JPH0779957A - Radiographic diagnostic apparatus - Google Patents

Abstract

PURPOSE:To provide a supporting device controlled by three axes which is capable of constantly showing the upright image even if the rotary angles of the three axes are changed by arbitrary degrees. CONSTITUTION:The radiographic diagnosis apparatus holds a rotation adjusting means 48, which is applied for the radiograhic diagnostic apparatus having the supporting apparatus 40 controlled by three axes, and is a method to conduct the rotation adjusting of the image to be observed when the first to third arms of 46, 44 and 42 driven around the three axes are rotated by arbitrary degrees from the reference position by determing the rotation adjustment angle phi of the image to be observed base on the rotation angle 7 from the reference position for the first arm 46, the rotation angle beta from the reference position for the second arm 44, and the rotaition angle alpha from the reference position for the third arm 42.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray diagnostic apparatus, especially X-ray diagnostic apparatus.
The present invention relates to rotation correction of an observation image when a line generator or the like is mounted on a holding device that controls three axes.

[0002]

2. Description of the Related Art In an X-ray diagnostic apparatus, an X-ray generator for irradiating a subject with X-rays and an X-ray generator are arranged so as to face the X-ray generator, and the X-rays transmitted through the subject are detected and optically detected. An image intensifier that outputs an image and a TV camera that converts the optical image into a video signal and outputs a perspective image of the subject are mounted, and the X-ray generator and the image intensifier are provided. There is known a three-axis control holding device that rotates about three axes orthogonal to each other while maintaining a relative position with the TV camera.

A schematic structure of this holding device is shown in FIG. In FIG. 3, the holding device 40 is connected to the X-ray generator 10, the image intensifier 20 provided to face the X-ray generator 10 with the subject 15 in between, and the image intensifier 20. The mounted TV camera 30 and independently rotates around three axes orthogonal to each other about the arm center O. FIG. 3 shows a schematic processing block of a signal output from the TV camera 30 in addition to the holding device 40. The video signal output from the TV camera 30 is A /
The digital signal is converted into a digital signal by the D converter 32, desired image processing is performed by the image processing device 34, converted into an analog signal by the D / A converter 36, and displayed on a display unit 38 such as a display. . The rotation correction unit 48 corrects the rotation of the arm and the like, which will be described in detail later.

The first rotation axis is a rotation axis which is orthogonal to the plane including the arm 42 and passes through the arm center. When the arm 42 slides with respect to the arm support column 44, the holding device 40 is moved to the first rotation axis. Rotates in the direction indicated by arrow α. This rotation angle is hereinafter referred to as “arm slide angle (using symbol α)”. The second axis of rotation is the arm post 44, which rotates in the direction of arrow β. Hereinafter, the rotation angle of the second rotation shaft will be referred to as "arm main rotation angle (using symbol β)". The third rotation shaft is the support column 46 of the main body of the holding device 40, and rotates in the direction of arrow γ. Hereinafter, the rotation angle of the third rotation shaft will be referred to as a "support column rotation angle (using symbol γ)".

In the three-axis control holding device 40 as described above, an image of the subject 15 obtained when the holding device 40 is at the reference position is called an "upright image", and the angle of each rotation axis at that time is 0. (Ie, α = β = γ = 0 °).

In this case, the holding device 40 is conventionally used.
Is rotated by an arbitrary angle about the above first to third rotation axes, the rotation correction unit 48
The TV camera 30 (to be exact, the camera head of the TV camera, but for the sake of simplicity, the TV
It is called a camera. The same applies hereinafter) is controlled. That is, for example, even when the arm 42 is inserted from the head side of the subject 15, or even when the arm 42 is inserted from the side of the subject 15, the subject 1
It is controlled so as to obtain an upright image of the subject 15 by rotating the TV camera 30 in an angle φ equal to the column rotation angle γ and in a direction indicated by an arrow φ so that the perspective images of 5 are oriented in the same direction. .

However, in the above conventional technique, the remaining two angles of the holding device 40, that is, the arm slide angle α and the arm main rotation angle β are not taken into consideration. Therefore, when only the support column 46 is rotated, an upright image is obtained, but when the rotation shaft other than the support column 46 is rotated, the image related to the rotation is not corrected, and thus the image is upright. Image may not be obtained. That is, when the remaining two axes are rotated at an arbitrary column rotation angle γ,
Since the upright image cannot be obtained due to the rotation correction of the TV camera 30, even if the past reference image that was taken and the fluoroscopic image that is currently being taken are compared at the same clinical angle, they become twisted images, making comparative diagnosis difficult. There is a problem.

[0008]

As described above, in the conventional holding device, the reference image obtained in the past at a given rotation angle of the support column does not match the fluoroscopic image currently being observed, which makes comparative diagnosis difficult. There was a problem.

The present invention has been made based on the above circumstances, and provides an X-ray diagnostic apparatus having a three-axis control holding device that always obtains an upright image even if the rotation angles of the three axes are arbitrarily changed. The purpose is to provide.

[0010]

The present invention has taken the following means in order to solve the above problems. The X-ray diagnostic apparatus of the present invention includes a first arm rotatable about a first axis, a second arm rotatably attached to the first arm about a second axis, and a third axis. Holding means having a third arm slidably mounted on the arc of the circle, and an X-ray generator mounted on one end of the third arm for irradiating a subject with X-rays. An image intensifier that is attached to the other end of the third arm facing the X-ray generator, detects an X-ray transmitted through the subject, and outputs an optical image, and the image intensifier. Connected to the T to output the fluoroscopic image of the subject by converting the optical image into a video signal.
A V camera and display means for displaying the fluoroscopic image are provided, and in addition, the same image as that obtained when the first arm is at the reference position when the first arm is rotated by an arbitrary angle from the reference position. When the observed image is rotationally corrected to the image obtained from the direction, the rotation angle of the first arm from the reference position, the rotation angle of the second arm from the reference position, and the rotation angle of the third arm from the reference position. It is characterized by comprising a rotation correction means for performing rotation correction based on a rotation angle.

[0011]

As a result of taking the above-mentioned means, the following effects occur. In the rotation correction of the reference image and the fluoroscopic image (observation image), the rotation correction of the image (of the TV camera) is performed by considering the arm slide angle and the arm main rotation angle in addition to the column rotation angle which is considered in the conventional holding device. Since the camera head is rotated or rotated by image processing), an upright image is always obtained at the same clinical angle, and diagnosis by comparing the reference image and the fluoroscopic image becomes easy. And
Since the fluoroscopic image can be easily compared with the reference image, the diagnostic speed is increased and the diagnostic time is shortened. Since the image rotation correction is automatically performed without looking at the display unit, the X-ray exposure amount is reduced and the burden on the operator is reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An X-ray diagnostic apparatus normally detects an X-ray generator which irradiates an object with X-rays and an X-ray generator which is arranged so as to face the X-ray generator and which transmits the object and optically detects the X-rays. An image intensifier that outputs an image, a TV camera that converts the optical image into a video signal and outputs a perspective image of the subject, and a perspective image of the subject that is output from the TV camera are displayed. And display means.

In the above-mentioned X-ray diagnostic apparatus, the X-ray generator, the image intensifier, and the TV camera are mounted, and these devices center on three axes orthogonal to each other while maintaining their relative positions. There is an X-ray diagnostic apparatus having a holding device that rotates independently with respect to each axis. Since the schematic structure of this holding device is the same as that described in FIG. 3, the illustration thereof is omitted, and the details of the present invention will be described with reference to FIG.

Further, as described above, the holding device 40
Independently rotates about three axes orthogonal to each other about the arm center O, and the three rotation axes are defined as follows similarly to the above. The first rotation axis is an axis orthogonal to the plane including the arm 42, and the holding device 40 rotates around the first rotation axis by the arm 42 sliding with respect to the arm support column 44. This rotation angle is hereinafter referred to as “arm slide angle (using symbol α)”. The second axis of rotation is the arm post 44. Hereinafter, the rotation angle around the second rotation axis will be referred to as “arm main rotation angle (using symbol β)”. Third
The axis of rotation of is the support column 46 of the main body of the holding device 40. Hereinafter, the rotation angle around the third rotation axis will be referred to as a "column rotation angle (using symbol γ)".

In addition, in the three-axis control holding device 40 as described above, an image of the subject 15 obtained when the holding device 40 is at the reference position is referred to as an "upright image", and an image of each rotation axis at that time is called. The angle is 0 ° (that is, α = β = γ = 0
°).

The details of the image rotation correction when the arm slide angle α, the arm main rotation angle β and the column rotation angle γ are changed will be described below. First, when the column rotation angle γ = 0 °, the image is always upright even when the arm slide angle α and the arm main rotation angle β are changed, so that it is not necessary to correct the image rotation.

However, when the column rotation angle γ ≠ 0 °, the image is not upright, so it is necessary to correct the image rotation. Therefore, when performing X-ray fluoroscopy at a certain clinical angle (γ ≠ 0 °), the TV when changing the arm slide angle α, the arm main rotation angle β, and the column rotation angle γ
By properly setting the rotation angle φ of the camera 30 (hereinafter, referred to as “image rotation angle”), an upright image can always be obtained.

The present invention discloses image rotation means for accurately setting the image rotation angle φ when the arm slide angle α, the arm main rotation angle β and the column rotation angle γ are arbitrarily changed as described above. To do.

The image rotation angle φ according to the present invention is obtained as follows. However, in the following equation, the unit of angle is "degree". First, using the arm slide angle α, the arm main rotation angle β, and the column rotation angle γ, X = sinα · cosγ−sinβ · cosα · sinγ (1) is set.

In the equation (1), when X = 1 or X = -1, the image rotation angle φ becomes a value that does not depend on the arm slide angle α, and (a) when X = 1, φ = 180− β (when γ = 0) (2) φ = β (when γ ≠ 0) (3) (b) when X = −1 φ = 180−β (when γ = ± 180) (( 4) φ = β (when γ ≠ ± 180) (5) The value of the image rotation angle φ is obtained.

In the equation (1), when X ≠ ± 1, when γ · cos β> = 0; φ = φ ₀ (6) When γ · cos β <0; φ = −φ ₀ (7) However, the image rotation angle φ is obtained by φ ₀ = cos ⁻¹ {(cos γ · cos α + sin β · sin α · sin γ) / (1-X ² ) ^1/2 } (8).

A case where the alignment is specifically performed by the above means will be described. In this case, the clinical angle (CRA, LA
Consider the case where the diagnosis is performed with O) = (30 °, 60 °).

It is assumed that images are obtained at two mechanical angles (α, β, γ) with respect to the above clinical angle.
Here, the first image is A (30 °, 60 °, 0 °) and indicates the reference image, and the second image is B (64 °, −8 °,
60 °) and shows a perspective image.

Therefore, the rotation angles of the first image and the second image are as follows: reference image; α = 30 °, β = 60 °, γ = 0 ° Perspective image; α = 64 °, β = -8 And γ = 60 °.

In this embodiment, when the conventional alignment method is used, since φ = γ, the image rotation angle φ
Becomes 60 °, rotate the TV camera 30 by 60 °,
Align images. This state is shown in FIG. In FIG. 1, (a) shows a reference image, and (b) shows a perspective image after rotation correction of the perspective image. As is apparent from FIG. 1, conventionally, when aligning images, the image rotation angle φ is set in consideration of the column rotation angle γ, but other arm main rotation angles β and column rotation angles are set. Since the influence of the two axes of γ is not taken into consideration, accurate alignment cannot be performed.
Therefore, even if the image rotation correction is performed as shown in FIG. 1B, an upright image cannot be obtained, and the reference image and the perspective image do not match.

An example of setting the image rotation angle φ when the means of the present invention is used is shown below. As described above, the reference image; α = 30 °, β = 60 °, γ = 0 ° Perspective image; α = 64 °, β = −8 °, γ = 60 ° Images have been obtained. When this image is matched, the reference image is the column rotation angle γ = 0 °
Therefore, the image is upright and correction by image rotation is unnecessary. Next, consider the perspective image.

From the equation (1), the value of X is X = sin64.cos60-sin (-8) .cos64.sin60 =
Since 0.502 is obtained and X ≠ ± 1, φ ₀ can be obtained by using the equation (8).
To calculate.

Φ ₀ = cos ^-1 {(cos60 · cos64 + sin (-
8) · sin64 · sin60) / (1-X 2) 1/2} = 82.
6 and γ · cosβ = 60 · cos (−8) = 59> 0, the image rotation angle φ is φ = 82.6 by using the equation (6), and by rounding off the decimal point, , The image rotation angle φ = 83 °. FIG. 2 shows a state in which the image rotation correction is performed using the image rotation angle φ thus obtained. In FIG. 2, (a) shows a reference image and (b) shows a perspective image after rotation correction of the perspective image. From FIG. 2, according to the present invention, it is confirmed that both the reference image and the perspective image are displayed upright and the images of both are in agreement. That is, according to the present invention, the image displayed on the display unit 38 that displays the reference image and the perspective image can be always displayed as an upright image.

Therefore, according to the present invention, an upright image can always be obtained regardless of whether the arm slide angle α or the arm main rotation angle β changes in addition to the column rotation angle γ. can get. Further, since both the reference image and the fluoroscopic image are always upright, the diagnosis by comparing the reference image and the fluoroscopic image becomes easy, and the speed of the diagnosis is high and the time is short.

In addition, since the rotation correction of the image is automatically performed without looking at the display unit 38, the X-ray exposure amount is reduced and the burden on the operator is reduced. In the above example,
Although the means for obtaining the upright image by rotating the TV camera 30 by the image rotation angle has been described as the image rotation, the image processing device 34 is not limited to this, and the display unit 38 is provided.
The rotation correction may be performed by rotating the image at the time of displaying the image. Besides, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the scope of the present invention.

[0031]

According to the present invention, the following effects can be obtained. In the rotation correction of the reference image and the fluoroscopic image (observation image), the rotation correction of the image (of the TV camera) is performed by considering the arm slide angle and the arm main rotation angle in addition to the column rotation angle which is considered in the conventional holding device. Since the camera head is rotated or rotated by image processing), an upright image is always obtained at the same clinical angle, and diagnosis by comparing the reference image and the fluoroscopic image becomes easy. And
Since the fluoroscopic image can be easily compared with the reference image, the diagnostic speed is increased and the diagnostic time is shortened. Since the image rotation correction is automatically performed without looking at the display unit, the X-ray exposure amount is reduced and the burden on the operator is reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a display example of a reference image and a perspective image on a display unit when image rotation correction is performed by a conventional technique.

FIG. 2 is a diagram showing a display example on a display unit of a reference image and a perspective image when image rotation correction according to the present invention is performed.

FIG. 3 is a diagram showing a schematic configuration of a holding device for three-axis control in an X-ray diagnostic apparatus.

[Explanation of symbols]

10 ... X-ray generator, 15 ... Subject, 20 ... Image intensifier, 30 ... TV camera, 32 ... A / D converter, 34 ... Image processing device, 36 ... D / A converter, 38
Display unit, O ... Arm center, 40 ... Holding device, 42 ... Arm, 44 ... Arm support, 46 ... Support, 48 ... Rotation correction unit, α ... Arm slide angle, β ... Arm main rotation angle, γ ...
Column rotation angle.

Claims (1)

[Claims] 1. A first arm rotatable about a first axis, a second arm rotatably attached to the first arm about a second axis, and a circular arm about a third axis. Holding means having a third arm slidably attached to the second arm on an arc, an X-ray generator attached to one end of the third arm for irradiating a subject with X-rays, and the X-rays An image intensifier which is attached to the other end of the third arm facing the generator and detects an X-ray transmitted through the subject to output an optical image; and an image intensifier connected to the image intensifier, T for converting an optical image into a video signal and outputting a fluoroscopic image of the subject
An X-ray diagnostic apparatus including a V camera and a display unit that displays the fluoroscopic image, obtained when the first arm is at the reference position when the first arm rotates an arbitrary angle from the reference position. When rotationally correcting the observed image to an image obtained from the same direction as the image, the rotation angle of the first arm from the reference position, the rotation angle of the second arm from the reference position, and the reference of the third arm. An X-ray diagnostic apparatus comprising rotation correction means for performing rotation correction based on a rotation angle from a position.