JPS61184977A - X-ray image pickup device - Google Patents

Abstract

PURPOSE:To eliminate the necessity of a complicated and expensive synchronous scanning mechanism, by scanning an object with X-ray fluxes produced through plural X-ray slits and picking up images without synchronizing the image pickup of a TV camera to the scanning position of the X-ray fluxes when an image is constituted by picking up the output image of an X-ray image tube with the TV camera. CONSTITUTION:Plural X-ray slits 2 are provided between an X-ray image source 1 and object and the object is scanned with X-ray fluxes 14 by irradiating X-rays in a pulse-like condition by means of the signal of a synchronizing signal generator 12. Output images of an X-ray image tube 5 is picked up as one frame of image by means of a TV camera at every one pulse of the X-rays and, before the object is scanned with an X-ray scanning slit, all the signals remaining in a frame memory 10 are erased and the signal from the TV camera 7 and signal of the frame memory 10 are compared with each other by a signal comparator 8. After the comparison, signals having larger values are recorded in another frame memory 9 and, when image processing of one frame quantity is completed, the record is shifted to the frame memory 10. This image-pickup recording is performed until the X-ray slit completes the scanning of the object and, after completion, the signal of the frame memory 10 is displayed on a receiver.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention is based on a method of scanning an object with a plurality of X-ray slits, integrating striped X-ray images resulting from the X-ray flux, and reproducing the image as an X-ray image of the object. The present invention relates to an X-ray imaging device that obtains clear X-ray images from which scattered X-rays and pale glare from an X-ray image tube are removed.

[Technical background of the invention]

Conventionally, for X-ray imaging, in order to remove scattered X-rays, an X-ray grid made by overlapping lead foil, aluminum foil or wooden foil that transmits X@ well is placed between the subject and the X-ray image tube. The primary X-rays are arranged to transmit as much of the primary X-rays as possible, and the scattered X-rays generated from the subject are removed as much as possible. However, in order to prevent the resolution of the X-ray image from deteriorating, this lead foil is not very thick. In addition, since the transmittance of primary X-rays is not significantly reduced, the lead foil cannot be made too thick or long. Therefore, the effect of removing scattered X-rays is not necessarily sufficient.

Furthermore, in an X-ray image tube, X-rays, light, and electrons are scattered within the tube, resulting in a large blur of images called Bering glare. In order to prevent these, we use an input window material with low X-ray scattering, use a columnar crystal structure phosphor surface that has a large light guiding effect on the input phosphor surface, and take measures to prevent unnecessary electrons from reaching the output phosphor surface. Efforts have been made to improve the electrode structure and reduce the transmittance of the glass substrate on the output fluorescent surface, but this is not always sufficient. Therefore, a plurality of X-ray slits are placed between the X-ray source and the subject so as to cover the entire surface of the X-ray image receiving surface, and the slits are scanned between the slits. Attempts have been made to remove the effects of X-ray scattered radiation and Bering glare by extracting only signals and combining them into a single X-ray image.

[Problems with background technology]

The object is scanned with multiple X-ray slits, and the position of the image is accurately controlled in synchronization with the scanning of the X-ray beam in order to image the part corresponding to the transmitted X-ray image of the object corresponding to the X-ray beam with a TV camera. There is a need to.

The accuracy of this control corresponds to the resolution required for the screen, so it must be extremely precise and cannot be easily achieved, resulting in a very expensive device. Furthermore, since the X-ray image tube has a large pink John-shaped image distortion as a characteristic, a straight line in an X-ray image is not necessarily a straight line, and alignment thereof is very difficult.

[Purpose of the invention]

The subject is scanned with X-ray flux from multiple X-ray slits, and the output image of the X-ray image tube is captured by the TV camera based on the X-ray image transmitted through the subject by the X-ray flux. The object of the present invention is to provide an apparatus that does not require a difficult and expensive synchronous scanning mechanism by capturing images without synchronizing with the scanning position of the beam.

[Summary of the invention]

The present invention arranges a plurality of X-ray slits between an X-ray source and a subject, irradiates X-rays in a pulsed manner, and scans the subject with an X-ray beam. One frame of the output image is captured with a TV camera, and before the X-ray scanning slit starts scanning the subject, all remaining signals in the frame memory are erased, and the signals from the TV camera and the signals in the frame memory are is compared for each pixel, and the larger value is recorded again in the frame memory as a signal. This image recording is continued until the X-ray slit finishes scanning the subject, and then the signal in the frame memory is transferred to the image receiver. The feature lies in the X-ray imaging device.

[Embodiments of the invention]

An embodiment of the invention will be described with reference to FIG.

Figure 1 shows the X-ray generator (1), X-ray slit (2), X-ray grid (4), X-ray image tube (5), and optical system (6).
, TV camera (7), signal comparator (8), frame memory A (9), frame memory B (1G, receiver αυ
, a synchronizing signal generator a3, an X-ray dose measuring element αG, and a scanning mechanism αη of an X-ray slit (2). X-ray generator (1
) is pulsed KX by the signal from the synchronization signal generator α.
Generate line 03. This X-ray α3 is transmitted through the X-ray slit (2)
generates a plurality of X-ray fluxes α4 of 77-n' shaped X-rays, which pass through the object (3) and pass through the X-ray grid (4).
), a considerable portion of the scattered X-rays generated by the object (3) are removed and enter the X-ray image tube (5). Since this system has a function to remove scattered X-rays, the X-ray grid (4) is not necessarily required, but it is preferable to use it together. The X-ray image tube (5) transforms the X-ray image into light. The place is X
The ray image tube (5) scatters X-rays, scatters light,
A large Bering glare is generated due to the generation of unnecessary electrons, and the scattered X-ray components of the incident X-ray image are added to this, and the output optical image of the X-ray image tube (5) becomes largely blurred. The brightness distribution of this output light image in the cross section of the X-ray slit (2) in the scanning direction is as shown in the first frame of FIG. 2. Here X
The scanning direction of the line slit (2) is a direction perpendicular to the slit. In Fig. 2, the brightness of the area b is the transmitted X of the X-ray flux α4.
It corresponds to the line. The brightness in areas a and C is caused by scattered X-rays, light scattering,
This book is caused by scattered X-rays from the subject (3), such as light emission by unnecessary electrons, and Bering glare from the X-ray image tube (5), which blurs the image and is unnecessary.

One frame of such light is captured with a TV camera (7). The image pickup tube of the TV camera (7) is of the type that accumulates a charge image on its input surface, such as a Bisiman, and the synchronization signal generator (13) pulses the X-ray image into the next image. The TV camera (7) takes an image by 17-ray beam scanning based on the signal ratio of the synchronizing signal generator a2 during the time period until the pulse .

The signal of this frame is obtained like the signal of the first frame in FIG. The frame memory BuI erases all the signals in the frame memory BαQ before imaging this first frame. This frame memory B (11
The signal from the TV camera (the force signal is also used as the signal from the synchronizing signal generator a3) and is compared for each pixel by the signal comparator (8), and the larger signal is recorded in the frame memory A (9). In the signal comparator (8), the dose of this X-ray pulse is measured by a dosimetry element (Le measurement), and the signal from the TV camera (sword is corrected according to the value) before comparison is made. When the image processing for one frame is completed, the record of frame memo!J-B (9) is transferred to frame memory A (1
(Move to IK. Next, the X-ray slit scanner αD moves the X-ray slit (2) in a range where the X-ray projections by the slit partially overlap using the signal from the synchronization signal generator α, and generates a synchronization signal. A second X-ray pulse is generated from the X-ray generator (1) according to the signal from the X-ray generator, and the X-ray pulse is
A TV camera (7) captures one frame of the output of the line image tube (5) using the signal from the synchronizing signal generator α2, and compares each pixel with the signal from frame memory A (1G) using a signal comparator (8). Record in memory B (9).TV
The signal from the camera (7) is corrected using the signal from the dosimetry element αB. Next, the record of frame memory B (9) is transferred to the frame memory person (11).In this way, at least This is carried out up to the Nth frame in which the entire surface is scanned by the X-ray flux I. Then, the transmitted shadow part of the X-ray flux I of each frame . The part caused by the scattered X-rays of the subject (3) and the pale glare of the X-ray image tube (5)・aI + G...an+'l
Scan 1 in Figure 2 with the +ct, cl... portions removed
A composite image of each batch is recorded.

The scanning of the X-ray flux α4 is performed so that one part overlaps, , , , bn partially overlaps each other, and the signal size in both overlapped parts is the same, so the Either is recorded, there is no slit gap due to variations in the manufacturing of the X-ray slit (2), or there is no missing image that would cause uneven scanning, and there is very little influence from X-ray scattering from the subject. A high-quality image with very little influence of Bering glare from the X-ray image tube (5) can be obtained. The record of this frame memory Bα is transferred to the receiver αυ.
to be copied.

Here, if the width of the X-ray slit (2) is increased, the widths of bl, ... bo in Fig. 2 will become wider, and bI
.

The influence of X-ray scattered rays and the Bering glare of the X-ray image tube (5) in the part b7 increases.

Furthermore, when the width of the slit is made smaller, the number of frames forming one screen increases, the load on the X-ray source (1) increases, and the time required to form one screen increases. If the slit gap is made thicker, the number of frames will increase when configuring one screen. Therefore, the slit width and slit gap must be appropriately set as necessary.

Note that if the intensity of the X-ray pulse from the X-ray generator (1) is sufficiently stable, the dosimetry element haze is not necessary. Also, the X-ray slit (
Instead of scanning the X-ray generator (1), the X-ray generator (1) may be scanned. This scanning may be performed by electronically scanning the X-ray source of the X-ray generator (1).

〔Effect of the invention〕

This device obtains X-ray images with less influence of scattered X-rays and less bering glare of the X-ray image tube by scanning the subject with X-ray flux using multiple X-ray slits, and eliminates the expensive synchronization mechanism associated with X-ray slit scanning. A device that does not require this can be obtained, and its economical effects are very large.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing an apparatus according to an embodiment of the present invention,
FIG. 2 is an explanatory diagram showing the construction of an image for explaining one embodiment of the present invention. 1. X-ray generator 2. X-ray slit 3. Subject 4. X-ray grid 5. X-ray image tube 7. TV left camera - Signal comparator 9.
10-Frame memory 11 ・Receiver 12
...Synchronization signal generator 16...Dose measurement element t7...
・X-ray slit scanner agent Patent attorney Kensuke Chika (and one other person) Figure 2 Slit, t, = i bow declination

Claims (1)

[Claims] 1. An X-ray image tube that receives an X-ray image transmitted through an X-ray source and a subject and converts the X-ray image into a light image, a TV camera that captures this light image, and a TV camera that captures this light image. In an X-ray imaging device including a receiver for imaging, a plurality of X-ray slits are provided between an X-ray source and a subject, covering at least the entire surface of the X-ray image receiving surface of the X-ray image tube, and at least each adjacent X-ray An X-ray slit device that scans a distance greater than the maximum slit gap in a direction perpendicular to the slit direction of the X-ray slit, and scans so that the scans overlap little by little. is installed, irradiates X-rays in a pulsed manner, and scans the subject with the X-ray flux.
One frame of image is captured with a TV camera for each pulse, and
Before the line slit device starts scanning the object, all remaining signals in the frame memory are erased, the signal from the TV camera and the signal in the frame memory are compared, and the larger value is recorded in the frame memory again as a signal. An X-ray imaging device characterized in that this imaging is carried out at least until the X-ray slit device finishes scanning the subject, and then the signals in the frame memory are displayed on the image receiver. 2. The X-ray imaging device according to claim 1, characterized in that an X-ray grid is disposed between the subject and the X-ray image tube. 3. An element for measuring the amount of X-rays is placed between the X-ray source and the X-ray slit device, and the signal from the frame memory is compared with a signal obtained by modifying the signal from the TV camera according to the amount of X-rays from the X-ray pulse. An X-ray imaging apparatus according to claims 1 or 2, characterized in that: 4. Claims 1 to 3, characterized in that instead of scanning the X-ray slit device, the X-ray source is scanned.
X-ray imaging device.