JPS61236887A - Apparatus for recording and reading radiation image information - Google Patents

Abstract

PURPOSE:To provide the titled apparatus having compact size and suitable for group test and capable of storing and recording a radiation image information to a specific fluorescent material, detecting the accelerated phosphorescence emitted by the irradiation with excitation ray, converting the acquired image information to electrical signal and converting the signal to visible image. CONSTITUTION:A fluorescent sheet represented by the principal compositional formula (MII is Ba, Sr or Ca; X and X' are Cl, Br or I; Xnot equal to X'; 0.1<=a<=10; 0<x<=0.2) capable of accumulating recording radiation image is circulated. In the course of circulation, radiation passed through the object is radiated to the fluorescent sheet to effect the storage and recording of the transmission radiation image on the sheet. The sheet is scanned with excitation light emitted from an excitation light source on the circulation path and the accelerated phosphorescence emitted from the sheet is detected by a detection means to obtain an image signal. Prior to the recording of the image on the sheet, the residual radiation energy on the sheet is dissipated in the erasion zone.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention stores and records radiation image information on a stimulable phosphor,
Next, it is irradiated with excitation light, detects the light that emits stimulated light according to the accumulated and recorded image information, reads the image information and converts it into an electrical signal, and then converts the read image information into a visible image. More specifically, the present invention relates to a radiation image information recording/reading device that reproduces radiation image information using a divalent europium-activated alkaline earth metal halide phosphor as a stimulable phosphor, and this phosphor is recycled and reused within the device. The present invention relates to a radiation image information recording/reading device.

(Technical background of the invention and prior art) Certain types of phosphors are exposed to radiation (Xl, 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 radiation image information recording and reproducing method has been proposed in which an image signal is obtained by photoelectrically reading the image and the image signal is processed to obtain a radiation image of a subject that is suitable for diagnosis. (For example, JP-A No. 55-12429, JP-A No. 56-11395, JP-A No. 5
No. 5-163472, No. 56-104645@, No. 5
5-116340, etc.) In this method, the final image may be reproduced as a hard copy or
It may also be played back on RT.

In any case, in such a radiation image information recording and reproducing method, a stimulable phosphor sheet (strictly speaking, it can take various forms such as a panel-like sheet or a drum-like sheet, but it is generally called " (referred to as "sheet")
This 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, so this stimulable phosphor sheet is designed to be used repeatedly. It is also possible to use it repeatedly, and it is extremely economical to use it repeatedly in this way.

By the way, the method of recording and reproducing radiation image information using a stimulable phosphor as described above is particularly effective when used for medical diagnosis. In other words, this method can obtain radiation image information suitable for the diagnostic structure by performing various signal processing on electrical signals, and can also reduce radiation exposure by adjusting the reading gain of the photodetector during photoelectric conversion. I! If! It has great advantages over conventional radiographic methods using silver salt emulsions, such as being able to significantly reduce k.

Therefore, diagnosis using this radiation image information recording and reproducing method can be carried out not only in medical institutions such as hospitals, but also in various locations using mobile examinations equipped with equipment, such as conventional X-ray indirect radiography vehicles. desired.

When a mobile station during X-ray imaging is equipped with a recording/reading device for radiographic image information, and when traveling to various locations for mass examinations to take X-rays, it is necessary to use stimulable phosphors. It is inconvenient to load multiple sheets,
Additionally, there is a limit to the number of seats that can be loaded onto a moving vehicle. Therefore, a reusable stimulable phosphor sheet is mounted on a moving vehicle, radiographic image information for each subject is recorded on it, and the image signal obtained by reading it is stored on a large storage device such as a magnetic tape. If the radiation images are copied onto a recording medium and the stimulable phosphor sheet is reused, it is possible to take radiation images of a large number of objects using a moving 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 order to reuse the stimulable phosphor sheet in this way, the radiation energy accumulated in the stimulable phosphor sheet after the stimulated luminescence light is read is used, for example, in Japanese Patent Laid-Open No. 56-1139
2, No. 56-12599, the stimulable phosphor sheet may be used again for radiographic image recording by emitting radiation to erase the tlB-ray image.

Therefore, there is an image recording section that irradiates radiation through a subject onto a reusable sheet made of stimulable phosphor, an image recording section that reads the image accumulated and recorded on this stimulable phosphor sheet, and an image recording section that If the erasing unit, which releases the radiation energy remaining in the fluorescent phosphor sheet and prepares for the next recording, is combined into one device and installed in a mobile vehicle, it will be easy to travel around for medical examinations, and it will also be useful for hospitals, etc. It is also easy to install and is convenient in practice.

By the way, as a new stimulable phosphor, MX2
5-aM X'2: XEIJ2+ (However, MIL is 3a
.

at least one alkaline earth metal selected from the group consisting of Sr and Ca; X and X' are C9J,
at least one halogen selected from the group consisting of Br and 1, and x+x'; and Ta is 0
．． A divalent europium-activated alkaline earth metal halide phosphor is disclosed, which is represented by the composition formula: 1≦a≦10.0, x is Q<x≦0.2. The above-mentioned phosphor exhibits stimulated luminescence when excited with electromagnetic waves in the wavelength range of 450 to 1000 na+ after irradiation, and especially
When excited with electromagnetic waves in the 0 nm wavelength range, it exhibits stimulated luminescence. Therefore, the above-mentioned phosphor has the advantage that it can generate sufficient stimulated luminescence light even when reading is performed using a laser light source with a relatively long wavelength such as a semiconductor laser; however, on the other hand, The above phosphor emits A4
After the image information is accumulated and recorded by siI, it has the disadvantage that the amount of stimulated luminescence light decreases over time, that is, there is a large amount of fading. In other words, even if the same excitation light is applied to the phosphor sheets on which the same image information has been accumulated and recorded, a recording medium with a long elapsed time from image recording to reading will be compared to a sheet with a short elapsed time. This means that less stimulated luminescence light can be obtained than with the sheet. For this reason, after an image is recorded on the phosphor sheet, it may be stored for several hours or more before being read, and it is not suitable for use in a recording and reproducing system where the storage time differs depending on the sheet. The problem was that there was no such thing.

Therefore, in order to use the above-mentioned phosphor sheet, a recording/reproducing system is required in which the time from image recording to reading is almost constant and short.

(Object of the invention) The present invention has been made in view of the above circumstances, and
The phosphor sheet that records radiographic images can be reused, it can be designed compactly, high-speed imaging is possible, equipment and transportation are easy, and it can be easily installed in screening models for mass medical examinations. and using the sheet of the divalent europium-activated alkaline earth metal halide phosphor,
The object of the present invention is to provide a radiation image information recording/reading device that can improve the sensitivity of the sheet.

(Structure of the Invention) The radiation image information recording/reading device of the present invention is capable of accumulating and recording radiation images.
However, MII is at least one alkaline earth metal selected from the group consisting of 3a, 3r and Ca;
X and X' are at least one halogen selected from the group consisting of (4, Br and
x'; and a is 0.1≦a≦10.0, × is Q
<x≦0.2). Circulating transport means for transporting at least one divalent europium-activated alkaline earth metal halide phosphor sheet along a predetermined circulation path, in the circulation path, irradiating the sheet with radiation through a subject; By doing so,
an image recording section that accumulates and records a radiographic image of the subject on the sheet; an excitation light source located in the circulation path that emits excitation light that scans the sheet on which the radiographic image is accumulated and recorded in the image recording section; an image reading section having a photoelectric reading means for reading the stimulated luminescence light emitted from the sheet scanned by the light to obtain an image signal; and a candy image reading section in the circulation path where image reading is performed. The present invention is characterized in that it includes an erasing section that releases the residual radiation energy on the sheet before an image is recorded on the sheet after the sheet has been stained.

In the radiation image information recording/reading device having the above structure, the sheets are used cyclically within the device while the radiation images are erased, so there is no need to handle one phosphor sheet for 111 shadows, and diagnostic processing Capacity is significantly improved.

In addition, in the apparatus of the present invention, the phosphor sheet is sent sequentially from the image recording section to the image reading section, so the elapsed time from recording to reading is short, and the phosphor sheet has 7 agings before reading. It almost never happens. Furthermore, since the phosphor sheet can be efficiently excited with long-wavelength excitation light as described above, it is also possible to use a semiconductor laser or the like as an excitation light source, making it possible to downsize the image reading section and the entire device. It becomes possible.

Although the apparatus of the present invention performs a reading operation and subsequent erasing, the image signal obtained by the reading operation may be temporarily stored in a storage medium such as a magnetic tape or a magnetic disk, or may be stored in a storage medium such as a CRT or the like. It may be displayed on a display for immediate observation, or it may be made into a hard copy and permanently recorded. A playback device for this purpose may be directly connected to the above device, may be temporarily played back at a remote location via a storage device, or may be placed at a remote location and receive signals wirelessly. It may also be played back. In this way, it becomes possible, for example, for an image taken by a mobile vehicle to be played back by a receiver/reproducer at a hospital, a specialist to observe the image, and to report the diagnosis result to the mobile vehicle by radio.

When the divalent europium-activated alkaline earth metal halide phosphor of the present invention is irradiated with radiation (X-rays, α-rays, β-rays, γ-rays, electron beams, ultraviolet rays, etc.), this radiation energy is released. It has the property of emitting stimulated luminescence light in an amount corresponding to the accumulated energy when a part of it is accumulated inside and then irradiated with excitation light such as visible light.

In the present invention, the phosphor sheet refers to a sheet-like recording medium made of the above-mentioned phosphor, and generally consists of a support and a phosphor layer laminated on the support. The phosphor layer is formed by dispersing the above phosphor in a suitable binder, but if this phosphor layer is self-supporting,
It can be used as a phosphor sheet by itself.

In the present invention, it is preferable that the wavelength range of the excitation light and the wavelength range of the stimulated emission light do not overlap in order to improve the S/N ratio, and the excitation light source should be selected so as to satisfy such a relationship. is preferred.

Specifically, it is desirable that the excitation light wavelength is 500 to 850 nm. In addition, the excitation light wavelength was set to 500 to 8
When it is 50 rv, efficient excitation is possible.

In addition, the following additives are added to the above M
It may be contained in the following proportions per mol of MIcX'z. bM X” (However, MII is R
is at least one alkali metal selected from the group consisting of b and C8, and X″ is F or CL.

[At least one halogen selected from the group consisting of 3r and I, and b satisfies O≦b≦10.0); CMgx″′2・dMTLX″″3
(However, vl is So, Y, La, Gd and l
at least one trivalent metal selected from the group consisting of: 1. X II , X ILL and x″″ are all at least one kind of halogen selected from the group consisting of F, C9, Br and r, and S, c and d each satisfy 0≦b≦2.0. 0≦C≦2.0.0≦
d≦2.0, and 2×10”≦b +c
+d); yB described in Japanese Patent Application No. 59-84356 Mei IIA (however, ■ is 2X104≦y≦
2X10-1); and patent application No. 59-84358.
bA described in No. 181 (However, A is S!0
2 and Pgos, and b is 104≦b≦2×10°
1); Patent application 1982-. bsio described in the specification of No. 240452 (however, b is Q<b≦3
104); Patent Application No. 59-240454, l
bSnXn2 (However, x
" is at least one kind of halogen selected from the group consisting of F, CL, Br and I, and b is Q<b≦1
0″3): Patent application filed by the applicant in 1980-
No. [Application filed on April 11, 1985 (2)] bC8x''/C3nx'''2 described in Mei II'I (however, X n and X''' are from F, CL, Br, and ■, respectively) at least one kind of halogen selected from the group consisting of halogen, and b and C are each 0 and b≦10.
0 and 104≦C≦2×104); and the bcs described in the specification of Japanese Patent Application No. 1983 [filed on April 11, 1985 (4)] by the present applicant.
X”-yLn (However, X II is F, C9,
At least one type of halogen selected from the group consisting of Br and I, and Ln is 3c.

Y, Ce, Pr, Nd, Sm, Gd, Tb
, Dy.

At least one rare earth element selected from the group consisting of HO, Er, Tll, Yb and lu, and b and y are Q<b≦10.0 and 104≦y≦, respectively.
1.8x104). For details of the divalent europium-activated alkaline earth metal halide phosphor used in the present invention, such as the manufacturing method, the specifications of each of the above-mentioned applications can be referred to.

Incidentally, the radiographic image information recording/reading apparatus has an extremely practical advantage in that it can record images over an extremely wide radiation exposure range compared to conventional radiographic systems using silver halide photography. In other words, in phosphors, it is recognized that the amount of emitted light that is stimulated by excitation due to accumulation and oxidation is proportional to the amount of radiation exposure over an extremely wide range, and therefore, depending on various imaging conditions, radiation exposure Even if the amount fluctuates considerably, the light amount of the emitted light is read by a photoelectric conversion means by setting the reading gain to an appropriate value and converted into an electrical signal, and this electrical signal is used to convert the light into a recording material such as a photographic light-sensitive material. A radiation image that is not affected by fluctuations in radiation exposure can be obtained by outputting it as a visible image on a display device such as a CRT.

In addition, according to this system, radiation image information stored and recorded on a phosphor sheet is converted into an electrical signal and then subjected to appropriate signal processing, and this electrical signal is used to display information on recording materials such as photographic light-sensitive materials, CRTs, etc. By having the apparatus output as a visible image, a very large effect can be obtained in that a radiation image that is suitable for reading in a dormitory (diagnostic suitability) can be obtained.

In this way, in a radiation imaging system using the above-mentioned phosphor sheet, the reading gain can be set to an appropriate value to photoelectrically convert the stimulated luminescence light and output it as a visible image. Due to causes such as variations in the radiation-exposed layer due to variations in voltage or MASli*, variations in the sensitivity of the phosphor sheet, variations in the sensitivity of the photodetector, changes in exposure amount due to subject conditions, or differences in radiation transmittance depending on the subject. Even if the energy stored in the phosphor sheet differs, or even if the amount of radiation exposure is reduced, it is possible to obtain a radiation image that is not affected by fluctuations in these factors, and even if the amount of radiation exposure is reduced. By first converting the emitted light into an electrical signal, and then applying appropriate signal processing to this electrical signal, the chest

It is possible to obtain a radiographic image suitable for a diagnostic site such as the heart, and to improve the aptitude for observation and interpretation.

However, in order to eliminate the influence of variations in imaging conditions or to obtain radiographic images with excellent observation and interpretation aptitude, it is necessary to change the recording state of radiographic image information stored and recorded on the phosphor sheet or the chest.

Visual images for observation and interpretation of recording patterns (hereinafter referred to collectively as "accumulated recorded information") determined by the part of the subject such as the abdomen, the imaging method such as simple or contrast enhancement, etc. It is essential to understand the information before outputting it, and to adjust the reading gain to an appropriate value based on the accumulated recorded information thus obtained, or to perform appropriate signal processing.

Furthermore, in order to obtain radiographic images that are highly suitable for observation and interpretation, it is necessary to determine the recording scale factor so that the resolution is optimized according to the contrast of the recorded pattern.

As a method for grasping the accumulated record information of radiation image information before outputting a visible image, Japanese Patent Laid-Open No. 55-501
The method disclosed in No. 80 is known.

This method is based on the knowledge that when the stimulable phosphor sheet is irradiated with radiation, the amount of instantaneous light emitted from the stimulable phosphor sheet is proportional to the amount of energy stored and recorded in the stimulable phosphor sheet. By detecting this instantaneous emitted light, the accumulated recorded information of radiographic image information is grasped, and appropriate signal processing is performed based on this information to obtain a radiographic image excellent in suitability for observation and interpretation.

According to this method, it is possible to adjust the reading gain to an appropriate value, to select an appropriate recording scale factor, or to perform appropriate signal processing, thereby eliminating the influence of fluctuations in imaging conditions. Alternatively, it is possible to obtain a radiographic image that is highly suitable for observation and interpretation, but since the image recording section and the image reading section are usually located apart, a signal transmission system must be constructed between them. However, there were disadvantages in that the equipment had to become complicated (q) and an increase in cost could not be avoided.

Therefore, prior to the reading operation to obtain a visible image for observation and interpretation, the accumulated recorded information of radiation image information accumulated and recorded on the stimulable phosphor sheet is detected simply and with high precision.
It is desired to reproduce radiographic images with excellent diagnostic performance based on this information.

This is done by using excitation light with an energy lower than that of the excitation light that should be irradiated during the reading operation (hereinafter referred to as "main reading") to obtain a visible image for m* image interpretation, prior to the main reading. A reading operation (hereinafter referred to as "pre-reading") is performed in advance to grasp the accumulated record information of the radiation image information accumulated and recorded on the stimulable phosphor sheet, and the accumulated record information of the radiographic image information is grasped. This can be achieved by performing actual reading later and appropriately adjusting the reading gain based on the pre-reading information, or by performing appropriate signal processing.

A preferred embodiment of the present invention is characterized by comprising this pre-reading means and further comprising a control means for setting reading conditions and/or image processing conditions for main reading based on the accumulated record information obtained by pre-reading. That is.

In the present invention, the energy of excitation light refers to the effective energy of excitation light received per unit area of the phosphor sheet described above.

In the present invention, it is sufficient that the energy of the excitation light to be applied to the phosphor sheet during pre-reading is lower than the energy of the excitation light during main reading. If the ratio between the excitation light energy of the pre-reading and that of the main reading is close to 1, the amount of radiation energy remaining and accumulated at the time of the near-excitation reading will be small; however, if this ratio is less than 1, the value of the reading gain should be It has been found that by making appropriate adjustments, radiographic images suitable for observation and interpretation can be obtained. However, in order to obtain radiographic images that are suitable for observation and interpretation, the radiographic image information accumulated and recorded on the phosphor sheet by pre-reading is sufficient to be used for selecting reading conditions or optimal image processing conditions. In other words, as long as the stimulated luminescence light emitted from the phosphor sheet can be sufficiently detected in the above sense, the ratio of the excitation energy of the pre-reading and the main reading is preferably as small as possible. %below,
It is preferably 10% or less, more preferably 3% or less. The lower limit of this ratio is determined by the accuracy of the pre-read stimulated luminescence light detection system.

As described below, in the present invention, it is preferable that the excitation light source and photoelectric reading means for the pre-reading device are shared with those for main reading, but in this case, the energy of the excitation light for pre-reading is smaller than the energy for main reading. Methods for achieving this include reducing the output of the laser light source, increasing the beam diameter of the laser beam, increasing the scanning speed of the laser beam, and increasing the transport speed of the stimulable phosphor sheet. Any known method can be used.

According to the above-described preferred embodiment of the present invention, it is possible to know in advance the recording state of the radiographic image information stored and recorded on the phosphor sheet. By appropriately adjusting the reading gain based on this recorded information, it is possible to obtain radiographic images that are always suitable for observation and interpretation even when the imaging conditions change.

In addition, since the recording pattern of radiation image information accumulated and recorded on the phosphor sheet can be grasped in advance, signal processing according to the recording pattern can be applied to the electrical signals after reading, or the recording scale can be adjusted. By optimizing the factors, it is possible to obtain radiographic images with excellent suitability for observation and interpretation.

Furthermore, since it is possible to know in advance the recording pattern of radiation image information stored and recorded on the phosphor sheet, it is possible to omit the main reading for parts where the recording pattern does not exist, and in this case, the reading time can be reduced. It becomes possible to shorten the length.

Furthermore, in a preferred embodiment of the present invention, the excitation light source and light m reading means for pre-reading are used in common with those for main reading, and the energy of the excitation light during pre-reading can be made smaller than the energy of the excitation light during main reading. An adjustment means is provided, and by passing the sheet twice over the same location, pre-reading and main reading are performed. As a result, even in a device that performs pre-reading, the overall size can be designed to be compact.

There are two common methods for this: one is to pass the sheet twice in the same direction at the same location, and then return it once after the first pass, and the other is a reciprocating method, in which advance reading is performed during the forward movement and main reading is performed during the backward movement. Seed methods are possible.

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

FIG. 1 is a schematic diagram showing an actual mff1 for photographing a radiographic image of a chest or the like while a subject is standing.

The imaging unit (image recording unit) is located at the height of the chest of subject 1.
10 is installed, where the accumulation case 1 in the supply position is installed.
Divalent eugovium-activated alkaline earth metal halide phosphor sheets (hereinafter simply referred to as sheets) 2 are supplied one by one from 1 or 15'. This photographing section 10 is
It consists of a pair of endless belts 12A and 123 that hold the sheet 2 from the front and back, and an auxiliary endless belt 13 that is located below and guides the sheet 2 rearward. sheet 2
A conveyor belt 14 is provided to convey the image toward the image reading section 20 located further behind.

In the reading section 20, a first feed belt 22 driven by a motor 21 and a second feed belt 24 driven by a motor 23 are arranged in series to feed the sheet 2 in the sub-scanning direction at a constant speed. There is. Photographing section 10 and reading section 2
0, a shutter 3 that can be opened and closed is provided so that no disturbance light enters from the photographing section 10 side during reading. The reading section 20 includes the first and second belts 22.2.
A laser light source 25 is installed above 4, and a mirror 26A is used to scan the output laser light 25A onto the sheet 2 on the belt 22° 24.

Galvanometer mirror 26B, mirror 26C, mirror 2
61) is provided, and a galvanometer mirror 26B is provided.
The laser beam 25A is main-scanned on the sheet 2 by the reciprocating swinging. At the scanning position on the sheet 2 of the laser beam 25A,
A condensing reflective mirror 27 is disposed along the main scanning line, and the stimulated luminescence light emitted by being excited from the sheet 2 irradiated with the laser beam 25A and the brightness reflected by the condensing reflective mirror 27 are disposed along the main scanning line. The exhausted light enters the condensing optical element 28 from the incident end surface 28A of the condensing optical element 28, and is guided through the condensing optical element 28 by total reflection to the photomultiplier 29 connected to the exit end surface 28B of this element 28. Light is received, and the stimulated luminescence light is read out in a charging manner. The image signal read here is recorded on the image signal recording device 80. If an image is recorded on a high-density recording medium in this way, the medium can be brought to a distant medical institution such as a hospital, and then put on a reproduction device at the medical institution.

Further, instead of using the image signal recording device, the electrical image signal output from the photomultiplier 29 may be immediately inputted to a reproduction device to obtain a hard copy or CRT display, or the above-mentioned method may be used. ii) The image signal may be input to the reproducing device and the recording medium at the same time. In other words, in the case of hospital use, the image signal is transmitted from the radiography room to a recording medium for record storage, and at the same time, this image signal is transmitted to a reproducing device such as a CRT in the examination dormitory so that it can be used for diagnosis immediately after imaging. It is also possible to make it possible to do so.

A feed belt 32 driven by a motor 31 is disposed downstream of the reading section 20, and further above (downstream) there is a group of endless belts 33A to 33E that clamp the sheet 2, and above (downstream) A pair of belts 34 for distributing the sheets 2 in two directions is provided so as to be swingable in a variable conveyance direction. The rear end of the feed belt 32 and the belt group 33
A guide plate 4 for guiding the sheet 2 from the former to the latter is arranged between the lower ends of A to 33E.

An erasing section 40 consisting of a pair of erasing units 41 .
A guide plate 5°6 is disposed between the entrance of the belt 42 and the belt pair 340. The erasing units 41 and 42 each consist of transparent endless belts 41A and 42A, and a large number of fluorescent lamp groups 418 and 428 arranged therein. In the erasing section 40, it takes a long time to erase, and in order to erase for a long time in a compact device, the speed of the feed belt must be slower than the speed of the upstream feed belt. For this reason, in the erasing section 40, the pair of endless belts 41A and 42A are alternately switched and their respective feed speeds are significantly lowered to obtain a long erasing time with a short belt. At the exit of the erasing unit 41.42, a distribution plate 17 and a guide plate 16 are arranged to sort the sheets 2 carried out from here via the guide plates 7A and 7B into a pair of accumulation (supply) cases 11.15. erase unit 41. , 42 are alternately distributed to cases 11.15.

In the illustrated state, the plate 17 guides the sheet 2 to the lower stacking case 15, the lower stacking case 15 is stacking the sheets, and the other (upper) stacking case 11 is photographing the sheet 2. It is in a state where it is being supplied to the section 10.

These pair of accumulation cases 11 and 15 are adapted to repeat accumulation and supply alternately. That is, all the sheets 2 accumulated in the lower accumulation case 11 are stored in the photographing section 10.
, the collection case 11 moves to the collection position indicated by the upper dashed line 11'. After that, the stacking case 15 in which the sheets 2 that were in the stacking position were stacked is moved to the upper chain J! ! 1
The sheet 2 is moved to the supply position indicated by 115', and from there the sheet 2 is sent out to the photographing section 10 again.

In this way, the stacking cases 11 and 15 are configured to be movable between the stacking position and the supplying position of the sheets 2, respectively. When sheets 2 are being supplied from one stacking case, the other stacking case is capable of stacking sheets 2, and when one stacking case becomes empty, it is switched to the other stacking case where sheets 2 are stacked. Sheets 2 can be supplied from the accumulation case.

Shutters 8A and 8B are arranged between the entrances of the shutter units 41 and 42 and the belt pair 34 to prevent light from the shutter units 41 and 42 from leaking outside.

In the embodiment described above, the path of the sheet 2 starts from the photographing section 10, passes through the reading section, the belt groups 33A to 33E1, and the erasing section 40 in this order, and then passes through the stacking case 11. It returns to Is, but is once accumulated in this accumulation case 11.15.

This accumulation is temporary, and when an appropriate number of sheets 2 are accumulated, the sheets 2 are transferred to the supply position and sent to the photographing section again for reuse.

Note that in the embodiment described above, the collection case 11.15 is provided between the photographing section 10 and the erasing section 40, but it is not limited to this position. For example, it may be provided before or after the reading section 20.

In the radiographic image information recording/reading device of the present invention, the sheet 2 once used for imaging is returned to the imaging unit 10 again.
Because it is automatically transported to, circulated, and reused,
The sheet 2 can be used repeatedly, the device is designed to be compact as a whole, and the speed of photographing can be increased. Furthermore, since the entire device is integrated into one device, it is easy to install it in a medical examination type.

For example, if the radiation image information recording/reading device is mounted on a vehicle 60 such as a bus, a mobile examination type 50 can be obtained. Furthermore, in the apparatus of the present invention, the image of the photographed sheet is immediately read without being stored for a long time, so that it is hardly affected by fading. Further, the transport time from photographing to image reading is relatively long, and even if slight fading occurs, the transport time is almost the same for each phosphor plate, so there will be no variation in reproduced images. In this case, since the amount of fading is constant, the amount of fading is detected in advance, and the fading is corrected by adjusting the reading conditions and image processing conditions, and playback is performed without the influence of fading. You can also get images. Furthermore, since the europium-activated alkaline earth metal halide phosphor of 21iIi can be efficiently excited particularly with excitation light in the wavelength range of 500 to 850 nm, it is also possible to use a semiconductor laser or the like as the laser light source,
It is also possible to make the entire device compact.

The device shown in FIG. 1 has the basic configuration shown in FIG. 1, and can be modified into various forms. For example, in order to perform the above-mentioned pre-reading and main reading in the reading section 20, the sheet 2 is once sent by the belt 22.24 for sub-scanning, and after the pre-reading is performed, the belt 22.24 is rotated in the opposite direction. It is possible to return the sheet 2 and then feed the sheet again in the same direction for main reading. Alternatively, when the belts 22, 24 are rotated in the opposite direction to return the sheet 2, it is also possible to carry out the main reading and then feed the sheet 2 in the direction of the light for the next process.

Hereinafter, various other embodiments of the radiation image information recording/reading apparatus of the present invention will be described with reference to the drawings.

FIG. 2, like FIG. 1, shows an example of an apparatus of a form (chest type) suitable for photographing the chest of a human body.

The radiation image information recording/reading device 120 is
It has an overall shape of a letter, and therein is an L-shaped circulation passage 10.
1 is formed, and four phosphor sheets 102 are circulated and conveyed on this circulation path 101 at appropriate intervals from each other by a conveying means such as a conveying roller or a conveying belt.

An image recording section (photographing section) 105 is located on the circulation path 101.
, an image reading section 106 , and an erasing section 107 are sequentially arranged in the sheet traveling direction (in the direction of the arrow).

In the photographing section 105, the radiation emitted from the radiation source 110 passes through the subject 101 and enters the sheet 102, so that the radiation a of the subject is transmitted to the sheet 102.
Image information is stored and recorded. In this embodiment, the position of the imaging unit 105 is configured to be adjustable up and down.

The photographed sheet is conveyed along the circulation path in the direction of the arrow by a circulation conveyance means 103 such as a driving port or a conveyor belt, and enters the image reading section 106 .

The image reading unit 106 includes an excitation light source 162 that emits excitation light 161 such as a laser beam that scans the sheet 102, and a photomultiplier that reads stimulated luminescence light emitted from the sheet 102 by scanning the excitation light and obtains an electrical image signal. It is composed of a photoelectric reading means 163 such as pliers. 1
64 is a galvanometer mirror. This image reading section 1
06 is a space 165 for one sheet where the sheet 102 is located just before the start of reading because the sheet 102 is read while advancing at a constant speed, and space 1 for one sheet where the sheet 102 is located immediately after the reading is completed.
It has 66.

The image signal read by the charge reading means 163 is sent to an image processing circuit (not shown), subjected to necessary image processing, and then sent to a necessary image reproduction device.

As mentioned above, this reproducing device may be a display such as a CRT, or a recording device that performs optical scanning recording on a photosensitive film. Or instead of the playback device, the fruit/1 in Figure 1! As in the embodiment, an image signal recording device such as a magnetic tape may be connected to the photoelectric reading means 163.

Note that the above-mentioned "pre-reading" and "main reading" can also be performed in this device [120]. That is, the sheet 102 is once sent by the endless belts 165 and 166 for sub-scanning, first read in advance, and then the endless belts 165 and 166 are reversed to scan the sheet 102.
Return to the reading position, then endless belt 16
Main reading can be performed by rotating 5 and 16G in the normal direction.

The read sheet 102 is sent to the erasing section 107 by the circulating conveyance means 103.

The erasing section 107 is equipped with an incandescent lamp and a tungsten lamp.

A large number of erasing light sources 171 such as sodium lamps, xenon lamps, iodine lamps, etc. are arranged, and the sheet 102 is irradiated with visible light from the erasing light sources 171 to emit residual radiation energy on the sheet.

The erasing section sheet is transferred to the photographing section 105 again by the circulating conveyance means 3.
sent to.

The erasing section 107 stores one sheet and performs the erasing process. After the sheet 102 is carried into this erasing section, it stops in the erasing section 107 and is exposed to light for the same time as the reading time. Then, the next sheet is carried into the erasing section and the same erasing process is repeated. In other words, the erasing processing conditions in this erasing section are such that the time interval at which the sheet is carried in from the erasing section matches the reading time, in other words, the light remains on the sheet by being irradiated with light for the same time as the reading time. Erasing processing conditions such as the amount of irradiated light per unit time are set so that a sufficient amount of light can be irradiated to emit the radiation energy.

Both of the above two embodiments have a chest-type photographing section (image recording section), but next, an embodiment having a bed-type photographing section will be described.

FIG. 3 shows an actual bed type tM1 in which radial transmission images of the chest, abdomen, etc. are photographed and recorded with the subject lying supine. Inside the device 201 is an endless belt 2.
02. 203. 204. 205. 206°20
7, 208. 209. 210. 211. 21
2. 213 and endless belt 203. 204.
207. 210. Guide roller 214. 215°216,
217. 218. 219. 220 and guide plate 2
21°222, 223. 224. 225. 22
A sheet circulation conveyance system is provided which includes a sheet conveyor 6 and nip rollers 227 and 228 and constitutes a circulation path. In this sheet circulation conveyance system, for example, six phosphor sheets 230 are circulated and conveyed at appropriate intervals in the direction of the arrow in the figure.

Endless belt 2 arranged at the top of the circulation conveyance system
An imaging stage 241 is provided above the imaging platform 241, and at a position opposite to the imaging position on the endless belt 202 (the right side of the endless belt 102 in FIG. 3) with the imaging stage 241 in between, there is, for example, an X-ray A radiation source 242 such as a radiation source is provided, and the imaging table 241 and the radiation source 242 constitute an image recording section 240.

During radiography of the subject 243, the sheet 230 used for radiography is placed at the radiography position on the endless belt 202 as shown in the figure, and the radiation source is placed while the subject 243 lies supine on the radiography table 241. 242 is driven to turn on. As a result, the transmitted radiation image of the subject 243 is projected onto the sheet 230, and the radiation image information of the subject 243 is projected onto the sheet 230.
It is accumulated and recorded in 30.

At the right end position in the figure of the sheet circulation conveyance system, there is an image reading unit 25.
0 is set. In this image reading section 250,
A laser light source 251 is installed above the endless belt 208 that constitutes the reading section 250, and the output laser light 252 is transmitted to the sheet 230 on the endless belt 208.
mirror 253 for scanning in the width direction. Galvanometer mirror 254. A mirror 255 and a mirror 256 are provided, and by the reciprocating movement of the galvanometer mirror 254, the laser beam 252 is main-scanned over the sheet 230 on which the radiation image has been accumulated and recorded. Note that after a radiation image is recorded on the sheet 230 in the image recording section 240, the sheet 230 is transferred to the image reading section 2 by driving the sheet circulating conveyance system.
It will be carried by 5G. Also, the sheet 2 of Rede Hikari 252
A condensing reflective mirror 257 is disposed along the main scanning line at a scanning position on 30, and stimulated luminescent light emitted from the sheet 230 by irradiation with the laser beam 252 is reflected directly or by the condensing reflective mirror 251. Condensing optical element 258
The light enters the condensing optical element 258 from the incident end surface 258A of the light beam, and the light enters the element 25 while being guided by total reflection.
The stimulated luminescence light is received by a photomultiplier 259 connected to the emission end surface 258B of the photoluminescent light emitting device 8, and is photoelectrically read. At the same time as the main scanning of the laser beam 252 is performed as described above, the sheet 230 is conveyed by the endless belt 208 in the direction of the arrow in the figure (i.e., the direction substantially perpendicular to the main scanning direction) to perform the sub-scanning. Radiographic image information accumulated over the entire surface of the sheet 230 is read.

The image signal read by the photomultiplier 259 is sent to an image processing circuit (not shown), subjected to necessary image processing, and then sent to a necessary image reproduction device. As mentioned above, this reproducing device may be a display such as a CRT, or a recording device that performs optical scanning recording on a photosensitive film. Alternatively, instead of the reproduction position 1A, an image signal recording section 3 such as a magnetic tape may be provided as in the embodiment shown in FIG.

Note that the time required to read the radiation image information from one sheet 230 is generally longer than the time required to record the radiation image information on the sheet 230 (j[l shadow); For example, endless belt 2
07. 206. 205. 204. 1 on 203
By leaving one sheet at a time, the six sheets 230 can be used one after another and recording can be completed within a short period of time. Also, as mentioned above, is it possible for observation and interpretation? l! ! Prior to the above-mentioned reading operation (main reading) to obtain &, an accumulation record of radiation image information stored in advance on a sheet using excitation light with lower energy than the excitation light to be irradiated in the main reading. A reading operation (pre-reading) is performed to grasp the information, and the accumulated record information of the radiation image information is grasped, and then the actual reading is performed, and the reading gain is appropriately adjusted based on the pre-reading information, or an appropriate reading operation is performed. If signal processing is applied, it is possible to eliminate the influence of fluctuations in imaging conditions or to obtain a radiation image that is highly suitable for observation and interpretation.
30, by reversing the endless belt 209 and the endless belts 207 and 208 and returning them to the image reading position, the above-mentioned "pre-reading" and "main reading" can be performed.

The sheet 230 whose image has been read is sent to the erasing section 270 by the endless belt 209. This erase section 2
Reference numeral 70 denotes a box 271 and a large number of erasing lights such as fluorescent lamps, tungsten lamps, sodium lamps, xenon lamps, iodine lamps, etc. arranged inside the box 271.
2, the sheet 230 is the shutter 21
3 is opened, it is conveyed by the endless belt 209 until its tip touches the nip roller 227. The sheet 23 is then rotated by the rotating nip roller 227.
0 is sent into the box 271. Sheet 230 is box 27
1, the shutter 273 is closed.

The erasing light @ 272 inside the box 211 mainly emits light in the excitation wavelength range of the phosphor of the sheet 230, and the radiation energy remaining in the sheet 230 after the image reading is transferred to the sheet 230. The light is emitted from the sheet 230 by being irradiated with such light. Note that since the shutter 273 is closed at this time, the erasing light does not leak and enter the image reading section 250 and generate noise in the read signal.

The sheet 230, on which the afterimage has been erased to such an extent that radiation image information can be recorded again, is discharged from the erasing section 270 by rotating the nip roller 228.

The discharged sheet 230 is attached to an endless belt 210°2
11, 212. 213, the image recording unit 240
However, if another sheet 230 is stuck first, it is placed on the endless belts 213, 212, 211, and 210 in order and waits.

Further, when the image recording and reading operations are completed for the time being, the last sheet 230 undergoes afterimage erasure in the erasing section 270, and then is sent onto the endless belt 209 by rotating the nip roller 227 in the opposite direction. It waits on the belt 209.

As explained above, the endless belts 202 to 213 and the nip rollers 22 constituting the sheet circulation conveyance system
7. 228 is an image recording section 240 and an image reading section 250
, and is controlled in conjunction with the operation of the erasing section 210 (this can be done by employing a known sequence control), and conveys or places the sheet 230.

Next, FIGS. 4 to 6 show further different modifications of the radiation image recording and reading apparatus.

FIG. 4 shows a chest type similar to the examples of FIGS. 1 and 2. In this example, a phosphor sheet (not shown) on which a radiographic image of the subject has been accumulated and recorded in the imaging section 410 is conveyed upward by a conveyor belt 411 and conveyed toward a reading section 420 .

In the reading section 420, the excitation light is scanned by a device similar to the embodiment shown in FIG. 1, and the stimulated luminescence light is read photoelectrically. In this reading unit 420, the sheet may be moved back and forth in the same manner as described above, and the first forward movement may perform pre-reading, and the second forward movement may perform main reading, or the first forward movement may perform pre-reading. It is also possible to do this and then read the book in the next return movement. The sheet that has passed through the reading section 420 is placed in the belt group 43
0, enters the erasing section 440, and then returns to the photographing section 41.
0 and reused.

FIG. 5 shows an example of a bed type in which imaging is performed while the subject is lying down, and the functions of each part are the same as in the two embodiments described above. The imaging unit 510 is positioned horizontally, and a bed (not shown) on which the subject lies is placed above it.

The photographed sheet is sent out to the right in the figure, and is sent to the reading section 520.
Pre-reading and main reading are performed by reciprocating motion. After reading, the sheet is sent to the erasing section 540 via the belt group 530, and then sent again to the photographing section 510, where the sheet circulates.

The belt group 530 has four parts (A
>, (B), (C), and (D), and the sheet that has passed through the reading section 520 enters the erasing section 540 via the waiting zones (A) to (D). These four waiting zones (A) to (D)
), four sheets that have been read after photography can be placed on standby. Reading section 52
Including the sheets before and after 0, a maximum of about 8 sheets can be reused. Note that in the above embodiment, the belt group 530
is provided between the reading section 520 and the erasing section 540, but it may also be provided upstream or downstream of the photographing section 510. .

Figure 6 also shows an example of a bed-type device.
After the sheet is sent from the photographing section 610 to the reading section 620, the sheet is reciprocated in the reading section 620 by a reciprocating roller 620A to perform pre-reading (S) and main reading (H), and then passes through the shutter 630 to the erasing section 640. Next, the sheet is sent to the photographing section 610 and circulated.

In this embodiment, the sheet is (S
Pre-reading is performed while moving in the ) direction, main reading is performed while moving in the opposite direction (H), and the data is directly sent to the next erasing section 640.

In each of the embodiments described above, it is preferable that reading is not performed at the timing when the sheet is fed into the erasing unit, so that strong light from a lamp such as a fluorescent lamp of the erasing unit does not enter the sensitive reading unit and cause noise. Also, at this time, it is desirable to turn off the power to the photomulti to prevent strong light from entering the photomulti.

(Effects of the Invention) As explained in detail above, in the radiation image information recording/reading device of the present invention, the phosphor sheet circulates through the photographing, II taking, and erasing sections, so that the sheet can be used repeatedly. and has a compact overall structure,
This is extremely advantageous in practice. It is particularly suitable for cases in which a large number of images are to be taken in succession, such as in group medical examinations, or in cases where it is carried on a bus or the like and used for transportation, making it extremely convenient in practice.

In addition, in the apparatus of the present invention, since the phosphor sheet that is photographed is immediately read, a divalent europium-activated alkaline earth metal halide phosphor with relatively large fading is used as the phosphor. This makes it possible to improve the sensitivity of the phosphor.

In addition, since divalent europium-activated alkaline earth metal halide phosphors can be excited particularly efficiently by excitation light in the wavelength range of 500 to 850 rv, a semiconductor laser or the like can also be used as an excitation light source provided in the reading section. Therefore, it is possible to reduce the size and cost of the device.

[Brief explanation of drawings]

1, 2, and 3 are schematic diagrams showing various embodiments of a radiation image information recording/reading device according to the present invention, and FIGS. 4 to 6 are respectively diagrams showing radiographic image information according to other embodiments of the present invention. FIG. 1 is a schematic diagram showing an overview of a recording/reading device. 1... Subject 2... Divalent europium activated alkaline earth metal halide phosphor sheet 3.8A, 8B, 33G... Shutter 4
．． 5.6, 7A, 78.16, 18.19... guide board 10, 110. 210. 310... Photographing section (image recording section) 11, . 15... Accumulation (supply) case 17
...The distribution is board 20, 120. 220. 320-fi Toribu (il
*! ! ! l1l) 22, 24...Feeding belt 25...
・Laser light source 28...Condensing optical element 29...Photo multiplier 34...Distribution is performed by pair of belts 40, 140. 240. 340... Erasing unit 70... Radiation image information recording/reading device 80...
...Image signal recording device 101 ...Circulation passage 102...2
europium-activated alkaline earth metal halide phosphor sheet 103... Circulating conveyance means 105... Image recording section 1
06... Image reading section 107... Erasing section 16
2... Excitation light source 163... Photoelectric reading means 20
1... Radiographic image information reading device 202-213... Endless belt 214-220
... Guide rollers 221 to 226 ... Guide plates 227, 228 ... Nip rollers 230, 290 ... Bivalent europium activated alkaline earth metal halide phosphor sheet 240 ... Image recording section 241 ...Photography stand 2
42... Radiation source 243... Subject (subject) 250... Image reading unit 252... Laser light 2
51--Laser light source 253, 255. 256. 257...
...Mirror -254...Galvanometer mirror 258...Condensing optical element

Claims (1)

[Claims] 1) M^IIX_2・a capable of storing and recording radiographic images
M^IIX'_2: x_Eu^2^+ (where M^II is at least one alkaline earth metal selected from the group consisting of Ba, S', and Ca; X and X' are Cl, Br
and at least one kind of halogen selected from the group consisting of 1, and X≠X'; a is 0.1≦a≦10.0
, where x is 0 < an image recording section that accumulates and records a radiographic image of a subject on the sheet by irradiating the sheet with radiation through the subject; an image reading unit having an excitation light source that emits scanning excitation light; and a photoelectric reading unit that reads stimulated luminescence light emitted from a sheet scanned by the excitation light to obtain an image signal; Radiation image information, characterized in that the image reading section comprises an erasing section that releases residual radiation energy on the sheet before the image is recorded on the sheet after the image has been read by the image reading section. Record reading device. 2) The circulating conveyance means sequentially conveys the plurality of phosphor sheets to an image recording section, an image reading section, and an erasing section, and at the same time, one sheet each of the image recording section and the image reading section is sent to an erasing section. The radiation image information recording/reading apparatus according to claim 1, wherein the radiation image information recording/reading apparatus is configured to stop at least one image at a time. 3) The radiographic image information recording/reading apparatus according to claim 1 or 2, wherein the circulating conveyance means comprises a plurality of endless belts arranged in series. 4) Among the circulating conveyance means, at least one of the conveyance means provided between the image recording section and the image reading section, between the image reading section and the erasing section, or between the erasing section and the image recording section. The radiation image information according to claim 1, 2, or 3, wherein each of the phosphor sheets has a sufficient length to hold at least one of the phosphor sheets. Record reading device. 5) Claims 1 to 4 are characterized in that the circulating conveyance means includes a portion for temporarily accumulating the sheets upstream or downstream of the image recording section.
A radiation image information recording/reading device as described in any one of the following paragraphs. 6) The radiation image information recording/reading device according to any one of claims 1 to 5, wherein the image reading unit performs both pre-reading and main reading of images. . 7) The radiation image information recording/reading apparatus according to claim 6, wherein the image reading section performs pre-reading and main reading using separate excitation light sources and photoelectric reading means. 8) The radiation cocoon image information recording/reading device according to claim 6, wherein the candy image reading section performs pre-reading and main reading using the same excitation light source and photoelectric reading means. 9) The image reading section performs pre-reading while feeding the sheet in one direction using the same excitation light source and photoelectric reading section, then returns the sheet once in the opposite direction, and then feeds it in the same direction as the one direction. 9. The radiation image information recording/reading device according to claim 8, wherein the radiation image information recording/reading device performs main reading while reading the information. 10) The image reading section is characterized in that the image reading section performs pre-reading while feeding the sheet in one direction using the same excitation light source and photoelectric reading means, and then performs main reading while returning the sheet in the opposite direction. Claim No. 8
The radiation image information recording/reading device described in Section 1.