JPS6397939A - Erasing device for remaining radiation image on radiation image conversion panel - Google Patents

Abstract

PURPOSE:To perform effective erasure by interposing an ultraviolet-ray removal filter between a fluorescent lamp and a panel storage part. CONSTITUTION:The fluorescent lamp 11 which functions as an erasing light source, the storage part 12 for the radiation image conversion panel P as an object of erasure, and the ultraviolet-ray removing filter 13 interposed between the fluorescent lamp 11 and panel storage part 12 are stored in a box-shaped housing 14. The panel P is processed for erasure while mounted on the panel storage part 12, and a handle 15 is provided to the panel storage part 12 and utilized to insert and extract the panel into and from an erasing device. The ultraviolet-ray removing filter 13 is preferably a filter which absorbs >=80% of light in a short-wavelength range of <=440nm wavelength. Consequently, a remaining radiation image is removed nearly completely in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a device for erasing a residual radiation image of a radiation image conversion panel using a stimulable phosphor.

[Background of the Invention] Recently, a radiation image information recording and reproducing system that obtains a radiation transmitted image of a subject using a stimulable phosphor has been attracting attention. Here, stimulable phosphor refers to radiation (X-rays, α-rays, β-rays, γ-rays,
When it is irradiated with radiation (rays, electron beams, ultraviolet rays, etc.), it accumulates some of that radiation energy, and when it is later irradiated with excitation light such as visible light, it emits stimulated luminescence according to the accumulated energy. The radiation image information recording and reproducing system described above uses this stimulable phosphor,
Radiation image information of a subject such as a human body is temporarily stored and recorded on a sheet having a layer made of stimulable phosphor (hereinafter referred to as a radiation image conversion panel), and this radiation image conversion panel is scanned with excitation light such as a laser. The resulting stimulated luminescent light is read photoelectrically to obtain an image signal, and based on this image signal, a visible image or image information is recorded on a recording material such as a photographic light-sensitive material or a CRT, etc. The output is as follows.

A radiation image conversion panel is also called a stimulable phosphor sheet, and is usually a rectangular or square shaped sheet (with a side length of approximately 20 to 50 cm), and its basic structure is as follows:
It consists of a support and a phosphor layer provided on one side of the support. Note that -fm is on the surface of this phosphor layer.
A transparent protective film made of a polymeric material is provided to protect the phosphor layer from chemical deterioration or physical impact.

The radiographic image conversion method described above causes much less damage than conventional radiographic methods. Because it is possible to obtain radiation images with a rich amount of information based on the amount of radiation, it is extremely useful in direct medical radiography such as X-ray photography for the purpose of medical diagnosis using the human body as an object.

In the radiation image information recording and reproducing system described above, the radiation image conversion panel is not for ultimately recording image information, but rather temporarily holds radiation image information in order to provide an image to a recording medium as described above. This radiation image conversion panel is extremely economical and effective if used repeatedly. In this case, in order to reuse the radiation image conversion panel, the radiation energy remaining in the radiation image conversion panel after reading has been performed by irradiation with excitation light is emitted by irradiation with light to erase the residual radiation image. Then, the radiation image conversion panel can be used again for recording radiation images.A technique for removing the radiation energy remaining in the radiation image conversion panel after the reading operation is disclosed in, for example, Japanese Patent Laid-Open No. 56-11392.
It is disclosed in the publication No.

In other words, a radiation image information reading device intended for repeated use includes a radiation image reading section for reading a radiation image recorded by irradiating the radiation image conversion panel with radiation that has passed through the subject, and a radiation image conversion panel. A radiation image erasing section is usually provided for erasing the radiation image remaining in the radiation image within a short time so that the radiation image conversion panel can be used in the next radiation image recording operation.

In order to erase the residual radiation image in a short time, it is necessary to apply high-energy erasing light to the radiation image conversion panel during the erasing operation. For this reason, the light source of the erasing light is generally arranged in a partitioned space, and the residual radiation image erasing operation is carried out by introducing a radiation image conversion panel to be erased into the space.

In order to use the radiation image conversion panel repeatedly, a radiation image erasing device is required, but it is desirable that the erasing operation in that device be performed in as short a time as possible, and that the remaining radiation image can be completely removed. Although it is difficult to achieve complete erasure in a short period of time, it is necessary to perform erasure as completely as possible to avoid problems in the next use. Fluorescent lamps, incandescent lamps, sodium lamps, etc. are used as the erasing light source, but in any case, high-energy erasing light can be generated by supplying a large amount of current.

Among the known light sources for erasing, fluorescent lamps have the advantage of being inexpensive, readily available with high stability, and generating less heat. However, according to the study conducted by the present inventor, it has been found that when a fluorescent lamp is used as the erasing light source, the residual radiation image is not always sufficiently erased.

[Object of the Invention] An object of the present invention is to provide an erasing device that enables efficient erasure of residual radiation images of a radiation image conversion panel used in a radiation image information recording and reproducing system.

One object of the present invention is to provide an erasing device that enables efficient erasing of residual radiation images, particularly by using a fluorescent lamp as a light source for erasing residual radiation images on a radiation image conversion panel.

[Summary of the Invention] The present invention irradiates a radiation image conversion panel on which a radiation image is recorded with excitation light to emit the radiation image as stimulated luminescence light, reads this stimulated luminescence light with an optical element, An erasing device for erasing a radiation image remaining on a radiation image conversion panel subjected to a radiation image reading step of converting the radiation image into an electrical signal by irradiating it with erasing light, the erasing device being used as an erasing light source. Residual radiation of a radiation image conversion panel characterized in that it includes a functioning fluorescent lamp, a housing part for a radiation image conversion panel to be erased, and an ultraviolet removal filter interposed between the fluorescent lamp and the panel housing part. The statue erasure bag is here.

[Detailed Description of the Invention] A device for erasing a residual radiation image of a radiation image conversion panel according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a partially cutaway perspective view showing an example of the structure of the erasing device of the present invention, and FIG. 2 is a sectional view taken along line 1--H of the erasing device of FIG.

To explain the configuration of FIG. 1 as an example, the residual radiation image erasing device 1O of the present invention includes fluorescent lamps (usually a plurality of fluorescent lamps, for example, about 10 used as a set) which function as erasing light sources. are arranged in parallel as shown),
A storage section 12 of the radiation image conversion panel P to be erased (in the figure, two panels are erased together), and an ultraviolet removal filter interposed between the fluorescent lamp ti and the panel storage section 12. 13, which are normally housed in a box-shaped housing 14. The panel P is subjected to the erasing process while being placed a in the panel accommodating portion 12.

The panel accommodating portion 12 is provided with a handle 15, and the handle 15 is used to insert and remove the panel from the erasing device.

Note that ultraviolet removal filters are usually used by placing them under a plurality of fluorescent lamps arranged in parallel as shown in Figures 1 and 2 in parallel with the row. The fluorescent lamps can be interposed between the fluorescent lamps and the panel accommodating portion by any method, such as wrapping an ultraviolet ray removal filter around the fluorescent lamps or arranging independent ultraviolet ray removal filters under each fluorescent lamp.

Further, the erasing device of the present invention may be an independent device,
Alternatively, it may be attached to the reading device of the radiation image conversion panel.

The ultraviolet removal filter used in the erasing device of the present invention is not particularly limited as long as it absorbs most of the ultraviolet rays, but it absorbs 80% of the light in the wavelength region shorter than 440 nm.
The absorption characteristics of the ultraviolet removal filter used advantageously in the present invention are preferably a filter that absorbs at least 85% of light in a wavelength region shorter than 440 nm, and particularly preferably a filter that absorbs at least 85% of light in a wavelength region shorter than 440 nm. As shown in Figure 3, in Figure 3, a, b, c, d, e
, f can all be used advantageously in the present invention.

Fig. 4 shows the residual radiation image erasing efficiency when using a known residual radiation image erasing device of a radiation image conversion panel using only fluorescent lamps, and 1. FIG. 4 is a diagram showing an example of erasing efficiency of residual radiation images when

This graph of erasure efficiency was created from values measured as follows.

First, the radiation image conversion panel is irradiated with X-rays with a tube voltage of 80 KVp, and then He-Ne laser light (wavelength: 632.8n
m) is scanned and excited to cause stimulated luminescence, and then
After performing an erasing operation by irradiating this panel with light from 10 15W white fluorescent lamps (light emission amount of each fluorescent lamp = 60,000 lux/second) to a predetermined exposure amount,
Leave it at a temperature of 5℃ for 3 hours, excite it again with He-Ne laser light, measure the amount of stimulated luminescence (residual luminescence amount), and calculate the value of the residual luminescence amount after the erasure processing time (to fluorescent lamp). (proportional to the exposure amount).

Fig. 4 shows the residual radiation image erasure curve (N) when using the known residual radiation image erasure device of the radiation image conversion panel using only fluorescent lamps, and the erasure device using the ultraviolet removal filter according to the present invention. It is clear from the erasure curve (F) of the residual radiographic image when using the method that the erasing device of the present invention is extremely effective in eliminating the residual radiographic image almost completely in a short time.

[Operation and Effect of the Invention] When the radiation image conversion panel is irradiated with a fluorescent lamp in order to erase the remaining radiation image, the remaining radiation image is erased, but the irradiated stimulable phosphor is absorbs new ultraviolet light emitted from fluorescent lights and accumulates it. Therefore, depending on the erasing operation using ordinary fluorescent lamps, the erasure will not reach a certain level even if it takes a long time.In contrast, in the present invention, ultraviolet ray removal that absorbs the ultraviolet rays generated from fluorescent lamps is possible. Filters can be used to achieve more complete erasure of the panel's radiation image without reducing erasure efficiency.

Therefore, by introducing the device for erasing the residual radiation image of a radiation image conversion panel of the present invention into a radiation image information recording and reproducing system using a radiation image conversion panel, a system that is inexpensive and has high performance stability can be obtained. It is now possible to erase residual radiation images on a radiation image conversion panel with high efficiency while using fluorescent lamps, which have the advantage of being easy to use and generating less heat.

In particular, if the radiation image information stored in the radiation image conversion panel is position information of a radioactively labeled polymeric substance obtained by imparting a radioactive label to a biologically derived polymeric substance, Due to the low level of accumulated radiation energy, it is necessary to use a highly sensitive readout device 21 (such as a highly sensitive photomultiplier), and in cases where such a readout system involved is highly sensitive, the erasure of the present invention The device can be used with particular advantage.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing a configuration example of an erasing device of the present invention. FIG. 2 is a cross-sectional view of the erasing device of FIG. 1 taken along line -H. FIG. 3 shows an example of the absorption characteristics of an ultraviolet removal filter advantageously used in the present invention. FIG. 4 shows the erasure curve (N) of the residual radiation image when using a known device for erasing the residual radiation image of a radiation image conversion panel using only fluorescent lamps, and the erasure curve (N) using the ultraviolet removal filter according to the present invention. An example of the erasure curve (F) of the residual radiation image when the device is used is shown. P: Radiation image conversion panel 1O: Remaining radiation image erasing device 11: Fluorescent lamp 12: Receiving section for radiation image conversion panel 13: Ultraviolet removal filter 14: Housing 15: Handle Patent applicant Fuji Photo Film Co., Ltd. Agent Patent attorney Yasuo Yanagawa Figure 1 Figure 3 Figure 4 Erasing light i1 (x IC)' 1ux-sec) Procedural amendment 1.71 rF Display of 1985 Patent Application No. 243561 2, Title of Invention Radiation Device for erasing residual radiation images of image conversion panel 3, relationship with the case of person making correction Patent applicant name (520) Fuji Photo Film Co., Ltd. 4, agent address 8 Mitsuya Yotsuya Building, 2-14 Yotsuya, Shinjuku-ku, Tokyo
Floor 6: Number of inventions increased by amendment None 7: Subject of amendment (1) “Detailed description of the invention” in the specification. (2) Drawings. 8. Contents of amendment (1) As shown in the attached sheet. (1) The “Detailed Description of the Invention” column of the specification will be amended as follows. ``Surface of phosphor layer'' on page 3, line 19 of the specification is corrected to ``surface of phosphor layer.'' (2) Measure li' from page 10, line 20 to page 11, line 1 of the specification. ” should be corrected to ``Measure,''. Figure 4

Claims (1)

[Claims] 1. A radiation image conversion panel on which a radiation image has been recorded is irradiated with excitation light to emit the radiation image as stimulated luminescence light, this stimulated luminescence light is read by an optical element, and then An erasing device for erasing a radiation image remaining on a radiation image conversion panel subjected to a radiation image reading process of converting the radiation image into an electrical signal by irradiating it with erasing light, the erasing device functioning as an erasing light source. A residual radiation image of a radiation image conversion panel characterized in that it includes a fluorescent lamp to be erased, a housing part for a radiation image conversion panel to be erased, and an ultraviolet removal filter interposed between the fluorescent lamp and the panel housing part. erasing device. 2. The residual radiation image erasing device according to claim 1, wherein the ultraviolet ray removal filter is a filter that absorbs 80% or more of light in a wavelength region shorter than 440 nm. 3. The residual radiation image erasing device according to claim 1, wherein the ultraviolet removal filter is a filter that absorbs 85% or more of light in a wavelength range shorter than 440 nm. 4. The radiation image information accumulated and recorded in the radiation image conversion panel is characterized in that it is position information of a radiolabeled polymeric substance obtained by imparting a radioactive label to a biologically derived polymeric substance. An apparatus for erasing residual radiation images according to any one of claims 1 to 3.