JPH04157443A - Radioaction image information recording and reading-out device - Google Patents

Abstract

PURPOSE:To permit the continuous photographing at a high speed by using a strip- shaped flexible accumulable phosphor sheet by installing a means for absorbing the tension variation of an accumulable phosphor body sheet due to the revolution speed difference between each taking-up shaft and a sprocket wheel. CONSTITUTION:The first suction means 47 in a sheet passage formed between a sprocket wheel 46 and the first taking-up shaft 22 consists of two fixed rollers 47a and 47b on which an accumulable phosphor sheet 26 is laid, dancer rollers 47c and 47d which are energized by an urging means, and a dancer roller 47c which is urged downward similarly. Further, the second suction means 48 similar to the first suction means 47 is installed in a sheet passage between the second taking-up shaft 23 and a roller 28. Accordingly, the generation of the trouble that an accumulation type fluorescent body sheet is pulled and cut or largely loosened and meandering is generated and the sheet is separated from a sheet feeding means can be prevented. Accordingly, the continuous photographing at a high speed is enabled, and the sheet is sent in the reverse direction and the speedy reading-out of the radioactive ray image information is enabled, and the need of the troublesome manual work is obviated, and the workability is improved.

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. It relates to a radiation image information recording/reading device that detects light emitted by stimulated luminescence to read image information and converts it into an electrical signal, and more specifically, a radiation image information recording device that reuses a stimulable phosphor sheet within the device. This relates to a reading device.

(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 the subject that is suitable for diagnosis (for example, Japanese Patent Application Laid-Open No. 1983-1981) No. 12429, 55-1.16340
No. 55-163472, No. 56-11395,
No. 56-104645, etc.). This final image can be reproduced as a hard copy or on a CRT. In any case, in such a radiation image information recording and reproducing method, the stimulable phosphor sheet does not ultimately record image information, but temporarily stores image information in order to provide an image to the final recording medium as described above. Therefore, this stimulable phosphor sheet may be used repeatedly, and such repeated use is extremely economical.

For example, when a mobile station such as an X-ray vehicle is equipped with a radiographic image information recording/reading device that uses a stimulable phosphor sheet, it can be used to travel to various locations for group examinations and take X-rays. However, it is inconvenient to stack a large number of stimulable phosphor sheets, and there is a limit to the number of sheets that can be loaded on a moving vehicle. Therefore, a stimulable phosphor sheet is made to be reusable and loaded onto a moving vehicle, radiation image information for each subject is recorded on it, and the image signal obtained by reading it is stored on a large storage capacity such as a magnetic tape. If the radiation images are copied onto a recording medium and the stimulable phosphor sheet or the like is circulated and reused, radiation images of a large number of objects can be taken using a mobile vehicle, which is extremely useful in practice. Furthermore, by using this cyclical reuse, it is possible to increase the speed of imaging in mass medical examinations by performing continuous imaging.
The practical effects are extremely large.

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. 56-12599, 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.

Therefore, the present applicant proposed a circulating conveyance means for conveying a stimulable phosphor sheet capable of storing and recording radiation images along a predetermined circulation path, and a means for irradiating the sheet with radiation through a subject in the circulation path. an image recording unit that accumulates and records radiation image information of the subject on this sheet;
An excitation light source that is located in the circulation path and emits excitation light to scan a sheet on which radiation image information is stored and recorded in the image recording section, and reads stimulated luminescence light emitted from the sheet scanned by the excitation light. an image reading section comprising a photoelectric reading means for obtaining an image signal; and an image reading section which is located in the circulation path and remains on the sheet after the image reading is performed in the image reading section before an image is recorded on the sheet. We have previously proposed a radiation image information recording/reading device in which a stimulable phosphor sheet is repeatedly used by circulating the stimulable phosphor sheet between the various parts, and an erasing part that emits radiation energy. 1983-1
No. 92240). According to the radiographic image information recording/reading device having such a structure, radiographic image information can be recorded and read continuously and efficiently.

Furthermore, based on the above-mentioned basic idea, the present applicant has discovered that the stimulable phosphor sheet can be used repeatedly, that the sheet feeding mechanism can be made simple and compact, and that it can be continuously recorded many times. We also proposed a radiation image information recording/reading device capable of (photographing) (see Japanese Patent Application Laid-open No. 91933/1983).

This radiation image information recording/reading device is characterized in that a band-shaped flexible stimulable phosphor sheet is wound and stored for use. One end side and the other end side of the sheet as described above are respectively wound around a winding shaft and a second winding shaft, and the sheet is reciprocated between both winding shafts by a sheet feeding means to record an image. The unit is configured to irradiate radiation having image information onto the stimulable phosphor sheet unwound from both winding shafts and stretched, and the image reading unit and erasing unit as described above
It is designed to read and erase images.

By the way, for example, in angiography of the human body, 1
It is required to take radiographic images of the same subject one after another at a rate of three or more images per second. Conventionally, for such photography, multiple stimulable phosphor sheets, X-ray film, etc. were placed in a bag made of vinyl, etc., and these were sent one after another at high speed to the photography position using a special changer. , and then I would take it out after shooting.

(Problem to be Solved by the Invention) However, the above method requires complicated work such as taking out the stimulable phosphor sheet from the pack in a darkroom after radiographic imaging and repacking it into a magazine to be loaded onto a reading device. Requires.

On the other hand, the radiation image information recording/reading device using the strip-shaped flexible stimulable phosphor sheet mentioned above does not require the above-mentioned complicated work, so from the point of view of workability, it is not possible to continuously It can be said that it is especially suitable for photography.

However, this type of conventional radiation image information recording/reading device is
This made it unsuitable for high-speed continuous shooting. In other words, if you want to speed up continuous shooting, it is naturally necessary to rotate the winding shaft at high speed, but in such a case,
This rotational inertia of the winding shaft makes it difficult to accurately stop a predetermined portion of the stimulable phosphor sheet at a predetermined imaging position (radiation irradiation position).

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a radiation image information recording/reading device that can perform continuous imaging at high speed using a band-shaped flexible stimulable phosphor sheet. This is the purpose.

(Means for Solving the Problems) A radiation image information recording/reading device according to the present invention includes the first and second winding shafts as described above, sheet feeding means,
In a radiation image information recording/reading device comprising an image recording section, an image reading section, and an erasing section, the stimulable phosphor sheet is provided with a plurality of sprocket engagement holes at a predetermined pitch in the sheet length direction. Also, the sheet feeding means includes a sprocket wheel that engages with the sprocket engagement hole, and a Geneva gear mechanism that intermittently rotates the second sprocket wheel by a fixed amount in one direction; The stimulable phosphor sheet is provided with a reverse sheet feeding means capable of moving the stimulable phosphor sheet at a constant speed in the opposite direction to the directional sheet feeding means, and each winding This device is characterized by providing means for absorbing changes in the tension of the stimulable phosphor sheet due to the difference in rotational speed between the shaft and the sprocket wheel.

(Operation and Effects of the Invention) By operating the Geneva gear mechanism described above, it is possible to intermittently feed a band-shaped flexible stimulable phosphor sheet in one direction. can be sequentially sent frame by frame to a predetermined photographing position, making it possible to take continuous photographs using each part of the sheet.

As is well known, this Geneva gear mechanism realizes extremely reliable intermittent feeding, so using this Geneva gear mechanism allows for highly accurate frame-by-frame feeding, making it possible to perform continuous photographing at high speed.

When the speed of sheet frame feeding by this Geneva gear mechanism is increased, the stimulable phosphor sheet is subjected to a large tensile force due to the inertia of the sheet winding shaft, or vice versa, becomes sagging. However, in the present invention, since the tension change absorbing means as described above is provided, there is no possibility that the stimulable phosphor sheet will be stretched and cut, or it will become loose and meander, or it will come off from the sheet feeding means. can be prevented.

On the other hand, if the reverse direction sheet feeding means is operated, the portion of the stimulable phosphor sheet on which the radiation image has been photographed (recorded) will be rewound, so if the sheet is fed in this direction at a constant speed, Radiation image information can be read. Of course, image deletion can also be executed at the same time.

At this time, image erasure may be performed at once after the reading process for a series of stimulable phosphor sheets has been completed. In that case, the sheet feeding speed by the reverse direction sheet feeding means does not have to be particularly constant.

As described above, according to the radiation image information recording/reading device of the present invention, it is possible to advance the stimulable phosphor sheet frame by frame with high precision and perform continuous imaging at high speed. Since radiation image information can be read immediately by feeding the phosphor sheet in the opposite direction, the workability is good without requiring complicated manual work.

(Example) Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

FIG. 1 shows in detail the main parts of a radiation image information recording/reading apparatus according to an embodiment of the present invention, and FIG. 2 shows the external appearance of this radiation image information recording/reading apparatus. As shown in FIG.
It is formed from a main body 20, which is appropriately set at a lower position, etc., and a radiation source storage section 30. Reference numeral 12 in the figure is a marker for positioning coarse images shot continuously, which will be described later.

As shown in FIG. 1, in the housing 29 of the main body 20, a first winding shaft 22 and a second winding shaft 23 are arranged in parallel with each other at intervals. These winding shafts 22.
23 are rotated in the directions of arrows A and B by motors 24 and 25, respectively, which constitute a part of the sheet feeding means. As described above, one end side of the stimulable phosphor sheet 26 capable of storing and recording radiation image information is wound around the first winding shaft 22 . This stimulable phosphor sheet 26 is formed into a long strip using a flexible support, and the other end is held on the second winding shaft 23, and the second winding It is adapted to be wound around a take-up shaft 23. Further, the stimulable phosphor sheet 26 is stretched between rollers 27 and 28. Here, the stimulable phosphor sheet 26 is located between the driving roller 27 and the driven roller 28, with the flexible support at the bottom in the figure and the stimulable phosphor layer carried on the support at the top. It is arranged so that

In the sheet path between the roller 27 and the first winding shaft 22, a Geneva gear mechanism 40 constituting a forward sheet feeding means is provided.
are arranged. This Geneva gear mechanism 40 includes a pin wheel 42 to which one pin 41 is attached, and four pin grooves 4.
This is a well-known type consisting of a crusader 44 having a crusader 44 having a crusader 3 and a crusader 44 having a crusader 44.

A pair of sprocket wheels 46 are connected to the crusader 44 via a speed increasing gear 49 with a clutch, spaced apart from each other in a direction perpendicular to the paper plane of FIG. This sprocket wheel 46 has a plurality of sprockets 4 on its circumferential surface.
It has 8A. - As shown in Figure 3, a large number of sprocket engagement holes 26A are provided at both ends of the stimulable phosphor sheet 260 at a predetermined pitch in the sheet length direction, and the stimulable phosphor sheet 26 is connected to these engagement holes 28A or the sprocket 4 [iA,
It is hung on the sprocket wheel 46.

In the above configuration, each time the pin wheel 42 rotates once, the pin 41 enters the pin groove 43, causing the crusader 44 to rotate 1/4 in the direction of the arrow. As a result, the sprocket wheel 46 rotates 1.5 revolutions under the action of the speed increasing gear 49.
The stimulable phosphor sheet 26 is moved in the direction of arrow E by 3/2 of its outer circumference. When the crusader 44 repeats intermittent rotation in this manner, the stimulable phosphor sheet 26 is fed frame by frame by a predetermined length.

On the other hand, a first absorbing means 47 is arranged in the sheet path between the subrocket wheel 46 and the first winding shaft 22. This first absorption means 47 is arranged between two fixed rollers 47a and 47b on which the stimulable phosphor sheet 26 is hung, and between these rollers 47a and 47b, and is urged upward in the figure by a biasing means (not shown). dancer roller 47C
, 47d, and a dancer roller 4 disposed between these dancer rollers 47c, 47d and similarly urged downward.
It consists of 7e.

Further, a second absorbing means 48 similar to the first absorbing means 47 is provided also in the sheet path between the second winding shaft 23 and the roller 28 . Fixed rollers 48a, 48b and dancer roller 48c14'8d that constitute this second absorption means 48
, 48e are the fixed rollers 47 a s 47 b
They are formed similarly to the s dancer rollers 47c, 47d, and 47e.

During radiographic imaging, the stimulable phosphor sheet 26 stretched between the rollers 27 and 28 faces the head 11. The above-mentioned radiation source storage section 30 houses a radiation source 33 such as an X-ray tube therein, and during radiographic imaging, the radiation source 33 is placed between the bed 11 and the above-mentioned stimulable phosphor. It faces the sheet 26.

The subject (subject) 34 is placed, for example, on his back on the bed 11, and in this state the radiation source 33 is activated.

As a result, the radiation 35 transmitted through the subject 34 is irradiated onto the stretched stimulable phosphor sheet 26, and the stimulable phosphor sheet 26 (more specifically, the stimulable phosphor sheet formed on the upper surface side of this sheet 26) is The radiation image information of the subject 34 is accumulated and recorded in the layer. As described above, in this embodiment, the image recording section is composed of the roller 27.2g and the radiation source 33. 13 here indicates a Butsky device which absorbs scattered radiation.

After photographing one radiation image as described above, if the motor 45 is operated to rotate the pin wheel 42 of the Geneva gear mechanism 40 once, the stimulable phosphor sheet 2
6 moves from the second winding shaft 23 to the first winding shaft 22 side by one frame, another radiation image is stored in the part of the stimulable phosphor sheet 2B newly located between the rollers 27 and 28. Can be recorded.

When performing continuous imaging such as the above-mentioned angiography, the pin wheel 42 is continuously rotated at high speed.

Then, the stimulable phosphor sheets 2B are fed one after another at high speed, so if the radiation source 33 is activated while the sheets 2B are stopped, continuous imaging can be performed at high speed.

In this case, the drive roller 27 is separated from the drive source by a known clutch means (not shown).

Further, an appropriate load is applied to the second winding shaft 23 by a known means, and the first winding shaft 22 is rotated in the direction of arrow A.

The continuous photographing is performed at a high speed of, for example, three frames per second or more. During this time, the first winding shaft 22 is rotated at a substantially constant speed, so its circumferential speed may be higher or lower than that of the sprocket wheel 46, which repeatedly rotates and stops rapidly. Therefore, although the tension of the stimulable phosphor sheet 26 between the sprocket wheel 46 and the first winding shaft 22 changes greatly, this tension change is absorbed by the first absorption means 47. That is, when the tension increases, the dancer rollers 47c, 47
d descends against the urging force, and dancer roller 47e rises against the urging force. The opposite is true when the tension decreases.

Furthermore, since the load applied to the second winding shaft 23 is constant, a similar change in tension occurs in the stimulable phosphor sheet 2B between the second winding shaft 23 and the sprocket wheel 46. . This tension change causes the second absorption means 48
absorbed by. The absorption mechanism is similar to that of the first absorption means 48 described above.

As described above, in this apparatus, the stimulable phosphor sheet 2B is reliably prevented from being pulled and cut, from sagging and meandering, and from coming off from the various rollers. Combined with the high-precision frame-by-frame advance function of the Geneva gear mechanism 40, reliable and highly reliable continuous shooting is realized.

Once the above-mentioned continuous photography or individual photography has been carried out several times and the entire stimulable phosphor sheet 26 or an appropriate length has been wound around the first winding shaft 22,
Next, the radiation image information is read. This radiation image information reading will be explained below.

An image reading section 50 is provided between the drive roller 27 and the sprocket wheel 46 on the left side of the stimulable phosphor sheet 26 in the figure. The image reading unit 50 includes a laser light source 51, a light deflector 53 such as a polygon mirror that reflects and deflects a laser light 52 as excitation light emitted from the laser light source 51, a mirror 58, and a deflected laser light 52.
a long mirror 59 that reflects and scans one-dimensionally on the sheet 26 (specifically, on the stimulable phosphor layer);
a drive roller 27 as a sub-scanning means rotated at a constant speed;
arranged so that the light receiving surface extends along the scanning line (main scanning line) on the stimulable phosphor sheet 26 by the laser beam 52;
It is composed of a long photomultiplier 54 as a photoelectric reading means, and a long reflecting mirror 55 for condensing light arranged along the long photomultiplier 54.

By rotating the drive roller 27, the stimulable phosphor sheet 26 is conveyed at a constant speed in the direction of arrow F in the figure. At this time, the second winding shaft 23 is rotated so that the stimulable phosphor sheet 2
6 is wound around the shaft 23. Further, an appropriate load is applied to the first winding shaft 22 side by a known means, so that the stimulable phosphor sheet 26 is always maintained in a tense state. At this time, the clutch of the speed increasing gear 49 interposed between the crusader 44 and the sprocket wheel 46 is disengaged, so that the stimulable phosphor sheet 26 is not subjected to any load from the Geneva gear mechanism 40. In this way, the sheet 26 is conveyed, and the laser light source 51 and the optical deflector 5
3 is activated, and the laser beam 52 scans over the sheet 26.

Stimulated luminescence light 56 carrying radiation image information stored and recorded on the stimulable phosphor sheet 26 is emitted from a portion of the stimulable phosphor sheet 26 that is irradiated with the laser beam 52 .

This stimulated luminescence light 56 is efficiently detected by the elongated photomultiplier tube 54 either directly or after being reflected by the condensing reflection mirror 55. The main scanning of the laser beam 52 is performed as described above, and the stimulable phosphor sheet 26 is conveyed as described above and sub-scanning is performed, so that the stimulable luminescent light is emitted two-dimensionally from the sheet 26. 56 (ie, radiation image information) is read. The read image signal S output from the long photomultiplier tube 54 is amplified, digitized, and subjected to image processing in the read circuit 57, and then sent to an image reproducing device (not shown) to reproduce the radiation image information. Provided for reproduction. This reproducing device may be a display means such as a CRT, a recording device that performs optical scanning recording on a photosensitive film, or a part of the image signal is stored in an image file on an optical disk, magnetic disk, etc. It may be replaced by a device.

The elongated photomultiplier tube 54 is disclosed in detail in, for example, Japanese Patent Laid-Open No. 16666/1983.

In addition, lead plates 81 and 82 are arranged at the upper part of the housing 29,
The radiation 35 emitted during radiographic imaging is prevented from being irradiated onto the sheet 26 before the reading process.

The portion of the stimulable phosphor sheet 26 whose image has been read as described above is wound around the second winding shaft 23 and stored there. In this way, when the stimulable phosphor sheet 26 is returned to the second winding shaft 23 side, the stimulable phosphor sheet 26 passes through the erasing section 60, and the sheet 26 forms an image (afterimage).
undergo erasure. This erasing section 60 includes, for example, a plurality of erasing light sources 61 arranged on the right side of the stretched sheet 2B in the figure.
It consists of

These erasing light sources 61 are composed of, for example, fluorescent lamps, etc., and mainly emit light in the excitation wavelength range of the stimulable phosphor of the sheet 26, and when the sheet 26 is returned to the second winding shaft 23 side, It will be lit. The radiation energy remaining in the stimulable phosphor sheet 26 after reading the image is emitted from the sheet 26 by irradiating the sheet with the above light.

In this way, the stimulable phosphor sheet 26 whose image (afterimage) has been erased to the extent that radiation image information can be recorded again is stored on the second winding shaft 23. It becomes possible to repeat image recording (photography) and reading of images. As the erasing light source 61, in addition to the above-mentioned fluorescent lamp, a tungsten lamp, a halogen lamp, an infrared lamp, a xenon flash lamp, etc., such as those shown in Japanese Patent Application Laid-Open No. 56-11392, can be arbitrarily selected and used. Furthermore, the erasing unit 60 includes a large number of erasing light sources 61 as described above, and also includes, for example, an LED (L
The light source may be constructed from a planar light source such as a panel in which lights are arranged two-dimensionally or an EL (electroluminescence) board.

Preferably, the stimulable phosphor sheet 26 is also irradiated with erasing light when it is fed out from the second winding shaft 23 for recording radiation image information.

If the stimulable phosphor sheet 26 has undergone image (afterimage) erasure in the erasing unit 60 and has been stored on the second winding shaft 23 without being used for a long period of time, the sheet 26 may
Is there any possibility that radioactive elements such as 226Ra contained as impurities in the phosphor or radiation energy from environmental radiation (which is a component of noise to stored recorded information) are accumulated? By irradiating the sheet 26 with erasing light, this radiation energy is also released. Note that the above-mentioned erasing light is blocked by a light shielding plate 71, and the stimulable phosphor sheet 26 is blocked by a light shielding plate 71.
It is designed so that it will not be irradiated.

[Brief explanation of the drawing]

FIG. 1 is a schematic front view showing a radiation image information recording/reading device according to an embodiment of the present invention, FIG. 2 is an overall perspective view of the above embodiment device, and FIG. 3 is a part of the above embodiment device. FIG. 20... Main body 22... First winding shaft 23... Second winding shaft 24.25.45.
...Motor 26...Stimulable phosphor sheet 28A...Sprocket engagement hole 27...Drive roller 28...Followed roller 30...Radiation source storage section 33...Radiation source 34... Subject 35... Radiation 40... Geneva gear mechanism 42... Pin wheel 44... Crusader 46... Sprocket wheel 47... First absorption means 47c, 47d, 47e, 48c, 48d, 48
e... Dancer roller 48... Second absorption means 49... Speed-up gear with clutch 50... Image reading section 51... Laser light source 52... Laser light 53... Optical deflector 5
4... Photomultiplier tube 56... Stimulated luminescence light 5
7...Reading circuit 60...Erasing section 61.
... Erasing light source 1 [tsu 1

Claims (1)

[Claims] A first winding shaft for winding one end of a band-shaped flexible stimulable phosphor sheet capable of storing and recording radiation image information; a second winding shaft that is arranged to wind the other end of the sheet; a sheet feeding means that reciprocates the sheet between the first and second winding shafts; an image recording section that accumulates and records radiographic image information on the unraveled and stretched sheet by irradiating the sheet with radiation having image information; an image reading unit that irradiates the sheet with excitation light from an excitation light irradiation unit and reads stimulated luminescence light emitted from the sheet by the excitation light irradiation with a photoelectric reading unit to obtain an image signal; In a radiation image information recording/reading device comprising an erasing section that releases radiation energy remaining on the sheet prior to recording an image on the sheet after reading, the stimulable phosphor sheet is , a plurality of sprocket engagement holes are provided at predetermined pitches in the sheet length direction, and the sheet feeding means includes a sprocket wheel that engages with the sprocket engagement holes, and a sprocket wheel that moves a certain amount in one direction. The stimulable phosphor sheet is composed of a forward sheet feeding means equipped with a Geneva gear mechanism that rotates the stimulable phosphor sheet intermittently, and a reverse sheet feeding means capable of moving the stimulable phosphor sheet at a constant speed in a direction opposite to the forward sheet feeding means. A radiation source characterized in that the sheet path between the Geneva gear mechanism and both winding shafts is provided with a means for absorbing a change in tension of the stimulable phosphor sheet due to a difference in rotational speed between each winding shaft and the sprocket wheel. Image information recording/reading device.