JPS62204688A - X-ray diagnostic equipment - Google Patents

Abstract

PURPOSE:To obtain an excellent picture having no halation without using an X-ray compensation filter by providing a control means for setting and controlling the light shield region of a light shield means based on an output from a detection means. CONSTITUTION:In exposing X rays while all liquid crystals of a liquid crystal filter are turned off, a picture subjected to halation for parts B except the heart A is fetched into a picture memory 9 through an A/D converter 8 from a TV camera 6. Then a CPU 10 reads the memory 9 and detects the parts subjected to halation and its degree and the result is outputted to a liquid crystal controller 11 as a control signal to set the liquid crystal corresponding to the part subjected to halation and the on-timing T1. The liquid crystal group causing halation by the operation of the controller 11 is turned on after the time T1 elapses after pulse X-ray irradiation and the light shield region as shown in hatched lines is formed on the filter 3 and the luminous quantity passing through the region is decreased in a rate of T1/T2 (T2 is the ON time of pulse X-ray).

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention involves exposing an object to X-rays and
The present invention relates to an X-ray diagnostic device that converts rays into optical images and displays them.

(Prior art) Conventionally, digital x-ray diagnostic equipment has been used as an example of this type of
There is a fluorography device.

A digital fluorography device converts X-rays that have passed through an object into light using an image intensifier (hereinafter referred to as ■ and ■), and converts the optical image into an electrical signal using a TV camera. This TV camera stores electrons proportional to the amount of light exposure on the light-receiving surface, and converts them into electrical signals by sequentially scanning them, but the range of light that the TV camera can detect (dynamic range) is Because the area is so narrow, when extracting a single image, parts may become overexposed (halation) and cannot be detected. This is due to the difference in X-ray absorption of bones, organs, etc. of the subject. For example, when taking an r-ray of an organ, the diagonally shaded area A in Figure 5 is the heart. When adjusting the amount of light (that is, the amount of X-rays) so that the camera's dynamic range is about 70%, the area outside the heart (the area outside the shaded area) B causes halation, making it impossible to detect the image. Put it away.

Conventionally, in order to prevent this halation, an X-ray compensation filter that absorbs some of the X-rays outside the heart was placed in the area B outside the heart to make the light uniform throughout the screen. .

This situation is not limited to digital fluorography equipment, but also applies to other X-ray diagnostic equipment (for example, X-ray cine imaging equipment), and even when imaging other organs. I made a shaped X-ray compensation filter to correct it.

(Problems to be Solved by the Invention) However, adjusting this compensation filter requires complicated work to match the shape of the organ, and furthermore, adjustment work must be performed every time the eclipse shadow area or the eclipse shadow angle is changed. This is a factor that prevents the speed of examination by X-ray diagnostic equipment.

Therefore, the object of the present invention is the above.

It is necessary to solve these problems and provide an X-ray diagnostic apparatus that can obtain good images without halation without using an X-ray compensation filter.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a detection means for detecting an overexposed area on an optical image corresponding to a halation portion of a TV camera, and an output of an X-ray-light conversion means. A light shielding means for shielding an arbitrary area on a two-dimensional plane substantially orthogonal to an optical axis connecting the surface and an input surface of a TV camera, and a light shielding area of the light shielding means is set and controlled based on an output from the detection means. and a control means.

(Function) Since the X-ray diagnostic apparatus according to the present invention has the above configuration, it functions as follows.

That is, the detection means detects the halation part in the optical image, and a control signal based on the detection result automatically forms a light-shielding area of the light-shielding means in the halation part in the optical image, thereby reducing the amount of light in the halation part. automatically reduced.

(Example) The illustrated embodiment will be described below.

FIG. 1 is a schematic diagram showing a recess of a digital fluorography device with light shielding means attached thereto, and FIG. 2 is a block diagram thereof.

Reference numeral 1 denotes a subject, which is placed between an Xa tube 12 and an image intensifier (I>2).

The X-ray tube 12 has its irradiation time etc. controlled by the CPU 10, and the equipment 2 converts the X-rays that have passed through the subject 1 into an optical image.

Reference numeral 7 denotes an optical system consisting of a second lens 5 and a second lens 5, which forms the optical image obtained in 2 and 2 on a TV camera 6. The TV camera 6 stores electrons proportional to the amount of light exposure on its light-receiving surface, scans the electrons sequentially, and converts them into analog electrical signals.

Reference numeral 3 denotes a liquid crystal filter as a light shielding means for shielding an arbitrary area on a two-dimensional plane substantially orthogonal to the optical axis connecting the output surface of step 2 and the input surface of the TV camera 6. In this embodiment, this liquid crystal filter 3° is provided between the lens 2 and the first lens 4, and as shown in FIG. 2, it can be turned on and off in units of a fine matrix. In the ON state, almost 100% of light is cut off, and in the OFF state, light is transmitted. In addition, liquid crystal filter 3
The device is not limited to one that operates as described above, but may be one that can vary the light shielding rate by adjusting the applied voltage or the like.

In FIG. 2, 8 is an A'/D converter, and the TV
The electrical signal output from the camera 6 is converted into a digital signal and output to the image memory 9.

The image memory 9 is configured to record an image obtained as a digital signal from the A/D converter 8.

The CPU 10 controls the X-ray tube 12 as described above, reads an image from the image memory 9, detects a halated portion in the image, and outputs the detection result as a control signal to the liquid crystal controller 11 for setting. It looks like this. For example, a portion where the image value exceeds 90% of the dynamic range of the A/D converter 8 is detected, and a signal is output to the liquid crystal controller 11 to turn on the liquid crystal corresponding to the corresponding portion. The CPU 10 also controls the timing of turning on the liquid crystal.

This is because, as mentioned earlier, the liquid crystal 3a cuts almost 100% of the light when it is on, so if it is simply turned on at the same time as the X-ray pulse, no light will pass through that part. This is because an image cannot be obtained. Specifically, for example, as shown in Figure 3, after a certain period of time T1 has passed after the pulsed X-rays are turned on, the liquid crystal is turned on.
It's supposed to be forced. As a result, the exposure time to the TV camera 6 for the part where the liquid crystal is ON is T1, and the exposure time to the TV camera 6 for the part where the liquid crystal is OFF is T2 time (usually about 1 Qms), which is the ON time of the pulsed X-ray. )
becomes. Therefore, by changing the ratio between T1 time and T2 time, it is possible to adjust the rate at which the light in the halation area is reduced.
The timing for turning on the liquid crystal, that is, 1 hour, is set as a control signal in the liquid crystal controller 11 according to the ratio of the image value to the dynamic range of the converter.

Based on the control signal from the CPU 10, the liquid crystal controller 11 controls the corresponding part (
The liquid crystal in the halation area of the image is turned ON (or OF[) at high speed in synchronization with the X-ray exposure. The rise and fall times of ON10FF of the liquid crystal are about ims, and the liquid crystal group in the ON state in the liquid crystal filter 3 forms a light-shielding region, and the amount of light passing through the region is reduced.

Note that the amount of light to be reduced can be adjusted more precisely by adjusting the T1 time for each individual liquid crystal, but it may be common to all areas.

Next, a case in which an image of the heart as shown in FIG. 5 is blocked will be explained in detail in a step-by-step manner.

First, when X-rays are irradiated with all the liquid crystals of the liquid crystal filter 3 turned off, an image of the area B outside the heart in a halated state is captured from the TV camera 6 through the A/D converter 8 to the image memory 9. It will be done.

Next, the CPU 10 reads the image memory 9, detects the halated area (that is, the area shown in FIG. 5B) and its degree, and sends the result to the liquid crystal controller 11 as a control signal.
output to the LCD corresponding to the halated area (
In other words, ON SUPEGI liquid crystal.

(liquid crystal in the shaded area in FIG. 4) and the timing T1 to turn it on are set.

When X-rays are irradiated again under the control of the CPU 10, the liquid crystal controller 11 operates in synchronization with this.
The liquid crystal group in the area where the halation was occurring is Pulse XI!
After T1 hours have elapsed since the switch is turned on, the liquid crystal filter 3 is turned on, and a light-shielding area B' as shown in the shaded area in FIG. , good images without halation can be obtained. Note that if the T1 time is set for each individual liquid crystal, even better images can be obtained.

In this way, according to Kinoji, the halation of TV cameras can be automatically masked by just collecting an image for one measurement, making digital fluorography inspection very easy. You will be able to do this.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and can be modified as appropriate within the scope of the gist of the present invention.

For example, the present invention is not limited to digital fluorography devices, but can be applied to prevent halation in X-ray cine imaging devices and indirect camera devices.

Further, in the above embodiment, a liquid crystal filter is used as the light shielding means, but any means can be used as long as a light shielding area is formed according to a control signal.

In addition, when the liquid crystal filter is turned on, the passage of light is reduced by approximately 1
Since the light would be cut by 00%, I turned it on at high speed to reduce the light to some extent as shown in Figure 5, but the light was cut to 100%.
If a device that can reduce the amount to a certain extent instead of cutting it is used, there is no need for high-speed ON10FF, and control becomes simpler.

[Effects of the Invention] As detailed above, according to the present invention, a halation portion in an optical image is detected by the detection means, and a control signal based on the detection result automatically blocks the halation portion in the optical image by the light shielding means. Since the area is formed and the amount of light in the halation area is automatically reduced, a good image without halation can be obtained without using an X-ray compensation filter.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a main part of an embodiment of the present invention, FIG. 2 is a block diagram of the same as above, FIG. 3 and FIG. 4 are explanatory views of the same as above, respectively, and FIG. 5 is a drawing showing an example of an image. DESCRIPTION OF SYMBOLS 1... Subject, 3... Light shielding means, 10... Detection means, 11... Control means, B-... Light shielding area. Figure 2 Figure 4

Claims (3)

[Claims] (1) In an X-ray diagnostic apparatus equipped with an X-ray-light conversion means that converts X-rays emitted toward a subject and transmitted through the subject into an optical image, and a TV camera that captures this optical image, a detection means for detecting an overexposed area on the optical image corresponding to a halation portion of the TV camera;
a light shielding means for shielding an arbitrary area from light on a two-dimensional plane substantially orthogonal to the optical axis connecting the output surface of the line-light conversion means and the input surface of the TV camera; An X-ray diagnostic apparatus comprising: a control means for setting and controlling a light-shielding area. (2) The light shielding means is ON-O for each unit in the matrix.
Claim 1, which is a liquid crystal filter capable of FF control
The X-ray diagnostic device described in Section 1. (3) The X-ray diagnosis according to claim 1 or 2, wherein the control means controls the ratio of the shielding time to the exposure time to the TV camera in synchronization with the X-ray exposure timing. Device.