JPH01105934A - Radiophotographic information photographing device - Google Patents

Abstract

PURPOSE:To appropriately control dose by providing a photodetector detecting instantaneously emitted light transmitted from a front plate and a control part stopping the action of a radial source when the instantaneously emitted light detected by the photodetector reaches a set value. CONSTITUTION:The front plate 32 is transparent, to which the photodetector 44b is connected optically. An object (a person to be examined) 43 stands between the front plate 32 and the radial source so as to be close to the front plate 32. When radial rays is made incident on an accumulating phosphor sheet 1, image information on the object 43 is accumulated and recorded on the accumulating phosphor sheet 30, and instantaneously emitted light is emitted at intensity to correspond with said accumulated energy. Said light is taken by the front plate 32, and photoelectrically detected by the photodetector 44b. The control part 44d outputs radial ray stop signals S4 when the light quantity of the instantaneously emitted light reaches a set light quantity. In receiving the stop signals S4, a driving circuit 46 stops the action of the radial source 42.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention irradiates a stimulable phosphor sheet capable of accumulating radiation energy with radiation that has passed through an object, and stores radiation image information of the object on the sheet. The present invention relates to a radiographic image information capturing apparatus for recording, and more particularly to a radiographic image information capturing apparatus having a function of setting the dose of radiation irradiated onto the sheet to an appropriate predetermined amount.

<Prior art and its problems> When a certain type of phosphor is irradiated with radiation (X-rays, α-rays, β-rays, γ-rays, electron beams, ultraviolet rays, etc.), part of this radiation energy is absorbed into the phosphor. It is known that when this phosphor is irradiated with excitation light such as visible light, the phosphor exhibits stimulated luminescence depending on the accumulated energy. It is called a stimulable phosphor.

Using this stimulable phosphor, radiation image information of a subject such as a human body is recorded on a stimulable phosphor sheet, and this stimulable phosphor sheet is scanned with excitation light such as a laser beam to produce stimulated luminescence. Generate light, photoelectrically read the resulting stimulated luminescent light to obtain an image signal, and based on this image signal, a radiation image of the subject is displayed as a visible image on a recording material such as a photographic light-sensitive material or a display device such as a CRT. The present applicant has already proposed a radiation image information recording and reproducing system that outputs as follows.
(Unexamined Japanese Patent Publication No. 55-12429, No. 56-11395□
, No. 56-11397, etc.).

This system has the practical advantage of being able to record 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, the amount of emitted light that is stimulated and emitted by excitation after storing and recording radiation image information is proportional to the amount of radiation exposure when storing and recording radiation image information over an extremely wide range. Therefore, even if the amount of radiation exposure changes considerably due to various imaging conditions, the amount of stimulated luminescence emitted from the stimulable phosphor sheet can be adjusted by setting the reading gain to an appropriate value. The radiation image is read by a conversion means and converted into an electrical signal, and this electrical signal is used to output the radiation image as a visible image to a recording material such as a photographic light-sensitive material or a display device such as a CRT, thereby influencing fluctuations in radiation exposure. It is possible to obtain radiographic images that are not

On the other hand, the reading gain when reading the light intensity of the above-mentioned stimulated luminescence light is often selected appropriately depending on the subject part, the purpose of imaging, etc., so the appropriate dose of irradiation radiation is determined by the preselected reading gain. It will change accordingly. That is, it is desirable to control the dose of radiation applied to the stimulable phosphor sheet to an appropriate amount according to the reading gain when reading the stimulable phosphor sheet.

Therefore, conventionally, as in the case of radiography using silver halide film, as shown in FIG. I was doing it. As is well known, the radiation phototimer 44 includes a fluorescent screen 44a arranged at a position where radiation emitted from a radiation source 42 and transmitted through a subject 43 is irradiated, and a fluorescent screen 44a emitted by the radiation irradiation, which is collected and transmitted. a transparent plate 44C, a photodetector 44b that detects the fluorescent light received and transmitted by the transparent plate 44C, and a radiation source 42 when the fluorescent light detected by the photodetector 44b reaches a predetermined set amount of light. and a control section 44d that stops the operation of the controller.

However, as shown in the figure, in the conventional phototimer, since a fluorescent plate 44a is disposed between the subject 43 and the stimulable phosphor sheet 30, the distance between the subject 43 and the stimulable phosphor sheet 30 is becomes larger, and
The fluorescent screen 44a itself absorbs the radiation passing through the subject 43 from 1 to
It is attenuated by about 20%. Therefore, the radiation originally used to record an image on the stimulable fluorescent sheet 30 is weakened before recording the image.

Therefore, in order to obtain an appropriate amount of exposure, the amount of radiation emitted from the radiation source 42 must be increased, which inevitably causes the problem that the amount of radiation that the subject is exposed to must be increased.

By the way, as a method for detecting the amount of radiation accumulated in a stimulable phosphor sheet, it is possible to detect the light emitted from the stimulable phosphor sheet (so-called "instantaneous emitted light") when a radiation image is recorded on the stimulable phosphor sheet. A method for detecting the accumulated amount of radiation energy has already been disclosed by the present applicant (see Japanese Patent Laid-Open No. 55-48672). This method utilizes the fact that the instantaneous emitted light is exactly proportional to the energy stored in the stimulable phosphor sheet.

Therefore, it is expected that the radiation energy storage amount detection method described above can be used in controlling the radiation dose applied to the stimulable phosphor sheet in accordance with the reading gain in the radiation image information capturing apparatus. That is, if the instantaneous emitted light can be detected by a suitable means, the energy stored in the stimulable phosphor sheet can be monitored and the dose of irradiated radiation can be controlled.
The fluorescent screen in the conventional phototimer can be made unnecessary, and the above-mentioned problems associated with the use of the conventional phototimer can be solved.

<Object of the invention> Therefore, the present invention provides a radiographic image information capturing apparatus that includes:
By making it possible to suitably detect the instantaneous light emitted from the stimulable phosphor sheet, the loss of radiation that has passed through the object until it enters the stimulable phosphor sheet can be eliminated, and the dose of irradiated radiation can be appropriately controlled. The purpose is to do so.

<Brief Description of the Invention> In order to achieve the above object, the present invention has a radiation-transparent front plate holding a stimulable phosphor sheet capable of accumulating radiation energy, and the stimulable phosphor sheet A radiation source is placed in front of the front plate holding the subject,
In a radiation image information recording device that irradiates the stimulable phosphor sheet with radiation that is emitted from the radiation source and passes through the subject, and stores and records radiation image information of the subject on the stimulable phosphor sheet, The plate is made of a transparent material that collects and transmits the instantaneous light emitted by the stimulable phosphor sheet when irradiated with radiation, and is optically connected to the front plate made of the transparent material and transmitted by the front plate. A radiation source characterized by comprising: a photodetector that detects the instantaneous emitted light; and a control section that stops the operation of the radiation source when the instantaneous emitted light detected by the photodetector reaches a set light amount. An image information capturing device is provided.

<Specific Structure of the Invention> The present invention will be described in detail below based on embodiments shown in the drawings.

In the drawings showing the embodiments of the present invention, the same reference numerals are given to the same components as those in the conventional image recording section shown in FIG.

FIG. 1 shows a radiographic image information recording/reading device to which an embodiment of the radiographic image information capturing device of the present invention is applied. It is formed to constitute a part (imaging section) of a radiation image information recording/reading device that stores and records radiation image information and reads radiation image information from the sheet.

Inside the radiation image information recording/reading device shown in FIG.
and endless belts 1.6.7.10, guide rollers 11.12.13.14, guide plates 15.16.17.18.19.20.21, and nip rollers 22.23.24. A circulation path 26 for conveying sheets is configured, and a plurality of (in this example, five) stimulable phosphor sheets 30 are arranged at appropriate intervals in this circulation path 26. , these stimulable phosphor sheets 30 are transported by the endless belts 1 to 10 as sheet circulation conveyance means and nip rollers 22 and 23.
．． 24 and 25, it is configured to be circulated and conveyed in the direction of arrow A in the figure.

The imaging unit 3 is provided with a radiation-transparent front plate 32 and a rear plate 33 so as to be able to hold the stimulable phosphor sheet 30 between them, and an imaging table is provided on the side of the front plate 32 (on the left side in the figure). 41 are provided.

Before photographing, the front plate 32 and the rear plate 33 have their upper ends opened and their lower ends closed so that the stimulable phosphor sheet 30 being conveyed can be locked between them. When photographing, the upper ends of the front plate 32 and rear plate 33, which were open, approach each other, sandwiching the stimulable phosphor sheet 30 between them, and approach the photographing table 41, and photographing is performed at that close position. When the photographing is completed, the lower ends of the front plate 32 and the rear plate 33 are opened, and the stimulable phosphor sheet 30 is conveyed to the next image reading section 50 (Japanese Patent Laid-Open No. 6
0-176032).

Further, a radiation source 42 such as an X-ray source is provided at a position facing the front plate 32 with the photographing table 41 in between, and the photographing section 3 and the radiation source 42 constitute an image recording section 40. . When radiographing a patient (subject) 43, the sheet 30 used for radiography is placed on the front plate 3 as shown in □ above.
2 and the rear plate 33 and held at a position close to the photographing table 41. Then, the subject 43 is placed on the imaging platform 4.
1, the radiation source 42 is activated.

As a result, the transmitted radiation image of the subject 43 is projected onto the sheet 30, and the radiation image information of the subject 43 is stored and recorded on the sheet 30. Note that the radiation image information capturing apparatus according to the present invention includes, in addition to the imaging table 41, radiation source 42, etc., a front plate 32 having a function of a radiation phototimer, which will be described in detail later, a photodetector, and a control section. It is characterized by being composed of

An image reading unit 50 is located at the lower right end position in the figure of the circulation passage 26.
is provided. In this image reading section 50, a laser light source 51 is installed above the endless belt 8 that constitutes a part of the reading section 50, and output laser light 52 is directed onto the sheet 30 on the endless belt 8 in the width direction thereof. A mirror 53 and a galvanometer mirror 54 are provided for scanning.

By this reciprocating movement of the Karbattler ram 54, the laser beam 52 is main-scanned over the sheet 30 on which the radiation image has been accumulated and recorded. Note that, after a radiation image is recorded on the sheet 30 in the image recording section 40, the sheet circulation conveyance means is driven to convey it to the image reading section 50. At the scanning position of the laser beam 52 on the sheet 30, there is a condensing reflecting mirror 55 and a light guide 5 along the main scanning line.
6 is placed. The stimulated luminescent light emitted from the sheet 30 irradiated with the laser beam 52 and directly proceeds to the light guide 56 and the stimulated luminescent light which is also emitted from the sheet 30 and reflected by the condensing reflective mirror 55 are transferred to the light guide 56. The light enters the light guide 56 from the entrance end surface 56A of the light guide 56, is guided through the light guide 56 by total reflection, and exits from the exit end surface 56B of the light guide 56.
The stimulated luminescence light is received by a photomultiplier 57 connected to the photomultiplier 57, and the stimulated luminescence light is read out photoelectrically. At the same time that 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 arrow A in the figure (that is, the direction substantially perpendicular to the above-mentioned main scanning method) to perform the sub-scanning. , the radiation image information accumulated over the entire surface of the sheet 30 is read. Photo multiplier 57
The image signal S1 read by the image processing circuit 60
After being subjected to necessary image processing, the image is sent to a necessary image reproduction device 61. As mentioned above, this playback device may be a display such as a CRT, a recording device that performs optical scanning recording on a photosensitive film, or for that purpose, it may be replaced with a device that records on a storage device such as a magnetic tape. It's okay to be hit.

The sheet 30 whose image has been read is conveyed along the guide plate 18 by the endless belt 9.10, and sent to the erasing section 70 through the nip roller 22, the guide plate 19, and the nip roller 23. This erasing section 70 is a box 71
A large number of fluorescent lamps, tungsten lamps, sodium lamps, xenon lamps,
After the shutter 73 is opened, the sheet 30 is conveyed into the box 71 by the nip rollers 23. When the sheet 30 is sent into the box 71, the shutter 73 is closed. The erasing light source 72 inside the box 71 mainly emits light in the excitation wavelength range of the stimulable phosphor of the sheet 30, and the radiation energy remaining in the sheet 30 after the image reading is transferred to the sheet 30. When such light is irradiated, the light is emitted from the sheet 30. Note that since the shutter 73 is closed at this time, the erasing light does not leak and enter the image reading section 50 and generate noise in the read signal.

The sheet 30 in which the image (afterimage) has been erased to such an extent that radiation image information can be recorded again is transferred to the nip roller 2.
4 is rotated and discharged to the outside of the erasing section 70. The discharged sheet 30 passes through the guide plate 20 and passes through the nip roller 25.
Next, the nip roller 25 sends the image along the guide plate 21 to the endless belt 1, and in the same manner as described above, it is sent to the image recording section 40 and used for radiography.

Next, the radiation dose control unit, which is a characteristic part of the apparatus of the present invention, will be explained.

As shown in detail in FIG. 2, the radiation dose control section in the present invention includes a front plate 32, a photodetector 44b such as a photomultiplier, and a control section to which the output S3 of the photodetector 44b is input. 44d.

Here, the radiation-transparent front plate 32 in the present invention not only functions as a holding plate for the stimulable phosphor sheet 30 but also captures instantaneous light emitted from the stimulable phosphor sheet 30 during radiation irradiation. , has the function of transmitting the light to the photodetector 44b provided at the end of the front plate 32. Therefore, the front plate 32 only needs to be transparent, and is made of a light-transmitting transparent material such as acrylic resin. A photodetector 44b is optically connected to such a front plate 32.

Here, being optically connected means that the light receiving surface of the photodetector 44b such as a photomultiplier is connected to the front plate 3 as shown in FIG.
2, and also includes the case where the light receiving surface of the photodetector 44b and the front plate 32 are optically joined by an optical transmission means such as an optical fiber.

In FIG. 2, the entire surface of the front plate is used as a daylighting field so that instantaneous light is emitted, but if necessary, only a part of the front plate may be used as a daylighting field. In such a case, black paper may be pasted or black paint may be applied to the surface of the front plate on the stimulable phosphor sheet 30 side other than the portion to be used as the lighting field.

A subject (subject) 43 is located close to the front plate 32 between the front plate 32 and the radiation source 42 .

Such a radiation dose control section operates as follows.

That is, the radiation emitted from the radiation source 42 and transmitted through the subject 43 is transmitted to the stimulable phosphor sheet 30 via the front plate 32.
incident on .

In this case, a conventional phototimer fluorescent screen for attenuating radiation is not provided between the subject 43 and the stimulable phosphor sheet 30, and the distance between the subject 43 and the stimulable phosphor sheet 30 is short. Therefore, the radiation transmitted through the subject 43 enters the stimulable phosphor sheet 30 without attenuation. When radiation enters the stimulable phosphor sheet, image information of the subject 43 is accumulated and recorded on the stimulable phosphor sheet 30, and instantaneous light is emitted with an intensity corresponding to the accumulated energy. This instantaneous emitted light is collected by the front plate 32, transmitted to the photodetector 44b, and photoelectrically detected by the photodetector 44b.

The control unit 44d receives the output S3 of the photodetector 44b indicating the level of the instantaneous emitted light, and issues a radiation source stop signal S4 when the amount of instantaneous emitted light (integrated light amount) reaches the set light amount.
Output. This stop signal S4 is sent to a drive circuit 46 of the radiation source 42, and this drive circuit 46 receives the stop signal S4.
4, the radiation source 42 is deactivated.

By doing so, the dose of radiation applied to the stimulable phosphor sheet 30 is controlled to an appropriate predetermined amount.

In the embodiment described above, an example has been described in which the radiation image information capturing apparatus of the present invention is applied to a so-called built-in device in which the stimulable phosphor sheet 30 is used cyclically within the radiation image information recording/reading apparatus, but the present invention is not limited to this. Instead, the stimulable phosphor sheet is fixed, and the image reading section and the erasing section are integrally provided so as to move back and forth relative to the stimulable phosphor sheet, thereby reducing the size of the entire device and simplifying the internal movement mechanism. The present invention may be applied to a so-called chest changer type device that aims at the following.

FIG. 3 shows an example in which the radiographic image information capturing device of the present invention is applied to a chest changer type radiographic image information recording/reading device.

The apparatus shown in FIG. 3 consists of a main body and a radiation source 42, such as an X-ray source, placed above an imaging table 41, which is the top surface of the main body.

A stimulable phosphor sheet 30 is fixedly held on a radiation-transparent front plate 32 on the lower surface of the photographing table 41' inside the main body of the apparatus, and below the stimulable phosphor sheet 30 are an image reading section 50 and an eraser. A reading/erasing unit 80 is provided in which the parts 70 are placed close to each other and integrally housed in a housing 81 to form a unit. This reading/erasing unit 80 faces the stimulable phosphor sheet 30 from the right end position (first position) shown by a solid line in FIG. 3 to the left end position (second position) shown by a broken line in the figure. A'
It is possible to reciprocate in the A'' direction or vice versa.

Here, the radiation image information capturing apparatus holds a radiation source 42, an imaging table 41, and a stimulable phosphor sheet 30, and emits instantaneous light emitted from the stimulable phosphor sheet 30, as in the case shown in FIG. A radiation-transparent front plate 32 that collects and transmits light, a photodetector 44b1 such as a photomultiplier optically connected to the front plate 32, and an output signal S3 from the photodetector 44b.
and a control section 44d that controls the drive circuit 46 of the radiation source 42 in response to the received radiation.

In such a radiation image information recording/reading device, the imaging table 4
After the subject 43 is placed on the stimulable phosphor sheet 30, the radiation source 42 is activated to irradiate the subject 43, and a transmitted radiation image of the subject 43 is projected onto the stimulable phosphor sheet 30 and stored and recorded.

When the photographing is completed, the image reading section 50 in the unit 80 reads the image information stored and recorded on the stimulable phosphor sheet 30.

Here, the image reading unit 50 includes a laser light source 82 such as a semiconductor laser, and a laser light 8 emitted from the laser light source 82.
A condensing lens 84 is provided on the optical path on the stimulable phosphor sheet 30, and the laser beam 83 that has passed through the condensing lens 84 is deflected in a direction perpendicular to the paper surface of FIG. It has a laser beam scanning means consisting of a rotating polygonal mirror 85 which is an optical deflector and mirrors 86a186b and 86c that change the optical path of the laser beam, and the laser beam 83 is repeatedly directed onto the stimulable phosphor sheet 30 by this excitation beam scanning means. Main scanning is performed.

On the other hand, since the unit 80 is conveyed at a constant speed in the direction of the arrow A' by a drive source (not shown) as described above, the scanning position of the laser beam 83 is changed to the direction of the arrow A'.
The stimulable phosphor sheet 3
0 is irradiated with laser light 83 over substantially the entire surface thereof.

Stimulated luminescent light is generated from the laser beam irradiated portion of the stimulable phosphor sheet 30 in accordance with the accumulated and recorded image information, and the stimulated luminescent light is detected by the photoelectric reading means of the image reading section 50.

The photoelectric reading means in this device includes a long photomultiplier tube (photomultiplier) 87 extending in the main scanning direction over the length of the main scanning line, and this photomultiplier 87.
A filter 88 is provided on the light-receiving surface of the photomultiplier 7 and selectively transmits only the stimulated luminescence light and cuts off the laser light reflected on the sheet surface from entering the photomultiplier. It consists of a condensing plate 8.9 that is attached to the incident end face of the pliers 87 and condenses the stimulated luminescence light well, and among these, the elongated photomultiplier 87 is, for example, a long box-shaped condenser plate 8.9. Examples include a photomultiplier or a long Venetian blind type photomultiplier. That is, it is possible to use the elongated photomultiplier disclosed in Japanese Unexamined Patent Application Publication No. 16666/1989 filed by the present applicant. Further, a mirror 90 is disposed at a position facing the photoelectric reading means across the scanning line, so as to efficiently reflect the stimulated luminescence light emitted to the mirror 90 side toward the light receiving surface of the light condenser. It has become.

The image signal photoelectrically read by the photomultiplier 87 is subjected to necessary image processing and then sent to a recording/reproducing device that performs optical scanning recording on a display such as a CRT or a photosensitive film. When the reading of the image information is completed, the reading/erasing unit 4 has moved to the second position as shown by the broken line in FIG.

When the reading of the image information is completed as described above, the reading/erasing unit 4 is conveyed in the direction of arrow A'' from the second position to the first position as shown in FIG. is irradiated with erasing light over its entire surface by the erasing section 70 in the unit 8o, which is transported in the direction of arrow A''.

The erasing unit 70 includes, for example, an erasing light source 91 such as a fluorescent lamp extending in the main scanning direction, and a reflecting plate 92 that reflects downward light emitted from the erasing light source 91 toward the sheet surface side.

In addition, in this embodiment, the erasing light source 91 is always turned on, so when recording and reading images, the erasing light source 91 is placed above the erasing light source 91 to block the erasing light as shown in FIG. A movable shutter 93 is provided that retreats above the photomultiplier 87 to expose the erasing light source 91 only during erasing. Note that if the erasing light source 91 is turned on only during erasing and turned off at other times, there is no need to provide a special shutter. The erasing light source 91 irradiates the entire surface of the stimulable phosphor sheet 30 as the unit 80 moves in the direction of arrow A''. The erasing light source 91 mainly emits light in the excitation wavelength range of the stimulable phosphor sheet. The radiation energy remaining in the stimulable phosphor sheet 30 after the image reading is emitted from the stimulable phosphor sheet 30 by irradiating the stimulable phosphor sheet 30 with such light.The stimulable fluorescence that has been erased The body sheet 30 is again in a state in which new recording can be performed by the image recording means, and the reading/erasing unit 80 is returned to the first position again.

Even in such a so-called chest changer type radiation image information recording/reading device, the dose of irradiation radiation when accumulating and recording radiation image information can be appropriately controlled in the same manner as described above by the radiation image information capturing device of the present invention. It will be done.

That is, the instantaneous light emitted when image information is stored in the stimulable phosphor sheet 30 is detected by the photodetector 44b through the front plate 32, which has a lighting and light transmission function.
It is output to the control section 44d. Then, when the integrated value of the output signal S3 from the photodetector 44b exceeds a predetermined setting amount, the control unit 44d outputs a stop signal S4 that stops the operation of the radiation source 42 to the radiation source drive circuit 46. This is done by doing this.

The above describes examples in which the radiation image information capturing device of the present invention is applied to two typical aspects of a radiation image information recording/reading device, but the radiation image information capturing device of the present invention may also be formed as a single imaging device. Of course it is possible.

<Effects of the Invention> According to the present invention, the radiation-transparent front plate, which is the holding plate for the stimulable phosphor sheet, has lighting and light transmission functions, and a photodetector is optically connected to the front plate. Therefore, the radiation that has passed through the subject is made incident on the stimulable phosphor sheet, and instantaneous light emitted when image information is stored and recorded is detected by the photodetector via the front plate. Since the instantaneous emitted light is detected in this way, the fluorescent screen of the phototimer that was conventionally installed between the subject and the stimulable phosphor sheet to monitor the irradiation dose to the stimulable phosphor sheet is no longer required. can do. Furthermore, the distance between the subject and the stimulable phosphor sheet can be made sufficiently close.

Therefore, the radiation that has passed through the object reaches the stimulable phosphor sheet with almost no attenuation on the way. That is,
According to the present invention, the dose of irradiation radiation can be appropriately controlled without loss of irradiation radiation. Also,
As a result, image information can be captured with a smaller amount of radiation irradiated to the subject than in the past.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view showing an embodiment of the device to which the present invention is applied, FIG. 2 is a schematic diagram showing a part of the device of the above embodiment, and FIG. 3 is a device to which the device of the present invention is applied. Schematic diagram illustrating another embodiment of the present invention. Fig. 4 is a schematic diagram illustrating a part of a conventional radiation image information capturing apparatus. Explanation of symbols 3...Photographing unit, 30...Stormable phosphor sheet, 32...Front plate, 33...Rear plate, 40...Image recording unit, 41...Photographing stand, 42 ... Radiation source, 43... Subject (subject), 44... Radiation phototimer, 44a... Fluorescent screen, 44b... Photodetector, 44c... Transparent plate, 44d... Control unit, 46...Radiation source drive circuit FIG, 1 FIG, 2 FIG, 3 i-do 54 FIG, 4

Claims (1)

[Claims] (1) It has a radiation-transparent front plate holding a stimulable phosphor sheet capable of accumulating radiation energy, and a radiation source is placed in front of the front plate holding the stimulable phosphor sheet through the subject. a radiation image information recording device for storing and recording radiation image information of the subject on the stimulable phosphor sheet by irradiating the stimulable phosphor sheet with radiation emitted from the radiation source and transmitted through the subject. In,
The front plate is made of a transparent material that collects and transmits instantaneous light emitted by the stimulable phosphor sheet during radiation irradiation, and is optically connected to the front plate made of the transparent material and transmitted by the front plate. and a control unit that stops the operation of the radiation source when the instantaneous emitted light detected by the photodetector reaches a set light amount. A radiation image information capturing device.