JPH0248079B2 - HOSHASENZOKIROKUSAISEISOCHI - Google Patents

Description

[Detailed description of the invention]

[Technical field to which the invention pertains] This invention relates to a radiation image recording and reproducing device for recording and reproducing radiation images, and in particular to an improved radiation image storage plate that uses fluorescent glass powder as a main component with high light collection efficiency. The present invention relates to a radiation image recording and reproducing apparatus using. [Prior art and its problems] Using radiation sources such as X-ray generators and radioactive isotopes (X-rays, γ-rays, β-rays, α-rays, etc.),
Techniques for observing radiographic images of a subject are widely used in the fields of medical diagnosis and non-destructive testing. A conventional radiation storage medium is generally a photographic plate using a silver-halogen photographic emulsion. However, in recent years, new radiation image recording and reproducing devices have been developed with the aim of saving silver resources and digitally processing image information. Examples of such prior art are shown in FIGS. 1a and 1b. First, in the radiation image recording state (a), X-rays generated from the X-ray tube 1 pass through the subject 2 and reach the fluorescent glass dosimeter plate 3 (a phosphate glass substrate activated with a small amount of silver). A fluorescent center corresponding to the radiation image is formed inside the glass. Next, in the radiation image reproduction state (b), He
- The light beam of the Cd laser (light wavelength 325 nm) 4 is surface-scanned with respect to the fluorescent glass plate 3 by the polarizer 5, and the fluorescence generated at this time is transferred to the condensing sheet 6 (acrylic resin that guides the light). etc.) and input them to the photomultiplier tube 7. The signal current obtained from the photomultiplier tube 7 is digitized and processed by a data processing device 8, and then a radiation image is displayed on an image display device 9. Figure 2 shows fluorescence generated from the fluorescent glass dosimeter plate 3 according to the density of fluorescence centers (light wavelength 500 to 700 nm).
is viewed from the cross-sectional direction, and shows the fluorescent component 12 that is lost due to reflection propagation within the glass plate from the point where the He-Cd laser beam 10 is incident, and the reflected fluorescent component 11 that is collected by the condensing sheet 6. has been done. The problems with the prior art example explained above are:
The fluorescent components collected by the condensing sheet 6 are limited to a reflected fluorescent component 11 and a reflected propagated fluorescent component 12.
is lost, resulting in a reduction in signal amount. Therefore, the quality of the obtained radiographic image deteriorates, and in order to avoid this, it is necessary to increase the intensity of radiation irradiated to the subject, which causes an impact on the human body and a burden on the system. [Object of the Invention] This invention improves the drawbacks of the conventional radiation image recording and reproducing apparatus described above, and provides a radiation image recording device that has good light collection efficiency during radiation image reproduction and has excellent image quality of the reproduced radiation image. The purpose is to provide a playback device. [Summary of the Invention] In the present invention, a radiation image storage plate formed of layers of fluorescent glass powder is used to record and reproduce radiation images. With the excitation light source formed and having a constant wavelength, more reflected fluorescent components are generated and the irradiated radiation dose is efficiently reproduced. [Effects of the Invention] According to the radiation image recording and reproducing apparatus of the present invention, the radiation image storage plate used is one formed of layers of fluorescent glass powder, so that reflection, which has been a problem with conventional fluorescent glass plates, is avoided. The propagating fluorescent component also undergoes light scattering by the glass powder and is ultimately collected as a reflected fluorescent component. Therefore, the efficiency of collecting light from the storage plate during radiation reproduction is improved, and the quality of the radiation image is improved. In other words, the radiation intensity required to obtain the same image can be reduced compared to the conventional method, and the influence on the human body and the burden on the system can be reduced. [Embodiment of the Invention] An embodiment of the present invention will be described with reference to FIG.
The overall configuration of the apparatus is the same as that shown in FIG. 1. First, in the recording state, as shown in FIG. The light enters the radiation image storage plate 13 formed in a layered manner, and a fluorescence center is formed in the storage plate 13 according to the amount of radiation irradiated. Next, in the reproducing state, as shown in Figure b, for example, He
- A light beam of a Cd laser (light wavelength 325 nm) 4 is surface-scanned with respect to the storage plate 13 by a polarizer 5, and the fluorescence generated at this time is collected by, for example, a light-condensing sheet 6 and sent to a photomultiplier tube 7. input. The signal current obtained from the photomultiplier tube 7 is digitized and processed by a data processing device 8, and then a radiation image is displayed on an image display device 9. FIG. 4 shows an example of the cross-sectional structure of the radiation image storage plate 13 used in the radiation image recording and reproducing apparatus of the present invention.
are deposited in layers. The storage plate 13 typically has an area of 20×30 cm ² and the Ni metal plate 14 has a thickness of about 1 mm. Further, it is preferable that the total thickness of the fluorescent glass powder layer is suppressed to about 1 mm. Furthermore, the particle size (diameter) of the fluorescent glass powder is preferably 5 to 500 μm, more preferably 10 to 500 μm.
100μm is good. This is because if the thickness is 50 μm or more, it will be difficult to obtain sufficient resolution, and if the thickness is 5 μm or less, the resolution will be good, but the light collection efficiency will decrease. In this example, the total thickness of the fluorescent glass powder layer is approximately 0.3 mm, and the diameter of the fluorescent glass powder is approximately 50 μm.
m, the number of layers is 6. Table 1 shows some examples of fluorescent glass powders in weight percent, among which Ag, P, O
is required. Furthermore, in these examples, it is also possible to reduce P a little and add Ba accordingly.
This Ba is effective in improving radiation stopping power and making the storage plate thinner.

【table】

[Other embodiments of the invention]

In the storage plate 13 shown in FIG. 4, an example in which chemicals are used to form a layer of fluorescent glass powder has been described above, but as shown in FIG. Board 18
It can also be fixed by crimping. In this case, the peripheral portion of the storage plate is fixed with screws 19, for example.
In this way, the glass powder 15 can be freely taken in and taken out, making it easy to replace the glass powder when the characteristics deteriorate, and furthermore, the manufacturing time can be shortened.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a conventional radiation image recording and reproducing device, Fig. 2 is a diagram showing the state of fluorescence when a radiation image is reproduced by a fluorescent glass dosimeter plate in the conventional device, and Fig. 3 is a diagram showing the present invention. FIG. 4 is a diagram showing an example of a radiation image storage plate in the apparatus of the present invention, and FIG. 5 is a diagram showing an example of a radiation image recording and reproducing apparatus according to A diagram showing the state of fluorescence during reproduction, FIG. 6 is a diagram comparing reproduced image signals by the conventional device and the device of the present invention, and FIG. 7 is a diagram showing another example of the radiation image storage plate in the device of the present invention. be. 1... X-ray tube, 2... Subject, 4... He-Cd
Laser, 5...Polarizer, 6...Condensing sheet, 7
...Photomultiplier tube, 8...Data processing device, 9...
...Image display device, 13...Radiation image storage plate, 14
...Ni metal plate, 15...Fluorescent glass powder, 18
...Transparent glass plate.

Claims (1)

[Scope of Claims] 1. A radiation image storage comprising a radiation source and a fluorescent glass powder layered together, and a fluorescent center corresponding to the radiation image is formed by irradiating radiation from the radiation source through a subject. a member, a light source for irradiating the radiation image storage member with a light beam, a means for receiving fluorescence emitted from the radiation image storage member by irradiation with the light beam, and processing a signal obtained from the light reception means. A radiation image recording and reproducing apparatus characterized in that it comprises means for reproducing said radiation image. 2. The radiation image recording and reproducing apparatus according to claim 1, wherein the particle size of the fluorescent glass powder is 5 to 500 μm, and the layered thickness of the fluorescent glass powder is 1 mm or less. 3. The radiation image recording and reproducing apparatus according to claim 1, wherein the fluorescent glass powder contains at least silver, phosphorus, and oxygen.