JPH01267635A - Recorder/reader for radiograph information - Google Patents

Abstract

PURPOSE:To detect stimulated luminous light inside a recording belt by using a transparent roller for one of rollers feeding the recording belt, scanning light for excitation on this roller, and providing a long-length photomultiplier in this roller. CONSTITUTION:A photoelectric reading means arranged inside the recording belt 1 is housed in the transparent roller 42 and consists of the long-length photomultiplier 28, a filter 29A, and a reflection guide 29B. This reflection guide 29B guides part of the stimulated luminous light which diverges from an excitation photoirradiating position as nondirectional light to the light receiving face of the photomultiplier 28 by total reflection. On the other hand, a photoelectric reading means provided outside the recording belt 1 consists of a photomultiplier 28', a filter 29C, and a light guide 29D. Two electric signals detected by these two photomultipliers 28 and 28' are added to be a picture signal. As a result, the stimulated luminous light emitted from the recording belt 1 can be detected inside the recording belt 1 while the light for excitation is scanned on the roller 42.

Description

Detailed Description of the Invention (Field of the Invention) The present invention involves accumulating and recording radiation-image information in a stimulable phosphor, then irradiating it with excitation light, and performing photostimulation according to the accumulated and recorded image information. It relates to a radiation image information recording/reading device that detects emitted light, reads image information, and converts it into an electrical signal.In particular, an endless belt-shaped recording belt having a stimulable phosphor layer is suspended on rollers and circulated. The present invention relates to a radiation image information recording/reading device.

(Conventional technology) Certain phosphors are exposed to radiation (X-rays, α-rays, β-rays.

When irradiated with γ-rays, electron beams, ultraviolet rays, etc., a part of this radiation energy is accumulated in the phosphor, and when this phosphor is irradiated with excitation light such as visible light, the phosphor changes depending on the accumulated energy. is known to exhibit stimulated luminescence, and phosphors exhibiting this property are called stimulable phosphors (stimulable phosphors).

Using this stimulable phosphor, radiation image information of a subject such as a human body is temporarily recorded on a recording medium having a stimulable phosphor layer, and this recording medium is scanned two-dimensionally with excitation light such as a laser beam. The resulting stimulated luminescent light is photoelectrically read by a photodetector to obtain an image signal, and based on this image signal, a recording material such as a photographic light-sensitive material, a display device such as a CRT, etc. The present applicant has already proposed a radiation image information recording and reproducing system that outputs a radiation image of a subject as a visible image. (Unexamined Japanese Patent Publication No. 12429/1983.

5B-11395 etc. ) This system has the practical advantage of recording images over a much wider range of radiation exposure compared to conventional radiographic systems using silver halide photography. In other words, in a stimulable phosphor, it is recognized that the amount of emitted light that is stimulated to emit light due to excitation after accumulation is proportional to the amount of radiation exposure over an extremely wide range.
Therefore, even if the amount of radiation exposure varies considerably due to various imaging conditions, the amount of stimulated luminescence emitted from the recording medium containing the stimulable phosphor can be read by setting the gain to an appropriate value and adjusting the photoelectric conversion means. is read and converted into an electrical signal, and this electrical signal is used to record materials such as photographic light-sensitive materials, CRT
By outputting a radiation image as a visible image on a display device such as the above, it is possible to obtain a radiation image that is not affected by fluctuations in radiation exposure amount.

In the radiation image information recording and reproducing system described above, the recording medium containing the stimulable phosphor does not ultimately record image information, but temporarily stores image information in order to provide an image to the final recording medium as described above. Since it is supported, this recording medium may be used repeatedly, and such repeated use is extremely economical.

In order to reuse the recording medium as described above, the radiation energy remaining in the stimulable phosphor after the stimulated luminescence light is read can be removed using the method disclosed in, for example, Japanese Patent Laid-Open No. 58-11392.

As shown in Japanese Patent No. 5B-12599, the stimulable phosphor may be irradiated with light or heat to emit the residual radiation image, and the stimulable phosphor may be used again for recording the radiation image.

Therefore, the present applicant has previously proposed a radiation image information recording/reading device that realizes efficient cyclical reuse of stimulable phosphors (for example, Japanese Patent Laid-Open No. 58-200269).

The above-mentioned apparatus comprises a support, a recording body consisting of a stimulable phosphor layer fixed on the support and capable of storing and recording a radiographic image, and a recording body that is formed by irradiating the recording body with radiation through a subject. an image recording section for accumulating and recording a radiographic image of a subject; an excitation light scanning means for scanning excitation light onto a recording body on which the radiographic image has been accumulated and recorded; An image reading section including a photoelectric reading means for reading stimulated luminescence light to obtain an image signal; and the recording medium on the support is read by repeatedly moving the support and the image reading section relative to each other. means for circulating the image relative to the image reading section, and emitting residual radiation energy on the recording medium prior to recording an image on the recording medium after the image reading is performed in the image reading section. The erasing section is incorporated into one device,
The recording medium is efficiently circulated and reused. If the recording medium is one in which a plurality of stimulable phosphor layers are formed on an endless support belt, the recording medium is suspended on a roller or the like and circulated, and the image recording section and the image reading section It is extremely convenient because it can pass through the section and erasing section sequentially.

By the way, in an apparatus using an endless belt-like recording medium (recording belt) as described above, it may be desired to detect stimulated luminescence light emitted from a stimulable phosphor layer from inside the recording belt. That is, in the above device, it is desirable to detect all stimulated luminescence light as efficiently as possible during image reading, and in order to increase the detection efficiency of stimulated luminescence light, the entire recording belt is formed of a stimulable phosphor. , the stimulable phosphor layer is optically exposed on the front and back surfaces of the recording belt by making the support transparent, etc., and the stimulated luminescence light emitted from the front and back surfaces of the stimulable phosphor layer is detected from both sides. In such a case, it is necessary to provide charge reading means both outside and inside the recording belt. Further, in order to make the entire apparatus compact, space can be efficiently saved by arranging the photoelectric reading means by utilizing the space inside the recording belt.

(Problems to be Solved by the Invention) However, in an apparatus having an endless belt-like recording belt as described above, excitation is generated on the recording belt on the circumferential surface of the roller where the conveying state of the recording belt is most stable. It is desirable to scan the light, but in that case the rollers would get in the way and it would be difficult to arrange the photoelectric reading means inside the recording belt facing the scanning line.

The present invention has been made in view of the above problems, and provides radiation image information recording in which stimulated luminescence light can be detected from inside the recording belt without impairing the conveyance stability of the recording belt during reading. The purpose of this invention is to provide a reading device.

(Means for Solving the Problems) The radiation image information recording/reading device of the present invention includes a recording belt that is an endless belt having a stimulable phosphor layer optically exposed on the front and back surfaces, and a recording belt in which the recording belt is suspended. transport,
a recording belt conveying means comprising a plurality of rollers; an image recording section that accumulates and records the image information on the stimulable phosphor layer by irradiating the stimulable phosphor layer with radiation having image information; and the image information an excitation light scanning means for scanning excitation light on the stimulable phosphor layer in which the stimulable phosphor layer is stored and recorded; and an image signal is obtained by reading the stimulated luminescence light emitted from the stimulable phosphor layer scanned by the excitation light. an image reading section having a photoelectric reading means, and residual radiation energy of the stimulable phosphor layer prior to image recording on the stimulable phosphor layer after the image reading is performed in the image reading section; one of the plurality of rollers constituting the recording belt conveying means; is a transparent roller, and the excitation light scanning means scans the stimulable phosphor layer on the transparent roller, and the charge reading means scans the light receiving surface extending along the scanning line of the excitation light. and a long photomultiplier housed inside the transparent roller.
It is characterized by having the following.

In this apparatus, the charge reading means may be only a long photo multiplier located inside the transparent roller, or may be a combination of this long photo multiplier and a photo provided outside the recording belt. It may also consist of two multipliers.

(Function) According to this reading device, one of the rollers for conveying the recording belt is a transparent roller, the excitation light is scanned on this roller, and a long photo multiplier is installed inside this roller. By arranging the recording belt, reading can be performed at a position where the recording belt is stably transported, and the stimulated luminescence light can be detected from inside the recording belt. Therefore, by using this device, it is possible to increase the detection efficiency by detecting stimulated luminescence light from both sides of the recording sheet, and to make the device more compact by housing the photoelectric reading means inside the recording sheet. .

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a side view showing an outline of a radiation image information recording/reading apparatus according to an embodiment of the present invention, and FIG. 2 is a plan view of the main parts thereof.

In this apparatus, a recording belt 1, which is an endless belt formed of a stimulable phosphor layer, is connected to two rollers 4.
The first roller part 40 consists of 1.42, and the distance between the first roller part 40 and the shaft 'fI! placed L apart, 2
The recording belt is suspended by a recording belt conveying means constituted by a second roller section 50 consisting of two rollers 51 and 52, and is circulated and conveyed in the direction of the arrow in the figure.

Note that the roller 42 is a hollow transparent roller.

Above the recording belt 1, there is an x
A radiation source R11 such as an X-ray source 11 is arranged, and this X-ray source 11
The upper part of the apparatus including the photographing stage 14 on which the subject 12 is placed serves as an image recording section IO.

In the image recording unit IO, when the radiation source 11 is activated via the subject 12 placed on the photographing stage 14, the transmitted radiation image of the subject I2 is projected onto the recording belt 1, and the radiographic image information of the subject is The information is accumulated and recorded in the stimulable phosphor layer that constitutes the recording belt. In addition, the two roller parts 40
．． The distance between the axes of 50 is approximately equal to the length of one image formed by the image recording (photographing) described above. Therefore, the radiographic image information is accumulated and recorded on the entire road side portion of the recording belt by one imaging operation. In addition, in order to minimize the length in the width direction of the device, the length from the edges of the two roller parts that are farthest from each other to the edges should be equal to the length of one screen, and If the length from edge to edge is at most 1.5 times the length of one screen above, then
This is preferable for downsizing the device.

The recording belt 1 emits a portion of the recording belt that performs photography while photography is being performed! The recording belt is stopped at a predetermined position facing the I source, but when the photographing is completed, it is transported by rollers 41, 42, 51, and 52 that rotate in the direction of the arrow in the figure, and the portion of the recording belt where the photographing was performed is recorded. The image is conveyed to an image reading section 20 provided on the left side of the belt 1. Note that the four rollers 41, 42. 51
．． Among the rollers 52, the roller 52 is a driving roller that is connected to the shaft 53a of the motor 53 by a belt or a chain 54, and the other rollers 41, 42, and 51 are driven rollers that rotate by following this roller 52. ing. Further, as shown in FIG. 2, a rotary encoder 55 is attached to the motor shaft 53a, and the rotation of the motor can be detected to perform various controls. It looks like this.

The image reading unit 20 includes a He-
An excitation light source 21 such as a Ne laser is provided on the outside of the recording belt and extends perpendicularly to the conveyance direction of the recording belt 1, and on the optical path of the excitation light 21, excitation light 21A is directed onto the recording belt with its width. A rotating polygon [24] which is an optical deflector for main scanning in the direction (perpendicular to the plane of the paper in FIG. 1) is provided. The excitation light 21A emitted from the excitation light source 2I has its optical path changed by a group of mirrors 22 as shown in FIG. The light enters the polygon mirror 24.

The excitation light 21A reflected and deflected by the rotating polygon mirror 24 is
As shown in FIG.
, 26c, 26d, and 26e, the recording belt 1 on the lower peripheral surface of the roller 42 is repeatedly main scanned. The mirror 26c is a cylindrical mirror that focuses the excitation light 21A only in a plane parallel to the paper plane of FIG. Even if the rotating polygon mirror 24 suffers from axial wobbling or surface tilt due to the action,
This prevents pitch unevenness of scanning lines from occurring on the recording belt. At the same time as the main scanning of the excitation light 21A, the recording belt 1 moves to the rollers 41, 42, 51, 5.
2 is conveyed at a constant speed in the direction of the arrow in FIG.
is irradiated. In the apparatus of this embodiment, each of the above-mentioned members in the image reading section constitutes an excitation light scanning means.

Stimulated luminescent light is generated from the excitation light irradiated portion of the recording belt 1 in accordance with the accumulated and recorded image information, and this stimulated luminescent light is detected by a photoelectric reading means.

In addition, since the recording belt is made of a stimulable phosphor layer as described above, the stimulated luminescence light is emitted from the front and back surfaces of the recording belt. One each is placed inside and outside of the recording belt 1.

The photoelectric reading means arranged inside the recording belt 1 is housed in the transparent roller 42, and is a long photomultiplier tube extending in the main scanning direction over the length of the main scanning line. (Photomultiplier) 28, which is provided on the light-receiving surface of the photomultiplier 28, selectively transmits only the stimulated luminescence light, and transmits the excitation light transmitted through the recording belt 1 to the photomultiplier=28. Filter 2 that cuts incident light
9A1, and reflection guides 29B provided at both ends of the light receiving surface of the photomultiplier along the direction in which the photomultiplier extends. This reflection guide 29B has an arcuate cross section and a mirror surface on its inner surface, and completely reflects a portion of the stimulated luminescence light emitted from the excitation light irradiation position as non-directional light to the photomultiplier 28. (see Figure 3 (described later)).
b)). Note that the photoelectric reading means within the roller 42 is fixed to the apparatus side independently of the roller 42 so that it stops at a predetermined position even if the roller 42 rotates.

On the other hand, the photoelectric reading means provided outside the recording belt 1 is a long photomultiplier having a structure similar to the photomultiplier 28 described above, and whose light receiving surface is arranged along the main scanning line. -28', and the filter 29A provided on the light receiving surface of this photomultiplier -28'.
A filter 29C having the same characteristics as (However, this filter cuts the excitation light reflected on the recording belt) and a filter 29C that is attached to the light receiving surface of the photomultiplier 28' through this filter 29C. , a light guide 29D that allows stimulated luminescence light to enter therein, totally reflects the stimulated luminescence light inside, and transmits the stimulated luminescence light to the light-receiving surface. Further, a mirror 29E is disposed at a position facing the light guide 29D across the main scanning line, so that the stimulated luminescence light emitted toward the mirror 29E is efficiently reflected toward the incident surface of the light guide 29D. ing.

The two photomultipliers 28, 28' are
- As an example, it has an electrode structure called Venetian blind type. Next, Figures 3 (a) and (b) are a perspective view of the photomultiplier 28 and a sectional view taken along the line I-I. The structure will be explained with reference to .

The photomultiplier 28 has a cylindrical main body 28A, a charging cathode 28b is provided along the main body 28A facing the light receiving surface 28a, and the above-mentioned filter 29A and reflection guide are provided on the light receiving surface 28a. 29B is attached as shown. In addition, what is shown by the broken line 12a in FIG. 3(b) is stimulated luminescence light. Below the photocathode 28b, a plurality of dynodes 2111c (13 in this embodiment) are stacked with an insulating member 28d interposed therebetween and fixed with a pin 28e to constitute a multiplier 28''.

Each of the dynodes 28c has a number of U-shaped notches formed in a single conductive plate, and is formed into a bent blind shape. A shield electrode 28g is connected to the bottle 2 below the multiplier 28f' via an insulating member 28d.
8e, and an anode 28h is provided within the shield electrode 28g. These electrodes are electrically connected to each terminal of the terminal group 281 provided on the side end of the main body 28A in a one-to-one correspondence. Note that the shield electrode 28g does not necessarily have to be provided.

FIG. 4 shows an electric circuit 60 for driving the photomultiplier 28 and taking out charging output, and parts corresponding to each part of the photomultiplier 28 are given the same reference numerals. A negative high voltage application terminal B is connected to the photocathode 28b.
A negative high voltage is applied through oa. Further, the negative high voltage applied to the negative high voltage application terminal 60a is applied to each of the dynodes 28c divided by the bleeder resistor group 60b.

Further, the shield electrode 28g is grounded, and the anode 28g is grounded.
h is grounded through a resistor 80c and connected to an amplifier 60d.
is input to one terminal of The other terminal of the amplifier 60d is grounded, and the charged image information is taken out as an electrical signal from the output terminal 60e. Further, the structure and drive circuit of the photomultiplier 28' are similar to the photomultiplier 28 described above, and in this device, two electrical signals detected by the two photomultipliers are added to produce an image signal. becomes.

After the image signals extracted in this manner are subjected to necessary image processing, they are sent to various image reproducing devices such as a display such as a CRT or a recording device that performs optical scanning recording on a photosensitive film. In addition, it stores printed circuit boards, etc.
The control circuit section 3 that controls the image processing and the like is provided within the loop of the recording belt 1, as shown in FIG. 1, for example. The part of the recording belt whose image has been read is further conveyed by roller sections 40 and 50 and sent to the erasing section 30. The erasing section 30 consists of a box 31 and three erasing light sources 32 such as fluorescent lamps arranged in a row inside the box 31. The erasing light source 32 inside the box 31 mainly emits light in the excitation wavelength range of the stimulable phosphor forming the recording belt, and the radiation energy remaining in the phosphor layer after reading the image is used for recording. The light is emitted by irradiating the entire image forming area of the belt while it is being conveyed. In addition, since a lead plate 2 for shielding radiation is arranged below the photographing table 14, the radiation emitted from the radiation source 11 during photographing is transmitted to the above-mentioned image reading section and erasing section and the records located therein. This does not cause any inconvenience such as affecting the belt. Further, in this apparatus, the above-mentioned reading and erasing are performed in parallel for a certain period of time for one image forming area. The recording belt portion that has been erased in the erasing section 30 is again conveyed to the image recording section 10 and becomes ready for new recording.

As described above, according to the apparatus of this embodiment, one of the rollers for conveying the recording belt is a transparent roller, and a long photomultiplier is disposed inside this roller, so that the excitation on the roller is It becomes possible to detect stimulated luminescence light emitted from the recording belt even from inside the recording belt while scanning the light. Therefore, it is possible to increase the detection efficiency of stimulated luminescence light by providing photomultipliers both outside and inside the recording belt. Furthermore, as in the device of this embodiment, the distance between the axes of the two roller parts 40 and 50 is made equal to the length of one screen, and the image recording part is arranged above the recording belt, and the image reading part and the erasing part are arranged below. in case of,
The horizontal length of the entire device can be reduced to nearly the length of one screen, and the conventionally large recording/reading device can be made much smaller. In addition, when attempting to miniaturize the apparatus in this manner, the length from one end edge to the other end edge of both roller parts may be set to 1 to 1.5 times the length of one screen. If the above-mentioned length is about 13.5 times, it is possible to record an image on the flat part of the recording belt with a margin while keeping the size of the apparatus small. In addition, the recording belt only needs to have the stimulable phosphor layer optically exposed on the front and back surfaces so that it can be read from the inner surface, and the entire recording belt is formed of the stimulable phosphor as in the above embodiment. Alternatively, a stimulable phosphor layer may be provided on the entire surface of an endless belt-like transparent support or, if necessary, on a part of the transparent support. Also,
The photoelectric reading means disposed within the transparent roller may have a long photomultiplier so that the whole is compact, and in the above embodiment apparatus, it is disposed outside the recording belt. A photoelectric reading means of the type consisting of an elongated photomultiplier, filter and light guide may be disposed within the transparent roller. moreover,
A long photomultiplier is created by extending a photomultiplier equipped with a multiplier made of electrodes other than the Venetian blind type described above or a multiplier made of a combination of multiple types of electrodes. It may be. Furthermore, the photoelectric reading means provided outside the recording belt does not necessarily have to have a long photomultiplier, but rather a conventional photoelectric reading means having an entrance end face extending along the main scanning line and an exit end face having a cylindrical shape. It is also possible to use one consisting of a shaped light guide and a relatively small photomultiplier connected to the exit end face of the light guide.

Further, the present invention may be any device that performs reading using at least a charged reading means disposed inside a transparent roller.
As mentioned above, the detection efficiency of stimulated luminescence light may be improved by using two charged reading means, or the reading may be performed only by the 18 photoelectric reading stages arranged inside the transparent roller, and the photoelectric reading means The apparatus may be made compact by being housed in the loop of the recording belt.

(Effects of the Invention) As explained above, according to the radiation image information recording/reading device of the present invention, the stimulable phosphor layer of the recording belt is optically exposed on the front and back surfaces of the belt, and the recording belt is barrel fed. By making one of the rollers transparent and arranging a long photomultiplier inside this roller, the excitation light can be scanned on the roller to achieve stable optical scanning while also scanning the inner surface of the recording belt ( It becomes possible to detect stimulated luminescence light from the back side). Therefore, according to the present apparatus, it is possible to make the entire apparatus compact and to increase the detection efficiency of stimulated luminescence light by disposing photomultipliers on both sides of the recording belt as necessary.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an outline of a radiographic image information recording/reading device according to an embodiment of the present invention, Fig. 2 is a plan view of its main parts, and Figs. 3 (a) and (b) are Venetian blind type. FIG. 4 is a perspective view of the photomultiplier and a sectional view taken along line I-1 of the photomultiplier. FIG. 4 is a drive circuit diagram of the photomultiplier.

Claims (1)

[Scope of Claims] A recording belt that is an endless belt having a stimulable phosphor layer optically exposed on the front and back surfaces, a recording belt conveying means consisting of a plurality of rollers that suspends and conveys the recording belt, and the storage an image recording unit that accumulates and records the image information on the stimulable phosphor layer by irradiating the stimulable phosphor layer with radiation having image information; an image reading section having an excitation light scanning means for scanning the excitation light with the excitation light, and a photoelectric reading means for reading the stimulated luminescence light emitted from the stimulable phosphor layer scanned by the excitation light to obtain an image signal; an erasing section that releases residual radiation energy in the stimulable phosphor layer prior to recording an image on the stimulable phosphor layer after the image reading is performed in the image reading section; One of the plurality of rollers constituting the belt conveying means is a transparent roller, and the excitation light scanning means scans the stimulable phosphor layer on this transparent roller, and the photoelectric reading means scans the stimulable phosphor layer. . A radiation image information recording/reading device comprising: a long photomultiplier having a light-receiving surface extending along a scanning line of the excitation light and housed inside the transparent roller.