JPH0322610B2 - - Google Patents

Description

Detailed Description of the Invention (Field of the Invention) The present invention accumulates and records radiation image information in a stimulable phosphor, then irradiates it with excitation light, and produces stimulated luminescence according to the accumulated and recorded image information. It relates to a radiation image information recording/reading device that detects light to read image information and convert it into an electrical signal, and more specifically, a sheet of stimulable phosphor is cyclically reused within the device; The present invention relates to a radiation image information recording/reading device that is capable of recording radiation image information on sheets stored in a cassette in addition to sheets.

(Technical Background and Prior Art of the Invention) Certain phosphors are exposed to radiation (X-rays, α-rays, β-rays,
When irradiated with γ-rays, ultraviolet rays, etc., part of the energy of this radiation is accumulated in the phosphor, and 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.

Using this stimulable phosphor, radiation image information of the human body, etc. is recorded on a sheet of stimulable phosphor,
A method has been proposed in which this is scanned with excitation light to cause stimulated emission, the stimulated emission light is read out photoelectrically to obtain an image signal, and this image signal is processed to obtain an image with good diagnostic suitability ( For example, JP-A No. 55-12429,
No. 56-11395, No. 55-163472, No. 56-104645
No. 55-116340, etc.). This final image may be reproduced as a hard copy or
It may also be played back 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 the image in order to provide the image to the final recording medium as described above. Since it carries information, the stimulable phosphor sheet may be used repeatedly, and such repeated use is extremely economical.

In addition, for example, a mobile station such as an X-ray vehicle may be equipped with a radiation image information recording/reading device that uses a stimulable phosphor sheet, and the mobile station can be used to travel to various locations for group examinations and take X-rays. in case of,
It is inconvenient to load a large number of stimulable phosphor sheets into a vehicle, and there is a limit to the number of sheets that can be loaded onto a moving vehicle. Therefore, a stimulable phosphor sheet is mounted on a moving vehicle so that it can be used repeatedly, radiographic image information for each subject is recorded on it, and the image signal obtained by reading it is stored on a storage device such as a magnetic tape. If the radiation images are copied onto a large recording medium and the stimulable phosphor sheet is reused, radiographic images of a large number of objects can be taken using a moving vehicle, which is extremely useful in practice. Furthermore, if continuous imaging is performed through this cyclical reuse, imaging speed can be increased in mass medical examinations.

In view of such demands, the present applicant has developed a circulating conveyance means for conveying at least one stimulable phosphor sheet as described above along a predetermined circulation path;
The circulation path includes an image recording section that accumulates and records a radiographic image of the subject on the sheet by irradiating the sheet with radiation through the subject; an image reading section having an excitation light source that emits excitation light for scanning a sheet on which an image has been stored and recorded; and photoelectric reading means for obtaining an image signal by reading stimulated luminescence light emitted from the sheet scanned by the excitation light; A radiation image information recording/reading device has already been described which includes: and an erasing section that releases the residual radiation energy on the sheet before the image is recorded on the sheet after the image reading is performed in the image reading section. A patent application was filed (Japanese Patent Application No. 58-66730). The erasing section described above implements the method shown in, for example, Japanese Patent Application Laid-open Nos. 56-11392 and 56-12599. According to this radiographic image information recording/reading device, the many demands mentioned above are met, and radiographic image capturing and reproduction processing operations are significantly streamlined.

On the other hand, for example, when taking radiographs of bones, etc.
There is a demand for photographing with the sheet as close as possible to the subject in order to minimize the adverse effects of scattered images caused by the subject. Radiography is then performed.
The apparatus disclosed in Japanese Patent Application No. 58-66730 is not originally intended for handling the above-mentioned cassettes, but it can only record radiation image information on the sheets of the cassettes. That is, a cassette is placed on the photographing stand of the image recording section of the apparatus, a subject is placed in close contact with the cassette, and the radiation source is turned on and driven. The radiation image information thus recorded on the sheet of the cassette can be read using a dedicated image reading device.

However, when radiography is performed using the cassette as described above, the recirculating sheet placed at the imaging position of the image recording section of the apparatus is exposed to the radiation transmitted through the cassette. Therefore, even though it is not recorded or read,
In order to erase the fog caused by the exposure in the erasing section, it is necessary to circulate the sheet, which makes the operation cumbersome.

(Objective of the Invention) Therefore, the present invention makes it possible to record and read radiographic image information by using a stimulable phosphor sheet in a cyclical manner, and to store a cassette without exposing the stimulable phosphor sheet to light. It is an object of the present invention to provide a radiation image information recording/reading device capable of recording radiation image information on a sheet stored in a sheet.

(Structure of the Invention) The radiation image information recording/reading device of the present invention comprises a stimulable phosphor sheet circulation conveying means as described above, an image recording section, an image reading section, and an erasing section. In the image information recording/reading device,
The circulating sheet of the image recording unit is moved between the normal position where radiation is irradiated (imaging position) and the retreat position outside the radiation irradiation field, and the sheet is selectively moved to either of these two positions. The present invention is characterized in that it is provided with a sheet moving means for arranging the sheets.

When recording radiation image information on sheets stored in a cassette, if the sheets to be circulated are placed in the above-mentioned retracted position by the sheet moving means, the sheets to be circulated will not be irradiated with radiation. This prevents the sheet from being exposed to radiation.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 schematically shows an apparatus according to one embodiment of the present invention for photographing and recording radiographic images of the chest, abdomen, etc. while the subject is lying down. Inside the device are endless belts 1, 2, 3, 4, 5, 6,
7, 8, 9, 10, 11, 12, 13 and endless belt 3, 4, 7, 10, 11, 12, 13
Guide rollers 14, 15, 16, 1 that rotate as a result of rotation
7, 18, 19, 20, and guide plates 21, 22,
23, 24, 25, 26, and nip roller 27,
A sheet circulation conveyance system consisting of 28 and forming a circulation path is provided. In this sheet circulation conveyance system, for example, six stimulable phosphor sheets 30 are circulated and conveyed in the direction of the arrow in the figure at appropriate intervals.

The two endless belts 1 and 2 placed at the top of the circulation conveyance system are arranged horizontally, and a photographing stage 41 is provided above these endless belts 1 and 2. A radiation source 42 such as an X-ray source is provided at a position facing the endless belt 1, and the image recording unit 4 is
0 is configured. During radiography of the subject 43, the sheet 30 used for radiography is placed on the endless belt 1 as shown in the figure.
The radiation source 42 is placed in a state where the patient is lying down on the imaging table 41.
is driven to turn on. As a result, a transmitted radiation image of the subject 43 is projected onto the sheet 30, and the subject 43 is projected onto the sheet 30.
3 radiographic image information is accumulated and recorded on the sheet 30.

An image reading section 50 is provided at the right end position in the figure of the sheet circulation conveyance system. This image reading section 50
A laser light source 51 is installed above the endless belt 8 constituting the reading section 50, and a mirror 53 and a galvanometer mirror are used to scan the output laser light 52 in the width direction of the sheet 30 on the endless belt 8. 54, mirror 55,
A mirror 56 is provided, and as the galvanometer mirror 54 swings back and forth, the laser beam 52 is main-scanned over the sheet 30 on which the radiation image has been accumulated and recorded. Note that this sheet 30 is used in the image recording section 4.
After the radiation image is recorded at 0, the sheet is conveyed to the image reading section 50 by the drive of the sheet circulation conveyance system. Further, a condensing reflective mirror 57 is disposed along the main scanning line at the scanning position of the laser beam 52 on the sheet 30, and the stimulated luminescence light emitted from the sheet 30 by the irradiation of the laser beam 52 and the The stimulated luminescent light reflected by the condensing reflecting mirror 57 enters the condensing optical element 58 from the incident end face 58A of the condensing optical element 58, and is guided through the condensing optical element 58 by total reflection until it reaches the exit end face of the element 58. The stimulated luminescent light is received by a photomultiplier 59 connected to 58B and read out photoelectrically. At the same time as the main scanning of the laser beam 52 is performed as described above, the sheet 30 is conveyed by the endless belt 8 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. The accumulated radiation image information is read over the entire surface of the sheet 30. The image signal read by the photoprinter 59 is transmitted 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 playback device may be a display such as a CRT,
It may be a recording device that performs optical scanning recording on a photosensitive film, or it may be one that temporarily records on a storage device such as a magnetic tape for that purpose.

Note that the time required to read the radiation image information from one sheet 30 is generally longer than the time required to record (photograph) the radiation image information on the sheet 30, but the recorded sheet 30 may be transferred to an endless belt, for example. By leaving one sheet on each sheet 7, 6, 5, 4, and 2, the six sheets 30 can be used one after another and recording can be completed within a short time. For example, JP-A-58-
As shown in No. 89245, prior to the above reading operation (main reading) to obtain a visible image for observation and interpretation, excitation light of a lower level than the excitation light to be irradiated in the main reading is used. , perform a reading operation (read ahead) to grasp the accumulated record information of the radiation image information accumulated and recorded on the stimulable phosphor sheet in advance, grasp the accumulated record information of the radiographic image information, and then read the actual information. and appropriately adjusting the reading gain based on the pre-read information,
Alternatively, by performing appropriate signal processing, it is possible to eliminate the influence of fluctuations in imaging conditions or to obtain radiographic images that are highly suitable for observation and interpretation. By reversing the endless belt 9 and the endless belts 7 and 8 and returning the image reading apparatus 30 to the image reading position, the above-mentioned "pre-reading" and "main reading" can be performed.

The sheet 30 whose image has been read is sent to the erasing section 70 by the endless belt 9. The erasing unit 70 consists of a box 71 and a large number of erasing light sources 72 such as fluorescent lights arranged inside the box 71. After the shutter 73 is opened, the sheet 30 is The paper is conveyed by the endless belt 9 until it contacts the nip roller 27. The sheet 30 is then rotated by the rotating Nitz roller 27.
is sent into the box 71. Sheet 30 is box 71
When the shutter 73 is sent inside, the shutter 73 is closed.
After that, the erasing light source 72 is turned on. These erasing light sources 72 mainly emit light in the excitation wavelength range of the stimulable phosphor of the sheet 30, and the radiation energy remaining in the sheet 30 after reading the image is absorbed by the sheet 30 in this manner. The light is emitted from the sheet 30 upon irradiation with light. Note that since the shutter 73 is closed at this time,
Erasing light does not leak and enter the image reading section 50 and generate noise in the read signal.

The sheet 30, 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 70 by rotating the nip roller 28. The ejected sheet 30 is attached to the endless belt 1
0, 11, 12, 13, the image recording section 40
However, if another sheet 30 is occupied first, it is sequentially placed on the endless belts 13, 12, 11, and 10 and waits. Further, when the image recording and reading work is finished for the time being, the last sheet 30 is deleted by the erasing section 70.
After the afterimage was removed at
0 is rotated in the opposite direction to the above and sent onto the endless belt 9, where it waits.

As explained above, the endless belts 1 to 13 and the nip rollers 27 and 28 that constitute the sheet circulation conveyance system are controlled in conjunction with the operations of the image recording section 40, the image reading section 50, and the erasing section 70. may use a known sequence control), the sheet 30 is conveyed or placed,
Two endless belts 1 and 2 of the image recording section 40
are capable of forward rotation (rotation in the direction of sending the sheet 30 from the endless belt 1 to the endless belt 2) and reverse rotation in the same direction as each other by manual operation buttons 80 and 81. As mentioned above, when radiographing a bone region or the like, for example, it may be desirable to arrange the stimulable phosphor sheet as close to the subject 43 as possible. Therefore, as shown in FIG. 2, a cassette 91 containing a sheet 90 similar to the sheet 30 is placed at the imaging position on the imaging table 41, a subject 43 is placed on it, and a radiation source 42 is placed on the cassette 91.
When the cassette 91 is turned on, a transmitted radiation image of the subject 43 is accumulated and recorded on the sheet 90 of the cassette 91, and the above requirement is satisfied. The sheet 90 of the cassette 91 in which radiation image information has been stored and recorded is image-read by using another image information reading-only device.

Prior to performing radiography using the cassette 91 as described above, the manual operation button 80
is pushed and the endless belts 1 and 2 are rotated in the forward direction. Therefore, the sheet 30 that has been placed at the normal position (photographing position) on the endless belt 1 and waiting to be photographed is sent onto the endless belt 2.
By being fed onto the endless belt 2, the sheet 30 is placed at a position (retreat position) out of the field of radiation from the radiation source 42, and in this state radiography is performed using the cassette 91. Even if radiation passes through the cassette 91, the sheet 30 is not exposed to the transmitted radiation. When radiography using the cassette 91 is completed, press the manual operation button 81 to reverse the endless belts 1 and 2, and
0 to its normal position on the endless belt 1.

In addition to the cassette 91 containing the stimulable phosphor sheet 90 as described above, it is also possible to perform radiography using a cassette containing conventional X-ray photographic film, and in that case, the procedure is exactly the same. Then, the seat 30 may be moved to the retracted position.

In the embodiment described above, the endless belts 1 and 2 and the manual operation buttons 80 and 81, which constitute a part of the sheet circulation conveyance system, constitute a sheet moving means, and the sheet 30 is moved to a retraction position within the sheet circulation path. However, the seat 30 may be retracted to a position away from the seat circulation path. That is, for example, a sheet shunting stand is provided on the side of the endless belt 1 (in a direction perpendicular to the sheet conveying direction) in alignment with the upper surface of the belt 1, and the sheet 30 is provided between the belt 1 and the sheet shunting stand. What is necessary is to provide a sheet moving mechanism for horizontally moving the sheet.

(Effects of the Invention) As is clear from the description of the embodiments above, in the radiation image information recording/reading device of the present invention, the stimulable phosphor moves cyclically through the photographing, reading, and erasing sections. Since the sheet can be used repeatedly and has a compact overall structure, it is extremely advantageous in practice. The apparatus of the present invention can perform radiography on stimulable phosphor sheets stored in a cassette or X-ray photographic film, etc., without wasting exposure on stimulable phosphor sheets that are used repeatedly. The radiation image information recording function is expanded by eliminating the need for the troublesome operation of circulating the sheets and sending them to the erasing section, and the range of practical use thereof is greatly expanded.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view showing an embodiment of the radiation image information recording/reading device according to the present invention, and FIG. 2 is a partial schematic diagram showing the state of the above-mentioned embodiment device during imaging using a cassette. 1-13... Endless belt, 14-20...
...Guide roller, 21-26...Guide plate, 27,
28... Nitz roller, 30, 90... Storable phosphor sheet, 40... Image recording unit, 41... Photographing table, 42... Radiation source, 43... Subject (subject), 50... Image Reading section, 52...Laser light,
51... Laser light source, 53, 55, 56, 57...
...Mirror, 54... Galvanometer mirror, 58
...Condensing optical element, 59...Photomar, 70...
... Erasing unit, 72... Erasing light source, 80, 81... Manual operation button.

Claims (1)

[Scope of Claims] 1. Circulating conveyance means for conveying a plurality of mutually independent stimulable phosphor sheets capable of accumulating and recording radiation images along a predetermined circulation path; an image recording unit that accumulates and records a radiographic image of the subject on the sheet by irradiating radiation through the subject; and an excitation unit that scans the sheet on which the radiation image has been accumulated and recorded in the image recording unit in the circulation path An image reading section having an excitation light source that emits light and a photoelectric reading means for reading stimulated luminescence light emitted from a sheet scanned by the excitation light to obtain an image signal; an image reading is performed in the image reading section; an erasing unit that releases residual radiation energy on the sheet prior to recording an image on the sheet after the image has been removed; and in the image recording unit, the sheet is transferred to a recording medium stored in a cassette outside the apparatus A radiation image information recording/reading device comprising a sheet moving means for moving a sheet from a normal radiation irradiation position to a sheltered position outside the radiation irradiation field when recording radiation image information.