JPH042996A - Accumulative phosphor sheet and reading device thereof - Google Patents

Abstract

PURPOSE:To make it possible to make a device compact and to make the speed of reading high by a method wherein an emitted light from an accumulative phosphor layer is taken in from the lateral side of an optical guide member, reflected repeatedly inside and led to the end face of the optical guide member. CONSTITUTION:A phosphor sheet 2 is composed of a supporting body 4 prepared by juxtaposing a number of slender optical guide members 4 (4a to 4c... 4n) and constructed in the shape of a sheet as a whole, and of an accumulative phosphor layer 6 laminated on the whole of the supporting body 4. Each optical guide member 4 takes in a light emitted from the accumulative phosphor layer 6, from the material side 4A thereof, reflects the light repeatedly inside and leads it to the end face 4B thereof. By pushing the accumulative phosphor sheet 2 into a housing 20 from an insertion port 20A, the end part 2A of the accumulative phosphor sheet 2 comes into contact with a multisensor 22. A reading mechanism being operated automatically or manually, a radiation image recorded on the accumulative phosphor sheet 2 is read in the course of an operation of discharging the phosphor sheet 2 from the housing 20.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention accumulates and records radiation image information on a stimulable phosphor sheet, then irradiates it with excitation light, and responds to the accumulated and recorded image information. The present invention relates to a new type of stimulable phosphor sheet in a radiation image information recording/reading system that detects stimulated light and reads image information as an electrical image signal, and further relates to a reading device thereof.

(Prior art) 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 accumulated in the phosphor. Then, when the phosphor is irradiated with excitation light such as visible light, the phosphor exhibits stimulated luminescence depending on the accumulated energy. A phosphor exhibiting such properties is called a stimulable phosphor (stimulable phosphor).

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 and illuminated. A method has been proposed in which the stimulated emitted light is photoelectrically read to obtain an image signal, and the image signal is processed to obtain a radiographic image of a subject that is suitable for diagnosis (for example, Japanese Patent Application Laid-Open No. 1983-1981). No. 12429, 55-1.1.634
No. 0, No. 55-4.63472, No. 5B-11395
No. 5 [No. i-1, 04845]. This final image can be played back as a hard copy or on a CRT.
You can play on it. In such radiation image information recording and reproducing methods, the stimulable phosphor sheet does not ultimately record image information, but temporarily carries image information in order to provide the 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.

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 has been read can be absorbed by, for example,
As shown in No. 2, No. 5B-12599, residual radiation images may be erased by irradiating the sheet with light or heat, and the stimulable phosphor sheet may be used again for recording radiation images.

(Problems to be Solved by the Invention) By the way, in this type of conventional radiation image information reading device, excitation light is scanned in the main scanning direction on the stimulable phosphor sheet, and at the same time, the stimulable phosphor sheet is scanned in the main scanning direction. A two-dimensional scanning method that moves in the sub-scanning direction is used, and various types of main scanning or sub-scanning of this two-dimensional scanning method have been proposed.

However, in both types, the scanning method is two-dimensional scanning, and the stimulated luminescence light emitted by this scanning is read in time series to obtain a one-dimensional time series image signal.

However, in this reading method, the image signal is read as a one-dimensional time series, so the reading speed is slow, and even faster reading is desired.

In addition, in the conventional reading method, the size of the light guide that collects the stimulated luminescence light emitted from the stimulable phosphor sheet is large, and the light collection efficiency is poor, so there is a need for a more compact and more efficient light guide. be done.

The stimulable phosphor C I of the present invention and its reading device include:
The purpose of this invention is to reduce the size of the light guide in the entire system, thereby making it possible to make the entire device more compact, and to further increase the speed of reading.

(Means for Solving the Problems) The stimulable phosphor sheet I according to the present invention has its support also serve as a light guide, eliminating the need to provide a special light guide in addition to the stimulable phosphor sheet. be. That is,
The stimulable phosphor sheet of the present invention is composed of a support having a sheet-like structure as a whole by arranging a large number of elongated light guide members in parallel, and a stimulable phosphor layer laminated entirely on the support. , characterized in that the light emitted from each of the light guide members or the stimulable phosphor layer is taken in from a side surface of the light guide member, is repeatedly reflected inside, and is guided to an end surface of the light guide member. It is something to do.

Here, the side surface of the light guide member means the circumferential surface of the elongated light guide, and the end surface means the end surface in the length direction.

Further, in the radiation image reading device according to the present invention, the radiation is emitted from the end face of each of the light guide portions of the stimulable phosphor sheet, facing an edge lined with the end face of the light guide member constituting the support. a multi-sensor having a large number of mutually independent light receiving elements that simultaneously detect light; and a multi-sensor having a plurality of independent light-receiving elements that simultaneously detect the light of the stimulable phosphor sheet; an excitation light irradiation means for irradiating the stimulable phosphor sheet, and a scanning means for moving the irradiation position of the linear excitation light by the excitation light irradiation means onto the stimulable phosphor sheet in a direction perpendicular to the parallel direction. .

Here, the parallel direction of the light guide members is the parallel direction in which a large number of light guide members are arranged adjacently in parallel, that is, along the plane of the support constituted by the large number of parallel light guide members. By direction, we mean a direction perpendicular to the length direction of each light guide member.

Furthermore, moving the irradiation position of the linear excitation light onto the stimulable phosphor sheet by the excitation light irradiation means in a direction perpendicular to the parallel direction means moving the irradiation position of the linear excitation light to the light guide. It means to move in the length direction.

This movement means that the excitation light and the stimulable phosphor sheet move relative to each other.The stimulable phosphor sheet may be fixed and the excitation light moved, or the excitation light may be fixed and the stimulable phosphor sheet moved. The phosphor sheet may be moved.

Further, in the reading device of the present invention, the multi-sensor, the excitation light irradiation means, and the scanning means are arranged in a housing, and the scanning means accommodates the entire stimulable phosphor sheet in the housing. The stimulable phosphor sheet is moved in the length direction of the light guide member that constitutes the support for the stimulable phosphor sheet from the position where the stimulable phosphor sheet is discharged to the outside of the housing. The excitation light irradiation means irradiates the stimulable phosphor sheet with excitation light while the stimulable phosphor sheet is being moved outside the nousing by the moving means. The multi-sensor is positioned within the nozzling of the support of the stimulable phosphor sheet while the stimulable phosphor sheet is irradiated with excitation light by the excitation light irradiation means. The device is characterized in that the light emitted from the end surface is detected by contacting the end surface toward the end surface.

(Operations and Effects) The stimulable phosphor sheet of the present invention has the above-described configuration, thereby propagating stimulated luminescence light within the support of the stimulable phosphor sheet, and causing stimulated luminescence at the end surface of the support. Since light can be detected, there is no need to provide a light guide in addition to the stimulable phosphor sheet, and the entire reading device can be made compact.

In addition, the reading device of the present invention uses an excitation light irradiation means that irradiates the stimulable phosphor sheet in a linear manner, and does not perform one-dimensional scanning like the main scanning in conventional systems, but simultaneously irradiates the stimulable phosphor sheet. Stimulated luminescent light emitted from the stimulable phosphor in the linear portion of the stimulable phosphor sheet is simultaneously incident on a number of parallel light guide members from the sides, propagated therein by total reflection, and then exits from the end face. With simultaneous reading, the multi-sensor detects the light from each light guide simultaneously.

Next, since the stimulable phosphor sheet and the excitation light move relative to each other (corresponding to sub-scanning in conventional systems), the above reading is repeated in sequence, resulting in stimulated luminescence light from the entire surface of the stimulable phosphor sheet. It can be detected at high speed.

Furthermore, since the reading device of the present invention reads the stimulable phosphor sheet inserted into the housing while it is being ejected to the outside, the reading operation is simple. For example, reading is started by pushing the stimulable phosphor sheet into the housing as it is or in a cassette, reading is performed while the stimulable phosphor sheet is gradually ejected from the housing, and reading is performed when ejection is completed. can be completed.

(Example) Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a stimulable phosphor sheet according to the present invention together with an embodiment of its reading device.

The stimulable phosphor sheet 2 includes a large number of elongated light guide members 4.
A, 4b, 4c, . , each of the light guide members 4 takes in the light emitted from the stimulable phosphor layer 6 from the side surface 4A of the light guide member 4, and repeats internal reflection 1 to the end surface 4B of the light guide member 4. I'm trying to guide you.

The support body 4 is a structure in which a large number of light guide members are arranged in parallel (in other words, adjacent to each other in a parallel plane), and each of the light guide members 4a, 4b, 4c, . . . 4n is a well-known structure. It can be constructed with optical fibers. These many optical fibers 4
A, 4b, 4c, . . . , 4n are arranged in parallel in a plate shape, and a stimulable phosphor is laminated thereon.

As a reading device, the light guide members 4a, 4b, 4c, .
. . . 8n, which are opposed to the edges where the end surfaces of the light guide members 4 are lined up and which simultaneously detect the light emitted from the end surfaces of the respective light guide members 4, are provided. a multi-sensor 8; and an excitation light irradiation means 10 for irradiating excitation light 10A onto the stimulable phosphor layer 6 of the stimulable phosphor sheet 2 in a linear manner extending in the parallel direction A of the light guide members 4; , a linear excitation light irradiation position 1 on the stimulable phosphor sheet 2 by the excitation light irradiation means 10;
2 in a direction B perpendicular to the parallel direction A can be used.

In FIG. 1, the end surface of the stimulable phosphor sheet 2 (the end surface on the left side in the figure) cannot be clearly seen, and the part is cut away for convenience of illustration, so the exact shape of the end surface 4B is not shown. However, it is the opposite end face 4C shown on the right side of the figure.
It has a similar shape.

As the light source of the excitation light 10A, for example, a light beam bundle emitted from a semiconductor laser (not shown) and diffused linearly (planarly) via a diffusing optical element 12 such as a reflecting mirror or a columnar lens can be used.

The number of multi-sensors 8 is large (for example, 500 to 1000).
mutually independent light receiving elements 8a, 8b...8n
] 2 Well-known, these many light receiving elements 8a, 8b...
...The light received by 8n is simultaneously detected, converted into a signal, and read. This signal is divided for each irradiation beam 12 and is continuously sent to a memory, a signal processing device, etc., where it is stored or processed.

In order to increase the reading efficiency, the wavelength of the excitation light 10A does not pass through somewhere in the optical path of the stimulated luminescent light emitted from the stimulable phosphor layer 6 until it reaches the multisensor 8, and the stimulated luminescent light is not transmitted. It is recommended to insert a filter that only transmits the emitted light. For example, a filter can be provided between the stimulable phosphor layer 6 and the support 4, on the end face of the support 4, in front of the multi-sensor 8, or just in front of it.

Alternatively, if the surface of the support body 4 is made appropriately rough, the excitation light is diffused there, and the light guide members 4a, 4b, 4c...
...The rate of entry into 4n is reduced, and reading efficiency can be increased.

A further embodiment of the above device is shown in FIGS. 2 and 3.
As shown in the figure. This is the insertion opening 2O in the housing 20.
During the operation of loading the stimulable phosphor sheet 2 by pushing it in from A, then automatically or manually operating the reading mechanism and ejecting the stimulable phosphor sheet 2 from the housing 20. stimulable phosphor sheet 2
It reads radiographic images recorded in

That is, the multi-sensor 22, the excitation light irradiation means 24, and the scanning means 26 are arranged in the housing 20. The length of the light guide members 4a, 4b, 4c, . The excitation light irradiation means 24 is composed of an endless belt 2BA that moves the stimulable phosphor sheet 2 in the direction (arrow B), and the excitation light irradiation means 24 moves the stimulable phosphor sheet 2 out of the housing 20 by the endless belt 28A. While the stimulable phosphor sheet 2 is exposed to the excitation light 24A, the multi-sensor 22 detects that the stimulable phosphor sheet 2 is exposed to the excitation light 24A by the excitation light irradiation means 24. During the irradiation, the light emitted from the end surface 2A of the support 4 of the stimulable phosphor sheet 2, which is located inside the housing 20, comes into contact with the end surface 2A and is detected.

The excitation light irradiation means 24 condenses the light emitted from the light source 24B with a condenser lens 24C, reflects it on a mirror 24D, and then irradiates it onto the stimulable phosphor sheet 2. At this time, the light is accumulated in a linear form. A slit 24E is arranged in front of the light source 24B so that the phosphor sheet 2 is irradiated with light.
A linear light source is formed by E, and this is applied to the stimulable phosphor sheet 2.
Linear irradiation is performed by focusing the image upward. Alternatively, the condensing lens 24C or the mirror 24D may be configured with a cylindrical lens or a mirror, thereby making it possible to linearize the light.

The multi-sensor 22 is locked to the endless belt 26A, and moves in the direction of arrow B and the opposite direction by forward and reverse rotation of the endless belt 26A. In order to make this movement, the endless belt 26A is equipped with a motor 2 that can rotate in forward and reverse directions.
BB is operatively connected via pulley 26C.

Insert the stimulable phosphor sheet 2 into the insertion opening 2OA of the housing 20.
When pushed in, the inner end 2A of the stimulable phosphor sheet 2
contacts the multi-sensor 22 inside the housing 20. This state is detected by a sensor (not shown), the light source 24B is turned on, and at the same time, the motor 2BB is driven to rotate the endless belt 26A to the right as shown in the figure, and the multi-sensor 22 rotates the stimulable phosphor sheet 2 so as to push it out. . The speed of this extrusion is constant, and during this time the excitation light 24A is linearly irradiating the stimulable phosphor sheet 2 in a direction perpendicular to the direction in which the stimulable phosphor sheet 2 is extruded. The entire surface of the body sheet 2 is two-dimensionally scanned with excitation light. Stimulated luminescence light is thereby emitted from the stimulable phosphor layer 6 of the stimulable phosphor sheet 2, which passes through the support 4 and is received by the multi-sensor 22 and detected. The radiation image recorded on sheet 2 is read.

The principles of recording and reading radiographic images are described in many of the above-mentioned conventional techniques and are well known, so a description thereof will be omitted.

In the above embodiment, the stimulable phosphor sheet 2 is inserted into the housing 20 of the reading device as it is, but it may also be inserted in a cassette. This is more practical because it can be operated in a bright room. Such examples are shown in Figures 4A, 4B, and 4C.

A cassette 40 containing the stimulable phosphor sheet 2 is inserted into the housing 30. (FIG. 4A) When the cassette 40 is inserted deep enough, the cassette 40 is opened using a known mechanism (not shown), leaving only the stimulable phosphor sheet 2 inside inside the housing 30, leaving only the cassette 40 inside the housing 30.
Return it outside. (FIG. 4B) Here, the stimulable phosphor sheet 2 is gradually moved to the housing 30 and read. When the reading is completed, the stimulable phosphor sheet 2 is automatically returned to the cassette 40.

In the above two embodiments, reading ends when the stimulable phosphor sheet 2 is ejected out of the housing, but in order to erase the afterimage on the stimulable phosphor sheet 2, the stimulable phosphor sheet 2 It is desirable to insert the stimulable phosphor sheet 2 into the housing and then irradiate the stimulable phosphor sheet 2 with a large amount of erasing light to erase it.

Alternatively, in the first embodiment, read at the time of insertion,
It can also be configured to be erased at the time of discharge. However, in that case, it is necessary to take measures so that the stimulable phosphor sheet 2 is inserted at a constant speed during insertion. If the insertion is not performed manually but is performed at a constant speed using an automatic conveying means, it is highly possible to achieve this goal.

[Brief explanation of the drawing]

Fig. 1 is a schematic perspective view showing a stimulable phosphor sheet according to the present invention together with a part of its reading device, Fig. 2 is a schematic sectional view showing an embodiment of the reading device according to the present invention, and Fig. 3 is its external appearance. FIGS. 4A, 4B, and 4C are schematic sectional views showing the operation of another embodiment of the reading device according to the present invention. 2...Stormable phosphor sheet 4...Supports 4a, 4
b, 4c...4n...Light guide 6...Storage phosphor layer 8.22...Multi-sensor 20.30...Housing 28...Scanning member 24... Excitation light irradiation means 40...cassette)/Figure 4C

Claims (1)

[Scope of Claims] 1) A support body having a sheet-like structure as a whole with a large number of elongated light guide members arranged in parallel, and a stimulable phosphor layer laminated entirely on this support body, A storage device characterized in that each light guide member takes in the light emitted from the stimulable phosphor layer from the side surface of the light guide member, repeatedly reflects it inside, and guides it to the end face of the light guide member. phosphor sheet. 2) Simultaneously detecting the light emitted from the end faces of each of the light guide members of the stimulable phosphor sheet according to claim 1, facing the edge where the end faces of the light guide members constituting the support are lined up. a multi-sensor having a large number of mutually independent light-receiving elements; and excitation light that irradiates linear excitation light onto the stimulable phosphor layer of the stimulable phosphor sheet extending in the parallel direction of the light guide members. irradiation means; scanning means for moving the irradiation position of linear excitation light from the excitation light irradiation means on the stimulable phosphor sheet in a direction perpendicular to the parallel direction; A reading device that reads radiation images stored and recorded on a fluorescent phosphor sheet. 3) The multi-sensor, the excitation light irradiation means, and the scanning means are arranged in a housing, and the scanning means scans the stimulable phosphor sheet from a position where the entire stimulable phosphor sheet is housed in the housing. means for moving the stimulable phosphor sheet in the length direction of the light guide member constituting a support for the stimulable phosphor sheet to a position where the stimulable phosphor sheet is discharged out of the housing, and the excitation light irradiation means is configured to irradiate the stimulable phosphor sheet with excitation light while the stimulable phosphor sheet is being moved out of the housing by the moving means, and the multi-sensor is configured to irradiate the stimulable phosphor sheet with excitation light. While the body sheet is being irradiated with excitation light by the excitation light irradiation means, light that comes into contact with the end face of the support of the stimulable phosphor sheet located in the housing and is emitted from the end face; 3. The stimulable phosphor sheet reading device according to claim 2, wherein the stimulable phosphor sheet reading device detects the stimulable phosphor sheet.