JPH01241536A - X-ray image detecting device - Google Patents

Abstract

PURPOSE:To reduce time required for photographing to image reproducing by controlling the temporary memory of X-ray irradiation, excitation photoirradiation, extinction photoirradiation, and fluorescence detection output. CONSTITUTION:Emitted fluorescence has its reflective laser component eliminated at a filter 18 through a condenser guide 16 and is detected as an electric signal by a photomultiplier tube 17. This electric signal is amplified by an amplifier 19 and then temporarily stored in an image memory 20 synchronizing to the movement of a drum 5 and a galvanomirror 14. An X-ray image display device 21 reads the content of the image memory 20 and displays the X-ray image of an object 1 being photographed. Meanwhile, an after image is eliminated by means of an extinction light source 22 through a cylindrical lens 23. As a results, the object 1 on a belt conveyer can be detected continuously at a high speed, while the drum 5 is rotated clockwise. The time required from the beginning of photographing to the end of image reproducing can be thereby reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an X-ray image detection device suitable for detecting internal defects in an object, and particularly relates to an X-ray image detection device that is suitable for detecting internal defects in an object. This invention relates to a significantly shortened X-ray image detection device.

[Prior Art] Conventionally, as an image detection device using X-rays, an
Transmitted X-rays are detected in real time using radiograph equipment, image intensifiers, X-ray television cameras, etc.
X-ray television devices and the like that display images on RT are known.

In addition, as a two-dimensional X-ray detection sensor to replace X-ray film, it has a sensitivity several tens of times higher than that of X-ray film.
A stimulable phosphor sheet is known that exhibits a highly linear response over a wide dynamic range. Regarding this, see “Measurement and Control” (Vol. 26, No. 8 (198
7)) from page 657 to page 664, and its outline is as follows.

That is, a stimulable phosphor sheet is an X-ray sensor in which a stimulable phosphor is coated on a plastic film, and the stimulable phosphor is barium fluoride (BaFBr:Eu!) doped with europium ions. +) etc. are used. When this phosphor is subjected to primary excitation by X-rays and then secondary excitation by visible light, it exhibits strong stimulated luminescence proportional to the intensity of the primary excitation. That is, when the stimulable phosphor sheet is exposed to X-rays, the X-ray image information at that time is stored and can be read out later as light.

X-ray images can be taken using the same equipment as film photography, and the information can be read out and used by later placing the photographed stimulable phosphor sheet on an image reading device. There is.

In a typical image reading device, as shown in FIG. 5, the stimulable phosphor sheet 6 is conveyed horizontally by a conveyor belt 26 while being spot-scanned by a laser beam from a laser light source 15. If the laser beam from the laser light source 15 is reflected by the galvano mirror 14 driven by the six motors 10, the laser spot will main scan the stimulable phosphor sheet 6. The fluorescence generated by this laser excitation is collected by a condensing guide 16 and detected as a time-series signal by a photomultiplier tube 17. By storing and processing this, X-ray information can be reproduced as an image. ing.

Incidentally, since the afterimage of the stimulable phosphor sheet is completely erased by irradiation with white light, it can be recycled and used any number of times.

[Problem to be solved by the invention] However, the conventional stimulable phosphor sheet
In detecting a ray image, it is necessary to reproduce the image using a single image reading device after taking an X-ray image. Therefore, a lot of time is required from photographing to image formation, and there is a problem that real-time performance is lacking compared to an X-ray television device or the like.

An object of the present invention is to provide an X-ray image detection device that can significantly shorten the time required from the start of imaging to the end of image reproduction when a stimulable phosphor sheet is used for X-ray image detection.

[Means for Solving the Problems] The above object is to integrate a means for photographing an X-ray image onto a stimulable phosphor sheet and a means for reading X-ray information from the phosphor sheet; Alternatively, this can be achieved by performing seal image reproduction processing immediately after photographing. More specifically, the X-ray image detection device includes an X-ray generating means for irradiating an object with X-rays, an object placing/holding means for placing or holding the object, and an X-ray beam that passes through the object. a stimulable phosphor sheet installed at a position to receive X-rays; a phosphor sheet holding means for holding the stimulable phosphor sheet; an excitation light irradiation means for irradiating the stimulable phosphor sheet with excitation light; a fluorescence detection means for detecting fluorescence generated from the stimulable phosphor sheet by light irradiation fill'; an afterimage erasing means for erasing the afterimage by irradiating the stimulable phosphor sheet with erasing light;
This can be achieved by configuring the apparatus to include at least an imaging control means for controlling at least X-ray irradiation, excitation light irradiation, erasing light irradiation, and temporary storage of fluorescence detection output.

[Function] When performing an immediate reading operation near the imaging position during or after taking an X-ray image on a stimulable phosphor sheet, there is no need to attach or remove the stimulable phosphor sheet or transport it over long distances. Therefore, the time required from imaging to image reproduction is significantly shortened.

[Example] Hereinafter, an image detection device according to the present invention will be explained with reference to FIGS. 1 to 4.

First, the first configuration aspect will be explained below with reference to FIG.

That is, to explain the outline of the operation, if X-rays are irradiated from the X-ray source 3 while rotating the drum 5 in a predetermined direction and moving the sample stage 12 in a predetermined direction, the X-rays will be emitted through the slits 4a, The object 1 is irradiated through the slit 4b onto the surface of the stimulable phosphor sheet 6 attached to the outer peripheral surface of the drum 5.

As a result, X-ray images of the object 1 are sequentially photographed on the stimulable phosphor sheet 6. On the other hand, while such imaging is being performed, the laser beam from the laser light source 15 mainly scans the photographed portion of the stimulable phosphor sheet 6 via the galvanometer mirror 14. The fluorescence generated from the 6 surfaces of the stimulable phosphor sheet by this scanning is detected as an electrical signal by the photomultiplier tube 17 via the condensing guide 16, and is temporarily stored in the image memory 20 via the amplifier 19. is image memory 2
0 and displayed as an X-ray image on the X-ray image display 21. In parallel with the above-mentioned photographing and scanning, erasing light is irradiated from the erasing light source 22 through the cylindrical lens 23 to the scanned photographed area, thereby erasing the afterimage in the irradiated area. be.

Now, to explain its configuration, the xMA is irradiated from the X-ray source 3 after its generated voltage and generated current are adjusted by the X-ray generation control section 2 under the control of the imaging control circuit 7. 3 may be of any type, and it is particularly advantageous in terms of post-resolution when using a microfocus X-ray source. Furthermore, the slits 4a and 4b installed parallel to each other in the front and rear X-ray irradiation paths of the object 1 have the function of narrowing the X-ray beam into a thin fan shape and at the same time reducing the influence of scattered X-rays. Therefore, the material is X such as lead.
It is difficult for X-rays to pass through it, and it needs to be thick enough to block X-rays. Now, the X-rays transmitted through the slit 4a, the object 1, and the slit 4b are transmitted through the slit 4a,
The X-rays reach the outer peripheral surface of the drum 5, which is a rotating surface about a central axis parallel to the central axis 4b, but since the stimulable phosphor sheet 6 is wrapped in advance on the outer peripheral surface of the drum 5, the X-rays are irradiated. When this happens, information proportional to the product of X-ray intensity and irradiation time is recorded in the irradiated area.

On the other hand, the stage drive circuit 8 and drum drive circuit 9 are synchronously controlled by the imaging control circuit 7, and thereby the sample stage 12 is moved in a predetermined direction at a predetermined speed via the stage drive circuit 8, motor 10a, and ball screw 11. It is now possible to do so. The sample stage 12 is made of a material with good X-ray transparency, such as carbon fiber, and if the sample stage 12 is moved little by little, the position at which the X-ray beam is irradiated into the object 1 will also be moved little by little. It is a matter of fact. Further, the drum drive circuit 9. Since the drum 5 is rotated via the motor tob, the X-ray recording position on the stimulable phosphor sheet 6 is eventually moved. At this time, if the moving speed of the object 1 projected onto the drum 5 is controlled to be equal to the moving speed of the stimulable phosphor sheet 6 due to the rotation of the drum 5, a good X-ray image can be recorded. become.

By the way, the imaging control circuit 7 also controls the galvano mirror drive circuit 13 simultaneously in synchronization with the above control, thereby controlling the galvano mirror 1 attached to the motor 10c.
4 is designed to be rotated.

The galvanometer mirror 14 reflects the laser light from the laser light source 15 in the direction of the drum 5, so that the surface of the stimulable phosphor sheet 6 is scanned by the laser spot. When the laser spot is irradiated onto the stimulable phosphor sheet 6, the irradiated area emits light in accordance with the recording X-ray exposure amount.
Fluorescence is emitted with a short lifetime. Note that it is desirable that the laser light source 15 has a wavelength suitable for excitation light of the phosphor, and for example, a helium neon laser or the like can be used.

The fluorescence emitted as described above passes through the condensing guide 16, filters 18 remove the reflected laser light component, and then the photomultiplier tube 17 detects it as an electrical signal, but this electrical signal is further passed through the amplifier 19. After being amplified, drum 5
The image memory 20 is synchronized with the movement of the galvanometer mirror 14.
It is once stored in the memory. X-ray image display 2
1, the X-ray image of the object 1 can be displayed as an image by reading and displaying the contents of the image memory 20. In addition to the above operation, white light is constantly irradiated from the erasing light source 22 to a certain range of the stimulable phosphor sheet 6 through the cylindrical lens 23, and an afterimage is generated in the area irradiated with the erasing light. It is to be deleted.

Therefore, when the above operations are performed simultaneously and continuously while rotating the drum 5 clockwise, it becomes possible to detect the object 1 on the belt conveyor at high speed and continuously, for example. Furthermore, the effects of scattered X-rays are reduced due to the function of the slits 4a and 4b, and a good X-ray image can be obtained.

In FIG. 1, reference numerals 24 and 25 indicate a photomultiplier tube power source and an erasing light source power source, respectively.

FIG. 2 shows a second configuration aspect. This embodiment is substantially different from the previous embodiment in that the stimulable phosphor sheet 6 is attached to the flat stage 27, and the sample stage 12 and the flat stage 27 are connected and movable so as to be interlocked. In this embodiment, since the flat stage 27 and the sample stage 12 are movable as a unit by the stage drive circuit 8, the X-ray image of the object 1 is displayed on the surface of the stimulable phosphor sheet 6 as in the previous embodiment. will be recorded. However, in this embodiment, the stimulable phosphor sheet 6 is placed on the flat stage 27.
It is mounted on the back side of the flat stage 27 with its phosphor screen facing downward, so that the X-ray image can also be read out from the back side of the flat stage 27. Since the X-rays reach the surface of the stimulable phosphor sheet 6 after passing through the flat stage 27, the flat stage 27 must also be made of a material that has good X-ray transparency.

Simultaneous operation is possible. In addition, the flat stage 27
and the sample stage 12 are connected, so there is no need to drive them individually in synchronization, and the stage drive circuit is
Only one is required, making control easier.

FIG. 3 shows a third configuration mode. In this aspect, the slits 4a and 4b are removed from the second configuration aspect, and the object 1 is not moved. In addition, depending on the imaging control circuit 7, the X-ray irradiation time and recording/
A series of reproduction and deletion procedures are controlled. Specifically, the imaging control circuit 7 is configured as a microcomputer programmed with a control procedure. In this embodiment, the flat stage 27 is not scanned during X-ray imaging, and by irradiating X-rays for a certain period of time, the entire image of the object 1 is exposed and recorded on the 6 surfaces of the stimulable phosphor sheet at once. It has become so.

Thereafter, the recorded X-ray image is reproduced while the flat stage 27 is scanned, and after the reproduction process is completed, the entire surface of the stimulable phosphor sheet 6 is irradiated with erasing light from the erasing light source 22, thereby creating an afterimage. is now deleted.

As described above, in this embodiment, images of the object 1 are recorded all at once, so the X-ray irradiation time is extremely short compared to the previous two embodiments, and while the X-ray image is being reproduced, the There is no need to hold the object 1, and samples can be exchanged, etc., and operability during continuous use is improved.

FIG. 4 shows a fourth configuration mode. In this embodiment, compared to the third embodiment, the plane stage 27 is also immovable, and image detection is performed. This embodiment is the same as the third embodiment in that X-ray images are collectively recorded on the phosphor sheet 6 on the back side of the flat stage 27, but the structure of the fluorescence detection system is different. That is, the galvano mirror drive circuit 13a,
13b, the main scanning galvano mirror 14a and the sub-scanning galvano mirror 14b are rotated in synchronism, so that the laser spot sequentially scans the entire surface of the stimulable phosphor sheet 6. In addition, the generated fluorescence is sequentially reflected by the galvano mirrors 14b and 14a, and then reflected by the half mirror 29, lens 28, and filter 18.
It is detected as an electrical signal by the photomultiplier tube 17 via the photomultiplier tube 17.

According to this aspect, there are only two galvanometer mirrors as movable parts, and the configuration is simplified accordingly.

[Effects of the Invention] As described above, according to the present invention, in X-ray image detection using a stimulable phosphor sheet, it is possible to detect an X-ray image using a stimulable phosphor sheet without attaching or detaching the phosphor sheet or transporting it over a long distance after recording an X-ray image. Since X-ray images can be detected by performing image reproduction processing near the imaging location, the time from imaging to image reproduction is significantly shortened.
This has the effect of improving real-time performance.

[Brief explanation of the drawing]

1, 2, 3, and 4 are diagrams showing the configuration of the X-ray image detection device according to the present invention, and FIG. 5 is a general reading method for a stimulable phosphor sheet. FIG. 1...Object, 3...X-ray source, 4a, 4b...
slit. 5... drum, 6... stimulable phosphor sheet, 7...
- Imaging control circuit, 8... Stage drive circuit, 9...
Drum drive circuit, loa~10d...motor, 12
...Sample stage. 13, 13a, 13b-galvano mirror drive circuit, 1
4.14a, 14b... Galvano mirror 115...
- Laser light source, 16... Focusing guide, 17... Photomultiplier tube, 18... Filter. 20... Image memory, 22... Erasing light source, 23...
・Cylindrical lens, 27...Flat stage, 2
8...Lens, 29...Half mirror-0 Agent Patent attorney Tadashi Akimoto Tube 1 Figure 2 Figure 3 4 Figure 5

Claims (1)

[Claims] 1. An X-ray generating means for irradiating an object with X-rays, an object placing/holding means for placing or holding the object, and receiving the X-rays transmitted through the object. a stimulable phosphor sheet installed at a position, a phosphor sheet holding means for holding the stimulable phosphor sheet, an excitation light irradiation means for irradiating the stimulable phosphor sheet with excitation light, and A fluorescence detection means for detecting fluorescence generated from a phosphor sheet, an afterimage erasing means for erasing an afterimage by irradiating the stimulable phosphor sheet with erasing light, and at least X-ray irradiation, excitation light irradiation, erasing light irradiation, and fluorescence An X-ray image detection apparatus characterized by a configuration comprising at least an imaging control means for controlling temporary storage of detection output. 2. In claim 1, a first fixed X-ray exposure slit is provided between the X-ray generating means and the object placing/holding means, and the first fixed X-ray exposure slit is provided between the object placing/holding means and the phosphor sheet holding means. A second fixed X-ray exposure slit is provided between the object mounting and holding means and the stimulable phosphor sheet are synchronized in a direction perpendicular to the direction of the first and second fixed X-ray exposure slits. An X-ray image detection device that is movable. 3. The X-ray image detection apparatus according to claim 1, wherein the phosphor sheet holding means is a fixed flat stage. 4. The X-ray image detection apparatus according to claim 1 or 2, wherein the phosphor sheet holding means is a movable flat stage. 5. An X-ray image detection device according to claim 2, wherein the phosphor sheet holding means is a rotating drum having a stimulable phosphor sheet wound and held on its outer peripheral surface. 6. In claim 3, the excitation light irradiation means has a galvano mirror for main scanning of the excitation light and a galvano mirror for sub-scanning of the excitation light, and the accumulation property via the two galvano mirrors is provided. An X-ray image detection device in which fluorescence from a phosphor sheet is captured by a fluorescence detection means through a half mirror inserted into an excitation light irradiation path and serving as a part of the fluorescence detection means. 7. The X-ray image detection device according to claim 4 or 5, wherein the excitation light irradiation means has a galvanometer mirror for main scanning of the excitation light.