JPS61156250A - Device for reading x-ray image information - Google Patents

Abstract

PURPOSE:To obtain reproduced X-ray pictures having excellent diagnostic characteristics, by inputting information of an area designated by means of an area designating means only out of accumulated recorded information obtained by previous reading in a control means. CONSTITUTION:Previous reading is is first performed to a carried accumulation type sheet 1. The sheet 1 is scanned with laser light 3 through a beam expander 4, ND filter 5, concave lens 7, polariscope 8, ftheta lens 10, and reflecting mirror 9. Accelerated phosphorescent light is made incident to a photodetector 13 through a conductive sheet 12. The output signal of the photodetector 13 is inputted in a computer 23 through an amplifier 21 and AD converter 22 and displayed by means of a CRT25. Area designation is performed to the computer 23 through a keyboard 24. The output of the AD converter 22 is sent to a control circuit 26 and the optimum reading gain set value (a), recorded scale factor set value (b), and reproducing picture processing conditions (c) are respectively sent to an amplifier 27, AD converter 28, and signal processing circuit 29 for final reading, and then, reproduced pictures having excellent diagnostic characteristics are obtained from detecting signals of final reading.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention involves irradiating excitation light onto a stimulable phosphor sheet on which radiographic image information is accumulated and recorded, thereby emitting radiation from the stimulable phosphor sheet. Regarding the radiation image information reading device that photoelectrically detects the stimulated luminescence light and reads the radiation image information, in particular, it is necessary to grasp the outline of the accumulated recorded information in advance, in advance of the actual reading for visible image reproduction. The present invention relates to a radiation image information reading device that performs pre-reading for reading information.

(Technical Background and Prior Art of the Invention) When a certain type of phosphor is irradiated with radiation (X-rays, α-rays, β-rays, γ-rays, electron beams, ultraviolet rays, etc.), a portion of this radiation energy is emitted by fluorescent light. It is known that when this phosphor is accumulated in the body and is irradiated with excitation light such as visible light, the phosphor exhibits stimulated luminescence depending on the accumulated energy; The fluorophore is called a storage fluorophore.

Using this stimulable phosphor, radiation image information of a subject such as a human body is temporarily recorded on a stimulable phosphor sheet, and this stimulable phosphor sheet is scanned with excitation light such as a laser beam. The generated stimulated luminescence light is read photoelectrically to obtain an image signal, and based on this image signal, the radiation of the subject is transmitted to a recording material such as a photographic photosensitive material or a display device such as a CRT. The applicant has already proposed a radiation image information recording and reproducing system that outputs images as visible images.

(JP-A-55-12429, JP-A-56-11395, etc.) This system has practical advantages in that it can record images over an extremely wide radiation exposure range compared to conventional radiographic systems using silver halide photography. It has advantages. In other words, in a stimulable phosphor, it is recognized that the amount of emitted light that is stimulated and emitted by excitation after accumulation is proportional to the radiation exposure ω over a very wide range. Therefore, depending on various imaging conditions, the radiation exposure Even if the amount fluctuates considerably, the amount of stimulated luminescent light emitted from the stimulable phosphor sheet can be read by the photoelectric conversion means by setting the reading gain to an appropriate value and converted into an electrical signal = 3-. However, by using this electrical signal to output the radiographic image as a visible image to a recording material such as a photographic light-sensitive material or a display device such as a CRT, a radiographic image that is not affected by fluctuations in radiation exposure can be obtained.

Furthermore, according to this system, radiation image information accumulated and recorded on a stimulable phosphor sheet is converted into an electrical signal, then subjected to appropriate signal processing, and this electrical signal is used to produce recording materials such as photographic light-sensitive materials, CRTs, etc. By outputting a radiographic image as a visible image on a display device such as the above, it is possible to obtain a very large effect that a radiographic image with excellent observation and interpretation suitability (diagnosis suitability) can be obtained.

In a radiation imaging system using a stimulable phosphor sheet, the read gain can be set to an appropriate value to photoelectrically convert the stimulated luminescence light and output it as a pA image. , fluctuations in radiation exposure due to fluctuations in the tube voltage or MAS value of the radiation source, fluctuations in the sensitivity of the stimulable phosphor sheet, fluctuations in the sensitivity of the photodetector, changes in exposure due to subject conditions, or variations in radiation depending on the subject. Obtain radiographic images that are not affected by variations in these factors, even if the energy stored in the stimulable phosphor differs due to factors such as differences in transmittance, or even if the amount of radiation exposure is reduced. becomes possible.

However, in order to eliminate the effects of fluctuations in imaging conditions or to obtain radiographic images that are suitable for observation and interpretation, it is necessary to change the recording state of the radiographic image information accumulated and recorded on the stimulable phosphor sheet, or the chest, Recording patterns (hereinafter collectively referred to as "accumulated recorded information") determined by the part of the subject such as the abdomen, decoy imaging methods such as plain imaging and contrast imaging, etc., are used for observation and interpretation. The appearance of the visual image is determined in advance, and the reading gain is adjusted to an appropriate value based on the accumulated recorded information, and the recording scale is adjusted so that the resolution is optimized according to the contrast of the recorded pattern. When the factors are determined and further image processing such as gradation processing is performed on the read image signal, it is necessary to optimally set the image processing conditions.

As a method of grasping the accumulated record information of radiation images before outputting visible images, Japanese Patent Application Laid-Open No. 58-67240
The method disclosed in No. This method uses excitation light at a lower level than the irradiation level excitation light during the reading operation (hereinafter referred to as "single reading") to obtain a visible image for observation and interpretation, and preliminarily prepares the image before the main reading. A reading operation (hereinafter referred to as "pre-reading") for grasping the accumulated record information of radiation images accumulated and recorded in the stimulable phosphor sheet I~
That's what it means. ) to grasp the outline of the accumulated radiographic image records, and when performing the actual reading, appropriately adjust the reading gain, determine the recording scale factor, or determine the image processing conditions based on this pre-read information. be. This method includes, for example, an excitation light irradiation means for irradiating excitation light onto a stimulable phosphor sheet on which radiographic image information is stored and recorded, as shown in Japanese Patent Laid-open Nos. 58-67242@ and 58-67243; A reading system comprising a means for transporting the stimulable phosphor sheet, and a photodetection means for photoelectrically reading the stimulated luminescent light carrying radiation image information emitted from the stimulable phosphor sheet by irradiation with excitation light; A pre-reading reading system is provided which performs pre-reading using excitation light with an energy lower than the energy of the excitation light used in similar book reading, prior to reading the visible image of image information (q), and by the above-mentioned pre-reading. This can be carried out by a radiation image information reading apparatus including a control means for setting the reading conditions and/or image processing conditions for the main reading based on the accumulated record information of the sheet.

Note that the fact that the excitation light used for pre-reading is at a lower level than the excitation light used for main reading means that the effective amount of excitation light that the stimulable phosphor sheet receives per unit area during pre-reading is It means that the energy is less than that when reading a book. Methods for making the pre-reading excitation light lower than the main reading excitation light include reducing the output of the excitation light source such as a laser light source, and using an ND filter, AOM, etc. in the optical path of the excitation light emitted from the light source. Attenuation method, light source for pre-reading and light for main reading =
7- There is a method of providing a separate source and making the output of the former smaller than the output of the latter.Furthermore, there are methods of increasing the beam diameter of the excitation light and increasing the scanning speed of the excitation light. method, and a method of increasing the transfer speed of the stimulable phosphor sheet 1.

According to the above method, the recording state and recording pattern of radiation image information stored and recorded on the stimulable phosphor sheet can be grasped in advance before actual reading.'C1 Reading with an exceptionally wide dynamic range Even without using a system, it is possible to appropriately adjust the reading gain based on this recorded information, determine the recording scale factor, and apply signal processing to the electrical signal after reading according to this recording pattern. , it becomes possible to obtain radiographic images with excellent suitability for observation and interpretation.

On the other hand, as shown in Japanese Patent Application No. 58-197193, for example, in the above-mentioned radiation image information recording and reproducing system, the radiation irradiation field is narrowed down to a desired size when recording radiation image information (radiation irradiation field). It is also proposed that In other words, the above-mentioned stimulable phosphor sheet is generally formed into several types of standard sizes, but if a stimulable phosphor sheet is used, it can be formed into a large stimulable phosphor sheet, such as one that can record radiographic images of the chest. The phosphor sheet is covered with palms and palms [
It also often happens that radiological images of extremely small lesions are recorded. If you record on an unnecessarily large sheet like this, when reading the image, large margins and surrounding areas other than the part you actually want to reproduce and observe will be read, making the image reading time unnecessarily long. .

In addition, when recording small lesions on the human body using radioactive rays, in addition to the above-mentioned problem of prolonging the image reading time, it is necessary to avoid the health problems of directing radiation to unnecessary tissues. The above problem also arises. Therefore, by narrowing down the radiation irradiation field according to the size of the subject, the above-mentioned problem can be solved.

However, when the radiation irradiation field is narrowed down as described above, scattered radiation is irradiated around the irradiation field of the stimulable phosphor sheet, so the reading conditions or image processing conditions based on the above-mentioned pre-reading may be inappropriately set. A problem arises in which the data is lost. That is, in the conventional apparatus, the pre-reading system reads images of the entire area of the stimulable phosphor sheets 1 to 1, and all of the read information is input to the control means. The reading information regarding the portion irradiated with radiation is also determined by the control means in determining the reading conditions or image processing conditions! They end up being taken advantage of. For example, if the image signal histogram of the image within the narrowed radiation irradiation field is as shown by the solid line in Figure 6, cumulative fluorescence will occur, including the area irradiated with the scattered radiation outside the irradiation field. When the image signal histogram is created for the entire area of the body sheet, the histogram will be as shown by the broken line in FIG. In other words, because of the outdoor radiation irradiation area, the irradiation field self-portrait is determined to have more low-density areas than it actually is. If the reading regulations or image processing conditions are determined based on the histogram that does not correctly reflect the accumulated record information of the radiation field white image in this way, the radiographic image reproduced according to those regulations f1 will not be suitable for observation and interpretation ( Those with poor diagnostic performance will be criticized.

(Purpose of the Invention) The present invention has been made in view of the above circumstances, and even when the radiation field is narrowed down, the reading line fl or image related to the image within the radiation field. It is an object of the present invention to provide a radiation image information reading device d that can appropriately set processing conditions.

(Structure of the Invention) The radiation image information reading device of the present invention is based on the above-described main reading reading system, pre-reading reading system, and information stored and recorded in the stimulable phosphor sheet 1 by the pre-reading. In a radiation image information reading device comprising a control means for setting reading conditions and/or image processing conditions for main reading, a monitor means for displaying an hIi ray image of the subject based on the image signal obtained by the prefetch reading system; An area specifying means for specifying an area within the radiation image displayed on the monitor means; The apparatus is characterized in that it is further provided with a signal selection means for inputting accumulated record information about the control means to the control means.

The above-mentioned pre-reading reading system may be provided separately from the main reading reading system as shown in JP-A-58-67242, or an excitation light irradiation means as shown in JP-A-58-67243, for example. , the means for transporting the stimulable phosphor sheet and the light detection means are shared with the main reading system, and an adjustment means is provided for setting the energy of the excitation light during pre-reading to be smaller than the energy of the excitation light during main reading. It may also be configured as follows.

(Function) In the radiation image information reading device having the above configuration, when reproducing a radiation image in which the radiation irradiation field has been narrowed down as described above, an area within the radiation irradiation field is specified by the area specifying means.
If so, the reading conditions and/or image processing conditions are determined based on the accumulated record information only within this irradiation field. Therefore, these conditions are appropriately set for the radiation in-field image.

(Embodiments) Hereinafter, embodiments of the present invention will be explained in detail with reference to the drawings.
Ru.

FIG. 1 shows a radiation image information reading device according to a first embodiment of the present invention. A stimulable phosphor sheet 1, which has been irradiated with radiation such as X-rays through a subject such as a human body, and has accumulated and recorded radiation image information regarding the subject, is transferred to a reading device shown in FIG. Normally, in this reading device, the transferred stimulable phosphor sheet 1 is first read in advance. A laser beam 3 emitted from a laser light source 2 passes through a beam expander 4, and its beam diameter is precisely adjusted. After that, this laser beam 3 is N
The beam passes through a D filter 5, a prism 6, and a concave lens 7, where its intensity is reduced and the beam diameter is expanded. The laser beam 3 is deflected by an optical deflector 8 such as a galvano mirror, enters the stimulable phosphor sheet 1 via a plane reflecting mirror 9, and linearly scans the sheet. An fθ lens 10 is disposed between the optical deflector 8 and the plane reflecting mirror 9, and the beam diameter of the laser beam 3 scanning the phosphor sheet 1 is made uniform. Here, the laser light source 2 is selected so that the wavelength range of the laser light 3 does not overlap with the wavelength range of the stimulated luminescence light from the stimulable phosphor sheets 1-1.

On the other hand, the stimulable phosphor sheet 1 is transported in the direction of arrow A by a transport means 11 to the sheet 1 such as an endless belt, and is sub-scanned, and as a result, the laser beam 3 is emitted over the entire surface of the phosphor sheets 1 to 1. is irradiated.

The part of the stimulable phosphor sheet 1-1 that is irradiated with the laser beam 3 emits stimulated luminescent light in an amount corresponding to the accumulated and recorded radiation energy, and this emitted light is transmitted to the light guiding sheet 12.
incident on . The light guide sheet 12 has a linear incident surface and is arranged to face the scanning line on the stimulable phosphor seamil 1, and an annular exit surface.
It is in close contact with the light receiving surface of the photodetector 13 such as a circle. This light guide sheet 12 is formed 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. Then, the stimulated luminescent light emitted from the stimulable phosphor sheet 1 is guided through the light guide sheet 12,
The light is emitted from the exit surface and received by the photodetector 13.

The preferred shape, material, etc. of the light-guiding sheet 12 are disclosed in Japanese Patent Application Laid-open Nos. 55-87970 and 56-11397.

A filter (not shown) is attached to the light-receiving surface of the photodetector 13, which transmits only light in the wavelength range of stimulated luminescence light and cuts light in the wavelength range of laser light 3 as excitation light. Ori,
It is designed to detect only stimulated luminescence light. The output of the photodetector 13 is sent to the look-ahead amplifier 2 via a switch 20.
1, amplified by the look-ahead amplifier 21, and A/
It is digitized by the D converter 22 and sent to the computer 2.
3rd place is broken.

Note that the read gain of the preread amplifier 21 is a constant value a.
', and the recording scale factor of the A/D converter 22 is also fixed at a constant value b'.

The computer 23 constitutes a part of the area specifying means and the signal selecting means, and is operated by the keyboard 24).
Based on the output signal of the A/D converter 22 and the output of the photodetector 13, an image is displayed on the CRT 25 as a monitor means. As mentioned above, the output of the photodetector 13 is accumulated t! 1 fluorescent sheet 1
The radiation image of the subject recorded on the stimulable phosphor sheet 1 is displayed on the CRT 25. For example, when the radiation that has passed through the subject is irradiated over the entire area of the stimulable phosphor sheet 1-1 and radiation image information is recorded (radiation removal), this radiation image is as shown in Figure 2, for example. On the other hand, if the radiation irradiation field is narrowed down and RLI ray picture information is recorded on the stimulable phosphor sheet 1, for example, as shown in FIGS.
It will look like the one shown in the figure. In FIGS. 3 and 4, a region mc around the radiation irradiation field B is an area irradiated with scattered radiation. Operator is C as above
Observing the monitor image displayed on R-25, you can see that the radiation image is as shown in Figure 2, that is, it is formed by irradiating the entire area of the stimulable phosphor sheets 1 to 12 with radiation. In some cases, the keyboard 24 is operated to instruct the recomputer 23 to deselect the signal.

As a result, the computer 23 converts the A/D converter 2
All the signals output from the main reading control circuit 26 are sent to the main reading control circuit 26.

On the other hand, the monitor images displayed on the CRT25 are shown in Figures 3 and 4.
If the radiation field is narrowed and formed as shown in the figure, surgery! The node instructs the computer 23 to select a signal by operating the keyboard 24, and at the same time, by operating the cursor on the keyboard 24, the node designates the radiation irradiation field B to be displayed on the monitor image. For example, if the monitor image is as shown in Figure 3, four points S1, S2, s3, and S4 may be specified, and if the monitor image is as shown in Figure 4, it is generally done. In such a case, it is sufficient to specify the position of the center 0 and the radius r.

In addition to the cursor operation on the keyboard 24, this area specification can also be made using a light pen or the like, for example.

The control circuit 26 is responsible for the output of the A/D converter 22 which is input via the computer 23 as described in Section 2 (as described above, it is responsible for the accumulated recorded information of the stimulable phosphor sheet 1).
The optimum reading gain setting value a, recording scale factor setting value b1 and reproduction image processing condition setting value C are determined according to the following.

Note that the operations of the excitation light irradiation means such as the laser light source 2 and the optical deflector 8, the light detection means such as the photodetector 13 and the switch 14, and the rice sheet transport means 11 are not shown in the figure, but are performed using known operation controls. It is controlled by the device.

When the pre-reading is completed as described in 11 below, the sheet transport means 11 is reversed, the stimulable phosphor sheets i to 1 are returned to the reading start position 17, and reading of the sample is started. In the main reading, the laser light 3 is emitted from the laser light source 2 in the same way as in the pre-reading, but in the case of the main reading, the ND filter 5, the prism 6, and the concave lens 7 are moved in the direction of the arrow 18 so as to be out of the optical path. Therefore, the energy level of the laser beam 3 (excitation light) is higher than the energy level of the excitation light during the pre-reading. Here, one energy of excitation light refers to the effective energy of excitation light that the stimulable phosphor sheet 1 receives per unit area.

Note that the closer the ratio of the excitation light energy in the pre-reading to that in the main reading is to 1, the less the radiation energy loss remaining and accumulated in the phosphor sheet 1 during the main reading will be.
It has been found that if this ratio is less than 1, a radiation image suitable for observation and interpretation can be obtained by appropriately adjusting the reading gain value. However, in order to obtain radiographic images with excellent observation and interpretation aptitude, it is desirable that the energy ratio of the excitation light for pre-reading and main reading be as small as possible, less than 50%, preferably less than 10%, and preferably less than 3%. is desirable. The lower limit of this ratio is determined by the accuracy of the pre-read stimulated luminescence light detection system.

After the beam diameter of this laser beam 3 is precisely adjusted by a beam expander 4, it is directed to an optical deflector 8, and is directed onto a sheet 1 of stimulable fluorescent light via a plane reflector 9. The incident light is deflected one-dimensionally. On the other hand, stimulable phosphor sheet 1
is transported at a constant speed in the direction of arrow A to perform sub-scanning, and as a result, the laser beam 3 is applied to the entire surface of the stimulable phosphor sheet 1.
is irradiated.

The stimulable phosphor sheets 1 to 1 that have been irradiated with the laser beam 3 emit stimulated luminescent light at a level corresponding to the accumulated and recorded radiographic image information, and this stimulated luminescent light is In exactly the same manner as in the case, the light enters the light guide sheet 12, is transmitted through the interior thereof, and is detected by the photodetector 13. Photodetector 1
The output of No. 3 is input to the main reading amplifier 27 via the switch 20, and is amplified into an electrical signal at an appropriate level by this main reading amplifier 27 whose sensitivity is set based on the reading gain setting value a. The amplified electrical signal is input to the A/D converter 28, converted to a digital signal with a scale factor (latitude) suitable for the signal fluctuation width based on the recording scale factor setting value, and then sent to the signal processing circuit 29. is input. This signal processing circuit 29 performs signal processing (image processing) on the above-mentioned digital signal based on the reproduced image processing condition setting value C to obtain a radiation image excellent in suitability for observation and interpretation. The generated digital signal is transmitted to an image reproduction device 19 that outputs the radiographic image as a visible image. The signal processing performed in the signal processing circuit 29 is described in Japanese Patent Application Laid-open No. 55-87970, No. 56-11038, and No. 56
-75137, 56-75139, 56-75
Frequency processing disclosed in JP-A No. 141, No. 56-104645, etc., JP-A-55-116339, JP-A No. 55-1
Examples include gradation processing disclosed in No. 16340 and No. 55-88740.

The reproducing device 19 reproduces the radiation image based on the image signal sent from the signal processing circuit 29. Reproduction methods include recording by scanning a photosensitive material with a laser beam, displaying it electronically on a CRT, etc., recording the radiation image displayed on a CRT, etc. on a video printer, etc., and using heat rays. Various recording methods can be used, such as recording on a thermosensitive recorder.

In this radiation image information reading device, as mentioned above, the accumulated recorded information of the stimulable phosphor sheets 1 to 1 is grasped in advance by pre-reading, and the R-type read gain setting value a and the recording scale factor are determined based on this information. Since the image is read according to the set value and the image processing is performed using the appropriate reproduction image processing condition setting (Illc), the radiographic image reproduced by the image reproduction device 19 is subject to observation interpretation overconfidence (diagnostic performance ) will be excellent.

In addition, in this radiation image information reading device, when reading radiation image information recorded with the radiation irradiation field narrowed to the stimulable phosphor sheets 1 to 1, the reading gain setting value 8
In order to determine the recording scale factor setting value b1 reproduction image processing condition setting value C, only the accumulated record information within the radiation irradiation field can be used. It becomes possible to correctly grasp the image and appropriately set each of the above conditions a, b, and c.

In addition, the energy level of laser beam 3 in pre-reading is
As an adjustment method to make it lower than that in the main reading,
In addition to the ND filter 5 for attenuating the laser beam 3 and the concave lens 7 for enlarging the beam diameter, there is also a light source switching means for selectively switching between a main reading laser light source and a pre-reading laser light source with a lower output. Alternatively, means for increasing the main scanning speed of the laser beam 3 by changing the period of the optical deflector 8, or means for increasing the sub-scanning speed by changing the sheet transporting speed of the sheet transporting means 11 may be used.

Next, another embodiment of the present invention in which a main reading reading system and a pre-reading reading system are provided separately will be described. FIG. 5 shows a radiation image information reading and reproducing system equipped with a second embodiment of the present invention. This radiation image information reading and reproducing system basically includes a pre-reading reading section 30, a main reading reading section 40, and an image reproducing section 50. A laser beam 202 emitted from a pre-reading laser light source 201 in the pre-reading reading section 30 is passed through a filter 203 that cuts the wavelength range of stimulated luminescence light emitted from the stimulable phosphor sheet 103 by excitation of the laser beam 202. After passing through the optical deflector 204 such as a galvanometer mirror,
The light is linearly deflected by the light beam and applied onto the stimulable phosphor sheet 103 via the plane reflecting mirror 205. Here, the 1F' light source 201 is selected so that the wavelength range of the laser light 202 as excitation light does not overlap with the wavelength range of the stimulated luminescence light emitted by the stimulable phosphor sheet 103. On the other hand, the phosphor sheet 103 is transferred to the sheet 1 by means 21 such as transfer rollers.
0 in the direction of the arrow 206, sub-scanning is performed, and as a result, the entire surface of the phosphor sheets 1 to 103 is irradiated with the laser light 202. Here, the laser light source 20
1, the beam diameter of the laser beam 202, the scanning speed of the laser beam 202, and the transport speed of the stimulable phosphor sheet 103. It is selected so that it is smaller than that of the main reading performed in section 40.

When the laser beam 202 is irradiated as described above, the stimulable phosphor sheet h103 emits stimulated luminescent light with an amount corresponding to the radiation energy stored therein, and this luminescent light is used as a pre-reading light guide. incident on the sexual sheet 2°1. The stimulated luminescence light is guided through the light guide sheet 2.7, exits from the exit surface, and is received by a photodetector 208 such as a photomultiplier. The light-receiving surface of the photodetector 208 transmits only light in the wavelength range of stimulated luminescence light, and cuts light in the wavelength range of excitation light.
A covering filter is attached so that only stimulated luminescence can be detected. The detected stimulated luminescence light is converted into an electrical signal carrying accumulated recording information, and is sent to an amplifier 20.
9. The signal output from the amplifier 209 is digitized by the A/D converter 211 and input to the main reading control circuit 314 of the main reading reading unit 40 via the :1 amplifier 23. This main reading control circuit 314 determines a reading gain setting value a, a recording scale factor setting value b, and a reproduction image processing condition setting value C based on the obtained accumulated recording information. The computer 23 and the keyboard 24 and CRT 25 connected thereto are similar to those in the first embodiment described above.

The stimulable phosphor sheet 103 that has undergone pre-reading as described above is transferred to the main reading reading section 40.

The laser light 302 emitted from the main reading laser light source 3°1 in the main reading reading section '40 is
A filter 30 that cuts the wavelength range of stimulated luminescent light emitted from the stimulable phosphor sheet 103 by the excitation of the stimulable phosphor sheet 103
3, the beam diameter is strictly adjusted by a beam expander 304, linearly deflected by a light deflector 305 such as a galvanometer mirror, and then passed through a plane reflector 306 to a stimulable phosphor. It is incident on sea 1-103. An fθ lens 307 is disposed between the optical deflector 305 and the plane anti-tfJi 1306, so that the beam diameter of the laser beam 302 scanning the stimulable phosphor sheet 103 is made uniform. On the other hand, stimulable phosphor sheet 1
The stimulable phosphor sheet h103 is transferred in the direction of an arrow 308 by a transfer means 320 to a sheet h103 such as a transfer roller for sub-scanning, and as a result, the entire surface of the stimulable phosphor sheet h103 is irradiated with laser light. When this J, sea urchin laser beam 302 is irradiated, the stimulable phosphor sheet 103 emits stimulated luminescent light with an amount of light corresponding to the radiation energy stored and recorded on it, and this luminescent light is used as a light guide for book reading. The light is incident on the sheet 309. 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 a photodetector 310 such as a photomultiplier.

A filter is attached to the light receiving surface of the photodetector 310 that selectively transmits only the wavelength range of the stimulated luminescence light.
10 detects only stimulated luminescence light.

The output of the photodetector 310 that photoelectrically detects the stimulated luminescence light without showing the radiation image recorded on the stimulable phosphor sheet 103 is determined based on the read gain setting value a determined by the control circuit 314. The electric signal is amplified to an appropriate level by an amplifier 311 with a set reading gain. The amplified electrical signal is input to the A/D converter 312, and based on the recording scale factor setting value, it is converted into a digital signal with a recording scale factor suitable for the signal fluctuation width, and then input to the signal processing circuit 313). be done. The digital signal is subjected to signal processing (image processing) in the signal processing circuit 313 based on the reproduction image processing condition setting value C so as to obtain a radiation image with excellent observation and interpretation suitability, and is output.

The image signal output from the signal processing circuit 313 is input to the optical modulator 401 of the image reproduction section 50. In the image reproducing unit 50, the SIA light 403 from the recording laser light source 402 is modulated by the optical modulator 401 based on the image signal input from the signal processing circuit 313, and is deflected by the scanning mirror 404. Photosensitive materials such as photographic film F! + Scan over 405.

The photosensitive material 1.11405 is then transported in a direction perpendicular to the scanning direction (arrow 406) in synchronization with the scanning, and a radiation image based on the image signal is output onto the photosensitive grain A405. As a method for recording a radiographic image, in addition to this method, the various recording methods described above can be used.

Also in the second embodiment device described above, the stimulable phosphor sheet 103 read by the pre-reading reading section 30
By optimally setting the reading gain setting value a1, the recording scale factor setting value b1, and the reproduction image processing condition setting value C based on the accumulated recorded information, it is possible to obtain a reproduction radiation image excellent in suitability for observation and interpretation. In addition, when reading radiation image information recorded with the radiation irradiation field narrowed down, the computer 28, computer 23, keyboard 24, and CR plate 25 are used to read out the scattered information in the irradiation field, as in the first embodiment. Each of the above conditions a1b, excluding the influence of radiation,
It becomes possible to appropriately set c.

[In the two embodiments described above, both the reading conditions (reading gain and recording scale factor) and image processing conditions are set based on pre-reading, but the present invention is of course The present invention can be similarly applied to a radiation image information reading apparatus that sets only reading conditions based on pre-reading, or a radiation image information reading apparatus that sets only image processing conditions based on pre-reading.

Further, according to the radiation image information reading device of the present invention, as described above, the read image signal of the area outside the radiation irradiation area is involved in determining the reading conditions or image processing conditions, and these conditions become inappropriate. In addition, when reading a radiation image formed by irradiating the entire area of a stimulable phosphor sheet with radiation, for example, it is possible to use only a certain area of the radiation image for diagnosis and use other areas. If you are not interested in this area, specify a part of the specific area using the area specifying means as J, and set the reading conditions so that the observation bladder image suitability 1!1 of this specified area is particularly excellent in the reconstructed radiographic image. (1
j3 J, bi/, J: It is also possible to override the image processing regulations.

(Effects of the Invention) As explained in μ2 in L.S.1 Revision, if the H-secant image information reading device of the present invention is used, it is possible to perform pre-reading and improve the diagnostic suitability of reproduced radiographic images. Furthermore, it is possible to prevent the reading conditions or image processing conditions from becoming inappropriate due to unnecessary areas such as outdoor areas irradiated with radiation radiation, making it possible to obtain urban hII radiation images with particularly excellent diagnostic suitability. It becomes possible.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of the first embodiment of the apparatus of the present invention; Figs. 2, 3 and 4 are schematic diagrams showing examples of monitor images obtained with the apparatus of the present invention; and Fig. 5 is a schematic diagram of the first embodiment of the apparatus of the present invention. Schematic diagram showing an embodiment. FIG. 6 is a graph showing an example of Hiss 1 to Duram of a read image signal according to the present invention. 1.103...Storage phosphor sheet 2...Laser light source 3...Laser light 4...Beam expander 5...Nl) Filter 6...Prism 7...
・Concave lens 8... Light deflector 11.210
．． 320...Sheet transport means 13...Photodetector
19... Image playback device 21.27.209.31
1...Amplifier 22.28.211.312...A/
D converter 23...Computer 24...Keyboard 25...CRT 26.314...
Main reading control circuit 29.313...Signal processing circuit 30...Reading section for pre-reading 40...Reading section for main reading 50...Image reproduction section 201...Laser light source for pre-reading 202...Laser for pre-reading Light 204... Light deflector for pre-reading 208... Photodetector for pre-reading 220... Pre-reading control circuit 301... Laser light source for main reading 302... Laser light for main reading 305... Light deflection for main reading Device 310... Photodetector for main reading a... Reading gain setting value b... Recording scale factor setting value C... Playback image processing condition setting value Fig. 2 Fig. 4 Fig. 3 (:l person→tsu

Claims (1)

[Claims] excitation light irradiation means for irradiating excitation light onto a stimulable phosphor sheet on which radiation image information of a subject is accumulated and recorded; means for transporting the stimulable phosphor sheet; A main reading reading system consisting of a photodetecting means for photoelectrically reading the stimulated luminescence light carrying the radiation image information emitted from the sheet, and a main reading system used in the main reading prior to the main reading to obtain a visible image of the radiation image information. a pre-read reading system that performs pre-reading using excitation light with an energy lower than that of the excitation light, and reading conditions and/or image processing conditions for the main reading based on the accumulated recorded information of the sheet obtained by the pre-reading. A radiation image information reading device comprising: a control means for setting a radiation image information reading apparatus, a monitor means for displaying a radiation image of the subject based on an image signal obtained by the prefetch reading system; an area specifying means for specifying an area, and accumulated record information obtained by the pre-reading;
A radiographic image information reading apparatus comprising: signal selection means for inputting accumulated record information only for the area designated by the area designation means to the control means.