JPS60150044A - Radiation image erasing device - Google Patents

Abstract

PURPOSE:To prevent the deterioration of a radiation storage sheet and to improve the erasure efficiency of radiation image information by absorbing heat rays generated by a light source by a light transmission type cooling means. CONSTITUTION:When a fluorescent material sheet 3 conveyed to the right below the light source 29 is irradiated with light which is emitted by the light source 29 and transmitted through the light transmission type cooling means 28, radiation image information stored on the fluorescent material sheet 3 is erased. Heat rays generated by the heat source 29 are absorbed by the light transmission type cooling means 28. The heat of the absorbed heat rays is absorbed by a cooling medium which passes through the hollow part 33 of the light transmission type cooling means 28 and radiated out. The fluorescent material sheet 3 is therefore irradiated with only light with wavelength necessary for erasure, so the radiation image information is erased without any temperature rise. Consequently, the heat source 29 is put closely enough to the fluorescent material sheet 3 and the erasure efficiency is improved.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a radiation image storage sheet that erases radiation image information stored in a radiation image storage sheet by irradiating the radiation image storage sheet with light. This relates to an erasing device.

[Technical background of the invention and its problems]

A radiation-119 imaging device that utilizes a radiation image storage sheet (hereinafter also referred to as a "phosphor sheet") having a stimulable phosphor;
For example, the configuration of digital radiography is shown in FIG. X-rays emitted from an X-ray tube pass through a subject 2 and are accumulated in a phosphor sheet 3 made of a stimulable phosphor formed into a sheet. This phosphor sheet 3 is applied to a radiation image information reading device 4 to read out image information as an electric material (readout), recorded in a recording device 7, and after appropriate image data processing is performed by an image processing device 5, the image is The recording means 6 prints it on the film 8, and the automatic developing means 9 prints xI! Obtain photo page 10. Control during this time is performed by the computer 11.

Next, the configuration of the radiation image information reading device 4 is shown in FIG. The laser beam emitted from the laser tube 21 passes through the lens 22
After being focused into a narrow beam with a diameter of about 100 μm, the beam is scanned by a scanning rotating reflecting mirror 23 onto a phosphor sheet 3 on which radiation image information has been accumulated. This phosphor sheet 3 is placed on the belt 24 which is running by the rotational drive of the rows 525.25, and moves in the direction of the arrow, for example, in synchronization with the scanning of the laser beam. In this way, the entire surface of the phosphor sheet 3 is uniformly scanned by the laser beam. When the phosphor sheet 3 is irradiated with laser light, stimulated light is generated from the phosphor sheets 1 to 3.

This stimulated light is collected by a light collecting means 26, and the photomultiplier tube (P
, M), 27, and then output as radiation image information to, for example, the image processing means 5 (FIG. 1).

By the way, when new radiation image information is again stored on the phosphor sheet after the radiation image information has been read, it is necessary to erase all of the previously stored radiation image information. Normally, part of the radiation image information stored in the phosphor sheet can be erased by laser light irradiation when reading information. However, J
It is not possible to completely erase all components, and afterimage components tend to remain on the phosphor sheet. Therefore, it is necessary to perform an operation to completely erase this afterimage component.

A conventional method for erasing radiation image information (including afterimage components) is to irradiate a phosphor sheet with light for approximately 200,000 x seconds.

That is, by using a plurality of halogen lamps or sodium lamps as a light source and irradiating the phosphor sheet with the vignetted light from the light source, the atoms of the stimulable phosphor contained in the stimulable phosphor are removed. The metastable state is returned to the unstable state, and all radiation image information stored in the phosphor sheet is erased.

Here, the emission spectrum distribution of the [1gen lamp] is
Fig. 4 shows the emission characteristics of the photostimulable phosphor with respect to the wavelength of irradiation light. What can be said from FIGS. 3 and 4 is that light with a wavelength of around 600 nm acts most effectively in erasing, and so-called infrared rays are not very useful.

It should be noted that the phosphor sheet subjected to −F+ erasure scanning also remained for a long time (
If the image is left for more than 24 hours (for example, for more than 24 hours), due to changes in the internal atomic state, a weak afterimage will appear again, making it necessary to erase it again. In this case, the amount of irradiation light is generally said to be about 70,000 A x seconds, but re-erasing must be performed just before the X-ray irradiation.

Incidentally, a phosphor sheet is usually made by coating a polyethylene or polyethylene plastic film with a stimulable phosphor.
There is a risk of deterioration in the above conditions.

However, since the amount of light received per unit area is inversely proportional to the square of the distance between the light source and the light receiving surface, it is preferable to place the light source as close to the phosphor sheet as possible from the point of view of effective use of light. There is a risk that the phosphor sheet will be heated and deteriorate in quality. For these reasons, it is not possible to bring the light source close enough to the phosphor sheet, and therefore, conventional radiation image erasing devices require a relatively large light source, and the erasure efficiency, that is, the erasure of the phosphor sheet relative to the light emitted by the light source, is The best ratio was bad.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and provides a radiation image erasing device that can erase radiation image information stored on a radiation image storage sheet with high efficiency without changing the quality of the radiation image storage sheet. Write the purpose.

[Summary of the invention]

To achieve the above object, the mat of the present invention has a light source, and the light generated from the light source is transmitted to the radiation image area (see 1-
q.1, the radiographic image d"1 erases the emission one-line image information stored in the radiographic image storage sheet, and has an inlet hole and an outlet hole, and has a cooling medium. A light transmitting type cooling means having a hollow portion through which the radiation image storage sheet can pass is interposed between the light source and the radiation image storage sheet.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 5 is a dimensional explanatory diagram showing the configuration of the radiation image erasing device according to the present invention. 29a, 29b, 29c, and 29d in the figure are light sources (hereinafter referred to as "light sources 29"), and for example, sodium lamps or halogen lamps are used.

Further, a belt 24, for example, a conveyance means that can run in the direction of the arrow by a drive means (for example, a roller shade) not shown.
-P on L? A light-transmissive cooling means 28, which will be described later, is provided between the radiation image storage sheet (phosphor sheet 84-C) 3 and the light source 29. Reference numeral 3o indicates a housing, and a light source 29 and a light transmission type cooling means 28 are attached to this housing 30. Note that the socket part of the light source 29 must be placed outside the housing 30, or
It is preferable to cool it by The reason for this is that if the socket part is exposed to high humidity of 200° C. or higher, there is a risk that the material to which the socket part is bonded may deteriorate.

Next, the configuration of the light transmission type cooling means 28 will be explained with reference to FIG. 6.

FIG. 6 is a sectional view of the light transmission type cooling means 28 shown in FIG. As shown in the figure, the light transmission type cooling means 28 has an inflow hole 31 and an outflow hole 32, and is configured with a hollow part 33 through which a cooling medium (for example, cold air, cold water, etc.) can pass. The material is a heat-resistant, light-transmitting member, such as glass (crown glass, flint glass, etc.). The reason why glass is used here is that glass has high heat resistance and excellent light transmittance as shown in FIG. 7, for example. In addition, the inflow hole 31 and the outflow hole 3
2 is connected to a cooling medium circulation means (for example, a pump, etc.) via, for example, a chicob, etc., although not shown.

Next, the operation of the apparatus configured as described above will be explained. When the light emitted from the light source 29 and transmitted through the light transmission type cooling means 28 is irradiated onto the phosphor sheet 3 conveyed by the belt 24 to just below the light source 29,
The radiation image information (including afterimage components) stored in the phosphor sheet 3 is erased. Here, the heat rays generated by the light source 29 are absorbed by the light transmission type cooling means 28.

The heat generated by the heat rays absorbed by the light-transmitting cooling means 28 is absorbed by a cooling medium (for example, cold air, cold water, etc.) passing through the hollow portion 33 of the light-transmitting cooling means 28, and is released to the outside. Therefore, since the phosphor sheet 3 is irradiated with only light of the wavelength necessary for erasing, the radiation image information can be erased without increasing the temperature. Therefore, it becomes possible to bring the light source 29 sufficiently close to the phosphor sheet 3, which is very advantageous in terms of erasing efficiency.

Furthermore, since the two light sources can be placed close to the phosphor sheet 3, the structure of this part can be made smaller. This is extremely important in realizing a device in which the erasing section (this device) is attached to the xm processing unit.

It goes without saying that the present invention is not limited to the embodiments described above, and that modifications can be made as appropriate within the scope of the gist of the present invention.

In the above embodiments, the radiation image storage sheet was explained as a phosphor sheet, but it goes without saying that a sheet using TLD or glass fluorescence development can also be applied. Further, the phosphor sheet 3 can be conveyed by any means that can convey the phosphor sheet 3 without being constantly connected to the belt 24.

Further, when cold water is used as the cooling medium, for example, the inner wall of the hollow portion 33 of the light-transmitting cooling means 28 may become dirty due to water scale or the like of the cold water. To prevent this,
For example, as shown in FIG. 8, pure water I'! It is preferable that the water purifying device 36 is activated when the cock 35 is tightened by using the second gas chamber 36.

Note that 34 indicates a cooling medium circulation means, such as a pump.

Furthermore, in the embodiment described above, the material of the light-transmitting cooling means 28 is glass, but any material may be used as long as it is a heat-resistant light-transmitting member, and is not limited to glass.

[Efficacy of invention Song Dynasty]

According to the present invention described above, the heat rays generated from the light source can be absorbed by the light transmission type cooling means.
The light source can be brought close enough to the radiation image storage sheet,
Therefore, it is possible to provide an 18-radiation image removing device that can erase radiation image information stored on a radiation image storage sheet with high efficiency without changing the quality of the radiation image storage sheet.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the configuration of digital radiography; Figure 2 is an explanatory diagram showing the configuration of a radiation image information reading device equipped in the apparatus shown in Figure 1; FIG. 4 is a characteristic diagram showing the emission characteristics of the stimulable phosphor with respect to the wavelength of irradiation light; FIG. 5 is an explanatory diagram showing the configuration of the radiation image erasing device according to the present invention; FIG. 6 is a sectional view showing a light transmission type cooling means included in the apparatus shown in FIG. 5, and FIG. 7 is a heat-resistant light transmission member (glass) applied to the light transmission type cooling means shown in FIG. 6. FIG. 8 is an explanatory diagram showing a modification of the device shown in FIG. 5. 3... Phosphor sheet (radiation image storage sheet), 28.
...Light transmission type cooling means, 29 (29a, 29b, 29c, 29d, ) -9
- Light source, 31... Inflow hole, 32... Outflow hole, 33.
...Hollow part. Agent Hikari Saraju Yu Enchika (h11 people) Figure 2 Figure 4 Table 1 (fLWL)

Claims (1)

[Claims] In a radiation image erasing device that irradiates a radiation image storage sheet with the light generated from the light source and erases the radiation and both image information accumulated on the radiation image storage sheet, an inflow hole and an inflow hole are used. A radiation image erasing device characterized in that a light transmission type cooling means having an outflow hole and having a hollow portion through which a cooling medium can pass is interposed between the light source and the radiation image storage sheet. Device.