JP4057226B2 - Radiation image information reader - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention irradiates a stimulable phosphor sheet on which radiographic image information is accumulated and recorded with excitation light, and photoelectrically reads the photostimulated luminescence emitted from the sheet at that time, thereby indicating the radiographic image. In particular, the present invention relates to a radiation image information reading apparatus that irradiates a stimulable phosphor sheet with excitation light in a linear shape and detects stimulated emission light by a line sensor.
[0002]
[Prior art]
Conventionally, a part of this radiation energy is accumulated when irradiated with radiation, and then, when irradiated with excitation light such as visible light or laser light, a stimulable phosphor (stimulated phosphor) that exhibits stimulated luminescence according to the accumulated radiation energy. Exhaustible phosphors) are known, and radiation image recording / reproducing systems using a stimulable phosphor sheet obtained by laminating this stimulable phosphor on a support have been widely put into practical use.
[0003]
This radiographic image recording / reproducing system accumulates and records radiographic image information of a subject on the stimulable phosphor sheet by irradiating the stimulable phosphor sheet with radiation that has passed through a subject such as a human body, and then a laser beam. The sheet is scanned two-dimensionally with excitation light such as that to generate stimulated emission light from the excitation light irradiated portion, and this stimulated emission light is read by a photoelectric reading means to generate an image signal indicating the radiographic image information. (See, for example, JP-A-55-12429, JP-A-55-116340, JP-A-56-104645, etc.).
[0004]
The image signal obtained by this system is subjected to image processing such as gradation processing and frequency processing suitable for observation interpretation, and the radiological image carried by the system is reproduced and recorded on the film as a diagnostic visible image. Or used for display on a CRT image display device or the like. When the storable phosphor sheet after reading the radiation image information is irradiated with erasing light and the remaining energy is released, the sheet becomes a state where the radiation image information can be accumulated and recorded again, and repeatedly. Can be used.
[0005]
In addition, in order to increase the detection quantum efficiency in radiation image formation, that is, the radiation absorption rate, the stimulated emission efficiency, and the extraction efficiency of the stimulated emission light, the radiation absorbing function and the energy storing function in the conventional stimulable phosphor sheet A new type of stimulable phosphor sheet that has been separated has also been proposed (Japanese Patent Application No. 11-372978).
[0006]
This stimulable phosphor sheet is capable of storing energy by absorbing light in the ultraviolet to visible region, and is dedicated to storage that emits the energy as stimulated emission light when excited by light in the visible to infrared region. It contains a photostimulable phosphor layer.
[0007]
This new type of stimulable phosphor sheet is preferably in a form to which a radiation absorbing phosphor layer containing a phosphor that absorbs radiation and emits light in the ultraviolet to visible region is added. In this case, the energy of ultraviolet to visible light emitted from the radiation-absorbing phosphor layer when irradiated with radiation having image information (this corresponds to the radiation image information) Accumulated in the layer of the active phosphor. Then, when this stimulable phosphor sheet is scanned with excitation light, stimulated emission light indicating radiation image information is emitted from the layer of stimulable phosphor.
[0008]
Further, this new type of stimulable phosphor sheet may be formed without the above-described radiation absorbing phosphor layer. In this case, the stimulable phosphor sheet is used in combination with a phosphor screen having a radiation-absorbing phosphor layer containing a phosphor that absorbs radiation and emits light in the ultraviolet to visible region.
[0009]
That is, if the phosphor screen is irradiated with radiation while the phosphor screen is in close contact with the stimulable phosphor sheet, the energy of the ultraviolet to visible light emitted from the radiation absorbing phosphor layer of the phosphor screen (this) Corresponds to radiation image information), but is accumulated in the photostimulable phosphor layer of the stimulable phosphor sheet. Therefore, in this case as well, if the stimulable phosphor sheet is scanned with excitation light thereafter, stimulated emission light indicating radiation image information is emitted from the photostimulable phosphor layer.
[0010]
Here, in the radiological image information reading apparatus used in the radiographic image recording / reproducing system described above, a CCD or the like is used as a photoelectric reading means from the viewpoint of shortening the reading time of the photostimulated emission light, making the apparatus compact and reducing costs, It has been proposed to apply a line sensor comprising: (Japanese Patent Laid-Open Nos. 60-111568, 60-236354, 1-101540, etc.).
[0011]
Such a radiological image information reader is basically
Excitation light irradiation means for linearly irradiating excitation light on a part of the stimulable phosphor sheet in which the radiation image information is accumulated;
A line sensor in which a plurality of photoelectric conversion elements are arranged in parallel along the linear excitation light irradiation portion of the stimulable phosphor sheet;
One of the line sensor, the excitation light irradiation means, and the stimulable phosphor sheet is moved relative to the other in the direction (sub-scanning direction) intersecting the length direction (main scanning direction) of the excitation light irradiation portion. Sub-scanning means is provided.
[0012]
As described above, the excitation light irradiation means for linearly irradiating the stimulable phosphor sheet with excitation light may be one that emits so-called fan beam-like excitation light, or a thin one. The beam may be deflected so as to be scanned linearly on the stimulable phosphor sheet.
[0013]
[Problems to be solved by the invention]
By the way, as described above, it is considered that one laser diode (semiconductor laser) is applied as the excitation light irradiation means for emitting fan beam-like excitation light from the viewpoint of downsizing and cost reduction of the apparatus. In that case, in order to ensure a large main scanning width, the laser beam emitted from the laser diode in a divergent light state is converged in the sub-scanning direction into a linear shape, while in the main scanning direction intersecting with the direction. An expanding lens optical system is also applied.
[0014]
However, in such a conventional configuration, if a large main scanning width is to be ensured, the distance from the laser diode to the stimulable phosphor sheet must be set considerably long, and thus the apparatus is sufficiently miniaturized. The problem of being difficult to do is recognized.
[0015]
In addition, the laser beam emitted from the laser diode has an intensity distribution called a Gaussian distribution in which the intensity is maximum at the center of the beam and decreases as it goes to the periphery of the beam. In the conventional radiographic image information reading apparatus using one laser diode as the excitation light irradiation means, there is a problem that the excitation light intensity becomes extremely nonuniform in the main scanning direction.
[0016]
Therefore, an object of the present invention is to sufficiently reduce the size of a radiation image information reading apparatus using a laser diode as an excitation light source and to make the excitation light intensity distribution in the main scanning direction uniform.
[0017]
[Means for Solving the Problems]
As described above, the first radiation image information reading apparatus according to the present invention is as follows.
Excitation light irradiation means for linearly irradiating excitation light on a part of the stimulable phosphor sheet on which radiation image information is accumulated and recorded,
A line sensor in which a plurality of photoelectric conversion elements are arranged in parallel along the linear excitation light irradiation portion of the stimulable phosphor sheet;
Sub-scanning means for moving one of the line sensor, the excitation light irradiation means, and the stimulable phosphor sheet relative to the other in a direction intersecting the length direction of the excitation light irradiation portion. In the radiographic image information reading device,
The excitation light irradiating means is configured so that the laser beams as the excitation light emitted from each of the excitation light irradiation means are continuous with each other in the length direction of the excitation light irradiation portion, and the beam divergence direction perpendicular to the joint surface substantially coincides with the continuous direction of the beams. A plurality of laser diodes arranged in an orientation;
A cylindrical lens that condenses the laser beams emitted from these laser diodes only in a plane perpendicular to their continuous direction and converges them on the stimulable phosphor sheet, It is what.
[0019]
Furthermore, the second radiation image information reading apparatus according to the present invention is similar to the above,
Excitation light irradiation means for linearly irradiating excitation light on a part of the stimulable phosphor sheet on which radiation image information is accumulated and recorded,
A line sensor in which a plurality of photoelectric conversion elements are arranged in parallel along the linear excitation light irradiation portion of the stimulable phosphor sheet;
Sub-scanning means for moving one of the line sensor, the excitation light irradiation means, and the stimulable phosphor sheet relative to the other in a direction intersecting the length direction of the excitation light irradiation portion. In the radiographic image information reading device,
The arrangement state of the plurality of laser diodes is made the same as in the first radiation image information reading device,
A cylindrical lens similar to that in the first radiological image information reader is provided, and
An optical element is provided between the cylindrical lens and the plurality of laser diodes to scatter laser beams emitted from the laser diodes .
[0020]
In each radiographic image information reading apparatus according to the present invention described above, the plurality of laser diodes may be arranged such that laser beams emitted from those adjacent to each other are overlapped with each other. desirable.
[0021]
Further, the stimulable phosphor sheet to be read by the radiation image information reading apparatus according to the present invention may be a stimulable phosphor sheet having both functions of radiation absorption and energy storage as described above, or Further, it may have a stimulable phosphor layer dedicated to energy storage.
[0022]
The latter type of stimulable phosphor sheet may be one in which the aforementioned radiation-absorbing phosphor layer is formed in addition to the stimulable phosphor layer dedicated to energy storage, or It may be used in combination with a fluorescent screen having a similar radiation-absorbing phosphor layer without having such a radiation-absorbing phosphor layer.
[0023]
【The invention's effect】
In the first radiological image information reading apparatus according to the present invention, the plurality of laser diodes constituting the excitation light irradiation means are configured so that the laser beams as the excitation light emitted from each of the laser diodes are connected to each other in the length direction of the excitation light irradiation portion. Since they are arranged, a long excitation light irradiation portion as a whole, that is, a main scanning width is ensured by their series. Therefore, even when it is intended to ensure a large main scanning width, the distance between each laser diode and the stimulable phosphor sheet can be set to be relatively short, thereby realizing a sufficiently small apparatus. The
[0024]
In the first radiological image information reading apparatus, the plurality of laser diodes constituting the excitation light irradiating means are arranged in a direction in which the beam divergence direction perpendicular to the bonding surface substantially coincides with the continuous direction of the beams. Therefore, the effect of downsizing the apparatus can be obtained.
[0025]
That is, in a general laser diode, the beam divergence angle θ _{H in the} direction parallel to the junction surface is about 8 to 10 °, whereas the beam divergence angle θ _{V in the} direction perpendicular to the junction surface is generally 20 to 25 °. Therefore, if each laser diode is arranged in the above-mentioned direction, the storage phosphor is expanded in a state where the laser beam is expanded more than in the case where the laser diode is arranged in the other direction. Incident on the sheet. If so, even when a large main scanning width is to be secured, the distance between the laser diode and the stimulable phosphor sheet can be set shorter, thereby further reducing the size of the apparatus. .
[0026]
Furthermore, when a plurality of laser diodes are arranged in the above-described direction to increase the spread of the laser beam, compared to a case where the laser beam is spread in another direction, that is, when the spread of the laser beam is smaller than that. The beam intensity (excitation light intensity) on the main scanning line changes more slowly. Therefore, when it is considered to secure a common main scanning width in these two cases, the intensity of excitation light within the main scanning width is more uniform in the former, that is, in the present invention.
[0027]
On the other hand, also in the second radiation image information reading apparatus according to the present invention, the laser beams as the excitation light emitted from the plurality of laser diodes constituting the excitation light irradiation means are connected to each other in the length direction of the excitation light irradiation portion. Therefore, as in the first radiographic image information reading apparatus, a long excitation light irradiation portion as a whole, that is, a main scanning width is ensured by their series. Therefore, even when it is intended to ensure a large main scanning width, the distance between each laser diode and the stimulable phosphor sheet can be set to be relatively short, thereby realizing a sufficiently small apparatus. The
[0028]
Furthermore, in the second radiation image information reading apparatus according to the present invention, an optical element that scatters a laser beam respectively emitted from the laser diode is provided between the cylindrical lens and the plurality of laser diodes. These laser beams are incident on the stimulable phosphor sheet in a state where the laser beam is further expanded. Therefore, the distance between the laser diode and the stimulable phosphor sheet can be set shorter, and thereby the apparatus can be further miniaturized.
[0029]
That is, in the second radiation image information reading apparatus according to the present invention, the arrangement state of the plurality of laser diodes is made the same as in the first radiation image information reading apparatus, and the laser beam is scattered as described above. Since the optical element is provided, the effect of downsizing the apparatus by those configurations can be obtained synergistically.
[0030]
Further, in the second radiation image information reading apparatus, the laser beam emitted from each of the plurality of laser diodes is scattered by the optical element, so that the original intensity distribution (Gaussian distribution) of the laser beam is disturbed by the scattering. Is done. Therefore, the intensity of the laser beam incident on the stimulable phosphor sheet as excitation light is made more uniform than in the case where it does not receive the above-mentioned scattering.
[0031]
In each radiographic image information reading device according to the present invention, when a plurality of laser diodes are arranged so that laser beams emitted from those adjacent to each other have an overlapping part, The effect of making the excitation light intensity uniform in the main scanning direction can be obtained more remarkably.
[0032]
That is, the laser beam emitted from the laser diode has an intensity distribution referred to as the above-described Gaussian distribution, that is, an intensity distribution in which the maximum intensity is taken at the center of the beam and the intensity decreases toward the periphery of the beam. Therefore, if the two laser beams have overlapping portions as described above, the peripheral portion of the originally low beam overlaps the peripheral portion of the adjacent beam, and the beam intensity (excitation light intensity) of that portion is increased. Thus, the excitation light intensity in the main scanning direction is made uniform.
[0033]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of a radiographic image information reading apparatus according to a first embodiment of the present invention. FIGS. 2 and 3 are side views of a reading optical system portion of the radiographic image information reading apparatus, respectively. The shape and the front shape are shown.
[0034]
As shown in FIG. 1, this apparatus includes a laser diode array 11 that emits fan beam-shaped excitation light 10, a cylindrical lens 12 that collects the excitation light 10 only in the plane shown in FIG. A lens array 15 that condenses the photostimulated luminescence 14 emitted from the portion of the stimulable phosphor sheet 13 that has been irradiated linearly, and the photostimulated luminescence 14 that has passed through the lens array 15 is disposed in the optical path. Excitation light cut filter 16, CCD line sensor 17 that detects the stimulated emission light 14 that has passed through the excitation light cut filter 16, and stimulable phosphor sheet 13 in the direction of arrow Y, that is, excitation light irradiation on the sheet 13 It has an endless belt 18 as sub-scanning means that feeds at a constant speed in a direction orthogonal to the length direction of the portion (arrow X direction).
[0035]
Further, an amplifier 20 for amplifying the analog photodetection signal S output from the CCD line sensor 17, an A / D converter 21 for digitizing the amplified photodetection signal S, and the A / D converter 21 Are provided with an image processing device 22 that performs image processing on the digital image signal D output from the image processing device 23 and an image reproduction device 23 that receives the digital image signal D after image processing.
[0036]
As shown in FIG. 3, the laser diode array 11 includes a plurality of laser diodes 11a, 11b, 11c,... Having an oscillation wavelength of 660 nm arranged in a line as an example. The divergent excitation light 10a, 10b, 10c,... Emitted from each laser diode 11a, 11b, 11c,... The continuous excitation light 10 irradiates a part of the stimulable phosphor sheet 13 linearly.
[0037]
The plurality of laser diodes 11a, 11b, 11c,... Are arranged in directions in which the beam divergence direction perpendicular to the respective joint surfaces coincides with the continuous direction of the excitation lights 10a, 10b, 10c,. That excitation light 10a appearing in FIG. 3, 10b, the beam divergence angle of 10c ...... is a divergence angle theta _V in the direction perpendicular to the bonding surface.
[0038]
The CCD line sensor 17 has a large number of sensor chips (photoelectric conversion elements) 17a arranged in a line as shown in FIG. In this example, the light receiving width of the CCD line sensor 17 in the direction orthogonal to the sensor chip juxtaposition direction, that is, the width W of the sensor chip 17a is about 100 μm.
[0039]
In the CCD line sensor 17, sensor chips 17a are arranged in a direction along the length direction (arrow X direction) of the excitation light irradiation portion on the stimulable phosphor sheet 13 of FIG. The CCD line sensor 17 may be configured by connecting a plurality of line sensors in the length direction in order to correspond to the storage phosphor sheet 13 having a large width.
[0040]
On the other hand, the lens array 15 has, for example, a large number of gradient index lenses 15a, 15b, 15c, 15d,. It will be. Each gradient index lens 15a, 15b, 15c, 15d... Condenses the photostimulated light 14 emitted from the stimulable phosphor sheet 13 and guides it to the CCD line sensor 17 as shown in FIG. . This lens array 15 is arranged so that the gradient index lenses 15a, 15b, 15c, 15d,... Are aligned along the length direction (arrow X direction) of the excitation light irradiation portion on the stimulable phosphor sheet 13. Has been.
[0041]
The operation of the radiological image information reading apparatus having the above configuration will be described below. The storable phosphor sheet 13 stores and records radiographic image information of the subject, for example, by irradiating the radiation that has passed through the subject, and the sheet 13 is sent by the endless belt 18 at a constant speed in the arrow Y direction. At the same time, excitation light 10 emitted from the laser diode array 11 is irradiated linearly onto a part of the stimulable phosphor sheet 13.
[0042]
From the portion of the stimulable phosphor sheet 13 that has been irradiated with the excitation light 10, the amount of stimulated emission light 14 diverges according to the stored and recorded radiation image information. For example, the blue stimulated emission light 14 is collected by the lens array 15 and guided to the CCD line sensor 17, and is detected photoelectrically by the CCD line sensor 17. The excitation light 10 reflected by the stimulable phosphor sheet 13 and traveling toward the CCD line sensor 17 is cut by the excitation light cut filter 16.
[0043]
The CCD line sensor 17 outputs an analog light detection signal S corresponding to the light amount of the stimulated emission light 14 (that is, indicating the radiation image information). This light detection signal S is amplified by an amplifier 20 and then converted into a digital image signal D by an A / D converter 21.
[0044]
The digital image signal D is subjected to image processing such as gradation processing in the image processing device 22 and then sent to the image reproduction device 23 to reproduce the radiation image recorded on the stimulable phosphor sheet 13. Provided. The image reproducing device 23 may be a display means such as a CRT display device or a recording device that performs optical scanning recording on a photosensitive film.
[0045]
Next, the spread state and intensity distribution of the excitation light 10a, 10b, 10c... Will be described in detail with reference to FIG. In this embodiment, the laser diodes 11a, 11b, 11c,... Constituting the laser diode array 11 each have an output of 50 mW, and 30 of them are used as an example. In this way, a number of laser diodes 11a, 11b, 11c,... Are used, and excitation light 10a, 10b, 10c,. As long as the main scanning width is the same, naturally, the distance from the laser diode to the stimulable phosphor sheet 13 can be shortened compared to the case where only one laser diode is used. Thereby, the radiation image information reading apparatus can be sufficiently downsized.
[0046]
Further, in each of the laser diodes 11a, 11b, 11c..., The beam divergence angle θ _{V in the} direction perpendicular to the junction surface shown in FIG. 3 is 22 °, whereas the beam divergence angle θ _{H in the} direction parallel to the junction surface is shown. Is 10 °. In the present embodiment, thus 22 ° beam spread direction large beam divergence angle theta _V is obtained, the excitation light 10a, 10b, 10c ...... the succession direction matching the laser in the direction diode 11a, 11b, 11c ... .. Is arranged, the excitation light 10a, 10b, 10c,... Enters the stimulable phosphor sheet 13 in a state where the excitation light 10a, 10b, 10c,. If so, the distance between the laser diodes 11a, 11b, 11c,... And the stimulable phosphor sheet 13 can be set shorter, thereby further reducing the size of the apparatus.
[0047]
Further, when the laser diodes 11a, 11b, 11c,... Are arranged in the above-described direction and the spread of the excitation light 10a, 10b, 10c,. Compared with the case where the spread of the light beams 10a, 10b, 10c... Is smaller than that, the beam intensity (excitation light intensity) on the main scanning line changes more slowly. (1) and (2) in FIG. 6 show this by taking one laser diode 11a as an example.
[0048]
In FIG. 1A, when the laser diode 11a is arranged as in the present embodiment, in FIG. 2B, the laser diode 11a is arranged such that the beam divergence direction parallel to the joint surface is pumping light 10a, 10b, 10c. The intensity distribution in the main scanning direction X of the excitation light 10a on the stimulable phosphor sheet 13 when arranged in a direction that coincides with the continuous direction is shown. As shown here, in consideration of securing the same main scanning width Ls in each case, the intensity of the excitation light 10a within the main scanning width Ls is more uniform in the case of this embodiment. It is clear that
[0049]
As shown in FIG. 3, in this embodiment, the laser diodes 11a, 11b, 11c,... Are excited light emitted from those adjacent to each other (that is, for example, excitation light 10a, excitation light 10b, excitation light 10b). The excitation lights 10c... Are arranged so as to be continuous with each other. As is apparent from the intensity distribution of the excitation lights 10a, 10b, 10c... Shown in the same figure in the main scanning direction, if the two excitation lights overlap each other, the excitation light with originally low intensity is used. The peripheral portion of the beam overlaps with the adjacent peripheral portion of the excitation light, and the excitation light intensity at that portion is increased as indicated by the broken line in the figure, and the excitation light intensity in the main scanning direction is made uniform.
[0050]
When it is difficult to make the excitation light intensity in the main scanning direction completely uniform, the digital image signal D may be corrected so as to compensate for the nonuniformity of the excitation light intensity.
[0051]
Next, another embodiment of the present invention will be described with reference to FIG. FIG. 7 shows the front shape of the reading optical system of the radiation image information reading apparatus according to the second embodiment of the present invention. In FIG. 7, the same elements as those in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted unless necessary (the same applies hereinafter).
[0052]
Compared with the apparatus of the first embodiment described above, the radiation image information reading apparatus of the present embodiment is provided between the plurality of laser diodes 11a, 11b, 11c... Constituting the laser diode array 11 and the cylindrical lens 12, respectively. , Except that a diffraction grating 30 for scattering the excitation lights 10a, 10b, 10c,... Is provided. In this configuration, the excitation lights 10a, 10b, 10c,... Are each diffracted by the diffraction grating 30, and enter the cylindrical lens 12 in a state of being scattered to some extent.
[0053]
Therefore, in this example, the excitation lights 10a, 10b, 10c,... Enter the stimulable phosphor sheet 13 in a state where the excitation lights 10a, 10b, 10c,. Therefore, as compared with the first embodiment, if the main scanning width to be secured is the same, the distance between the laser diodes 11a, 11b, 11c,... And the stimulable phosphor sheet 13 can be set shorter. This can further reduce the size of the apparatus.
[0054]
Further, in the radiation image information reading apparatus of the second embodiment, since the excitation lights 10a, 10b, 10c,... Are diffracted and scattered by the diffraction grating 30, respectively, the excitation lights 10a, 10b, 10c,. The intensity distribution (Gaussian distribution) it has is disturbed by scattering. Therefore, the intensity of the excitation light 10a, 10b, 10c... Incident on the stimulable phosphor sheet 13 can be made more uniform than in the case where the excitation light 10a, 10b, 10c.
[0055]
Note in this second embodiment, like the first embodiment, and more beam spread direction large beam divergence angle theta _V is obtained, that matches the excitation light 10a, 10b, and succession direction 10c ...... orientation Are disposed in the laser diodes 11a, 11b, 11c, etc., but when the laser diodes 11a, 11b, 11c,. ... may be scattered, and the same effect as described above can be obtained.
[0056]
However, it is particularly preferable to arrange the laser diodes 11a, 11b, 11c,... In the above-mentioned direction and provide the diffraction grating 30 thereon, because the effects of both configurations can be obtained synergistically.
[0057]
In addition to the diffraction grating 30 described above, as an optical element that scatters the excitation light 10a, 10b, 10c..., A number of optical fibers are bundled as in the third embodiment shown in FIG. It is also possible to use a fiber bundle 40 arranged so that the excitation lights 10a, 10b, 10c,.
[0058]
Further, the stimulable phosphor sheet to be read by the radiation image information reading device of the present invention may be a stimulable phosphor sheet having both a radiation absorption function and an energy storage function, or both functions thereof. The stimulable phosphor sheet disclosed in the aforementioned Japanese Patent Application No. 11-372978 may be used in which a storage-only phosphor layer is provided for separation. In the case of using the stimulable phosphor sheet provided with this accumulation-dedicated phosphor layer, the detection quantum efficiency in radiation image formation, that is, the radiation absorption rate, the stimulated emission efficiency, the extraction efficiency of the stimulated emission light, and the like are increased overall. Therefore, the quality of the reproduced radiation image can be improved.
[0059]
Further, the stimulable phosphor sheet to be read has two stimulable phosphor layers having different radiation energy absorption characteristics, and two types of brightness carrying the radiographic image information recorded in each layer. It may be a stimulable phosphor sheet for radiation energy subtraction that can emit exhausted light separately from the front and back surfaces of the sheet.
[0060]
In that case, the radiation image information reading apparatus according to the present invention includes line sensors on both sides of the stimulable phosphor sheet, and displays image signals indicating image information read from both sides of the stimulable phosphor sheet. You may be provided with the reading means which carries out a subtraction process by making the pixel of a back surface correspond.
[0061]
In addition, the above-described stimulable phosphor sheet for radiation energy subtraction is so-called anisotropic, for example, having a structure that is subdivided into a number of microtufts by an excitation light reflecting partition member extending in the thickness direction of the sheet. Also, a stimulable phosphor sheet can be used.
[0062]
Furthermore, in the embodiment described above, the stimulable phosphor sheet 13 is conveyed at a constant speed by the endless belt 18 for the excitation light sub-scanning, but the means for sub-scanning the excitation light is not limited to this. In addition, for example, a roller that transports the stimulable phosphor sheet 13 with a roller, or a device that moves the excitation light irradiation means and the line sensor relative to the fixed stimulable phosphor sheet 13 can be applied. It is.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a radiation image information reading device according to a first embodiment of the present invention. FIG. 2 is a side view showing a reading optical system of the radiation image information reading device shown in FIG. FIG. 4 is a plan view of a line sensor used in the radiation image information reading apparatus. FIG. 5 is a front view of a lens array used in the radiation image information reading apparatus in FIG. 1) and side view (2)
FIG. 6 is an explanatory view for explaining the effect of the present invention. FIG. 7 is a front view showing a reading optical system of a radiation image information reading apparatus according to a second embodiment of the present invention. Front view showing reading optical system of radiation image information reading device according to form
10a, 10b, 10c Excitation light
11 Laser diode array
11a, 11b, 11c Laser diode
12 Cylindrical lens
13 Storage phosphor sheet
14 Excited light
15 Lens array
15a, 15b, 15c gradient index lens
16 Excitation light cut filter
17 CCD line sensor
17a CCD line sensor sensor chip
18 Endless belt
20 Amplifier
21 A / D converter
22 Image processing device
23 Image playback device
30 diffraction grating
40 fiber bundles

Claims (3)

Excitation light irradiation means for linearly irradiating excitation light on a part of the stimulable phosphor sheet on which radiation image information is accumulated and recorded,
A line sensor in which a plurality of photoelectric conversion elements are arranged in parallel along the linear excitation light irradiation portion of the stimulable phosphor sheet;
Sub-scanning means for moving one of the line sensor, the excitation light irradiation means, and the stimulable phosphor sheet relative to the other in a direction intersecting the length direction of the excitation light irradiation portion. In the radiographic image information reading device,
The excitation light irradiating means is configured so that the laser beams as the excitation light emitted from each of the excitation light irradiation means are continuous with each other in the length direction of the excitation light irradiation portion, and the beam divergence direction perpendicular to the joint surface substantially coincides with the continuous direction of the beams. A plurality of laser diodes arranged in an orientation;
A cylindrical lens that condenses the laser beams emitted from these laser diodes only in a plane perpendicular to their continuous direction and converges them on the stimulable phosphor sheet, Radiation image information reading device. Excitation light irradiation means for linearly irradiating excitation light on a part of the stimulable phosphor sheet on which radiation image information is accumulated and recorded,
A line sensor in which a plurality of photoelectric conversion elements are arranged in parallel along the linear excitation light irradiation portion of the stimulable phosphor sheet;
Sub-scanning means for moving one of the line sensor, the excitation light irradiation means, and the stimulable phosphor sheet relative to the other in a direction intersecting the length direction of the excitation light irradiation portion. In the radiographic image information reading device,
The excitation light irradiating means is configured so that the laser beams as the excitation light emitted from each of the excitation light irradiation means are continuous with each other in the length direction of the excitation light irradiation portion, and the beam divergence direction perpendicular to the joint surface substantially coincides with the continuous direction of the beams. A plurality of laser diodes arranged in an orientation;
A cylindrical lens for condensing the laser beam emitted from each of these laser diodes only on a plane perpendicular to the direction of their series and converging on the stimulable phosphor sheet;
A radiographic image information reading apparatus comprising: an optical element that is disposed between the cylindrical lens and the plurality of laser diodes and scatters laser beams emitted from the laser diodes. 3. The plurality of laser diodes are arranged such that laser beams emitted from adjacent ones of the plurality of laser diodes are connected to each other with overlapping portions. The radiation image information reading device described.

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