JP2000004397A - X-ray diagnostic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cost and the size of a lens system in an X-ray diagnostic equipment. SOLUTION: This equipment is provided with a camera device 17, and a lens system 21 which is arranged between the camera device 17, and the output fluorescent lamp face 19 of an X-ray image tube and introduces a visible image projected on the output fluorescent face 19 to the camera device. A diaphragm or a transmissivity adjusting filter controlling the light quantity of the visible image projected on the output fluorescent face at displaying of the visible image projected on the output fluorescent face is positioned between lenses which constitute the lens system. Thus, the size and the cost of the lens system are reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an X-ray diagnostic apparatus comprising an X-ray image tube and a television camera.
X to TV camera while allowing wide variation of line intensity
The present invention relates to an X-ray diagnostic apparatus capable of deriving a line image.

[0002]

2. Description of the Related Art An X-ray image tube has an input phosphor screen, a photocathode formed on the surface of the input phosphor screen, an output phosphor screen disposed opposite to the input phosphor screen, an input phosphor screen and an output phosphor screen. A focusing electrode disposed near the tube wall between the surfaces for accelerating and focusing the photoelectrons emitted from the input phosphor screen; and a focusing electrode disposed near the output phosphor screen and emitted from the input phosphor screen and focused by the focusing electrode. It consists of an anode for accelerating photoelectrons and a vacuum envelope for holding them in a vacuum.

In the above-mentioned X-ray image tube, X-rays that have passed through a subject, that is, a human body as an observation target, are converted into visible light by an input phosphor screen, and converted into photoelectrons by a photocathode on the input phosphor screen. The light is focused and accelerated by an electrostatic electron lens system including a focusing electrode and an anode, and is irradiated on an output phosphor screen.

[0004] Photoelectrons from the photocathode illuminated on the output phosphor screen are converted into a visible light image by the output phosphor screen, and are visible as visible images from outside the output phosphor screen.
The X-ray diagnostic apparatus is an apparatus in which an image pickup device such as a solid-state image pickup device, that is, a CCD camera, is integrally disposed on an output fluorescent screen of the above-described X-ray image tube using a lens system. Can be seen through.

As a method of integrally disposing the lens system on the output fluorescent screen, there is a method of disposing the lens system by using a mounting member called "C mount". The “C mount” is available as a single lens in a state where it is formed integrally with the lens system in advance.

However, when a single lens system using a C mount is used, it is difficult to improve the optical performance of the single lens. For this reason, in the X-ray diagnostic apparatus positioned at a higher rank, a first lens system having a focal length of, for example, about 100 mm and a first lens system having a focal length of, for example, about 33 mm are provided between the output fluorescent screen of the X-ray image tube and the CCD camera. The second lens system is arranged, the output image of the output fluorescent screen of the X-ray image tube is once converted into parallel light by the first lens system, and the image is formed on the imaging surface of the CCD camera by the second lens system. Widely used.

In such an X-ray diagnostic apparatus which is positioned at a higher rank, the amount of X-rays incident on the X-ray image tube is, for example, X-ray fluoroscopic observation or angiography (Digital Angiogra
phy Subtraction), the degree of light emission of the output image output from the output phosphor screen of the X-ray image tube, that is, the brightness, varies between the darkest case and the brightest case. , About 1000 times.

As described above, in order to enable imaging by a CCD camera with respect to brightness that changes over a wide range,
It is required to adjust the amount of light incident on the imaging surface of the CCD camera within a certain range. For this reason, in many cases
A stop and a light amount adjusting mechanism, which is a transmittance adjusting mechanism, are provided at a portion where the output image between the first lens system and the second lens system is treated as parallel light.

These light quantity adjusting mechanisms play a role of adjusting the light intensity of the output image condensed by the first lens system to the sensitivity of the CCD camera.
A larger aperture is required than the lens diameter of the lens on the entrance side of the lens system. That is, when the output image of the output phosphor screen of the X-ray image tube is, for example, 30 mm and the aperture ratio of the second lens diameter is, for example, 0.95, the diameter required for the aperture is about 35 mm. .

However, a diaphragm having an outer diameter of about 35 mm and capable of realizing a light amount ratio of 1: 1000 is not commercially available and needs to be specially developed and manufactured. For this reason, the price of the entire optical system is increased. Further, a driving device and the like required for operating the diaphragm, that is, for changing the size of the aperture of the diaphragm are also likely to be large, and there is a problem that the whole device becomes large.

[0011]

As described above, a diaphragm capable of realizing a light amount ratio of 1: 1000 is difficult to obtain, and even if it is available, it is very expensive. For this reason, a method of increasing the aperture ratio of the second lens diameter can be easily analogized, but in this case, the utilization rate of the light intensity of the output image of the X-ray image tube is reduced, and the sensitivity of the diagnostic apparatus as a whole is reduced. A problem arises that cannot be raised. In addition, if the X-ray dose incident on the X-ray image tube is increased in order to increase the sensitivity, the exposure to the human body to be observed is increased.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the cost required for a lens system and to operate a filter, which is a light amount adjusting mechanism, in an X-ray diagnostic apparatus by making it possible to use a widely used diaphragm. An object of the present invention is to provide an X-ray diagnostic apparatus capable of reducing the size of the apparatus and the diagnostic apparatus as a whole.

[0013]

SUMMARY OF THE INVENTION The present invention has been made based on the above-mentioned problems, and has a focusing electrode provided between an input phosphor screen and an output phosphor screen integrally formed with a photocathode and both phosphor screens. X-ray image tube having a vacuum envelope for holding the anode and the anode in a vacuum, and a camera provided in contact with an output fluorescent screen of the X-ray image tube and taking a visible image output on the output fluorescent screen An X-ray diagnostic apparatus comprising: a device and a lens system disposed between the camera device and the output phosphor screen, and guiding a visible image projected on the output phosphor screen to the camera device, wherein the lens system includes: When guiding the visible image projected on the output phosphor screen to the camera device, a diaphragm or a transmittance adjusting filter for controlling the light amount of the visible image projected on the output phosphor screen is provided between the lenses. X-ray diagnostic device

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic diagram illustrating an outline of an X-ray diagnostic apparatus according to an embodiment of the present invention.

As shown in FIG. 1, an X-ray diagnostic apparatus 1
Is an X-ray generator 11 that generates X-rays, and an X-ray image that enhances and converts an X-ray, that is, an X-ray image from the X-ray generator 11 that has passed through a subject O, for example, a human body, into a visible light image A tube 13, a monitor device 15 for monitoring an output image converted into a visible light image via the X-ray image tube 13 without using a recording medium such as a film, and a monitor device 1
Camera device 1 that captures an output image of X-ray image tube 13 and outputs an electric image signal to display an output image converted into a visible light image by X-ray image tube 13 for 5
7 are provided.

An output image of the output fluorescent screen 19 of the X-ray image tube 13 is transmitted to a CCD of a CCD camera of the camera apparatus 15 by a lens system, ie, an image forming optical system 21 provided between the camera apparatus 17 and the fluorescent screen 19. The image is projected on the imaging surface of the imaging device at a predetermined magnification. The visible light image projected on the imaging surface of the CCD image sensor is subjected to predetermined image processing by an image processing device (not described in detail) and displayed on the monitor device 15.

FIG. 2 shows an example of the configuration of an imaging optical system 21 provided between the output fluorescent screen 19 of the X-ray image tube 13 and the camera device 17 in the X-ray diagnostic apparatus 1 shown in FIG. It is a schematic diagram.

As shown in FIG. 2, the imaging optical system 21
Is a first lens system 23 located on the side of the output fluorescent screen 19 of the X-ray image tube 13 and an extension of the optical axis of the system of the first lens system 23, on the camera device 17 side. The second lens system 25 located, and the transmittance adjusting mechanism 27 located between the first lens system 23 and the second lens system 25
And a diaphragm 29 provided between arbitrary lenses in a lens group constituting the second lens system 25. The transmittance adjusting mechanism 27 includes a filter (not shown) whose transmittance is changed according to the input voltage, and a driving device that supplies a driving voltage.

The first lens system 23 has a focal length set to, for example, 100 mm, includes, for example, seven lenses of five groups, and is a visible light that is an output image output to the output fluorescent screen 19 of the X-ray image tube 13. The image is converted into parallel light and guided to the transmittance adjusting mechanism 27. The size of the output image output to the output phosphor screen is 30 mm in diameter.

When the imaging area of the CCD imaging device has a diameter of about 10 mm, the second lens system 25 has, for example, six elements in six groups, a focal length of 33 mm, and an aperture ratio of 0.9.
5 Accordingly, the diameter of the lens provided on the transmittance adjusting mechanism 27 side of the second lens system 25 is approximately 35 mm.

As described above, the stop 29 of the imaging optical system 21
Is provided between the third lens and the fourth lens of the second lens system 25, for example, so that the diameter of the diaphragm 29 is
Compared to a case where the diaphragm 29 is located between the first lens system 23 and the second lens system 25, about 35 mm to 20 m
m. The position where the diaphragm 29 is arranged is determined by the design of the lens, and may be any position as long as a desired diaphragm diameter can be obtained.

This makes it possible to use, as the stop 29, a general small stop commercially available in the market. In addition, a stop that is easily available in the market can be used as the stop incorporated in the lens system. For example, when the stop is damaged, the waiting time for obtaining the stop is reduced.

FIG. 3 is a schematic diagram showing another embodiment of the imaging optical system 21 shown in FIG. As shown in FIG. 3, the imaging optical system 21 includes an output fluorescent screen 19 of the X-ray image tube 13.
A first lens system 23 positioned on the side of the first lens system 23, a second lens system 25 positioned on the camera device 17 side on the extension of the optical axis of the system of the first lens system 23, The transmittance adjusting mechanism 27 provided between arbitrary lenses of the lens groups constituting the second lens system 25, and the diaphragm 29 located between the first lens system 23 and the second lens system 25. Consists of That is, the example shown in FIG. 3 is different from the example shown in FIG. 2 in that the positions of the diaphragm 29 and the transmittance adjusting mechanism 27 are replaced.

As described above, by disposing the transmittance adjusting mechanism 27 between, for example, the third lens and the fourth lens of the second lens system 25, the filter of the transmittance adjusting mechanism 27 The size can be reduced from about 35 mm to about 20 mm as compared with the case where the transmittance adjusting mechanism 27 is provided between the first lens system 23 and the second lens system 25.

As a result, the drive voltage required to operate a drive device (not shown) for driving the filter of the transmittance adjusting mechanism 27 can be reduced, for example, from 24 V to 12 V.
That is, the power required by the driving device is approximately １ ／.
Becomes Further, the size, that is, the capacity of the driving device is also reduced. The response speed is also improved by reducing the size of the filter.

FIG. 4 is a schematic diagram showing still another embodiment of the imaging optical system 21 shown in FIGS. As shown in FIG. 4, the imaging optical system 21 includes the X-ray image tube 13.
First lens system 23 located on the side of the output phosphor screen 19
And on the extension of the optical axis of the first lens system 23,
Second lens system 25 located on the side of camera device 17
And a transmittance adjusting mechanism 27 provided between arbitrary lenses in the lens group constituting the second lens system 25, and a diaphragm 29 located near the transmittance adjusting mechanism 27. That is, the example shown in FIG.
And the aperture 29 are arranged in the second lens system 25.

According to this configuration, the size of the diaphragm 29 is reduced, as described above with reference to FIG. 2, so that the cost required for the diaphragm 29 is reduced. FIG.
As described above, the size of the filter of the transmittance adjusting mechanism 27 and the capacity of the driving device are reduced.
The output visible light image is transmitted as parallel light between the first lens system 23 and the second lens system 25 in accordance with the change in the position of the adjusting mechanism 27, its driving device, and the diaphragm 29. Since the section to be performed can be shortened, the problem that the amount of peripheral light decreases is also improved. Therefore, the imaging optical system 21
Is reduced, and the cost of the camera device 17 is reduced. Thereby, the cost of the whole X-ray diagnostic apparatus 1 is also reduced.

[0028]

As described above, according to the present invention,
In an X-ray diagnostic apparatus, the size and cost of a lens system for guiding a visible light image, which is an output image output on an output fluorescent screen of an X-ray image tube, to a camera apparatus so that the image can be captured by the camera apparatus are reduced. . In addition, a stop that is easily available in the market can be used as the stop incorporated in the lens system. For example, when the stop is damaged, the waiting time for obtaining the stop is reduced. As a result, if the X-ray diagnostic apparatus fails, the time during which the apparatus cannot be used is reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an X-ray diagnostic apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an example of a lens system incorporated in the X-ray diagnostic apparatus shown in FIG.

FIG. 3 is a schematic view showing another embodiment of the lens system shown in FIG. 2;

FIG. 4 is a schematic diagram showing still another embodiment of the lens system shown in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... X-ray diagnostic apparatus, 11 ... X-ray generator, 13 ... X-ray image tube, 15 ... Monitor device, 17 ... Camera device, 19 ... Output fluorescent screen, 21 ... an imaging optical system, 23 ... a first lens system, 25 ... a second lens system, 27 ... a transmittance adjusting mechanism, 29 ... a diaphragm.

Claims (5)

[Claims] An X-ray image tube having a vacuum envelope for holding an input phosphor screen, an output phosphor screen, and a focusing electrode and an anode provided between the two phosphor screens integrally formed with a photocathode in a vacuum. And provided near the output phosphor screen of the X-ray image tube,
A camera device for photographing the visible image projected on the output phosphor screen; and one or more cameras disposed between the camera device and the output phosphor screen for guiding the visible image projected on the output phosphor screen to the camera device. An X-ray diagnostic apparatus comprising: a lens system, wherein the lens system converts the visible image projected on the output fluorescent screen when the visible image projected on the output fluorescent screen is guided to the camera device. An X-ray diagnostic apparatus comprising a diaphragm or a transmittance adjusting mechanism for controlling the amount of light between lenses. 2. A lens system comprising: a first lens system for converting a visible image projected on an output phosphor screen of an X-ray image tube into parallel light; and a camera device for converting the parallel light from the first lens system into a camera device. And a second lens system for guiding the first lens system.
2. The X-ray diagnostic apparatus according to claim 1. 3. The lens system according to claim 1, wherein the diameter of the filter of the diaphragm or the transmittance adjusting mechanism is smaller than the diameter of the exit lens of the first lens system of the lens system.
2. The X-ray diagnostic apparatus according to claim 1. 4. A filter according to claim 1, wherein the aperture or the filter of the transmittance adjusting mechanism is located between any lenses of the lens group constituting the second lens system.
An X-ray diagnostic apparatus according to any one of the preceding claims. 5. The filter according to claim 1, wherein the aperture and the filter of the transmittance adjusting mechanism are located between arbitrary lenses of a lens group constituting the second lens system.
An X-ray diagnostic apparatus according to any one of the preceding claims.