JPS61137146A - Noise eliminating device for memory type fluorescent material sheet - Google Patents

Abstract

PURPOSE:To eliminate noises effectively without increasing the size of a radiation image information recorder and reader or device dedicated to recording and reading by adding a noise erasing function to a sheet conveyor roller for conveying a memory type fluorescent material sheet. CONSTITUTION:A circulation passage for sheet conveyance which consists of a guide roller, guide plate, nip roller 22, etc., is provided to the radiation image information recording device or device dedicated to recording and reading; and plural memory type fluorescent sheets 30 are arranged on this circulation passage at specific intervals and circulated by an endless belt and the roller 22 as shown by an arrow A. This roller 22 consists of a driven roller 22a and a driving roller22b which contact the top and reverse surfaces of the sheets 30, and the roller 22b is rotated by a driving motor 22c. The noise erasing function composed of a light source 35 for erasure which is as long as the overall length of the sheets 30 and a reflecting mirror 36 which reflects light from the light source 35 to the side of the roller 22b is provided in the roller 22a. Thus, noises are eliminated effectively without increasing the size of the device.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention involves accumulating and recording radiation image information in a stimulable phosphor sheet, then irradiating the same with excitation light, and responding to the accumulated and recorded image information. The present invention relates to a device for erasing noise from the above-mentioned stimulable phosphor sheet used in a radiation image information recording and reproducing system that detects stimulant light, reads image information, and converts it into an electrical signal. .

(Technical Background and Prior Art of the Invention) When a certain type of phosphor is irradiated with radiation (X-rays, α-rays, β-rays, γ-rays, ultraviolet rays, electron beams, etc.), part of the energy of this radiation is absorbed into the phosphor. When the energy is accumulated in a phosphor and the phosphor is then irradiated with excitation light such as visible light, the phosphor exhibits stimulated luminescence in response to the accumulated energy. Fluorophores that do not exhibit these properties are called storage fluorophores.

Using this stimulable phosphor, radiation image information of a subject such as a human body is recorded on a stimulable phosphor sheet (hereinafter referred to as a stimulable phosphor sheet), which is then scanned with excitation light. A method has been proposed in which the stimulated luminescence is caused by photostimulation, the stimulated luminescence is read photoelectrically to obtain an image signal, and the image signal is processed to obtain an 64-ray image of the subject that is suitable for diagnosis (
For example, JP-A-55-12429, JP-A-55-11634
0, No. 55-163472, No. 56-11395, No. 56-104645, etc.). In this method,
The final image can be reproduced as a hard copy or on a CRT. anyway,
In this J: Una radiation image information recording and reproducing method,
The stimulable phosphor sheet does not ultimately record image information, but temporarily carries image information in order to provide an image to the final recording medium, as described in j above. The light sheet may be used repeatedly, and such repeated use is extremely economical.

In addition, a mobile station such as an X-ray removal vehicle is equipped with a radiation image information recording/reading device that uses stimulable fluorophores 1~, and the mobile station travels to various locations for group examinations and takes X-rays. In such a case, it is inconvenient to load a large number of sheets onto the stimulable phosphor sheet 1, and there is a limit to the number of sheets that can be loaded on the moving vehicle. Therefore, accumulation 1(1
A phosphor sheet is made to be reusable and loaded onto a moving vehicle, and radiation image information for each subject is recorded on it, and the image signal obtained by reading it is recorded on a recording medium with a large storage capacity such as a magnetic tape. If the photocopies, stimulable phosphor sheet 1, etc. are recycled and reused, radiation images of a large number of objects can be taken by a moving vehicle, which is extremely useful in practice. Furthermore, if continuous imaging is performed for this cyclical reuse, the imaging speed can be increased in mass medical examinations, which has an extremely large practical effect.

In order to reuse the stimulable phosphor sheet as described above, the radiation energy remaining in the stimulable phosphor sheet after the stimulated luminescence light is read can be absorbed by, for example,
No. 2, No. 56-12599, the sheet is irradiated with light or heat to release it, and the residual radiation image that becomes noise for the next recording and reproduction of radiation image information is erased, and this cumulative fluorescence is removed. The body sheet can be used again for radiographic image recording.

Therefore, the present applicant proposed a circulating conveyance means that covers eleven stimulable phosphor sheets capable of accumulating and recording radiographic images along a predetermined circulation path, and a circulation means that is located in the circulation path and emits radiation through the sheet through a subject. an image recording section that accumulates and records radiographic image information of the subject on the sheet by irradiation; and an excitation light that is located in the circulation path and scans the sheet on which radiographic image information has been accumulated and recorded in the image recording section. an image reading section comprising an excitation light source emitting light and a photoelectric reading means for reading stimulated luminescence light emitted from a sheet scanned by the excitation light to obtain an image signal; and an erasing section that releases radiation energy remaining on the sheet after being read prior to recording an image on the sheet, and the above-mentioned stimulable phosphor sheet is inserted between the above-mentioned sections. It was proposed that the radiographic image fK+information be circulated and used repeatedly between reading and reading of information (Japanese Patent Application No. 1982-66730). According to the radiographic image information recording/reading device having such a structure, radiographic image information can be recorded and read continuously and efficiently.

However, in the radiation image information recording/reading apparatus having the above configuration, there is a problem in that the erasing section occupies a large space within the apparatus, which hinders miniaturization of the apparatus. It has also been considered to combine the above-mentioned erasing unit with a recording-only device that only records (photographs) radiation image information, or a read-only device that only reads radiation image information.
A similar problem occurs in this case as well.

(Object of the Invention) Therefore, the present invention provides a noise canceling method for a stimulable phosphor sheet that does not occupy a large space and can be formed sufficiently compact in a radiographic image information recording/reading device, a recording-only device, or a read-only device as described above. The purpose is to provide a device.

(Structure of the Invention) The noise erasing device for a stimulable phosphor sheet of the present invention is such that, in the radiation image information recording/reading device, recording-only device, or read-only device, the stimulable phosphor sheet is conveyed. This method was developed by focusing on the fact that a sheet conveying roller is often provided for this reason, and in an apparatus that performs at least one of the above-mentioned accumulation recording and reading of stimulated luminescence light, the above-mentioned luminescent light is A sheet conveyance roller that conveys the sheet after reading the exhaustion light is formed hollow from a transparent material, and an erasing light source that emits light in the excitation wavelength range of the stimulable phosphor of the sheet is disposed within the roller. It is set up.

(Act III! i Aspect) The present invention will be described in detail below based on the embodiments shown in the drawings.

FIG. 1 shows a radiation image information recording/reading apparatus provided with a stimulable phosphor sheet noise canceling device according to a first embodiment of the present invention. As shown in the figure, the radiographic image information recording/reading device contains endless bells 1 to 1.2.
3.4.5.6.7.8.9.10, guide rollers 11.12.13.14 and guide plates 15.16.17, which rotate following the endless belt 1.6.7.10, respectively.
．． 18.19.20.21 and nip roller 22.23
．． A circulation path 26 for general feeding of sheets 1 consisting of sheets 1 and 24 is constructed, and within this circulation path 26, a plurality (in this example, five sheets) of stimulable phosphor sheets 1 to 30 are placed in contact with each other. These stimulable phosphor sheets 30 are arranged at appropriate intervals.
is the above-mentioned endless bell 1 as a sheet circulation conveyance means.
1 to 10 and nip rollers 22, 23, and 24,
It is designed to be circulated and conveyed in the six directions of arrows in the figure.

The endless belts 2.3 are configured to vertically hold and cover the stimulable phosphor sheet 30 between them, and to the side of the endless belts 2.3 (to the left in the figure) A photographing table 41 is provided, and a commercial radiation source 42 such as an X-ray source is provided at a position facing the endless belt 2.3 with the photographing table 41 in between. The image recording unit 40 is configured with a source 42 . During radiographic imaging of a subject (not to be examined) 43, the sheet 30 used for imaging is held between the endless belts 2.3 as shown in the figure, and the patient 43 is positioned in front of the imaging table 41. Radiation source 42 is activated. As a result, the transmitted radiation image of the subject 43 is projected onto the sheet 30, and the radiation line image information of the subject 43 is projected onto the sheet 30.
is accumulated and recorded.

An image reading unit 50 is located at the lower right end position in the figure of the circulation passage 26.
is provided. In this image reading section 50, a laser light source 51 is installed above the endless belt 8 constituting a part of the reading section 50, and its output laser light 5
A mirror 53 and a galvanometer mirror 54 are provided for scanning the sheet 30 on the endless belt 8 in the width direction thereof.

By this reciprocating movement of the galvanometer mirror 54, the laser beam 52 is main-scanned over the sheet 30 on which the radiation image has been accumulated and recorded. Note that the sheets 1 to 30 are conveyed to the image reading section 50 by driving a sheet circulation conveying means after radiation images are recorded in the image recording section 40 . At the scanning position on the sheet 30 of the laser beam 52,
A condensing reflection mirror 55 and a condensing optical element 56 are arranged along the main scanning line. Stimulated luminescent light is emitted from the sheet 30 irradiated with the laser beam 52 and proceeds directly to the condensing optical element 56, and stimulated luminescent light is also emitted from the sheet 30 and reflected by the condensing reflective mirror 55. The emitted light enters the condensing optical element 56 from the incident end surface 56A of the condensing optical element 56, is guided by total internal reflection, and passes through the photomultiplier 57 connected to the exit end surface 56B of the element 56. The light is received by
The stimulated luminescence is read out photoelectrically. At the same time that the main scanning of the laser beam 52 is performed as described above, the sheet 30
is conveyed by the endless belt 8 in the six directions indicated by the arrows in the drawing (that is, in a direction substantially perpendicular to the above-mentioned main scanning direction), sub-scanning is performed, and the accumulated radiation image information is read over the entire surface of the sheet 30. The image signal 81 read by the FJ]-circle 57 is transmitted to an image processing circuit 60, subjected to necessary image processing, and then sent to a necessary image reproduction device 61. As mentioned above, this playback 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 data on a storage device such as a magnetic tape for that purpose. .

The sheet 30 whose image has been read is conveyed along the guide plate 18 by an endless belt 9.10, and then transferred to the guide plate 19 by nip rollers 22, 23, 24.
．． 20 and 21 to the endless belt 1.

Hereinafter, the nip roller 22 according to the present invention will be explained in detail with reference to FIG. 2. The nip roller 22 is
It consists of a driven roller 2'2a that is in contact with the front surface (recording surface) of the stimulable phosphor sheet 30, and a drive roller 22b that is in contact with the back surface of the sheet 130, and the drive roller 22b is rotated by a drive motor 22c and is The phosphor sheet 30 is conveyed. The driven roller 22a is made of a transparent material such as acrylic and has a hollow cylindrical shape, and is rotatably held by a roller holding roller 34 to support the driving roller 22.
It rotates as a result of b.

Inside the driven roller 22a are an erasing light source 35 having a length spanning the entire width of the stimulable phosphor sheet 30, and a reflecting mirror 36 that reflects the light emitted by the erasing light source 35 toward the driving roller 22b. It is arranged. The above erasing light source 35
The device emits light in the excitation wavelength range of the stimulable phosphor of 30 to the sea 1, for example, a tungsten lamp, a halogen lamp, an infrared lamp, a xenon flash as shown in Japanese Patent Application Laid-open No. 56-11392. Lamps, fluorescent lamps, etc. can be arbitrarily selected and used.

When the stimulable phosphor sheet 30 passes through the nip roller 22 after the image has been read as described above, the sheet 30 is irradiated with the above-mentioned light emitted from the erasing light source 35, so that the image cannot be read. The radiation energy remaining in the reading contact sheet 30 (which will become noise if the next radiation image information record reading is continued) is released, and the stimulable phosphor sheet 30 can be reused. It becomes possible.

Note that, for example, if the stimulable phosphor sheets 1 to 30 are placed on the endless belt 9 after image reading and are not used for a long period of time, impurities may be contained in the phosphor sheets 30. Radiation energy from radioactive elements such as 22GRa and environmental radiation, that is, the same noise components as described above, may be accumulated, but of course such noise components are also emitted at the same time.

In this embodiment, the remaining two pairs of nip rollers 23.
The nip roller 24 is also formed in the same manner as the nip roller 22, so that the stimulable phosphor sheet 30 undergoes noise cancellation at three locations in total. The number of nip rollers equipped with the erasing light source 35 inside can be determined by determining the amount of erasing light necessary to erase 30 noise components from the stimulable phosphor sheet 1, and then determining the illuminance of the erasing light source 35 and the stimulable phosphor sheet 1. Light sheet 3
It may be determined based on the transfer speed of 0. Further, in this embodiment, light shielding plates 70, 71, and 72 surrounding the nip rollers 22, 23, and 24 are provided, and the stimulable phosphor sheet 30 in the image recording section 40 and the image reading section 50 is
Light from the erasing light source 35 is not irradiated.

Next, a second embodiment of the present invention shown in FIG. 3 will be explained. In this embodiment, of the driven roller 122a and the driving roller 122b constituting the nip roller, the driving roller 122b is formed of a transparent material into a hollow cylindrical shape. An erasing light source 35 and a reflecting mirror 36 similar to those shown in FIG. Note that the hollow drive roller 122b is connected to four roller holding rollers 134 that hold the roller 122b.
Of these, two on one side are driven by being rotated by a drive motor 122G.

In the two embodiments described above, the erasing light source 35 is disposed inside one of the pair of nip rollers, but the noise erasing device of the present invention is applicable not only to the nip roller but also to other sheet conveyance rollers. It can also be configured using For example, in the third embodiment of the present invention shown in FIG.
is formed of a transparent material into a hollow cylindrical shape, and an erasing light source 35 and an anti-fouling mirror 36 are disposed inside it.

Note that this sheet conveying roller 200 is driven by rotation of a driving roller 201 that is in contact with its circumferential surface, and moves an endless belt-shaped stimulable phosphor sheet 230 in the direction of arrow A.
Send in the direction. Further, in this embodiment, a condensing lens 37 made of a cylindrical lens is provided inside the sheet conveyance roller 200, so that the light emitted by the erasing light 1 [i35] can be used to more efficiently erase noise from the stimulable phosphor sheet 230. I'm trying to get it used.

Note that the noise canceling device of the present invention is not limited to the radiation image information recording/reading device as shown in FIG. In the former case, the transport roller transports the stimulable phosphor sheet before recording radiation image information, and in the latter case, the transport roller transports the stimulable phosphor sheet after reading the radiation image information. An erasing light source may be incorporated into the conveyance roller.

(Effects of the Invention) As explained in detail above, the noise canceling device for a stimulable phosphor sheet of the present invention has a noise canceling function added to the sheet conveying roller necessary for conveying the stimulable phosphor sheet. Therefore, according to this noise canceling device, a radiation image information recording/reading device or a recording/reading-only device can be formed into almost the same size as a case where the noise canceling device is not incorporated, and is significantly smaller than conventional devices. become □.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a radiation image information recording/reading device equipped with a noise canceling device according to a first embodiment of the present invention, FIG. 2 is a perspective view showing details of the device according to the above embodiment, and FIGS. The figures are perspective views showing second and third embodiment devices of the present invention, respectively. 22.23.24...Nip roller 22a...Followed roller 30.230...Storage phosphor sheet 35...Erasing light m40...ii! ii Image recording section 50... Image reading section 122b... Drive roller 200... Sheet conveyance roller

Claims (1)

[Claims] Radiation that has passed through the object is irradiated onto a stimulable phosphor sheet to accumulate and record radiation image information of the object on the sheet, or excitation light is irradiated onto the sheet on which the radiation image information has been accumulated and recorded. In the device for photoelectrically reading the stimulated luminescence light emitted from the sheet, the sheet conveying roller that conveys the sheet before the accumulation recording or after reading the stimulated luminescence light is formed hollow from a transparent material. A noise canceling device for a stimulable phosphor sheet, comprising: an erasing light source that emits light in the excitation wavelength range of the stimulable phosphor of the sheet, and provided within the roller.