the noise is obtained, and the noise is detected by using this signal. It is possible to obtain few tomographic images.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings. FIG. 1 is a structural diagram showing a first embodiment of a slip ring type X-ray CT apparatus of the present invention, and FIG. 2 is a structural diagram showing the slip ring and brush of FIG.

First, the slip ring type X-ray CT of the present invention
A first embodiment of the device will be described with reference to FIG. FIG.
(A) is the front of the scanner (viewed from the insertion direction of the subject)
FIG. 1B is a sectional view taken along the line AA ′ of FIG.

The signal transmission system and the rotation mechanism system of the scanner structure of the present invention have the same structure as described in the prior art.

As shown in FIG. 1B, the fixed frame 6 forms a "U" -shaped accommodating portion 20. The slip ring 7 and the brush 8 are housed in the housing portion 20. Here, the material of the housing portion 20 is a conductive metal such as iron, copper, or an alloy containing these. Then, the housing portion 20
Is grounded to enhance the shielding effect.

Next, the slip ring structure will be described with reference to FIG. 2 (a) is a diagram showing a multi-channel slip ring structure, FIG. 2 (b) is a diagram showing an example of a mode of contact between the slip ring and the brush, and FIG. 2 (c) is a diagram showing an example of the brush. 2 (d) is a diagram showing an example of a brush different from that in FIG. 2 (c). As shown in FIG. 2A, the slip ring structure is a multi-channel routing ring 71 formed by various combinations of conductive metal surfaces such as copper and silver plated with gold, silver or copper, and these routing rings. An insulating ring 72 sandwiched between the path rings so as to insulate and isolate 71, and a brush 8 that contacts each channel of these path rings 71.
Consists of The contact between the slip ring 7 and the brush 8 is, for example, as shown in FIG.
Place the brush so that it contacts the inner circumference of the. Further, the brush 8 has a first conductor 81 made of a conductive metal such as gold, silver and copper, and a second conductor 82 made of a conductive carbon compound such as graphite and carbon fiber. There is. This is because even if the brush 8 side is worn, replacement is relatively easy. Further, the second conductor 82 of the brush 8 is shown in FIG.
As shown in (c), it may be formed in a leaf spring shape. Moreover, the second conductor 82 may be formed of a plurality of electric wires.

In the first embodiment, the fixed frame 6 forms the accommodating portion 20, and the slip ring 7 is formed in the accommodating portion 20.
And the brush 8 are housed, the noise from the contact point between the slip ring 7 and the brush 8 is shielded by the housing unit 20, and the X-ray detection is installed behind the housing unit 20. Since the noise is prevented from being mixed into the system, the S / N ratio of the detection circuit of the X-ray detection system with respect to the noise is improved, so that the object of the present invention of obtaining a tomographic image with less influence of the noise can be achieved.

Next, second and third embodiments will be described with reference to FIG. FIG. 3A is a diagram showing a second embodiment. Here, one side of the accommodation portion 20 is extracted and drawn. Moreover, since the components other than those described below are the same as those in the first embodiment, the description thereof will be omitted. In the structure of the second embodiment, if the fixed frame 6 as shown in FIG. 3 (a) is arranged in line symmetry with respect to the rotation center axis, the "U" -shaped accommodating portion 20 will be formed. . The slip ring 7 and the brush 8 are housed in the housing portion 20. According to the second embodiment having such a structure, since the structure is directly attached to the disc member 41 of the rotary frame 4, the object of the present invention can be achieved with a simpler structure than the first embodiment. it can.

FIG. 3B is a diagram showing a third embodiment. Here, one side of the accommodation portion 20 is extracted and drawn. Further, the description is omitted because it is the same as that of the first embodiment except what is described below. In the structure of the third embodiment, if the fixed frame 6 as shown in FIG. 3B is arranged line-symmetrically with respect to the central axis, the "0" -shaped accommodating portion 20 can be obtained.
Will be formed. The slip ring 7 and the brush 8 are housed in the housing portion 20. According to the third embodiment having such a structure, the structure is surrounded on three sides rather than on the grounded fixed frame 6 as in the first and second embodiments. Therefore, the object of the present invention can be achieved with a structure in which the effect of shielding noise is further enhanced.

Next, a fourth embodiment will be described with reference to FIG. FIG. 4 is a diagram showing a fourth embodiment. here,
The one side of the accommodation portion 20 is extracted and drawn. Further, since it is the same as the first embodiment except the one described below,
I will omit the explanation. In the structure of the fourth embodiment, if the fixed frame 6 as shown in FIG. 4 is arranged line-symmetrically with respect to the rotation center axis, the "U" -shaped accommodating portion 20 will be formed. The slip ring 7 and the brush 8 are housed in the housing portion 20. Here, the brush 8 is the slip ring 7
It is a conventional type that is installed on the outer peripheral portion of and contacts the outer peripheral portion of the slip ring 7. According to the fourth embodiment having such a structure, the object of the present invention is achieved without providing a mechanism for contacting the brush 8 with the inner peripheral portion of the slip ring 7 as in the first to third embodiments. Can be achieved.

In the method of forming the multi-channel slip ring of the first to third embodiments described above, the path ring and the insulating ring are alternately arranged, but a plurality of grooves are provided in the inner diameter portion. Alternatively, a thick hollow cylindrical insulator and a conductive ring fitted in the groove of the insulator may be used.

Modification of the embodiment described above,
It goes without saying that the combination can achieve the object of the present invention.

[0020]

Since the present invention has the above-described structure, noise from the contact points of the slip ring and the brush for supplying power to the X-ray generation source is shielded by the accommodating portion. It is possible to obtain a signal from the detection circuit that is less affected by noise and obtain a tomographic image that is less affected by noise by using this signal.

[Brief description of drawings]

FIG. 1 is a structural diagram showing a first embodiment of the present invention.

FIG. 2 is a structural diagram showing the slip ring and the brush of FIG.

FIG. 3 is a structural diagram showing second and third embodiments of the present invention.

FIG. 4 is a structural diagram showing a fourth embodiment of the present invention.

FIG. 5 is a structural diagram showing a conventional technique.

[Explanation of symbols]

 1 X-ray tube 2 X-ray detector 3 Detection circuit 4 Rotating frame 5 Rotating bearing 6 Fixed frame 7 Slip ring 8 Brush 20 Housing section

Claims (1)

[Claims] 1. An X-ray detection system comprising an X-ray generation source, an X-ray detector arranged to face the X-ray source, and a detection circuit for amplifying a detection signal from the X-ray detector into a digital signal. Rotating frame, a fixed frame that rotatably supports the rotating frame via a rotating bearing, power supply to the X-ray generation source, the X-ray detector, and the detection circuit on the rotating frame, or the detector. In a slip ring type X-ray CT apparatus having a slip ring and a brush for extracting a signal from a circuit, the fixed frame forms an accommodating portion, and the accommodating portion accommodates the slip ring and the brush, and A slip ring type X-ray CT apparatus in which an X-ray detection system is installed behind the housing.