JPS637211Y2 - - Google Patents

Description

[Detailed description of the invention] This invention uses a tomography apparatus, in particular, scans a predetermined tomographic plane of a subject with radiation, for example, an
The present invention relates to a so-called computer tomography apparatus that constructs an image of a linear absorption coefficient distribution in a predetermined tomographic plane by processing the obtained data using a Fourier transform method or the like.

When performing tomography of a subject with this type of tomography device, the angle at which the tomography is taken with respect to a predetermined reference line set on the subject has important clinical significance. . For example, in tomography of a human head, a line connecting the eyes and ears of a subject is used as a reference line (generally referred to as the OM line), and the tomographic plane to be tomographically imaged is determined with respect to this reference line OM line.

Therefore, in this type of tomography apparatus, it is possible to accurately set a tomographic plane at a desired angle with respect to the reference line on the subject prior to tomography, and to produce a tomographic image cut at the set desired angle. It is necessary to be able to accurately set the position of the subject's head or the direction of the X-ray beam, that is, the inclination angle of the frame that holds the X-ray source and X-ray detector facing each other, so as to obtain the following.

However, at present, to set the tomographic plane when performing tomography with this tomography device, the desired tomographic plane relative to the OM line is determined by applying a protractor or similar directly to the subject's head, and the angle is read.
In reality, the position of the subject's head or the direction of the radiation beam is adjusted accordingly to set the radiation scanning plane.

Therefore, the shape of the subject's head is not flat.
The desired angle of the OM line or the tomographic plane to be tomographically scanned relative to it cannot be accurately read, and even if the angle is accurately read, the head of the subject must be adjusted so that tomographically scanned at that angle is possible. It is difficult to accurately adjust the position of the section or the direction of the radiation beam, the reproducibility is poor, and the operation of setting the tomographic plane is extremely troublesome and requires a long time.

In view of the above, this invention projects a linear index indicating a tomographic plane onto the subject, and the radiation of the linear index is adjusted in accordance with a desired tomography angle with respect to a predetermined reference line on the subject. By providing a projector that can change the angle with respect to the scanning plane and matching the linear index set at this angle with the reference line on the subject, the tomographic plane can be set at a desired angle with respect to the reference line on the subject accurately and quickly. It is an object of the present invention to provide a tomography apparatus capable of performing the following functions.

Therefore, according to this invention, the linear index of the projector is tilted, and the angle between it and the radiation scanning surface determined by the radiation beam direction is set to a desired angle with respect to the reference line, and this set linear index is By simply aligning the reference line on the subject with the reference line, a tomographic plane at a desired angle with respect to the reference line can be automatically set accurately, easily, and quickly.

This invention will be explained below with reference to embodiments shown in the drawings. Note that in the embodiment, an X-ray source is used as the radiation source.

In FIGS. 1 and 2, the X-ray beam emitted from the X-ray tube 3 toward the subject 2 lying supine on the top plate 1 is directed to the X-ray detector 4 arranged opposite to the X-ray tube 3. Therefore, the X-rays are detected as transmitted X-rays of the subject 2, and the X-ray tube 3 and X-ray detector 4 are aligned with the height axis (body axis) of the subject 2.
X Direction perpendicular to _B (direction of arrow A in Figure 1)
In FIG. 2, the scanner is configured to move in a direction perpendicular to the plane of the drawing to scan a desired cross section. Furthermore, the X-ray tube 3 and the X-ray detector 4 are configured to be able to rotate around an axis O ₁ (normally, this axis O ₁ coincides with the body axis X _B ), and the In the example, the scanning mechanism and rotation mechanism are also shown as a frame 5. The frame 5 is rotatably supported on a support shaft 7 via a support shaft 6 so as to be tiltable with respect to the body axis _XB . Reference numeral 8 in the figure denotes a head support for supporting the head of the subject 2, which is provided at the end of the top plate 1, and is pivoted around an axis _O2 , and is configured so that it can be fixed at any rotational position. ing. Further, 5' is an opening formed in the frame 5 into which the head is inserted.

The above configuration is well known as this type of computer tomography apparatus, and in order to collect data regarding the transmitted X-ray intensity at each part within a predetermined tomographic plane with this apparatus,
A combination of movement (scanning) of the X-ray tube 3 and X-ray detector 4 in the direction of arrow _A in FIG. After scanning, the X-ray tube 3 and the X-ray detector 4 are scanned in the opposite direction by rotating them by a predetermined angle, for example, 1 degree, and in this way, the X-ray tube 3 and the X-ray detector Scanning of the X-ray tube 3 and X-ray detector 4 is repeated every time the instrument 4 is rotated by a predetermined angle, and the X-ray tube 3 and the X-ray detector 4 are rotated around the subject 2 at a predetermined angle (180° or
By rotating the X-ray beam by 240 degrees, the X-ray beam can be scanned completely within a given tomographic plane.

The transmitted X-ray intensity of each part within the tomographic plane due to scanning at this time is detected by the X-ray detector 4, and its output is sent to the A/D
After being converted to a digital signal through a converter,
The signal is sent to a digital signal processing circuit such as a computer, undergoes predetermined signal processing such as Fourier transform, and displays a two-dimensional distribution of X-ray absorption coefficients on a CRT or the like to reconstruct a tomographic image. Note that the A/D converter, digital signal processing circuit, etc. are omitted from the figure because they are not directly related to the gist of this invention.

9 is a reference line (for example, OM line) on the subject 2
This is a projector that projects a linear index for indicating a tomographic plane at a desired angle with respect to the object, and in this embodiment, it is a projector that projects a fan-shaped beam 10 as shown in FIG.

Therefore, the fan-shaped beam 10 is projected onto the projection plane onto the subject 2 as a linear index 10'.

This projector 9 can project a fan-shaped beam 10 onto the subject 2 along the inclined surface (side surface of the frame) from the side of the inclined surface including the support shaft 6 of the frame 5, and the fan-shaped beam 10 projected by the projector 9 It is rotatably held on a bracket 11 fixed to the center of the side surface of the frame 5 so that the angle formed between the surface 10'' of the X-ray tube 3, that is, the tomographic plane X of the apparatus can be changed (tilted). Note that O ₈ indicates the rotation axis of the projector 9.

Furthermore, as shown in FIG. 3, the bracket 11 has an angle θ formed between a linear index 10' projected onto the subject 2 by the projection fan beam 10 of the projector 9 and the tomographic plane (radiation scanning plane) X of the apparatus. An angle scale 12 is provided to indicate the angle, and a reading line 13 thereof is provided on the projector 9.

The angle scale 12 and the reading line 13 are such that when the reading line 13 reaches 0° on the angle scale 12,
Surface 1 of the fan-shaped beam 10 projected by the projector 9
0'', that is, the linear index 10' and the tomographic plane (radiation scanning plane) X of the apparatus are set to be parallel to each other.

Next, the configuration device described above performs an operation for setting a tomographic plane having a predetermined angle with respect to the reference line during head photography.
The case where the OM line is set as the reference line will be explained.

First, determine the angle of the tomographic plane to be obtained with respect to the OM line, and let this angle be θ. Rotate the projector 9 to adjust this angle θ to the angle scale 12 and reading line 1.
Set in 3.

Therefore, the plane 10'' of the fan-shaped beam 10 projected by the projector 9 and the tomographic plane (radiation scanning plane) of the device
X forms θ as shown in FIG.
Normally, the frame 5 is positioned perpendicular to the body axis _XB , as shown by the two-dot chain line in the figure. 2 as 10 ₁ '.

Next, with the fan-shaped beam 10 projected onto the subject 2, the frame 5 is rotated around the axis 6, and the linear index ₁₀₁ ' projected onto the subject 2 is aligned with the eye of the subject 2. Match the OM line O-M connecting the ears. Second
The figure shows a state in which the linear indicator 10' is aligned with the OM line OM.

In addition, instead of rotating the frame 5, only the head holder 8 is rotated around the axis _O2 , and the linear index ₁₀₁ '
The OM lines OM may be made to match.

In this state, the tomographic plane T of the subject 2 is parallel to the tomographic plane (radiation scanning plane) X of the device, and the tomographic plane (radiation scanning plane) X of the device is parallel to the reference line OM line O.
−M and an angle θ. Therefore, in this set state, by moving the subject 2 by a predetermined amount into the opening 5' of the frame 5 and setting it, and scanning as described above, a tomographic plane T having a predetermined angle θ with respect to the OM line can be obtained. A tomographic image will be obtained.

In addition, in the above embodiment, the projector 9 is used as an optical sight.
is provided at the center of the frame 5, but it may be located above or below the center position and project the fan-shaped beam from an oblique direction to project the linear indicator.

Further, in the embodiment, a fan-shaped beam is projected from the projector, but a parallel beam condensed into a straight line may also be used. In this case, it is necessary to use a linear light source as the light source.

In addition, in the embodiment, the floodlight was fixed to the frame, but the floodlight was placed in a separate location from the frame so that it could be rotated to a predetermined position, and moved in the same direction in conjunction with or synchronized with the tilting operation of the frame. The same action and effect can be obtained even if the angle is rotated.

Furthermore, in the embodiment, this invention was applied to a computer tomography apparatus that applies linear scanning motion and rotational motion to the X-ray tube and X-ray detector to collect data regarding the intensity of transmitted X-rays at various parts within the tomographic plane. The present invention can also be applied to a tomography apparatus in which a fan-shaped beam is emitted from a tube, the X-rays transmitted through the object are detected by multiple X-ray detectors, and data is collected only by rotational movement.

As described above, this device is equipped with a light projector that projects onto the test subject a linear indicator that indicates a tomographic plane at a desired angle with respect to a preset reference line (for example, the OM line), and the projector's linear indicator Since the linear indicator is configured to be tiltable with respect to the radiation scanning plane, the linear indicator is tilted and the angle formed between it and the radiation scanning plane is set to a desired tomographic angle with respect to the reference line, and the linear indicator with this angle set is By aligning with a predetermined reference line on the subject, a tomographic plane at a desired angle with respect to the reference line can be automatically set.

Therefore, when setting a tomographic plane, the tomographic plane can be set accurately, easily, and quickly because the tomographic plane is optically indicated by a projector without the need for measurement using a protractor or the like as in the conventional method. The device has a simple configuration and provides various effects such as not causing any hindrance to the movement of the subject or the operation of the device.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an embodiment of this invention, Fig. 2 is an enlarged side view of Fig. 1, which also serves as an explanatory diagram of the operation, and Fig. 3 is a schematic diagram showing an embodiment of this invention.
The figure is an enlarged view of the main part of FIG. 1...Top plate, 2...Subject, 3...X-ray tube, 4
. . . X-ray detector, 5 .
10... Fan-shaped beam, 10... Linear index, 11...
...Bracket, 12...Angle scale, 13...Reading line.

Claims (1)

[Claims for Utility Model Registration] 1. A radiation source and a radiation detector arranged opposite to each other with a subject in between, the radiation source and the radiation detector being rotated around the body axis of the subject. In a tomography apparatus that scans a desired tomographic plane with radiation and collects data regarding the intensity of transmitted radiation at each part within the tomographic plane, a projector projects a linear index indicating a tomographic plane onto a subject. a support mechanism that rotatably supports the projector so that the linear indicator of the projector can be tilted with respect to the radiation scanning surface; the projector and the support that indicate the angle of inclination of the linear indicator with respect to the radiation scanning surface; An angle indicating mechanism consisting of an angle scale and an angle reading line provided on the mechanism is provided, and the projector is configured to rotate in relation to an operation of tilting the radiation scanning surface with respect to the body axis of the subject. Characteristic tomography equipment. 2 The projector supports the radiation source and the radiation detector in a tiltable manner, and uses a support mechanism provided on the frame to tilt the radiation scanning surface with respect to the body axis of the subject, so that the radiation scanning surface can be tilted with respect to the axis parallel to the tilt axis of the frame. The tomography apparatus according to claim 1, wherein the tomography apparatus is rotatably supported at the center.