JPH03132641A - Radiation image information record reader - Google Patents

Abstract

PURPOSE:To perform energy subtraction without performing complicated work by using one accumulable phosphor belt of endless belt shape and one reader. CONSTITUTION:A loop is formed by connecting the accumulable phosphor belts 25 in form of so-called (Mobius' belt), and one reading part 50 and one erasure part 60 are arranged on the plane on one side of the accumulable phosphor belt 25, and both planes of the accumulable phosphor belt 25 are read or erased by travelling the fluorescent belt 25 circularly. At such a case, by using the supporter 25b of the accumulative type fluorescent belt 25 also as a radiation absorbing filter or changing the radiation absorbing characteristic for the surface 25C of the accumulative type fluorescent belt 25 differently from that of the back plane 25D, the fluorescent belt can be irradiated from one side with radia tion, and the recording of data on both the surface and back plane can be performed simultaneously, and they can be read and subtracted. Thereby, the energy subtraction can be easily performed.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention accumulates and records radiation image information on a stimulable phosphor sheet, then irradiates the same with excitation light, and generates images according to the accumulated and recorded image information. It relates to a radiation image information recording/reading device that detects photostimulated light and reads image information as an electrical image signal.More specifically, by overlapping stimulable phosphor sheets and photographing, images with good S/N can be obtained. The present invention relates to a radiographic image information recording/reading apparatus that is capable of obtaining a signal or an image signal that extracts and represents only a part of the structure in an image.

(Prior art) When a certain type of phosphor is irradiated with radiation (X-rays, α-rays, β-rays, γ-rays, ultraviolet rays, electron beams, etc.), part of the energy of this radiation is accumulated in the phosphor. Then, when the phosphor is irradiated with excitation light such as visible light, the phosphor exhibits stimulated luminescence depending on the accumulated energy. A phosphor exhibiting such properties is called a stimulable phosphor (stimulable phosphor).

Using this stimulable phosphor, radiation image information of a subject such as a human body is recorded on a stimulable phosphor sheet (hereinafter referred to as a stimulable phosphor sheet), which is then scanned with excitation light and illuminated. A method has been proposed in which the stimulated emitted light is photoelectrically read to obtain an image signal, and the image signal is processed to obtain a radiographic image of a subject that is suitable for diagnosis (for example, Japanese Patent Application Laid-Open No. 1983-1981). No. 12429, No. 55-116340, No. 55-183472, No. 5B-11395, No. 5B-104645, etc.). This final image can be reproduced as a hard copy or on a CRT. In any case, in such a radiation image information recording and reproducing method, the stimulable phosphor sheet does not ultimately record image information, but temporarily stores image information in order to provide an image to the final recording medium as described above. Therefore, this stimulable phosphor sheet may be used repeatedly, and such repeated use is extremely economical.

In order to reuse the stimulable phosphor sheet as described above, the radiation energy remaining in the stimulable phosphor sheet after the stimulated luminescence light has been read can be absorbed by, for example,
As shown in No. 2, No. 5B-12599, residual radiation images may be erased by irradiating the sheet with light or heat, and the stimulable phosphor sheet may be used again for recording radiation images.

On the other hand, a radiation image superposition process has been known for some time (see, for example, Japanese Patent Laid-Open No. 11399/1983).

Radiographic images are generally used for diagnostic and other purposes, and their use requires excellent detection of minute differences in radiation absorption of the subject.

The degree of detection in a radiographic image is called contrast detectability or simply detectability, and it can be said that the higher the detectability, the higher the diagnostic performance, and the radiological image has higher practical value. Therefore, to improve diagnostic performance,
It is desirable to improve this detection ability, but the most significant impediment factor is various noises.

In a radiation image recording method using a stimulable phosphor sheet, the following noise is recognized to exist in the step of accumulating and recording a radiation image on the stimulable phosphor sheet and reading it out.

(1) Quantum noise of the radiation source (noise due to non-uniform distribution of phosphor coating or phosphor particles on the stimulable phosphor sheet) (3) Excitation that causes the image stored and recorded on the stimulable phosphor sheet to emit stimulated light Optical noise (4) Electrical noise in the system that detects stimulated luminescent light and converts it into an electrical signal (5) Noise of stimulated luminescent light emitted from a stimulable phosphor sheet The superposition process eliminates these noises. This is a method that greatly reduces radiation absorption and makes it possible to clearly observe even the slightest radiation absorption difference in the subject in the final image, in other words, it greatly improves the detection ability.The general techniques and effects of superposition processing are as follows. It is.

Radiographic images are taken on multiple stacked stimulable phosphor sheets (
A plurality of image signals obtained by reading the plurality of sheets are superimposed. Due to this,
The various noises mentioned above can be reduced. In other words, the noises (1) to (5) described above often have different distributions for each sheet image, so by overlapping the images of these sheets, each noise is averaged and the overlapping process is performed. Noise becomes less noticeable in the image. In other words, an image signal with a good S/N ratio can be obtained. More specifically, noises (1) to (5) include many noises that can be approximated by Poisson statistics, and in particular, noise of the radiation source is one of the dominant factors in the noise of radiological images. This is an example. Here, if we assume that noise can be approximated by Poisson statistics and that two radiation images have signals S1, S2 and noise N1, N2 of equal size, then The magnitude of the signal and noise is SL + S2 for the signal, and Nl for the signal and X.
+NZ”.

On the other hand, S
/N, the S/N of each image before superimposition is Sl /Nl and Sz /Nz, respectively, but by performing the superposition process, the S/N becomes C8s + S
2) / Nl ” +N2 dingtona l), S/N
will improve. Furthermore, when performing superimposition processing, it is possible to optimize the S/N improvement by weighting each signal.

When a radiation image is finally displayed based on the image data that has been superimposed, it is preferable for diagnosis to perform gradation processing to improve the contrast of the image. It is also possible to perform so-called frequency emphasis processing that improves only specific frequency components, or to perform both. When superimposing image data, it is better to add or average image data obtained from a stimulable phosphor sheet closer to the radiation source with greater weight than to simply add or average each image data. However, good images can be obtained.

The optimum value of this weighting coefficient varies depending on the number of stacked stimulable phosphor sheets, the thickness of the stimulable phosphor sheets, and the like.

Conventionally, in order to actually perform this superimposition process, for example, two stimulable phosphor sheets were stacked in a cassette, the subject was photographed, and the two stimulable phosphor sheets were scanned in a normal manner. By sequentially performing the same reading process as the processing,
A method is used in which two sets of image signals are obtained.

On the other hand, subtraction processing of radiographic images has been conventionally known. This radiographic image subtraction is a process in which two radiographic images taken under different conditions are photoelectrically read out to obtain digital image signals, and then these digital image signals are subtracted by matching each pixel of both images. , is a method of obtaining a difference signal that extracts a specific structure in a radiation image, and by using the difference signal obtained in this way, it is possible to reproduce a radiation image in which only the specific structure has been extracted.

There are basically two methods for this subtraction process: That is, (1) Extracting a specific structure by subtracting (subtracting) the image signal of a radiographic image in which no contrast agent has been injected from the image signal of a radiographic image in which a specific structure has been emphasized by contrast agent injection. (2) irradiating the same subject with radiation having different energy distributions, or irradiating the radiation that has passed through the subject with different energy distributions to two radiation detection means; As a result, an image in which a specific structure differs is made to exist between two radiographic images, and then subtraction (subtract) is performed with appropriate weighting between the image signals of these two radiographic images to identify a specific structure. This is a so-called energy subtraction process that extracts images.

Since this subtraction processing is an extremely effective method, especially in medical diagnosis, it has attracted much attention in recent years, and its research and development are actively progressing by making full use of electronic engineering technology.

In the radiation image information recording and reproducing system using the stimulable phosphor sheet described above, the radiation image information recorded on the sheet is directly read in the form of an electrical image signal, so according to this system, It becomes possible to easily perform the subtraction process as described above. In order to perform energy subtraction processing using this stimulable phosphor sheet, it is necessary to record (photograph) images on two stimulable phosphor sheets so that the image information of the part corresponding to a specific structure is different. More specifically, two-shot methods are used, in which imaging is performed twice using two types of radiation with different energy distributions, and, for example, two overlapping stimulable phosphor sheets are simultaneously exposed to radiation that has passed through the subject. The 15hot method is known in which both sheets are irradiated with radiation having different energy distributions.

The energy subtraction of the l5hot method includes (1
) A method of obtaining radiation with different energy distributions by interposing a filter made of metal or the like that absorbs the low-energy components of radiation between two stimulable phosphor sheets, and (2) One imaging without using a filter. Two stimulable phosphor sheets with different types of phosphor layers are used to record the necessary images.
Among these stimulable phosphor sheets, a sheet having a stimulable phosphor layer with higher radiation absorption characteristics for low-energy components is placed on the subject side (radiation source side) to record images (Japanese Patent Application Laid-Open No. (See No. 1983-83486, etc.) has been proposed.

(Problem to be solved by the invention) However, when photographing is carried out by stacking multiple stimulable phosphor sheets as described above, since the stimulable phosphor sheets are placed in one cassette, it is necessary to perform the reading process. When loading the cassettes into the reading device, it is necessary to reload these stimulable phosphor sheets into separate cassettes, which has the disadvantage that the work is very complicated and time consuming.

Furthermore, if a plurality of stimulable phosphor sheets are sequentially read as described above, the time required for the reading process will naturally increase.

Although superimposition processing and energy subtraction are effective diagnostic methods, they have the drawbacks of being complicated and time-consuming as described above, so they are rarely used in mass medical examinations and the like.

Therefore, the above-mentioned superimposition process or energy subtraction (more specifically, 15hot energy subtraction that does not use an energy conversion filter) using stimulable phosphor sheets can be performed without complicated work such as taking out sheets from a cassette. The present applicant proposed a practical radiation image information recording/reading device that can perform reading in a short time. (Japanese Patent Application No. 1-53179) This method uses two flexible band-shaped stimulable phosphor sheets, arranges these two stimulable phosphor sheets in parallel, and radiation image information is recorded by each radiation exposure, and an image reading section that reads the radiation image information accumulated and recorded on the stimulable phosphor sheet, and an image reading unit that reads the radiation image information accumulated and recorded on the stimulable phosphor sheet, and An erasing unit for erasing radiation images is provided exclusively for each of the two stimulable phosphor sheets, so that the two radiation image information can be read simultaneously in parallel.

This allows superposition processing and subtraction processing to be performed quickly and easily without using a cassette, and is particularly advantageous in mass medical examinations and the like where high-speed processing is required.

However, since the above device uses two stimulable phosphor sheets, it requires two readers to read the radiation image from each stimulable phosphor sheet, making the entire device significantly more complex. There are some difficulties.

Therefore, the present invention uses one endless belt-like stimulable phosphor belt to provide one reader, and performs the above-mentioned superimposition process or energy subtraction (more specifically, 15hot energy subtraction) in a cassette. It is an object of the present invention to provide a more practical radiographic image information recording/reading device that can be used without complicated operations such as taking out sheets from a radiograph.

A further object of the present invention is to provide a radiation image information recording/reading device that can efficiently read and record records of ordinary radiographing.

(Means and Effects for Solving the Problems) A radiation image information recording/reading device according to the present invention is provided by twisting a long belt-shaped stimulable phosphor comprising a support and a stimulable phosphor layer on both sides. a stimulable phosphor belt in the form of an endless belt formed by butting and joining the stimulable phosphor belt so that the front and back sides are connected; a belt feeding means for circulating and transporting the stimulable phosphor belt while stretching the stimulable phosphor belt; an image recording unit that accumulates and records the radiation image information on the stimulable phosphor belt by irradiating a part of the stimulable phosphor belt with radiation having image information; and a circulation transport path of the stimulable phosphor belt. Excitation light is irradiated to the stimulable phosphor belt installed nearby and on which the radiation image information is accumulated and recorded, and photoelectric reading means detects stimulated luminescence light emitted from the stimulable phosphor belt by the irradiation with the excitation light. an image reading unit that obtains an image signal by reading the image; It is characterized by comprising an erasing section that releases the remaining radiation energy.

In other words, stimulable phosphor belts are connected to form a ring in a shape called a ``Möbius strip.'' This allows for one reading section and one erasing section to be placed on one side of the stimulable phosphor belt. By circulating the stimulable phosphor belt, both sides of the stimulable phosphor belt can be read and erased.

With this, if you record images only on one side,
The stimulable phosphor belt can be used in double lengths, which has the advantage of doubling the effective length without taking up space.

Furthermore, if the support of the stimulable phosphor belt can also be used as a radiation absorption filter, or if the radiation absorption characteristics are changed between the front and back sides of the stimulable phosphor belt (in this case, the front and back sides will be switched at the seam). ), if radiation is irradiated from one side and recorded simultaneously on the front and back sides, energy subtraction can be performed by reading and subtracting this information.

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

FIG. 1 shows a radiation image information recording/reading apparatus according to a first embodiment of the present invention. As an example, the apparatus of this embodiment performs superimposition processing. 3 rollers 2B
, 27 and 28 are rotated in the direction of arrow A by a motor 24 constituting belt feeding means. A stimulable phosphor belt 25 that stores and records radiation image information is wound and stretched around these rollers 26, 27, and 28. This stimulable phosphor belt 25 is formed into a Möbius strip shape using a flexible support. The stimulable phosphor belt 25 is stretched between rollers 26, 27, and 28, and is circulated and conveyed in the direction of the arrow by the motor 24. Here, the stimulable phosphor belt 25 is provided on both the front and back sides of a flexible support through which radiation can pass well, so that the stimulable phosphor layers are exposed on both sides.

The stimulable phosphor belt 25 stretched as described above is sandwiched between the upper two rollers 26 and 27 in the figure at a position where the radiation 35 is irradiated through the subject 34.
It is stretched flat.

A photographing stand 32 is provided at a position facing the stimulable phosphor belt 25 stretched between the rollers 2B and 27. The radiation source storage section 30 above it has an X inside, for example.
A radiation source 33 such as a radiation tube is housed therein, and this radiation source 33 faces the imaging table 32 . When radiographically photographing the subject 34, the subject 34 is placed on the imaging table 32, and the radiation source 33 is activated in this state. As a result, subject 34
The radiation 35 transmitted through the stimulable phosphor belt is irradiated onto the surface portion 25a of the stretched stimulable phosphor belt (more specifically, the stimulable phosphor layer formed on the surface of the belt 25). b) Radiation image information of the subject 34 is accumulated and recorded.

Furthermore, the radiation 35 transmitted through the surface portion 25a of the stimulable phosphor belt is transmitted through the back portion 25b of the stimulable phosphor belt.
25 of the stimulable phosphor belt.
Radiographic image information of the subject 34 is also accumulated and recorded in the area b.

As is clear from the above description, in the apparatus of this embodiment, the imaging table 32 and the radiation source 33 constitute the image recording section 40.

The radiation image information accumulated and recorded on the front and back sides 25a and 25b of these stimulable phosphor belts is read as an electrical image signal by the image reading section 50. Image reading section 5
0 is a laser light source 51, a light deflector 53 such as a polygon mirror that reflects and deflects a laser light 52 as an excitation light emitted from the laser light source 51, and a light deflector 53 such as a polygon mirror that reflects and deflects the laser light 52 emitted from the laser light source 51; a scanning lens 54 that focuses to a small spot of a predetermined diameter at every scanning position;
A motor 24 that also serves as a sub-scanning means for transporting the stimulable phosphor belt 25 at a constant speed at least during reading, and a laser beam 5
A long photomultiplier tube (photomultiplier) as a photoelectric reading means is disposed so that its light receiving surface extends along the scanning line (main scanning line) on the stimulable phosphor belt 25 according to 2.
) 55, and a long light guide 5B and laser beam 5 optically coupled to the light receiving surface of the long photomultiplier tube 54.
2 from entering the photomultiplier 55 (not shown).

Regarding long photomultiplier tubes, for example, Japanese Patent Application Laid-open No. 1982-
A detailed description is given in No. 16868.

Both the front and back surfaces 2 of the stimulable phosphor belt 25 are prepared as described above.
After the radiographic image information of the subject 34 is accumulated and recorded on 5a and 25b, the belt 25 is conveyed at a constant speed in the direction of the arrow in the figure by rotating the motor 24.

At this time, an appropriate load is applied to the stimulable phosphor belt 25 by a known means, so that the stimulable phosphor belt 25 is always maintained in a tensioned state.

While the stimulable phosphor belt 25 is conveyed, the laser light source 51 and the optical deflector 53 are activated, and the laser beam 52 is activated.
scans over the portion 25b of the belt 25.

Stimulated luminescence light carrying radiation image information stored and recorded on the belt back surface 25b is emitted from a portion 25b of the stimulable phosphor belt 25 that is irradiated with the laser beam 52. This stimulated luminescence light is guided by a light guide 58 and efficiently detected by a long photomultiplier tube 55. The main scanning of the laser beam 52 is performed as described above, and the stimulable phosphor belt 25 is conveyed as described above and sub-scanning is performed. The exhaust light (ie, radiographic image information) is read.

The output S1 of the long photomultiplier tube 55 is sent to a reading circuit 59.

Further, by conveying the stimulable phosphor belt 25, the portion 25a on the surface of the stimulable phosphor belt reaches the image reading section 50. Here, the radiation image information recorded in this portion 25a is read.

At this time, the output S2 of the elongated photomultiplier tube 55 of the image reading unit 50 (that is, the one indicating the radiation image information recorded on the front stimulable phosphor belt surface portion 25a)
is also sent to the reading circuit 59. The outputs S1 and S2 sent to the reading circuit 59 are each sequentially sent from the memory 82 to the signal processing circuit 8B, subjected to signal processing, and then output to the image reproduction device 88.

Next, the processing after the reading circuit 59 will be explained with reference to FIG. 2, which schematically shows the configuration thereof. The output S of the long photomultiplier tube 55 is sent to a reading circuit 59, logarithmically amplified by a logarithmic amplifier 80, and then digitized by an A/D converter Ill. The digital read image signal 1ogs1 thus obtained is temporarily stored in the memory 82,
The signal is then read out from there and input to the superposition calculation circuit 83 of the signal processing circuit 8B. Similarly, the output s2 of the long photomultiplier tube 54' is also sent to the reading circuit 59, logarithmically amplified by the logarithmic amplifier 84, and then digitized by the A/D converter 85. The digital read image signal 1ogS2 thus obtained is also temporarily stored in the memory 82, and then read out from there and input to the superimposition calculation circuit 83 of the signal processing circuit 8B.

The superposition calculation circuit 83 receives two input image signals 1.
ogs1 and logS2 are weighted appropriately and added for each corresponding pixel to obtain a digital addition signal 5add +wae l0g51 +b 1ogs
2 [a, b are weighting coefficients]. This addition signal S add is the image processing circuit 8
After being subjected to image processing such as gradation processing and frequency processing in step 7, the image is sent to an image reproducing device 88 and used for reproducing a radiographic image. This reproducing device 88 may be a display means such as a CRT, a recording device that performs optical scanning recording on a photosensitive film, or a part of the image signal is stored in an image file on an optical disk, magnetic disk, etc. It may be replaced with a device that allows

In this embodiment, the image signals S1 and Sl are each passed through the logarithmic amplifiers 80.84 for logarithmic amplification.
5 may be digitized and a superposition calculation may be performed based on those values. In that case, the formula for the superposition operation is 5add −a' Sl +b'
-Sl[a', b' are weighting coefficients].

When performing the superposition operation as described above, the coefficient a.

If b or a' and b' are appropriately determined, radiation image information with a high S/N ratio, that is, with good detectability, can be obtained from the obtained addition signal 5add. When performing this superimposition operation, it is necessary to perform addition between corresponding pixels as described above. for that purpose,
For example, as shown in FIG. 1, a marker 92 is placed near the subject 34, and both image signals 10g5l, +og
Positioning may be performed using the signal indicating this marker 92 at sH as a reference signal.

Note that the read image signals 1ogs1 or 10g52 are not sent to the superimposition calculation circuit 83;
It is also possible to reproduce a normal radiation image based on g5l or logs2, and for this purpose, these image signals 10g5l and +ogs2 may be recorded and stored in an image file such as an optical disk.

Further, in the above embodiment, two sets of logarithmic amplifiers 80 and 84 are provided in the reading circuit 59 for the two outputs 5lSS2.
and A/D converters 81.85 are provided, which convert two types of outputs Sl, Sl into one logarithmic amplifier and A/D converter 81.85.
It goes without saying that when inputting to the converter and outputting to the memory 82, the signals may be distributed and outputted at different timings.

Each portion 25a, 25b of the stimulable phosphor belt 25, whose image has been read as described above, is moved by the roller 26.
．． At the same time, another part of the stimulable phosphor belt 25 is stretched between the rollers 26 and 27 by 27 and 28, and radiographic image information is applied to this part of the stimulable phosphor belt 25 in the same manner as described above. can be recorded.

In this way, radiation image information is recorded over substantially the entire length of the stimulable phosphor belt 25. At this time, the roller 28
The portions 25a, 25b of the stimulable phosphor belt 25 pass through the erasing unit 60 disposed between the image forming apparatus and the image forming apparatus 26, and the belt portions 25a, 25b undergo image (afterimage) erasure. The erasing section 60 is composed of an erasing light source 61 placed on the side of the stretched belt 25 on which the stimulable phosphor layer is located. This erasing light source 61 is composed of, for example, a fluorescent lamp, and mainly emits light in the excitation wavelength range of the stimulable phosphor of the belt 25, and is turned on when the belt 25 moves between the rollers 28 and 26. . The radiation energy remaining in the stimulable phosphor belt 25 after reading the image is released by irradiating the belt 25 with the above light.

In this way, the stimulable phosphor belt 25, whose image (afterimage) has been erased to the extent that radiation image information can be recorded again, is circulated by the rollers 26, 27, and 28. It becomes possible to repeat the above-described image recording (photographing) and reading. As the erasing light source 61, in addition to the above-mentioned fluorescent lamp, for example, a
A tungsten lamp, a halogen lamp, an infrared lamp, a xenon flash lamp, etc. as shown in No. 11392 may be arbitrarily selected and used. Further, the erasing unit 60 includes an erasing light source as described above, and also includes, for example, an LED (
LightE mittlng D 1ode) 2
It may be composed of planar light sources such as dimensionally arranged panels or EL (electroluminescence) plates.

The above embodiment is for superposition processing, but when energy subtraction processing is performed,
As shown in FIG. 3A, the support 25 of the stimulable phosphor belt
Either a radiation absorption filter such as Cu is used for B, or the stimulable phosphors 25C and 25D on the front and back sides have different radiation absorption characteristics as shown in FIG. 3B. At this time, the front and back sides are reversed at the seam of the stimulable phosphor belt 25 (indicated by a two-dot chain line 25A in FIG. 1). That is, the above-mentioned front and back mean the front and back before connecting both ends to form a Möbius strip.

With the above configuration, images with different radiation energies are recorded on the front and back sides of the stimulable phosphor belt 25 by - times of radiation irradiation. That is, the upper stimulable phosphor belt portion 25a accumulates and records radiation images caused by high-energy radiation, and the lower stimulable phosphor belt portion 25b accumulates and records radiation images caused by low-energy radiation. be done. therefore,
By subtracting the image signals read from these stimulable phosphor belt portions 25a and 25b, an energy subtraction image is obtained. Energy subtraction processing is described in detail in JP-A-59-83486 and JP-A-61-98341.

Furthermore, if the support is made of a material having the function of a radiation cut filter such as a PB plate, recording can be performed on only one side of the stimulable phosphor belt 25 and the stimulable phosphor belt 25 can be transferred by circulation. It is possible to effectively record over twice the length.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view showing a radiation image information recording/reading device according to an embodiment of the present invention, and FIG. 2 is a block diagram showing the configuration of a radiation image information reading circuit, memory, signal processing circuit, etc. of the above embodiment device. , 3A and 3B are cross-sectional views showing other examples of stimulable phosphor belts used in the apparatus of the present invention. 24... Motor 25... Accumulative phosphor belt 25a, 25b... Portion 2 of the stimulable phosphor belt
6.27.28...Roller 30...Radiation source storage unit 32...Photographing table 33...Radiation source 34...Subject 35...Radiation 40...Image recording unit 51... Laser light source 52... Laser light 53... Light deflector 5
4... Condensing scanning lens 55... Photomultiplier tube 56... Light guide 59... Reading circuit 6
0... Erasing section 61... Erasing light source 80
．． 84...Logarithmic amplifier 81.85...A/D
Converter 82...Memory 83...Superposition calculation circuit 86...Signal processing circuit 1ogs1, +ogs2...Read image signal S add
... Addition signal S sub ... Difference signal Fig. 1 5D

Claims (1)

[Scope of Claims] 1) A long belt-shaped stimulable phosphor having stimulable phosphor layers provided on both sides of a support is twisted and joined by abutting both ends of the belt so that the front and back sides are connected. A stimulable phosphor belt in the form of an endless belt; a belt feeding means for circulating and transporting the stimulable phosphor belt while stretching it; and radiation having image information on a part of the stretched stimulable phosphor belt. an image recording unit that accumulates and records the radiation image information on the stimulable phosphor belt by irradiating the stimulable phosphor belt; an image reading section that irradiates the stimulable phosphor belt with excitation light and reads stimulated luminescence light emitted from the stimulable phosphor belt by the irradiation of the excitation light with a photoelectric reading means to obtain an image signal; and an erasing section that releases radiation energy remaining in the stimulable phosphor belt prior to image recording on the portion of the stimulable phosphor belt after the image reading is performed in the image reading section. Information recording and reading device. 2) Adding two image signals read by the one image reading unit from the stimulable phosphors on both the front and back surfaces of the portion of the stimulable phosphor belt that is simultaneously irradiated with radiation once. The radiation image information recording/reading device according to claim 1, further comprising a calculation section. 3) subtracting the two image signals read by the one image reading section from the stimulable phosphors on both the front and back sides of the portion of the stimulable phosphor belt that is simultaneously irradiated with radiation once; The radiation image information recording/reading apparatus according to claim 1 or 2, further comprising a calculation section.