JPH0578818B2 - - Google Patents

Description

Detailed Description of the Invention (Field of the Invention) The present invention involves storing and recording radiation image information on a stimulable phosphor sheet, then irradiating the same with excitation light,
It relates to a radiation image information recording/reading device that detects photostimulated light according to accumulated and recorded image information, reads the image information, and converts it into an electrical signal. The present invention relates to a radiation image information recording/reading device that is transported through a circulation path by a circulation conveyance means and reused.

(Technical Background of the Invention and Prior Art) Certain types of phosphors are exposed to radiation (X-rays, α-rays, β-rays,
When irradiated with γ-rays, electron beams, ultraviolet rays, etc., a portion of the energy of this radiation is accumulated in the phosphor, and when the phosphor is then irradiated with excitation light such as visible light, it responds to the accumulated energy. The phosphor exhibits stimulated luminescence. A phosphor exhibiting such properties is called a stimulable phosphor.

Using this stimulable phosphor, radiation image information of a subject such as a human body is stored and recorded on a sheet of stimulable phosphor, and this is scanned with excitation light to cause stimulated luminescence. A radiographic image information recording and reproducing method has been proposed that obtains an image signal by photoelectrically reading it and processes this image signal to obtain a radiographic image of a subject that is suitable for diagnosis (for example,
No. 12429, No. 56-11395, No. 55-163472, No. 56
-104645, 55-116340, etc.). In this method, the final image may be reproduced as a hard copy or as a visible image on a CRT. In any case, in such a radiation image information recording and reproducing method, the stimulable phosphor sheet does not ultimately record image information, but temporarily stores image information in order to provide an image to the final recording medium as described above. Therefore, this stimulable phosphor sheet may be used repeatedly, and such repeated use is extremely economical.

Also, for example, when a mobile station such as an X-ray imaging vehicle is equipped with a radiation image information recording/reading device that uses a stimulable phosphor sheet, and the mobile station travels to various locations for group medical examinations to take X-ray images. for,
It is inconvenient to load a large number of stimulable phosphor sheets into a vehicle, and there is a limit to the number of sheets that can be loaded onto a moving vehicle. Therefore, a reusable stimulable phosphor sheet is mounted on a mobile vehicle, radiation image information for each subject is recorded on it, and the image signal obtained by reading it is stored on a magnetic tape or other storage device with a limited storage capacity. If the radiation images are copied onto a large recording medium and the stimulable phosphor sheet is recycled, radiographic images of a large number of objects can be taken using a mobile vehicle, which is extremely useful in practice. Furthermore, if continuous imaging is performed through this cyclical reuse, the imaging speed can be increased in mass medical examinations, which has an extremely large practical effect.

In addition, in order to reuse the stimulable phosphor sheet in this way, the radiation energy remaining in the stimulable phosphor sheet after the stimulated luminescence light has been read can be used, for example, in JP-A-56-11392, JP-A-56-11392; The stimulable phosphor sheet may be used again for recording radiation images by emitting it to erase residual radiation images using the method shown in Japanese Patent No. 12599.

Based on the above-mentioned viewpoints, the present applicant has proposed a circulating conveyance means for conveying a stimulable phosphor sheet capable of accumulating and recording radiographic images along a predetermined circulation path, and a means for conveying a stimulable phosphor sheet capable of accumulating and recording radiographic images, and a method for passing a subject through the sheet in the circulation path. an image recording section that accumulates and records radiation image information of a subject on the sheet by irradiating radiation; and an excitation that scans the sheet on which radiographic image information is accumulated and recorded in the image recording section in the circulation path. an image reading unit having an excitation light source that emits light; a photoelectric reading unit that reads stimulated luminescence light emitted from a sheet scanned by the excitation light to obtain an image signal; An erasing section that releases the residual radiation energy on the sheet prior to recording an image on the sheet after the image has been read in the reading section is incorporated into one device, and the above-mentioned stimulable phosphor sheet is , a radiographic image information recording/reading device (hereinafter referred to as
We previously proposed a built-in type device (Japanese Patent Application No. 1983-66730).

However, when the stimulable phosphor sheet is recycled and reused within the above-mentioned apparatus, fine dust floating in the air and fine dust generated within the apparatus become attached to the surface of the stimulable phosphor sheet. If such dust adheres to the surface of the sheet on which the stimulable phosphor is supported, the stimulated luminescence from the dust-attached part will be obstructed when reading radiation image information, and this part will not be visible in the reproduced image. It becomes white. For example, in a radiographic image of a cancer lesion, areas where the cancer has progressed and become calcified appear as white spots, and other lesions may also appear as white spots in radiographic images, so the above-mentioned When a white spot due to dust occurs, as shown in the figure, there is a high risk that this area will be mistaken for a lesion.

Therefore, it is conceivable to clean the surface of the stimulable phosphor sheet to remove the dust prior to reading the radiation image information. However, the sheet circulation conveyance means (e.g., endless belts, nip rollers, etc.) within the device are often dirty due to adhesion of dust from sheets that have already been conveyed, and the stimulable phosphors that have been diligently cleaned are often contaminated. When the sheet is conveyed by this circulating conveyance means, it becomes soiled again, resulting in the above-mentioned problem of white spots.

The above problems can be solved by cleaning the circulation conveyance means appropriately to remove dust, but the circulation conveyance means that conveys the thin stimulable phosphor sheet has a complicated mechanism, so cleaning cloths and cleaning liquid are not required. Cleaning work using such tools is extremely difficult.

(Object of the Invention) The present invention has been made in view of the above problems, and uses a stimulable phosphor sheet as an image recording section,
A built-in type device that circulates between an image reading section and an erasing section for reuse, and is equipped with a cleaning means that can easily clean the circulating conveyance means that circulates the stimulable phosphor sheet. The purpose is to provide

(Structure of the Invention) The device of the present invention is the above-mentioned built-in type device, which is equipped with a cleaning sheet provided with an adhesive layer on at least one surface, and this cleaning sheet is always used simultaneously with the stimulable phosphor sheet. It is characterized in that it is transported within the apparatus by the circulation transport means. In other words, if the above-mentioned cleaning sheet is conveyed by the circulation conveyance means in the same way as the stimulable phosphor sheet, the dust adhering to the circulation conveyance means will be attached to the adhesive layer on the surface of the cleaning sheet and transferred to the circulation conveyance means. removed from The cleaning sheet is formed in a shape that can be conveyed by the circulation conveyance means, that is, it has a thickness, rigidity, etc. comparable to that of the stimulable phosphor sheet conveyed by the circulation conveyance means.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic side view showing a radiation image information recording/reading apparatus according to one embodiment of the present invention.

As shown in FIG. 1, this device has an L-shaped circulation path 1, and the stimulable phosphor sheet 2 is moved along this circulation path 1 by an endless belt 3A, a guide roller 3B that rotates following the endless belt, Guide plate 3
C, it is circulated and conveyed by a circulation conveyance means consisting of a nip roller 3D.

An image recording section (photographing section) 5 is provided on the circulation path 1.
, an image reading section 6 , and an erasing section 7 are sequentially arranged in the sheet traveling direction (direction of arrow A), and as an example, four stimulable phosphor sheets 2
are spaced apart from each other so that they can be circulated and conveyed in the direction of arrow A in the figure.

In the photographing section 5, the radiation emitted from the radiation source 10 passes through the subject 11 and forms the sheet 2.
By entering the beam, radiation image information of the subject is accumulated and recorded on the sheet 2.

The photographed sheet is conveyed along the circulation path in the direction of arrow A by circulation conveyance means such as the guide roller 3B and the endless belt 3A, and enters the image reading section 6.

The image reading unit 6 includes an excitation light source 62 that emits an excitation light 61 such as a laser beam that scans the sheet 2, and a photoprinter that reads stimulated luminescence light emitted from the sheet 2 by scanning the excitation light and obtains an electrical image signal. and a photoelectric reading means 63. 6
4 is a galvanometer mirror. This image reading unit 6 reads the sheet 2 while advancing it at a constant speed, so the image reading unit 6 reads the sheet 2 immediately before starting reading.
It has a space 65 for one sheet in which the sheet 2 is located, and a space 66 for one sheet in which the sheet 2 immediately after reading is located. The photoelectric conversion means 6
The image signal read by 3 is transmitted to an image processing circuit (not shown), subjected to necessary image processing, and then sent to a necessary image reproduction device. This reproducing device may be a display such as a CRT, a recording device that performs optical scanning recording on a photosensitive film, or a device that temporarily records on a recording device such as a magnetic tape for that purpose.

The sheet 2 whose image has been read is sent to the erasing section 7 by an endless belt 3A or the like. The erasing unit 7 consists of a box 71 and a large number of erasing light sources 72 such as fluorescent lamps, tungsten lamps, sodium lamps, xenon lamps, and iodine lamps arranged inside the box 71. The remaining radiation energy on the sheet is emitted by visible light irradiation from the erasing light source 72.

The erased sheet is sent to the photographing section 5 again by the circulating conveyance means.

Furthermore, in the embodiment shown in FIG. Two waiting zones 91 and 92 are provided in which the erased sheets are kept on standby, and the positions of the circulated sheets 2 are adjusted so that the sheets do not overlap each other.

Incidentally, in the apparatus of the present invention, a cleaning sheet 102 is provided for cleaning the circulation conveyance means. This cleaning sheet can be made by, for example, applying an adhesive material (such as an acrylic solvent-based adhesive) directly to both sides of a base sheet (such as a polyethylene terephthalate sheet) similar to the stimulable phosphor sheet 2, or by transferring it from a release paper. It has approximately the same thickness and rigidity as the stimulable phosphor sheet 2, and its size is the same as or slightly larger than the stimulable phosphor sheet 2. In the embodiment shown in FIG. 1, when the circulation conveyance means is not cleaning, the cleaning sheet is held in a cleaning sheet standby section 100 that branches laterally from the circulation path above the erasing section 7. As shown in the enlarged view of the vicinity of this standby section 100 in FIG. When the plate 103 is in the position indicated by the solid line in the figure, the cleaning sheet 102 is held in the standby section,
The image recording section 5, image reading section 6, and erasing section 7 on the circulation path 1 are each in an operable state. on the other hand,
When cleaning the circulation conveyance means, the sheet guide plate 103 is moved to 10 indicated by the broken line in the figure.
3', the nip roller 104 rotates in the direction indicated by the solid arrow, and the cleaning sheet is sent into the circulation path 1. When the cleaning sheet is carried in, the image recording section 5, the image reading section 6, and the erasing section 7 are not operated, but the sheet circulation conveyance means is driven, and the stimulable phosphor sheet 2
At the same time, the cleaning sheet 102 is conveyed. Since both surfaces of the cleaning sheet 102 have appropriate adhesiveness, when the cleaning sheet 102 is conveyed through the circulation path 1, it is attached to the endless belt 3A, the guide roller 3B, the guide plate 3C, and the nip roller 3D.
The dust adhering to the surface of the cleaning sheet 102 becomes attached to the surface of the cleaning sheet 102. Therefore, when the cleaning sheet 102 is circulated and conveyed in the circulation path 1 as described above, the endless belt 3
The above-mentioned dust is removed from the surfaces of the guide roller 3B, guide plate 3C, and nip roller 3D.

If the cleaning sheet 102 is conveyed through the circulation path 1 at the same time as the stimulable phosphor sheet 2 as described above, the endless belt 3A and the guide roller 3
B, the guide plate 3C, and the nip roller 3D have been cleaned and are free of dust, so the stimulable phosphor sheet 2 conveyed during recording and reading of radiographic image information is not attached to the endless belt 3A, The guide roller 3B, guide plate 3C, and nip roller 3D are no longer contaminated by dust, and the above-mentioned white spots in the read image are prevented from occurring. In the above embodiment, four sheets can be conveyed as described above, so when the cleaning sheet is circulated, three stimulable phosphor sheets are circulated at the same time. Furthermore, in addition to cleaning the circulating conveyance means as described above, it is desirable to appropriately clean the stimulable phosphor sheet 2 itself as described above.

After recording and reading radiation image information on the stimulable phosphor sheet 2 as described above, the sheet guide plate 103 is placed at the position 103' to guide the cleaning sheet toward the standby section 100. , the cleaning sheet is stored in the standby section 100 by rotating the nip roller 104 in the direction of the dashed arrow. After storing the cleaning sheet, the sheet guide plate 103 is returned to the position indicated by the solid line.

The structure of the standby section is not limited to that in the above embodiment, and as shown in FIG.
may be made into a bypass shape. In this case, even if the cleaning sheet has made one cycle, the portion 1a of the circulation path 1 that is parallel to the standby section 100A has not been cleaned, so the position of the sheet guide plate 103A is switched and the cleaning sheet is moved to the standby section 1.
After exiting from 00 and making one round through the circulation passage, the cleaning sheet may be made to make one more round so as to pass only through the circulation passage, and the cleaning may be performed in two rounds as one unit. Further, the standby section does not necessarily have to be provided, and the cleaning sheet and the stimulable phosphor sheet may always be conveyed through the circulation path at the same time.

In addition to forming an adhesive layer on both surfaces of the base sheet as in the cleaning sheet 102 of the above embodiment, the cleaning sheet used in the present invention may also have an adhesive layer formed only on one surface of the base sheet. good. However, if adhesive layers are formed on both surfaces of the sheet, it is convenient because there is no need to check the front and back sides of the cleaning sheet when cleaning the circulating conveyance means. In addition, if a nip roller is used as the circulation conveyance means, even if the roller that contacts the back side of the stimulable phosphor sheet (the side opposite to the image forming side) is dirty, this roller will not be used as the paired roller, i.e. Since the rollers in contact with the surface of the sheet on the image forming side become dirty, it is preferable to form an adhesive layer on both surfaces of the cleaning sheet to clean both rollers.

Further, the cleaning sheet used in the present invention may be made of an adhesive material formed into a sheet shape. A specific example of an adhesive material that can be formed into a sheet shape and can itself be used as a cleaning sheet is low-hardness urethane. Cleaning sheets made of low-hardness urethane (of course, both surfaces are adhesive) can be washed with water to remove dirt attached to them, and can be reused, making them convenient and economical.

(Effects of the Invention) As described above in detail, according to the radiation image information recording/reading device of the present invention, the cleaning sheet is provided and the cleaning sheet is simply circulated in the circulation path simultaneously with the stimulable phosphor sheet. The circulation conveyance means can be effectively cleaned, dust is prevented from adhering to the stimulable phosphor sheet from the circulation conveyance means, and high-quality images without image defects can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic side view showing a radiation image information recording/reading device according to an embodiment of the present invention, and FIG. 2 is a partially enlarged view showing the vicinity of the cleaning sheet standby part of the device shown in FIG. FIG. 3 is a partially enlarged view similar to FIG. 2 showing the vicinity of the waiting area of the cleaning sheet in another embodiment of the present invention. 1...Circulation passage, 2...Stormable phosphor sheet,
3A... Endless belt, 3B... Guide roller, 3C... Guide plate, 3D... Nitz roller,
5... Image recording section, 6... Image reading section, 7... Erasing section, 100... Standby section, 102... Cleaning sheet, 103... Sheet guide plate.

Claims (1)

[Scope of Claims] 1. A plurality of stimulable phosphor sheets capable of accumulating and recording radiographic image information; circulatory conveyance means for conveying the stimulable phosphor sheets along a predetermined circulation path; , an image recording unit that accumulates and records radiation image information of a subject on the sheet by irradiating radiation through the subject; in the circulation path, radiographic image information is accumulated and recorded in the image recording unit; an image reading section having an excitation light source that emits excitation light that scans the sheet, and a photoelectric reading means that obtains an image signal by reading stimulated luminescence light emitted from the sheet scanned by the excitation light; an erasing section that releases residual radiation energy on the sheet prior to recording an image on the sheet after the image reading is performed in the image reading section; What is claimed is: 1. A radiation image information recording/reading device comprising: a cleaning sheet having an adhesive layer provided on its surface; wherein the stimulable phosphor sheet and the cleaning sheet are always conveyed and circulated in the circulation path at the same time. 2. A cleaning sheet standby section branching from the circulation path and holding the cleaning sheet is provided on a side of the circulation path, and the cleaning sheet is conveyed within the circulation path only during cleaning;
The radiation image information recording/reading apparatus according to claim 1, wherein the cleaning sheet is held in a standby section during non-cleaning.