JPH0247730B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention causes radiation image information to be stimulated to emit light from a stimulable phosphor sheet by irradiating the stimulable phosphor sheet storing radiation image information with excitation light, The present invention relates to a radiation image information reading device that photoelectrically reads the obtained stimulated luminescence light using a photodetector.

Certain fluorophores are exposed to radiation (X-rays, α-rays, β-rays,
When irradiated with γ-rays, ultraviolet rays, etc., a part of this radiation energy is accumulated in the phosphor, and when this phosphor is irradiated with excitation light such as visible light, the phosphor increases depending on the accumulated energy. is known to exhibit stimulated luminescence, and phosphors exhibiting this property are called stimulable phosphors.

Using this stimulable phosphor, radiation image information of the human body, etc. is recorded once on the stimulable phosphor provided on the sheet, and this phosphor sheet is scanned with excitation light such as a laser beam. A radiation image in which stimulated luminescence is generated, the resulting stimulated luminescence is read out photoelectrically to obtain an image signal, and based on this image signal, it is output as a visible image to a recording material such as a photographic light-sensitive material, CRT, etc. A record reading method has already been proposed by the applicant. (JP-A-55-12429, JP-A No. 56-11395, etc.) This method is extremely capable of recording images over an extremely wide radiation exposure range compared to conventional radiographic systems that use silver halide photography. It has practical advantages. In other words, in stimulable phosphors, it is recognized that the amount of emitted light that is stimulated and emitted by excitation after accumulation is proportional to the amount of radiation exposure over an extremely wide range. Even if the amount of radiation exposure varies considerably depending on the photographing conditions, the amount of light emitted is read by the photoelectric conversion means by setting the reading gain to an appropriate value and converted into an electrical signal, and this electrical signal is used to perform photographic exposure. A radiation image that is not affected by fluctuations in radiation exposure can be obtained by outputting it as a visible image on a recording material such as a recording material or a display device such as a CRT.

In addition, according to this system, after converting the radiation image information accumulated and recorded in the stimulable phosphor into an electrical signal, appropriate signal processing is performed, and this electrical signal is used to produce recording materials such as photographic light-sensitive materials, CRTs, etc. By outputting the image as a visible image on a display device, a very large effect can be obtained in that a radiation image with excellent suitability for observation and interpretation (diagnosis) can be obtained.

In this way, in a radiation imaging system using a stimulable phosphor, the reading gain can be set to an appropriate value to photoelectrically convert the stimulated luminescence light and output it as a visible image. tube voltage or
Fluctuations in radiation exposure due to fluctuations in MAS values, variations in the sensitivity of stimulable phosphors, variations in sensitivity of photodetectors, changes in exposure due to subject conditions, or differences in radiation transmittance depending on the subject, etc. Even if the energy accumulated in the stimulable phosphor differs depending on the cause, and even if the amount of radiation exposure is reduced, it is possible to obtain radiographic images that are not affected by fluctuations in these factors. In addition, by first converting the stimulated luminescence light into an electrical signal and applying appropriate signal processing to this electrical signal, it is possible to obtain radiographic images suitable for diagnostic areas such as the chest and heart, improving the suitability for observation and interpretation. It becomes possible to do so.

However, in order to eliminate the need for imaging due to fluctuations in imaging conditions, or to obtain radiation images that are highly suitable for observation and interpretation, it is necessary to change the recording state of radiation image information accumulated and recorded on the stimulable phosphor sheet, or the chest and abdomen. Recording patterns (hereinafter referred to collectively as "accumulated recorded information") determined by the part of the subject, imaging method such as simple or contrast imaging, etc. (hereinafter referred to collectively as "accumulated recorded information") can be It is essential to understand this prior to outputting the image, and to adjust the reading gain to an appropriate value or perform appropriate signal processing based on the accumulated recorded information thus obtained.

Furthermore, in order to obtain radiographic images that are highly suitable for observation and interpretation, it is necessary to determine the recording scale factor so that the resolution is optimized according to the contrast of the recorded pattern.

A method disclosed in Japanese Patent Application Laid-Open No. 50180/1983 is known as a method of grasping the accumulated recorded information of radiation image information prior to outputting a visible image.
This method is based on the knowledge that when the stimulable phosphor sheet is irradiated with radiation, the amount of instantaneous light emitted from the stimulable phosphor sheet is proportional to the amount of energy stored and recorded in the stimulable phosphor sheet. Based on this, by detecting this instantaneous emitted light, the accumulated recorded radiation image information is grasped, and based on this information, appropriate signal processing is performed to obtain a radiation image that is highly suitable for observation and interpretation. It is something. According to this method, it is possible to adjust the reading gain to an appropriate value, to select an appropriate recording scale factor, or to perform appropriate signal processing, thereby eliminating the influence of fluctuations in imaging conditions. Alternatively, it is possible to obtain radiographic images that are suitable for observation and interpretation, but
Since the radiation irradiation section and the radiation image information reading section are usually located at a distance, a signal transmission system must be constructed between them, making the equipment complicated and increasing costs. The disadvantage is that it cannot be avoided.

Also, as disclosed in Japanese Patent Application Laid-open No. 55-116340,
A non-storage phosphor is provided near the stimulable phosphor sheet, and a photodetector detects the light emitted by the non-storage phosphor when recording radiation image information, and the light is stored and recorded in the stimulable phosphor. A method of estimating the recording state or recording pattern of the radiographic image information that has been used is also considered, but in addition to the drawbacks of the method disclosed in JP-A No. 55-50180, this method Since it is not used as a detection means, it can only indirectly infer the accumulated recorded information of image information accumulated and recorded in the stimulable phosphor.
The drawback was that the reliability of the information obtained in this way was low.

The present invention provides a device that can easily and accurately detect radiographic image information accumulated and recorded in a stimulable phosphor prior to a reading operation to obtain a visible image for observation and interpretation. The purpose is to

Another object of the present invention is to easily and accurately detect accumulated radiation image information stored in a stimulable phosphor prior to a reading operation to obtain a visible image for observation and interpretation. The object of the present invention is to provide an apparatus that can reproduce radiographic images with excellent diagnostic performance based on this information.

As a result of extensive research to achieve this objective, the present inventor has determined that the energy of the excitation light to be irradiated during the reading operation (hereinafter referred to as "reading") to obtain a visible image for observation and interpretation. A reading operation (hereinafter referred to as "pre-reading") for grasping the accumulated recording information of radiographic image information stored in the stimulable phosphor in advance prior to the actual reading using low-energy excitation light. After that, perform the actual reading and adjust the reading gain or determine the recording scale factor (hereinafter referred to as reading gain and recording scale factor) based on the read-ahead information. (The actors together are referred to as "reading conditions.") Or, by determining appropriate image processing conditions and performing signal processing, it is possible to obtain radiographic images that are unaffected by fluctuations in imaging conditions or that are highly suitable for observation and interpretation. ,
It has been found that the above objectives are achieved. Even if one selects a stimulable phosphor that is considered to have the highest sensitivity at present, the amount of stimulated luminescence emitted by the stimulable phosphor upon excitation light irradiation is extremely weak, so it is important to Until now, it was considered an essential requirement for this system that the amount of light should be detected by a photodetector (Japanese Patent Application Laid-Open No.
(No. 12492, No. 55-48674, No. 55-87970, etc.)
In light of this, it is nothing short of absurd to intentionally dissipate the radiation energy stored and recorded in the stimulable phosphor by reading in advance before reading the book, and the above findings are extremely surprising.

The present invention is based on this knowledge, and includes excitation light irradiation means, stimulable phosphor sheet transport means,
A pre-reading reading system including a photodetecting means for photoelectrically reading the stimulated luminescence light from the stimulable phosphor sheet, and in which the energy of the excitation light is smaller than the energy of the excitation light in the main reading, is provided separately from the main reading reading system. It is characterized by the fact that it has been provided.

In the present invention, the energy of excitation light refers to the effective energy of excitation light received per unit area of the stimulable phosphor sheet.

In the present invention, it is sufficient that the energy of the excitation light to be applied to the stimulable phosphor during pre-reading is lower than the energy of the excitation light during main reading. The closer the ratio of the excitation light energy of the pre-reading to that of the main reading is to 1, the smaller the amount of radiation energy remaining and accumulated during the main reading, but if this ratio is less than 1, the value of the reading gain should be adjusted appropriately. It has been found that radiological images suitable for observation and interpretation can be obtained by adjusting the However, in order to obtain radiological images that are suitable for observation and interpretation,
In other words, as long as the accumulated record information of radiation image information accumulated and recorded in the stimulable phosphor can be grasped to a sufficient degree to be used for selecting reading conditions or optimal image processing conditions by reading ahead, in other words, accumulation is possible. As long as the stimulated luminescence light emitted from the phosphor can be sufficiently detected in the above sense, the ratio of the energy of the excitation light in the pre-reading and the main reading is preferably as small as possible, and is preferably 50% or less, preferably 10% or less, and The content is preferably 3% or less. The lower limit of this ratio is determined by the accuracy of the pre-read stimulated luminescence light detection system.

In the present invention, methods for making the energy of the excitation light in pre-reading smaller than the energy in main reading include methods of reducing the output of the laser light source, increasing the beam diameter of the laser light, and increasing the scanning speed of the laser light. Known methods such as a method of increasing the transport speed of the stimulable phosphor sheet and a method of increasing the transport speed of the stimulable phosphor sheet can be used.

In the present invention, it is desirable that the pre-reading be performed within one hour before the main reading. The radiation energy stored and recorded in the stimulable phosphor has a characteristic of fading over time. Therefore, in order to effectively use the recorded information obtained by pre-reading for main reading, It is desirable to minimize the time it takes to read the book. However, according to the research of the present inventor, the attenuation of the radiation energy stored and recorded in the stimulable phosphor is greatest immediately after recording radiation image information on the stimulable phosphor, and decreases approximately 1 hour after recording. Approximately 10% of radiation energy is lost due to attenuation, but it is recognized that the rate of attenuation decreases after that. In this case, the accumulated record information obtained by pre-reading is used to detect the accumulated record information of the radiographic image information accumulated and recorded in the stimulable phosphor, and this is used to set the reading conditions for the main reading or to set the read condition after reading. It has been found that even when signal processing is performed, a radiation image with sufficient suitability for observation and interpretation can be obtained for practical use. Therefore, if the time interval between pre-reading and main reading is set to 1 hour or less, the difference in accumulated amount will always be 10% or less, and it is guaranteed that radiological images with sufficient suitability for observation and interpretation for practical purposes will be obtained. ,preferable.

According to the present invention, since it is possible to know in advance the recording state of radiographic image information stored and recorded in a stimulable phosphor, the recorded information can be read without using a reading system having a particularly wide dynamic range. By appropriately adjusting the reading gain based on the above, it is possible to obtain radiographic images that are always suitable for observation and interpretation even when the imaging conditions vary.

Furthermore, according to the present invention, it is possible to know in advance the recording pattern of radiation image information stored and recorded in the stimulable phosphor, so that signal processing according to the recording pattern is applied to the electrical signal after reading. By applying this method or by optimizing the recording scale factor, it becomes possible to obtain radiographic images with excellent suitability for observation and interpretation.

Furthermore, according to the present invention, it is possible to know in advance the recording pattern of the radiographic image information stored and recorded in the stimulable phosphor, so it is possible to omit the actual reading of parts where the recording pattern does not exist. , it becomes possible to shorten the reading time.

In the present invention, it is preferable that the wavelength region of the excitation light and the wavelength region of the stimulated luminescent light do not overlap in order to improve the S/N ratio, and the excitation light source and the stimulable fluorescent light are selected so as to satisfy such a relationship. It is preferable to choose a light body. Specifically, Japanese Patent Application Publication No. 1983-
As disclosed in Publication No. 12492, the excitation light wavelength is 600 to 700 nm, and the stimulated emission light wavelength is 300 to 700 nm.
It is desirable to set the wavelength to 500 nm.

As described above, examples of stimulable phosphors that emit stimulated luminescent light of 300 to 500 nm and can be preferably used in the present invention include rare earth element-activated alkaline earth metal fluorohalide phosphors [specifically, ,
It is described in Japanese Patent Application Laid-Open No. 55-12143 (Ba ₁
−x−y, Mgx, Cay) FX: aEu ²⁺ (X is Cl
and Br, x and y are 0<x+y≦0.6 and xy≠0, and a
is 10 ^-6 ≦a≦5×10 ^-2 ), - Japanese Patent Application Laid-Open No. 1987-
It is described in Publication No. 12145 (Ba ₁ −x, M〓
x) FX: yA (However, M〓 is Mg, Ca, Sr, Zn and
at least one of Cd, X is at least one of Cl, Br and I, A is Eu, Tb, Ce,
At least one of Tm, Dy, Pr, Ho, Nd, Yb and Er, x is 0≦x≦0.6, y is 0≦y
≦0.2), etc.]; ZnS: Cu, Pb, BaO x Al ₂ O ₃ : Eu
(however, 0.8≦x≦10) and M〓O・xSiO ₂ :A (however, M〓 is Mg, Ca, Sr, Zn, Cd or Ba,
A is Ce, Tb, Eu, Tm, Pb, Tl, Bi or Mn
and x is 0.5≦x≦2.5); and LnOX:xA described in JP-A-55-12144 (however, Ln is at least one of La, Y, Gd, and Lu, and X is at least one of Cl and Br
1, A is at least one of Ce and Tb;
x is 0<x<0.1); Among these, rare earth element-activated alkaline earth metal fluorohalide phosphors are preferred, and among these, barium fluorohalides shown as specific examples are particularly preferred because of their excellent stimulable luminescence.

Furthermore, metal fluorides are added to barium fluorohalide phosphors as disclosed in JP-A-56-2385 and JP-A-56-2386, or as disclosed in JP-A-56-74,175. As described above, it is preferable to add at least one of a metal chloride, a metal bromide, and a metal iodide because the stimulated luminescence is further improved.

Further, as disclosed in JP-A-55-163500, when the phosphor layer of a stimulable phosphor plate prepared using the above-mentioned stimulable phosphor is colored with a pigment or dye, This is preferable because the sharpness of the finally obtained image is improved.

The signal processing used in the present invention includes:
JP-A-55-87970, JP-A-56-11038, JP-A-56-
No. 75137, No. 56-75139, No. 56-75141, No. 56
−Frequency processing disclosed in JP-A No. 104645, etc., JP-A No. 55-116339, JP-A No. 55-116340, JP-A No. 55-88740
For example, the gradation processing disclosed in No.

Hereinafter, embodiments of the present invention will be described in detail based on the accompanying drawings.

The drawing is a schematic diagram of an X-ray image information recording system including an X-ray image information reading device that is an embodiment of the present invention.

In the drawings, 1 is a photographing section, 2 is a pre-reading reading section, 3 is a main reading reading section, and 4 is a reproduction/recording section.

In the imaging unit 1, X-rays emitted from an X-ray source 101 toward a subject 102 are absorbed by a stimulable phosphor sheet 103 after passing through the subject 102, and the phosphor sheet 103 absorbs the X-ray image information is accumulated and recorded. The phosphor sheet 103 on which the X-ray image information has been stored and recorded in this way is sent to the pre-reading section 2.

In the prefetch reading unit 2, a laser light source 201
The laser beam 202 emitted from this laser beam 2
After passing through a filter 203 that cuts out the wavelength region of the stimulated luminescent light emitted from the stimulable phosphor sheet 103 by the excitation of 02, the stimulable luminescent light is passed through a flat reflecting mirror 205 by an optical deflector 204 such as a galvano mirror. The light is incident on the phosphor sheet 103 while being one-dimensionally deflected. Here, the laser light source is selected so that the wavelength range of the excitation light does not overlap with the wavelength range of the stimulated emission light from the stimulable phosphor. On the other hand,
The phosphor sheet 103 is conveyed in the direction of the arrow 206 for sub-scanning, and as a result, the entire surface of the phosphor sheet 103 is irradiated with laser light. Here, the power of the laser light source 201,
The beam diameter of the laser beam 202, the scanning speed of the laser beam 202, and the transport speed of the phosphor sheet 103 are selected so that the energy of the laser beam 202 for pre-reading is smaller than that for main reading. When the laser beam 202 is irradiated in this manner, the stimulable phosphor sheet 103 emits stimulated luminescence light with an amount proportional to the accumulated and recorded X-ray energy, and this luminescent light is transmitted to the pre-reading light guide sheet. 207. The light guide sheet 207 has a linear incident surface and is placed adjacent to and opposite to the scanning line on the stimulable phosphor sheet 103, and has an annular exit surface that allows light such as photoprints to pass through. It is brought into close contact with the light receiving surface of the detector 208. This light guiding sheet 207 is made by processing a transparent thermoplastic resin sheet such as acrylic resin, and is configured so that the light incident from the incident surface is transmitted to the exit surface while being totally reflected inside. The stimulated luminescent light from the stimulable phosphor sheet 103 is transmitted through the light guiding sheet 2.
07 and exits from the exit surface to the photodetector 2.
The light is received by 08. Preferred shapes, materials, etc. of the light guiding sheet are disclosed in Japanese Patent Application Laid-Open Nos. 55-87970 and 56-
It is disclosed in Publication No. 11397, etc.

A filter is attached to the light-receiving surface of the photodetector 208, which transmits only light in the wavelength range of the stimulated luminescence light and cuts out light in the wavelength range of the excitation light, and detects only the stimulated luminescence light. It's getting wet. The output of the photodetector 208 is amplified by an amplifier 209 and
The image is output as a visible image on an output device 210 such as the following. By visually observing this visible image, it becomes possible to grasp the accumulated recording information of the X-ray image information, that is, the recording state or recording pattern, in advance of the actual reading. The stimulable phosphor sheet 103 on which the pre-reading has been completed is transferred to the reading section 3 for main reading.

In the reading unit 3 for main reading, a laser beam 302 emitted from a laser light source 301 for main reading is passed through a filter that cuts out the wavelength range of stimulated luminescence light emitted from the stimulable phosphor sheet 103 by excitation of the laser beam 302. After passing through the beam expander 303, the beam diameter is strictly adjusted by the beam expander 304, and then the beam is passed through the optical deflector 3 such as a galvanometer mirror.
05, the light is deflected onto the stimulable phosphor sheet 103 through a plane reflecting mirror 306, and then enters the stimulable phosphor sheet 103. An fθ lens 307 is arranged between the optical deflector 305 and the plane reflecting mirror 306, and the phosphor sheet 103
Even when the laser beam 302 scans the top, it always has a uniform beam diameter. On the other hand, the phosphor sheet 103 is moved in the direction of arrow 308 to perform sub-scanning, and as a result, the entire surface of the phosphor sheet 103 is irradiated with laser light. When the laser beam 302 is irradiated in this way, the stimulable phosphor 103 emits stimulated luminescent light with an amount proportional to the accumulated and recorded X-ray energy, and this emitted light is transmitted to the book reading light guiding sheet 309. incident on . The light guide sheet 309 for main reading has the same material and structure as the light guide sheet 207 for prereading. The stimulated luminescent light guided through the light guiding sheet 309 for main reading while undergoing repeated total reflection is emitted from its exit surface and is received by the photodetector 310. A filter that selectively transmits only the wavelength range of the stimulated luminescence light is attached to the light receiving surface of the photodetector 310, so that the photodetector 310 is designed to detect only the stimulated luminescence light. . The output of the photodetector 310 is amplified by an amplifier 311,
After being A/D converted by the A/D converter 312,
A signal processing circuit 313 performs signal processing to obtain an X-ray image that is suitable for observation and interpretation.
The amplification factor of the amplifier 311, the recording scale factor of the A/D converter 312, and the signal processing conditions in the signal processing circuit 313 are determined by the input device 315 in the control circuit 314 based on the visible image obtained in the prefetch reading section 2. The most appropriate conditions can be selected by manually operating.
Furthermore, by observing the visible image output on the output device 210 such as a CRT, the relative position of the stimulable phosphor sheet 103 in the radiation image information reading device can be found, so that high precision When using an overlay method or a subtract method that requires alignment, the relative position of the stimulable phosphor sheet 103 can be determined with high accuracy by providing a control zone in front of the main reading system. can. The image signal output from the signal processing circuit 313 is input to the optical modulator 401 of the recording section 4.

In the recording section 4, a recording laser light source 402
A laser beam 403 from the scanning mirror 40 is modulated by an optical modulator 401 based on an image signal.
4, a photosensitive material 405 such as photographic film is scanned. At this time, since the photosensitive material 405 is transported in a direction perpendicular to the scanning direction (arrow 406) in synchronization with the scanning,
A line image is output.

It goes without saying that the present invention is not limited to the above-described embodiments, and that various modifications can be made.

For example, in the embodiment described above, the actual reading conditions are set by manually operating the control circuit based on the visible image obtained by pre-reading, but depending on the operation of the control circuit 313, the output of the CRT, etc. A control system may be provided so that the visible image displayed on the device 210 is suitable for observation and interpretation, and in this way, conditions can be set so that the control circuit can perform appropriate processing more easily. can do.

Furthermore, the recording method in the recording section 4 does not have to be a direct recording method using a laser light source; for example, the final signal obtained in the reading section for main reading may be displayed as is on a display device such as a CRT. Furthermore, the final radiation image displayed on a CRT or the like may be displayed on a video printer or the like. Furthermore, various known recording methods such as recording with heat rays using a heat-sensitive recording material can be employed.

Furthermore, the laser light source as an excitation light source in the pre-reading reading section and the main reading reading section can be replaced with an LED array having a wavelength range different from that of the stimulated emission light. In this case, an optical deflector such as a galvano mirror can be omitted.

Further, the photodetector does not have to be a single one with a light guide sheet, but it is also possible to use a plurality of photodetectors or phototransistors arranged in a straight line in the main scanning direction. Furthermore, it is also possible to uniformly expose the entire surface of the stimulable phosphor sheet and use a photodetector capable of two-dimensionally capturing the light, such as a television camera.

Furthermore, a prefetch reading section 2 and a main reading reading section 3 are provided.
The laser light sources 201 and 301 do not necessarily need to be separate, and a single laser light source may be used and divided by a half mirror or the like.

In addition, the reading gain can be adjusted by changing the amplification factor of the amplifier of the photodetector as explained in the above embodiment, or by changing the voltage applied to the photomultiply when a photomultiplier is used as the photodetector. By doing so, the gain of the photodetector may be directly changed. This has the advantage that only the signal is amplified and the noise is not increased.

Further, in the embodiments described above, pre-reading is performed over the entire surface of the stimulable phosphor sheet, but it is not necessarily necessary to perform over the entire surface of the phosphor sheet. Normally, in the case of an X-ray photograph, there is no image information to be observed and interpreted at the periphery of the phosphor sheet, so for example, for a few centimeters of the periphery, pre-reading can be omitted, and if necessary When the storage recording area of radiation image information is known, it is sufficient to pre-read only that area, and by pre-reading only the effective area in this way, the reading time can be shortened.

[Brief explanation of drawings]

The drawing is a schematic diagram of an X-ray image information recording system including an X-ray image information reading device that is an embodiment of the present invention. 1... Photography department, 101... X-ray source, 102...
Subject, 103...Storage phosphor sheet, 2...
Pre-reading reading unit, 201... Laser light source for pre-reading, 202... Laser light, 203... Filter, 204... Optical deflector, 205... Plane reflecting mirror, 206... Transfer direction, 207... Pre-reading guide Optical sheet, 208...Photodetector, 209...Amplifier, 210...Display device, 3...Reading unit for main reading, 301...Laser light source for main reading, 302...
Laser light, 303... Filter, 304... Beam expander, 305... Light deflector, 30
6...Plane reflecting mirror, 307...fθ lens, 308
...Transfer direction, 309...Light guide sheet for book reading, 310...Photodetector, 311...Amplifier, 3
12... A/D converter, 313... Signal processing circuit, 314... Control circuit, 315... Input device,
4...Reproduction/recording section, 401...Optical modulator, 402
... Recording laser light source, 403 ... Laser light, 4
04...Scanning mirror, 405...Photosensitive material.

Claims (1)

[Scope of Claims] 1. Excitation light irradiation means for irradiating excitation light onto a stimulable phosphor sheet on which radiation image information is stored and recorded; means for transporting the stimulable phosphor sheet; A radiation image information reading device including a photodetecting means for photoelectrically reading stimulated luminescent light carrying radiation image information emitted from a stimulable phosphor sheet, an excitation light irradiation means, a means for transporting the stimulable phosphor sheet, and It includes a photodetection means for photoelectrically reading stimulated luminescence light carrying radiation image information emitted from the stimulable phosphor sheet by irradiation with excitation light, and the energy of the excitation light is smaller than the energy of the excitation light in main reading. A radiation image information reading device characterized in that a pre-reading reading system is provided separately from a main reading reading system. 2. The radiation image information reading device according to claim 1, wherein the excitation light irradiation means in the main reading reading system and the pre-reading reading system scans the excitation light over the stimulable phosphor. . 3 Excitation light irradiation means for irradiating excitation light onto a stimulable phosphor sheet on which radiation image information is accumulated and recorded; means for transporting the stimulable phosphor sheet; In a radiation image information reading device including a photodetecting means for photoelectrically reading stimulated luminescence light carrying emitted radiation image information, an excitation light irradiation means, a means for transporting the stimulable phosphor sheet, and a means for transporting the stimulable phosphor sheet, and the accumulation by the excitation light irradiation. A pre-reading reading system includes a photodetecting means for photoelectrically reading stimulated luminescence light carrying radiation image information emitted from a phosphor sheet, and the energy of the excitation light is smaller than the energy of the excitation light in main reading. A radiation image information reading apparatus characterized in that a monitor means is provided separately from the main reading system and displays the output of the light detection means of the prefetch reading system.