JPS63298333A - Radiograph information reader - Google Patents

Abstract

PURPOSE:To miniaturize the entire of a device by making the length from an excitation light radiating position to one end of a cassette shorter than that of an accumulative type fluorescent sheet and providing an erasion part between a reading part and a cassette holding part. CONSTITUTION:A reader provides the cassette holding part 10 which holds the cassette 2 which can house the accumulative type fluorescent sheet 1 to freely load and unload, the reading part 20 for reading image information accu mulated to be recorded in the accumulative fluorescent sheet 1 and an erasion part 30 which executes the erasion of the image information which remains in the sheet 1 after completing to read. And the carried distance of the accumula tive type fluorescent sheet 1 from one end of the cassette 2 held in the cassette holding part 10 to the excitation light radiating position in the reading part 20 shorter than the length of carrying direction of the sheet 1 and the erasion part 30 is arranged on the carrier path of the accumulative type fluorescent sheet 1 between the cassette holding part 10 and the reading part 20. Thus, the size of the entire device is nearly specified by the small-sized reading part and the cassette holding part and the entire device can be made compact.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a radiation image information reading device used in a radiation image information recording and reproducing system. It is related to the device.

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

Gamma rays? ! ! When the phosphor is irradiated with excitation light such as visible light, a portion of this radiation energy is accumulated in the phosphor, and when the phosphor is irradiated with excitation light such as visible light, the phosphor is exhausted according to the accumulated energy Phosphors that are known to emit light are called stimulable phosphors (stimulable phosphors).

Using this stimulable phosphor, radiation image information of a subject such as a human body is recorded on a sheet of stimulable phosphor, and this stimulable phosphor sheet (hereinafter simply referred to as a sheet) is exposed to laser light, etc. Scanning with excitation light produces stimulated luminescence light, photoelectrically reads the obtained stimulated luminescence light to obtain an image signal,
The applicant has already proposed a group 1Al9 image information recording and reproducing system that outputs a radiation image of a subject as a visible image to a recording material such as a photographic light-sensitive material, a CRT, etc. based on this image signal. (JP-A No. 55-12429, No. 56-11395, No. 55-163472 bow, 5G
-No. 104645.

No. 55-116340 etc. ) The stimulable phosphor sheet in the above system is
It stores and records line image information and temporarily holds the recorded image information until it is read by the excitation light scanning. Therefore, after the image information has been read, it remains on the sheet. It is desirable to delete the image information on the sheet and reuse the sheet.

Based on such demands, a 14-meter image information reading device has been proposed that includes a reading section for reading image information recorded on a sheet and an erasing section for erasing image information remaining on the sheet. There is.

In the radiographic image information reading device, a cassette containing a stimulable phosphor sheet that has been imaged by an external imaging device is loaded into the cassette holding section, and the stimulable phosphor sheet is taken out from the cassette and is taken out into the reading section. At the same time, the sheet that has been read is further sent to an erasing section to erase the image information remaining on the sheet. The sheet that has been erased is taken out of the reading device and becomes ready for recording image information again.

It is desirable that these radiation image information reading devices be made as small as possible so that they can be used even in a limited space. Therefore, the present applicant has proposed various reading devices in which the size of the device is reduced by devising the arrangement of the reading section, the erasing section, etc.

For example, in Japanese Patent Application No. Sho GO-264482, as shown in FIG. 7, a cassette 102 which houses a stimulable phosphor sheet 101 on which image information is stored and which can be closed with fFl at one end is detachably held. The cassette holding part 110,
In the device including the reading section 1201 and the erasing section 130, the distance from one end of the cassette to the scanning position P where the excitation light 121 is reflected and deflected by the optical deflector 122 in the reading section 120 and performs main scanning is 'M'. A device has been proposed in which the overall size of the device is reduced by making the length L of the multilayer phosphor sheet 101 smaller. That is,
Inside the cassette holding section 110, a roller 111 serving as a sheet take-out means moves from the position shown by the broken line in the figure to the position shown by the solid line and rotates, and after taking out the stimulable phosphor sheet 101 inside the cassette 102, the stimulable phosphor sheet 101 is removed. The phosphor sheet 101 is transported to the reading section 12 by a sheet conveying means 140.
However, since the distance IIIL is smaller than the best value of the stimulable phosphor sheet, the front end of the stimulable phosphor sheet is read with the rear end of the stimulable phosphor sheet inside the cassette. is started. In this way distance III
If tL is equal to or less than the length Q, the inside of the cassette can be used as a conveyance zone for the stimulable phosphor sheet during reading, so the reading section can be made more compact. Stimulated luminescence light emitted from the scanning position of the excitation light 121 is photoelectrically detected by a long photomultiplier 123 arranged along the main scanning line.

Furthermore, as described in, for example, Japanese Patent Laid-Open No. 58-67240, G
In reading the image information, prior to the reading (actual reading) to obtain the image signal for outputting the visible image described above, pre-reading is performed to read the outline of the M copper wire image information stored and recorded on the sheet in advance. In some cases, the reading conditions for performing the main reading are determined based on the image information obtained by this pre-reading, and the main reading is performed according to the reading conditions.

Therefore, when the reading unit 120 also performs pre-reading prior to main reading, the stimulable phosphor sheet 101 is conveyed by the sheet conveying means 140 and the excitation light is first scanned over the entire surface of the TI stimulable phosphor sheet. A method is to perform pre-reading, then switch back the conveyance means to return the stimulable phosphor sheet to the scanning start position, and then carry out main reading by conveying the stimulable phosphor sheet again in the same direction as when pre-reading was performed. used. In the above @ position, the cassette 102 in the cassette holding section 110 can also be used as a switchback zone after the pre-reading is completed, so the pre-reading can be performed in rows 4T without increasing the size of the reading section itself.
It is also possible to move.

The stimulable phosphor sheet that has been read by the reading unit 120 is sent to the erasing unit 130, where all songs are irradiated with erasing light from an erasing light source 131 at the position indicated by the broken line in the figure.
After the reading is completed, erasure is performed in which the radiation image information remaining in the stimulable phosphor sheet is released. The stimulable phosphor sheet 101 that has been erased is transferred to the sheet conveying means 140.
The cassette 102 is switched back and carried into the empty cassette 102 in the cassette holder 110.

(Problems to be Solved by the Invention) However, in the above device, the stimulable phosphor sheet that has been read in the reading section is further transported in the transport direction during reading and sent to the erasing section. Therefore, it is necessary to provide a relatively long transportation path for the stimulable phosphor sheet between the excitation light irradiation position and the erasing zone, and the erasing section must be large enough to accommodate at least one stimulable phosphor sheet. Therefore, it is relatively large.

Therefore, in such an apparatus, there is a disadvantage that the portion on the side opposite to the cassette holding portion (the portion on the erasing portion side) becomes large.

The present invention has been made in view of the above-mentioned problems, and it is possible to miniaturize the reading section, prevent the device from becoming large due to the erasing section, and extremely effectively downsize the entire device. It is an object of the present invention to provide a radiation image information reading device that can read images of radiation.

(Means for solving the problem) Radiation image information reading of the present invention! Place A conveys the stimulable phosphor sheet taken out from the cassette in the cassette holder together with the reading section, erasing section, and cassette holding section described above to the reading section, and switches back the stimulable phosphor sheet after reading. The stimulable phosphor sheet is provided with a sheet transporting means for transporting the sheet into the cassette in the cassette holding part, and the transporting distance of the stimulable phosphor sheet from one end of the cassette in the cassette holding part to the excitation light irradiation position of the reading part is determined by the direction of transport of the sheet. It is small in size and is characterized in that the erasing section is inserted into the transport path of the stimulable phosphor sheet between the cassette holding section and the reading section.

The erasing unit may operate the erasing means such as an erasing light source only when erasing the stimulable phosphor sheet, and may prevent the erasing means from operating at other times. The erasing means may be kept in operation at all times and may include means for blocking the erasing means from the outside of the erasing unit except during erasing.

(Function) According to this device, by making the distance from the excitation light irradiation position to one end of the cassette smaller than the length of the stimulable phosphor sheet, it is possible to read the cassette in the cassette holder and transport the sheet during the auction. This space can be used to downsize the reading unit. Furthermore, when performing pre-reading, the inside of the cassette can be used as a space that allows the switchback of the stimulable phosphor sheet, so both pre-reading and main reading can be performed within the reading section without increasing the size of the reading section. Furthermore, according to this device, since the erasing section is provided between the reading section and the cassette holding section, it is possible to perform erasing while returning the cassette, which is a stimulable phosphor sheet, after reading is completed. Therefore, the inconvenience of increasing the size of the device does not occur.

(Main Example) Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing an outline of a radiation image information reading device according to an embodiment of the present invention, and is a conceptual side view of FIG.

The reading device of the present invention has a cassette retainer 15 that detachably holds a cassette 2 that can accommodate a stimulable phosphor sheet 1.
0, 1li accumulated and recorded on the stimulable phosphor sheet 1
A reading section 20 for reading i-image information. Sea 1-1 after reading
The device is equipped with an erasing section 30 for erasing image information remaining in the cassette 2, and a transport section 30 for receiving the stimulable phosphor sheet 1 taken out from the cassette 2 and transporting it to the reading section 20 and the erasing section 30. A sheet conveying means 40 consisting of rollers 41 and an endless belt 42 is provided.

In an external photographing device (not shown), the cassette 2 in which the stimulable phosphor sheet 1 housed inside was photographed is
The cassette holder 10 is loaded horizontally as shown by the arrow in the figure. The cassette 2, as shown in FIG. Then, the lid portion 2B is rotated from the closed position shown by the broken line in the figure to the open position shown by the solid line in the figure. Inside the cassette holding section 10, there is a sheet ejecting means for taking out the stimulable phosphor sheet 1 from the cassette 2.
When the lid 2B of the cassette 2 reaches the open position, it moves from the first position indicated by the broken line in the figure to the second position IWt indicated by the solid line in the figure, and rotates in contact with the stimulable phosphor sheet 1. , the stimulable phosphor sheet 1 is taken out from the cassette 2.

'lA1! in the cassette holding section 10! The position of one end of the stimulable phosphor sheet stored in the cassette 2 on the reading unit side is at position P1. As described above, the roller 11 rotates in contact with the portion near the tip of the sheet 1, so that
Unloading of the stimulable phosphor sheet 1 from the cassette 2 is started, and the stimulable phosphor sheet 1 is passed to the transport roller 41.

The stimulable phosphor sheet 1 is carried into the reading section 20 by the transport row 541 and the endless belt 42.

Note that in this device, the cassette holding section 10 and the reading section 20 are
In between, an erasing section 30 is provided, in which an erasing light source 31 extending in the width direction of the stimulable phosphor sheet is disposed in a semi-cylindrical reflecting plate 32. The erasing light source 31 is turned off until the reading section 20 finishes reading the image information stored and recorded on the stimulable phosphor sheet 1, as will be described later.

The reading unit 20 scans the stimulable phosphor sheet 1 on which image information has been accumulated and recorded with excitation light 21A such as a laser beam emitted from a laser light source 21, and as a result of the scanning, the stimulable phosphor sheet 1 that has stored image information is emitted from the sheet 1-1. The stimulated luminescent light is read in a charging manner by a long photomultiplier 17-22, which is a light 11 reading means, to obtain an electrical image signal for outputting a visible image. In the figure, 25 is a light deflector such as a galvanometer mirror, 23 and 24 are mirrors that reflect the excitation light 21A and make them enter the light deflector 25, 26 is a scanning lens such as a θ lens, and 27 is a mirror that reflects the excitation light 21A. stimulable phosphor sheet 1
It is a mirror that allows the light to be incident on the The elongated photomultiplier 22 is mainly a first multiplier having an electrode structure called a Venetian blind type, as disclosed in Japanese Patent No. 17IL No. 161366/1983. It is formed to extend along the scanning line, and a small light guide 22A is provided on its light receiving surface. The excitation light 21A is transmitted to the sheet conveyance means 4.
By repeatedly main-scanning the stimulable phosphor sheet 1 that is conveyed (sub-scanned) by the
It scans dimensionally, and stimulated luminescence light carrying image information is emitted from the scanning position of this excitation light. This stimulated luminescence light passes through the light guide 22A to the photomultiplier 2.
The photomultiplier 22 photoelectrically reads this stimulated luminescent light and outputs an image signal.

The stimulable phosphor sheet 1 is conveyed by the sheet conveying means 40 in the direction of arrow A1 as shown in FIG. ! IP 2
When this is reached, reading can be performed by scanning the excitation light. On the other hand, the transport distance of the stimulable phosphor sheet 1 from one end of the cassette in the cassette holding unit 10 on the reading unit side to this scanning position iaP 2 is smaller than the length of the stimulable phosphor sheet 1 in the transport direction. When the leading end of the stimulable phosphor sheet 1 is at position 1]2, the portion near the rear end of the sheet 1 remains in the cassette 2, as shown by the solid line in FIG. Therefore, stimulable phosphor sheet 1
Reading is started before the cassette 2 is completely removed from the cassette 2. In addition, when the above-mentioned pre-reading is performed in the reading unit 20 along with the main reading, the stimulable phosphor sheet 1 is placed at the leading edge. '? While moving in the direction of arrow A2 from P2 to position P3, the excitation light 21A is irradiated to first perform pre-reading.

When the pre-reading is completed as described above, the endless belt 4
2 and the conveying roller 41 are reversed by switchback, and the stimulable phosphor sheet 1 is conveyed in the direction of arrow A3 from the position where the one end is at position P3 to the position where the one end is at position P3! t
It is returned to its position at Pz.

When the stimulable phosphor sheet 1 is returned to the position where one end is at position 2), that is, the scanning start position, it is conveyed again in the direction of arrow A4 and the main reading is performed. As mentioned above, in the apparatus of this embodiment, the cassette 2 is loaded relatively close to the reading unit 20, so after pre-reading the stimulable phosphor sheet, the stimulable phosphor sheet is switched back and the cassette 2 is loaded relatively close to the reading unit 20. The inside of the cassette 10 is used as a space for the stimulable phosphor sheet to move when the sheet is reversed and the stimulable phosphor sheet is conveyed into the reading section 20 again. While the image remains in the cassette 2, it is irradiated with excitation light and the actual reading is started. As described above, in the device of the present invention, by using the inside of the cassette as a space for moving the stimulable phosphor sheet, there is no need to provide a space for switchback etc. in the reading section itself, and the reading section can be made smaller. be able to.

The stimulable phosphor sheet 1 whose image information has been read in the reading section 20 is moved by the sheet conveying means 40 to the arrow A5.
The cassettes 2 are transported backwards in the direction shown in FIG. Also, before being carried into the cassette 2, the stimulable phosphor sheet passes through the erasing section 30 and is irradiated with erasing light over its entire surface, so that any r remaining on the stimulable phosphor sheet after reading is completed is irradiated with erasing light. It is made to emit radioactive energy.

Any erasing method may be used in the erasing unit 30, but in this embodiment, as described above, the erasing light source 31, such as a fluorescent lamp, tungsten lamp, sodium lamp, xenon lamp, or iodine lamp, is used. By passing the MMJ phosphor sheet below,
Upon receiving light irradiation from the erasing light source 31, residual radiation on the stimulable phosphor sheet, L energy, is emitted. Note that the erasing light source 31 is connected to the arrow A8 of the stimulable phosphor sheet 1.
The light is turned on only from the time the sheet is conveyed in the direction until the sheet is completely conveyed into the cassette 2.

In this apparatus, since the erasing section 30 and the cassette holding section 10 are arranged extremely close to each other, the stimulable phosphor sheet is carried into the cassette 2 while being irradiated with erasing light, and is moved to the second position within the cassette 2. The circle 11 located at 1 rotates in the opposite direction to the direction in which the stimulable phosphor sheet 1 is carried out of the cassette 2, and the sheet 1 is completely carried into the cassette 2. When the conveyance of the sheet 1 is completed, the roller 11 returns to the first position, and in preparation for loading the next cassette, the lid 2B of the cassette 2 is returned to the closed position and the cassette 2 is pulled out from the cassette holding section 10. It will be done.

In this way, if the erasing part is provided between the reading part and the cassette holding part and erasing is performed while returning the stimulable phosphor sheet to the cassette, an extremely small erasing part will be sufficient. There is no need for a special conveyance path for this purpose.

Therefore, the size of the device 6 is not increased due to the erasing section, and the entire device can be made extremely compact.

Note that the specific configurations of the reading section, erasing section, etc. in the apparatus of the present invention are not limited to those shown in the above embodiments, and for example, a reading section and an erasing section as shown in FIG. 3 may be used. good.

In the embodiment shown in FIG. 3, the reading unit 220 includes an LED array 221 which is composed of light emitting diodes arranged in a line substantially perpendicular to the conveyance direction of the stimulable phosphor sheet 1, and which emits excitation light in a line. and an excitation light irradiation means 223 consisting of a cylindrical lens 222 that is provided on the excitation light exit surface of the L-ED array 221 and focuses the excitation light only in the transport direction of the stimulable phosphor sheet; It is comprised of a line sensor 224 which is a photoelectric reading means that is disposed at a position looking into the irradiation position of the excitation light by the means and receives stimulated luminescence light emitted from the linear excitation light irradiation position.

As shown in FIG. 4, the line sensor 224 includes a pixel-divided light receiving element array 224A fixed to a support 224B extending in the width direction of the stimulable phosphor sheet 1. Further, on the light receiving element 7 ray 224A, the stimulable phosphor sheet 1
A filter 225 is arranged to transmit the stimulated luminescence light emitted from the stimulable phosphor sheet 1 and absorb the excitation light reflected on the stimulable phosphor sheet 1. The stimulated luminescent light is received by the light receiving element array 224A of the line sensor 224 via this filter 225. The light-receiving element array 224A has a large number of solid-state photoelectric conversion elements 224a that are aligned in the width direction of the stimulable phosphor sheet 1 and each corresponds to one pixel, and the stimulated luminescent light is transmitted to these solid-state photoelectric conversion elements 224a. light is received at the same time. Each element 224a that receives light generates photocarriers and temporarily stores signals obtained thereby. The accumulated signals are sequentially read out by the scanning circuit 226, and 1
Reading of information from the tree-shaped irradiation section (corresponding to a scanning line) is completed.

Next, the stimulable phosphor sheet is transported by one scanning line by the sheet transport means described above, and the above reading step is repeated. By repeating this step over the entire image recording area of the stimulable phosphor sheet 1, the radiation image information recorded on the stimulable phosphor sheet 1 is read out.

Next, the scanning circuit 226 following the line sensor 224 will be explained. FIG. 5 shows a circuit including an in-sensor and a scanning circuit using a photoconductor. A signal from a photocarrier generated when the stimulated luminescence light hits a solid-state photoelectric conversion element 224a using a photoconductor is transmitted to a capacitor ci <t −1°2, . . . n within the photoconductor 224a. ). The signal of the accumulated photo main 11 is transferred to a switch unit 22 controlled by a shift register 221.
8 are sequentially opened and closed, and thereby a time-series image signal can be obtained. The image signal is then amplified by the amplifier 229 and output from its output terminal 230.

Note that the M2S section including the switch section 228 and the shift register 221 may be replaced with a COD.

Further, in the embodiment shown in FIG. 3, an LED array 231 extending in the width direction of the stimulable phosphor sheet is used as the erasing light of the erasing section 230.

The lighting period of this LED array 231 is the same as that of the erasing light source in the embodiment described above. Note that the erasing light source and the LED array in the first embodiment described above are both kept on at all times, and cover these erasing means when taking out and reading the cassette of the stimulable phosphor sheet. A shutter may be provided that can be moved to lower the exposure.

Furthermore, as an excitation light irradiation means, in addition to the above-mentioned LED array, the present applicant has previously applied for patent application No. 62-2.
A fluorescent light-concentrating sheet disclosed in No. 1957 may be used. In other words, a fluorescent light-concentrating sheet is a sheet-like molded product containing phosphor, and when its surface is irradiated with light, the phosphor inside the fluorescent light-concentrating sheet is excited and fluorescence is generated. This fluorescence undergoes repeated total internal reflection and travels toward the end surface. So the 6th
As shown in the figure, excitation is carried out by an elongated fluorescent lamp 322, a fluorescent light-concentrating sheet 321 formed to surround the entire circumference of this fluorescent lamp 322, and a cylindrical lens 323 provided on one end surface of this fluorescent light-concentrating sheet. The light irradiation means is composed of a fluorescent lamp 322 that is turned on during excitation light irradiation, and the light generated by the fluorescent lamp 322 causes fluorescence in the fluorescent condensing sheet 321. If the fluorescent light is emitted from one end surface of the light-condensing sheet, this fluorescence can be used as linear excitation light. Note that the fluorescent light-condensing sheet may be selected from one that emits fluorescence in the excitation wavelength range of the stimulable phosphor sheet by light emitted from a fluorescent lamp. Further, instead of a fluorescent lamp, a sodium lamp, a mercury lamp, an electroluminescent panel, etc. can be used.

Furthermore, a cassette holding part in the apparatus of the present invention.

The arrangement of the reading section, erasing section, etc. is not limited to that shown in the above-described embodiments, and the direction of conveyance of the stimulable phosphor sheet does not necessarily have to be a straight direction.

(Effects of the Invention) As explained above, according to the radiation image information reading device of the present invention, the cassette is installed near the reading section, and the accumulation rate from the tip of the cassette in the mounting direction to the excitation light scanning position of the reading section is increased. By making the transport distance of the phosphor sheet smaller than the length of the stimulable phosphor sheet, the stimulable phosphor sheet can be moved using the space inside the cassette.
The reading section can be downsized even if the possibility of pre-reading is taken into consideration.In addition, according to the device of the present invention, an erasing section is provided between the reading section and the cassette holding section, thereby reducing the storage capacity. By carrying out erasing while carrying the phosphor sheet into the cassette, the erasing section can be made smaller and there is no need to provide a special conveyance path to convey the stimulable phosphor sheet to the erasing section. Therefore, in this apparatus, the size of the entire apparatus is substantially determined by the above-mentioned small-sized reading section and cassette holding section, so that the entire apparatus can be bridged and made compact.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an overview of a radiographic image information reading device according to an embodiment of the present invention, FIG. 2 is a conceptual side view of the device, and FIG. 3 is a reading section and an eraser in another embodiment of the present invention. FIG. 4 is a schematic front view of the crawl-in sensor; FIG. 5 is a scanning circuit diagram following the line sensor; FIG. 6 is a perspective view of excitation light irradiation means using a fluorescent light-concentrating sheet; FIG. 7 is a conceptual side view of a conventional radiation image information reading device. 1...Stormable phosphor sheet 2...Cassette 10.
...Cassette holding part 11...Roller 20...
Reading section 21A... Excitation light 22... Photo multiplier 30... Off, entry section 31... Light source for erasing 40... Sheet transport means Fig. 1%! 41 -1-N--J

Claims (1)

[Scope of Claims] Excitation light is irradiated by an excitation light irradiation means onto a stimulable phosphor sheet on which radiation image information has been accumulated and recorded, and stimulated luminescence light emitted from the sheet by the irradiation of the excitation light is photoelectrically read. a reading unit that reads an image signal by means of a means; a sheet that removably holds a cassette that can store a stimulable phosphor sheet and has one end that can be opened and closed; and a sheet that takes out the stimulable phosphor sheet in the cassette from the one end; a cassette holding section having a take-out means, transporting the stimulable phosphor sheet taken out from the cassette to the reading section, and transporting the stimulable phosphor sheet that has been read into the cassette in the cassette holding section by switchback; a sheet conveying means for erasing radiation image information remaining on the stimulable phosphor sheet after reading is completed; The transport distance of the stimulable phosphor sheet to the irradiation position is smaller than the length of the sheet in the transport direction, and the erasing unit is located in the transport path of the stimulable phosphor sheet between the cassette holding unit and the reading unit. A radiation image information reading device, characterized in that it is arranged in a.