JP3676021B2 - Radiation image information reader - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radiation image information reading apparatus, and more particularly to an improvement of an apparatus for reading radiation image information recorded on a stimulable phosphor sheet.
[0002]
[Prior art]
A part of this radiation energy is accumulated when irradiated with radiation, and then a stimulable phosphor (stimulable fluorescence) that exhibits stimulated emission according to the accumulated radiation energy when irradiated with excitation light such as visible light or laser light. Body), radiation image information of a subject such as a human body is once stored and recorded on a sheet-like stimulable phosphor sheet formed by laminating a stimulable phosphor on a support. Light is scanned pixel by pixel to generate stimulated emission light sequentially from each pixel, and the resulting stimulated emission light is sequentially read photoelectrically to obtain an image signal, while the stimulable phosphor after reading this image signal A radiation image recording / reproducing system that irradiates a sheet with erasing light and releases radiation energy remaining on the sheet is already well known and put into practical use.
[0003]
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 image signal after this processing is recorded on the film as a diagnostic visual image. Or displayed on a high-definition CRT for diagnosis by a doctor or the like. On the other hand, the stimulable phosphor sheet from which the residual radiation energy irradiated with the erasing light is emitted can again store and record radiation image information and can be used repeatedly.
[0004]
[Problems to be solved by the invention]
However, in the radiographic image information reading apparatus used in the radiographic image recording / reproducing system described above, a high-quality laser beam is used as the excitation light, and an expensive photomultiplier (photoelectron) is used to photoelectrically detect the stimulated emission light. And a laser beam scanning system and a condensing optical system for detecting the stimulated emission light emitted from the stimulable phosphor sheet as a signal for each pixel. It is quite expensive. This high price is one of the obstacles to widespread use of this system.
[0005]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an inexpensive radiographic image information reading apparatus by reducing the manufacturing cost by using inexpensive parts.
[0006]
[Means for Solving the Problems]
The radiation image information reading apparatus of the present invention uses a light source of excitation light that excites the stimulable phosphor sheet as a line light source and uses the excitation light as pulse light, and is emitted with a response delay from a portion irradiated with the pulse light. The linear stimulated emission light is detected from the front surface or the back surface of the sheet by dividing the pixel by the pixel-divided photoelectric reading means after the completion of the pulse light irradiation.
[0007]
That is, the radiation image information reading apparatus of the present invention is a line light source that linearly irradiates excitation light on a part of the stimulable phosphor sheet on which radiation image information is accumulated and recorded, and the excitation light of the sheet is irradiated with the excitation light. The stimulating emission light corresponding to the radiation image information emitted from the portion and / or the back surface portion corresponding to this portion is divided into pixels in the length direction of the irradiated portion, and a plurality of pixels obtained by the pixel division are obtained. Pixel division photoelectric reading means for photoelectrically reading pixels in a two-dimensional array, and scanning for moving the line light source, the pixel division photoelectric reading means and the sheet in a direction substantially orthogonal to the length direction. A radiological image information reading apparatus comprising means,
The pulse of the excitation light whose emission time is shorter than the response delay time from the start of irradiation of the excitation light of the stimulable phosphor contained in the stimulable phosphor sheet until the stimulated emission light shows the maximum intensity Light,
The pixel-divided photoelectric reading unit reads the stimulated emission light due to the response delay in a period after the end of the emission of the pulsed light.
[0008]
Here, the above-mentioned pixel division means to divide the substantially linear stimulated emission light into a minute size corresponding to the pixel, and does not mean to divide the pixel.
[0009]
Note that the surface of the sheet on which the pixel-divided photoelectric reading means detects the stimulated emission light may be either the front surface or the back surface of the sheet as described above, or may be detected substantially simultaneously from both surfaces. In order for the photoelectric reading means to eliminate the crosstalk light caused by the stimulated emission light emitted from the adjacent pixels as much as possible, it is necessary to make it as close as possible to the sheet without interfering with the light source. And the pixel-divided photoelectric reading means are preferably detected from the back surface of the sheet (surface opposite to the surface irradiated with the excitation light). The surface on the side where the stimulated emission light is read by the pixel-divided photoelectric reading means is preferably the surface on the side where the radiation is incident when a radiation image is taken on the sheet. This is because the transmitted radiation carrying the radiation transmission image information of the subject is scattered inside the sheet, so that the signal is blurred when read from the side where the radiation is emitted.
[0010]
To read photoelectrically in a two-dimensional array means to read two-dimensionally and photoelectrically. Therefore, the stimulated emission light emitted linearly is obtained by photoelectrically reading the two-dimensionally arranged pixels arranged in the length direction, that is, one-dimensionally.
[0011]
The pixel-divided photoelectric reading unit includes a photoelectric conversion unit having the photoelectric conversion unit in which a large number of photoelectric conversion elements are two-dimensionally arranged, and each incident end surface emits the stimulated emission light of the sheet. Arranged so as to be arranged in the length direction of the linear irradiation portion so as to face the portion (the front surface and / or the back surface of the sheet), and arbitrarily so that each emission end face faces the different photoelectric conversion elements. An optical fiber bundle composed of a large number of optical fibers arranged, a reference table in which a correspondence relationship between each optical fiber and each photoelectric conversion element on the incident end face is set in advance, and each electric signal detected by each photoelectric conversion element And reconstructing means for reconfiguring the optical fiber on the incident end face according to the arrangement of the optical fibers based on the correspondence set in the reference table. It can be applied such as those configured.
[0012]
The response delay time of the stimulable phosphor is preferably 1 μsec or more, and the stimulable phosphor preferably contains BaFC1.
[0013]
【The invention's effect】
According to the radiation image information reading apparatus of the present invention, the light source of excitation light for exciting the stimulable phosphor sheet is a line light source, and the stimulated emission light emitted along the line light source is on the same side as the light source and / or Alternatively, by providing pixel-divided photoelectric reading means that detects pixels by dividing them from the surface opposite to the light source, the laser light is mainly detected while detecting the image information in the extending direction of the line light source corresponding to the pixels. A scanning optical system such as a rotary polygon mirror and an fθ lens necessary for scanning is unnecessary, and an inexpensive and compact radiation image information reading apparatus can be provided. Moreover, since the pixel division photoelectric reading means is used, an inexpensive linear light source can be used as the excitation light source. That is, in the past, pixel-by-pixel reading was performed by time-division reading in accordance with the scanning timing of the laser beam. However, in the present invention, it is not necessary to use an expensive device such as a laser light source, and the light source itself can be made inexpensive. You can also
[0014]
Further, the excitation light has an emission time longer than a response delay time from the start of irradiation of the excitation light to the stimulable phosphor contained in the stimulable phosphor sheet until the stimulated emission light exhibits the maximum intensity. By making the pulse light short, the pixel-divided photoelectric reading means does not read during the light emission period of this pulse light, but reads the stimulated emission light due to the delayed response of the stimulable phosphor in the period after the end of the light emission of the pulse light. The excitation light can be cut and only the stimulated emission light can be detected without providing a separate means for removing the excitation light such as an excitation light cut filter, and this stimulated emission light can be detected accurately. .
[0015]
That is, since the excitation light cut filter is generally thick in the light transmission direction, the stimulated emission light, which is a signal light component, diffuses to some extent while passing through the inside. Such diffusion is likely to cause crosstalk between pixels, and the reproduced image is blurred based on the read signal. It is preferable not to use the excitation light cut filter. In particular, in the case of performing pixel-divided reading on the reading means side as in the reading device of the present invention, this crosstalk is likely to occur. Therefore, the degree of improvement in S / N by not using the excitation light cut filter is the conventional level. This is larger than a reading device that performs scanning by pixel division (spatial decomposition) on the excitation side.
[0016]
In addition, the effect of cutting the excitation light described above by using the excitation light as pulse light is more effective in combination with a configuration in which pixels for one line are simultaneously excited using a light source as a line light source as in the reading apparatus of the present invention. Appears as a practical effect. That is, for example, when the response delay time of the stimulable phosphor is 1 μsec and the irradiation time of the pulsed excitation light is slightly shorter than 1 μsec, reading is performed within 10 μsec immediately after the end of the excitation light irradiation. In this case, in the reading apparatus of the present invention configured to excite pixels for one line at the same time, irradiation with excitation light and reading for pixels for one line (for example, 2000 pixels) are completed in 11 μsec, and an image of 2000 lines is obtained. Then, reading is completed in 22 seconds in calculation. Such a reading time is sufficiently practical. On the other hand, in a conventional reading apparatus configured to divide one line into pixels by performing excitation sequentially for each pixel and detecting photostimulated emission light from all pixels for one line in time series, excitation is performed for each pixel. Irradiation and reading require 11 μsec, and other pixels cannot be irradiated during reading of pixels on the same line, so that excitation light irradiation and reading for pixels for one line takes 22 seconds. Line images require about 12 hours to calculate and are not practical.
[0017]
In addition, the pixel-divided photoelectric reading unit includes a photoelectric conversion unit in which a large number of photoelectric conversion elements are arranged in a two-dimensional manner, and each incident end surface is linearly opposed to a portion where the photostimulated light is emitted. An optical fiber bundle composed of a number of optical fibers arranged so as to be aligned in the length direction of the irradiated portion, and each output end face facing a different photoelectric conversion element, and each optical fiber and each photoelectric conversion element on the incident end face Based on the correspondence table set in advance in the reference table and each electrical signal detected by each photoelectric conversion element based on the correspondence relationship set in the reference table, it is reconfigured into an arrangement according to the arrangement of the optical fibers on the incident end face. And the reconfiguring means, the incident end face of each optical fiber, that is, the end face facing the sheet is a line along the extending direction of the line light source. But they are arranged in a row, whereas, not only there is no need to be arranged in the same order as the emission end face is always incident end face, not even need to be arranged in a row in a linear, may be arranged in any shape.
[0018]
Therefore, it is not necessary to use a high-cost line-shaped photoelectric conversion means due to difficulty in manufacturing.
[0019]
Therefore, it is appropriate to use a general-purpose product in which photoelectric conversion elements are arranged two-dimensionally as the photoelectric conversion means. Photoelectric conversion means such as a CCD (charge-coupled device) in which such photoelectric conversion elements are two-dimensionally arranged are generally inexpensive because they are generally easy to manufacture. As described above, the linear stimulated emission light emitted from the sheet can be easily guided to the two-dimensional surface of the photoelectric conversion means by using the optical fiber bundle.
[0020]
In this case, since the optical fiber bundle alone does not need to know in advance the positional relationship of the individual optical fibers in the entire fiber bundle at the entrance end face and the exit end face, the cost of manufacturing the fiber bundle is It can be made very cheap compared to the fiber bundle used.
[0021]
That is, in a set state in which the optical fiber bundle and the photoelectric conversion means are combined, the correspondence between the position of each fiber on the incident end face of the optical fiber bundle and each photoelectric conversion element constituting the photoelectric conversion means is obtained, and this is referred to as a reference table. By referring to this reference table after acquiring image data and rearranging this data digitally according to the arrangement order on the incident end face of the optical fiber, Data can be obtained according to the order.
[0022]
Here, the correspondence relationship between the position of each fiber on the incident end face of the optical fiber bundle and each photoelectric conversion element constituting the photoelectric conversion means is such that laser light or the like (about the diameter of the optical fiber) spot light is a plurality of What is necessary is just to scan along the incident end face of the optical fiber bundle which arranged the optical fiber in 1 row, and to obtain | require based on the time-sequential photoelectric detection result by each photoelectric conversion element which comprises the photoelectric conversion means at this time.
[0023]
An image recorded on the stimulable phosphor sheet is generally represented by image data of about 2000 pixels in the horizontal direction (main scanning direction) × 2000 pixels in the vertical direction (sub-scanning direction). Here, a line light source is arranged along the main scanning direction in the conventional radiographic image information reading apparatus, and 2000 optical fibers corresponding to 2000 pixels are arranged along this direction so that the incident ends thereof are in a line. In this case, the 2000 optical fibers are bundled so that the emission end face extends in a two-dimensional shape such as a substantially rectangular shape or a substantially circular shape, and this is configured to be photoelectrically detected by a 250,000 to 400,000 pixel CCD that is widely used. If this is done, the number of CCD pixels that one fiber (one pixel of the stimulable phosphor sheet) can handle is 125 to 200 pixels, and the number of pixels on the CCD side has room, so increase the number of optical fibers. Therefore, it is possible to cope with the improvement of the resolution of the obtained image.
[0024]
If it is difficult to bring the optical fiber bundle between the incident end face and the sheet, or the exit end face of the optical fiber bundle and the photoelectric conversion means, it is possible to obtain the difficult one by separating them. Depending on the mode in which the condensing optical system is arranged in the space, it can be replaced with the mode of approaching.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, specific embodiments of the radiation image information reading apparatus of the present invention will be described with reference to the drawings.
[0026]
1 is a block diagram showing an embodiment of a radiation image information reading apparatus according to the present invention, FIG. 2 is a view showing an example of a radiation image information reading and recording apparatus using the radiation image information reading apparatus shown in FIG. FIG. 2 is a view showing an optical fiber bundle of the radiation image information reading apparatus shown in FIG. 1.
[0027]
The radiographic image information reading apparatus 20 shown in FIG. 1 has radiation recorded and recorded in IP10 extending in a direction substantially perpendicular to the conveying direction X of the stimulable phosphor sheet (hereinafter referred to as IP) 10 by the conveying belts 28a and 28b. Line light source 21 that irradiates IP10 with pulsed excitation light (red wavelength band of 633 nm to 690 nm) that generates stimulated emission light according to image information, and a large number of photoelectric conversion elements (approximately 400,000 pixels = vertical 632 pixels × horizontal 632 pixels) two-dimensionally arranged, and as shown in FIG. 3, each incident end face 22a corresponds to the IP10 portion irradiated with the excitation light from the line light source 21. It is arranged so as to face the back side portion in close contact and to be arranged in a line along the direction in which the line light source 21 extends, and each emission end face 22b is bundled so as to spread in a two-dimensional plane and is formed on the light receiving surface of the CCD 25. Many optical fibers facing each other in close proximity The optical fiber bundle 22 composed of the bars 22i, the reference table 26 in which the correspondence between each optical fiber 22i and each photoelectric conversion element at the incident end face is set in advance, and each signal S detected by each photoelectric conversion element in the reference table 26 Based on the set correspondence relationship, the reconstruction means 27 for reconfiguring the optical fiber 22i on the incident end face and reconfiguring the pulsed excitation light to the line light source 21 at a predetermined timing for 1 μsec. In the period when the line light source 21 emits pulsed excitation light to the CCD 25, the photoelectric signal stored by the input light is reset, and immediately after the end of emission of the pulsed light. And a timing control means 29 for controlling so as to store a photoelectric signal due to the above-mentioned delayed response of the stimulated emission light in a period of 10 μsec. .
[0028]
IP10 has a storage phosphor layer laminated on the lower side of the figure (the side where the optical fiber bundle 27 is arranged, not the side where the light source 21 is arranged), and uses BaFCl as its component. The optical characteristics are as shown in FIG. That is, this stimulable phosphor layer has a predetermined response delay Δt (= t1−) from the start of excitation light irradiation (time t0) until the stimulated emission light (wavelength band 350 nm to 450 nm) shows the maximum intensity (time t1). t0), and this response delay Δt is set to be slightly over 1 μsec in this embodiment.
[0029]
FIG. 6 shows the afterglow characteristics of the IP 10 and the control timing of the line light source 21 and the CCD 25 by the timing control means 29 collectively.
[0030]
The line light source 21 has a configuration in which a pulse light source 21a is provided inside a cylindrical reflecting mirror 21b having a slit 21c along a direction parallel to the central axis on a part of its peripheral surface, and passes through the slit 21c. The pulsed light becomes a linear light and irradiates IP10. In order to improve the degree of collection of light emitted from the slit 21c, a cylindrical lens having no power in the extending direction of the slit 21c may be provided along the slit 21c.
[0031]
The optical fiber bundle 22 is composed of, for example, 2000 optical fibers 22i. Each optical fiber 22i has a diameter of 0.1 mm and a core of 90%. As described above, the incident end face of the 2000 optical fibers 22i extends in the extending direction of the line light source 21. Although arranged so as to be arranged in a line in parallel (see FIG. 3 (1)), the emission end faces are randomly bundled as shown in (1) or (2).
[0032]
The CCD 25 as the photoelectric conversion means is disposed very close to the emission end face 22b of the fiber bundle 22, and light from each optical fiber 22i is incident on the photoelectric conversion surface on which the photoelectric conversion elements of 400,000 pixels are arranged substantially evenly. Are arranged to be. Note that the CCD 25 has an aperture ratio of 50% and a QE of 60%, but these numerical values merely show a desirable example that can collect the photostimulated emission light with high efficiency. It is not restricted to the thing of these aspects.
[0033]
As shown in FIG. 1, in the present embodiment, the line light source 21 and the optical fiber 22 and the like are arranged on different surfaces with the IP 10 interposed therebetween. This is because it is necessary to make the incident end face of the optical fiber bundle 22 very close to the IP in order to efficiently enter the emitted light into the optical fiber and to prevent crosstalk of the stimulated emitted light from the adjacent pixel portion. Therefore, when the light collection efficiency does not deteriorate or when crosstalk can be effectively prevented, a configuration in which the optical fiber 22 and the like are arranged on the same side as the line light source 21 may be employed. Further, these may be arranged on each side of the IP 10 so that both sides are read.
[0034]
Further, when it is difficult to make the optical fiber bundle 22 between the incident end face 22a and IP10, or between the outgoing end face 22b of the optical fiber bundle 22 and the CCD 25, FIG. 7 (1) or (2). As shown in FIG. 4, it is possible to adopt a configuration in which the light is separated between them, and a condensing optical system 24 such as a condensing lens is arranged in the separated space. Light or the like is condensed and guided to the incident end face of each optical fiber 22i, or the stimulated emission light or the like that diverges and exits from the exit end face of each optical fiber 22i is collected to collect the photoelectrical light of the CCD 25 as shown in FIG. What is necessary is just to make it guide to a conversion element. In the configuration in which the incident end face 22a of the optical fiber bundle 22 and the IP10 are separated from each other as in the embodiment shown in FIG. 7 (1), the cluster to be arranged in the space between the incident end face 22a and the IP10. In the optical optical system, the stimulated emission light emitted from a small portion of the IP needs to be incident on the incident end face of each corresponding optical fiber 22i, so that the array is opposed to the incident end face of each optical fiber 22i. It is appropriate to use a graded index lens array (for example, “Selfoc Lens” (registered trademark)), which is an array of minute graded index lenses.
[0035]
Further, the exit ends of the 2000 optical fibers 22i and the CCD 25 having 400,000 pixels correspond to each other as shown in FIG.
[0036]
A radiographic image information reading / recording apparatus 100 shown in FIG. 2 is a radiographic image information reading / recording apparatus that includes the radiographic image information reading apparatus 20 of the embodiment shown in FIG. An image reading unit 20 that reads an image signal corresponding to the radiation image information from the IP 10 on which the image is stored and recorded, and a signal such as gradation processing and frequency processing for the image signal S obtained by reading by the image reading unit 20 An image processing unit 50 that performs processing, an image output unit 60 that outputs a visible image P ′ represented by the image signal S ′ to the dry film 61 based on the image signal S ′ after the signal processing, IP 10 including a CRT monitor 70 for displaying a visual image P ′ on the display surface, and suction means 41 that sucks IP 10 accommodated in the cassette 11 mounted on the main body and draws it into the main body 90 from the cassette 11. Image reading unit 20, IP In this configuration, a transport means 40 for transporting to the tray 30 and a power source 80 are provided.
[0037]
Here, the power supply 80 and the image processing unit 50 are arranged at the bottom, the image reading unit 20 is arranged at the top, and the image output unit 60 is arranged at the top, so that the operator can stand up. When this apparatus is operated, the dry film 61 on which a visible image is recorded is ejected to a height position where the operator can easily see.
[0038]
The dry printer 60 performs thermal recording on a so-called cut sheet thermal material as a dry film 61. The dry printer 60 adsorbs a large number of dry films 61 housed in a removable magazine 62 one by one. It comprises a transport means 64 including a sheet means 63 to be carried in, and a thermal head device 65 for performing thermal recording on the transported film 61. The thermal head device 65 more specifically records a thermal surface image on a thermal material. A thermal head body (hereinafter, illustration of the configuration of the thermal head device is omitted), a heat sink as a cooling means fixed directly to the thermal head body, and a heat sink. Cooling fan that constitutes the means, sheet heater for heating the thermal head body, sheet shape with cooling fan And a control means for controlling driving of Ta.
[0039]
Next, the operation of the radiation image information reading / recording apparatus 100 of this embodiment will be described.
[0040]
When the IP tray 30 is mounted in the tray mounting port 92 of the main body, and the cassette 11 containing the IP10 in which the radiation image information of the patient is stored and recorded is mounted in the cassette mounting port 91, the lid portion of the cassette 11 is shown in FIG. The suction means 41 is opened as shown in 2), and the IP 10 accommodated in the cassette 11 with the lid portion opened is sucked and pulled out into the main body 90. The extracted IP 10 is carried into the image reading unit 20 by the conveying means 40.
[0041]
The image reading unit 20 carries IP10 on the two conveyor belts 28a and 28b and conveys it in the direction of arrow X. During this time, the surface of the IP 10 (the upper surface in the figure) is irradiated with 1 μsec of linear pulsed light from the line light source 21 under the control of the timing control means 29. The linear portion of IP10 that has been irradiated with the pulsed light has the maximum amount of stimulated emission light at time t1, which is delayed by Δt from the start of irradiation of the pulsed light (t0) due to the response delay of the storage phosphor in the portion. To emit.
[0042]
This stimulated emission light occurs on the front side of the IP10, but also on the back side. Further, during the period of irradiation of this pulsed light (between time t0 and 1 μsec), not only the above-mentioned stimulated emission light but also IP10 of the excitation light irradiated on the surface of IP10 from the back surface of this IP10. A part of the light transmitted through is also emitted. Then, the light (stimulated emission light and excitation light) emitted from the back surface of the IP10 is guided to the inside of each optical fiber 22i from the incident end face 22a of each optical fiber 22i facing each generated minute portion, and the optical fiber It is divided as a minute optical signal corresponding to 2000 pixels which is the number of 22i.
[0043]
Each of the optical fibers 22i repeats total reflection and is guided to the exit end face 22b. The stimulated emission light and the excitation light for each pixel are emitted from the exit end face 22b and are provided in close contact with the exit end face 22b. The light is guided onto the light detection surface of the CCD 25. The image formation state on the light detection surface (photoelectric conversion element surface) of the CCD 25 at this time is, for example, FIG. 4 when the way of bundling the emission end face of the optical fiber bundle 22 is as shown in FIG. It will be as shown in
[0044]
Here, as shown in FIG. 6 (3), the CCD 25 resets the photoelectric signal input by the timing control means 29 during the period when the pulse light is irradiated (between time t0 and 1 μsec). Charge is not accumulated ((4) in the figure).
[0045]
On the other hand, after 1 μsec has elapsed from time t 0, the pulse light of the line light source 21 is turned off by the timing control means 29. Here, even if the pulsed light, which is the excitation light, is extinguished, the linear portion of IP10 that has been irradiated emits further stimulated emission light due to the response delay of the stimulable phosphor in the portion.
[0046]
This stimulated emission light passes through IP10 and exits to the back side of IP10 as in the case described above. Since the excitation light is already extinguished, it does not exit from the back surface of the IP10.
[0047]
The light emitted from the back surface of the IP10 (stimulated emission light only) has the same action as described above, and enters the inside of each optical fiber 22i from the incident end face 22a of each optical fiber 22i facing each of the generated minute portions. And is divided into minute optical signals corresponding to 2000 pixels, which is the number of optical fibers 22i, and is guided to the output end face 22b by repeating total reflection inside each optical fiber 22i, and is emitted from each output end face 22b. The light is guided onto the light detection surface of the CCD 25 provided in close contact with the emission end face 22b.
[0048]
Here, as shown in FIG. 6 (3), the CCD 25 accumulates the input photoelectric signal by the timing control means 29 after the pulsed light is extinguished (after 1 μsec has elapsed from time t0). 4)).
[0049]
Here, only the stimulated emission light is accumulated in the CCD 25 and does not include the excitation light. Therefore, this accumulated signal can reproduce the image information accumulated and recorded in IP10 with high accuracy, and is a signal with improved S / N.
[0050]
By the way, since the optical fiber bundle 22 is randomly bundled on the exit end face side, it is not known where the single fiber designated on the exit end face side is located on the entrance end face side. Therefore, it is necessary to associate the incident end face side and the exit end face side of the optical fiber bundle 22 in advance. Therefore, in the apparatus according to the present embodiment, if the optical fibers 22i are sequentially replaced and light is incident on the incident end face 22a of each fiber 22i, it is determined based on the detection signal of the CCD 25 which light has exited from which exit end face. The result of this correspondence is often tabulated as a reference table 26. Then, when the image is read later, the detection means for each photoelectric conversion element of the CCD 25 corresponds to the arrangement order of the fibers 22i at the incident end of the optical fiber bundle 22 while the reconstruction means 27 refers to the table 26. Can be rearranged.
[0051]
When 10 μsec has elapsed from when the pulsed light is extinguished (after 1 μsec has elapsed from time t 0), the electrical signal accumulated in the CCD 25 by the timing control means 29 is transferred to the reconstruction means 27 for each photoelectric conversion element constituting the CCD 25. By the operation of the reconstruction means 27 described above, an image signal S ′ having a high S / N corresponding to the spatial position of IP10 can be obtained, and the obtained image signal S ′ is input to the image processing unit 50. The
[0052]
The image processing unit 50 performs various signal processes on the input image signal S ′. The image signal S ″ after the signal processing is output to the image output unit 60 and the CRT monitor 70.
[0053]
On the other hand, the IP 10 after the image signal is read by the image reading unit 20 is transported by the transport means 40 and stored in the IP tray 30. A configuration in which an erasing unit for irradiating erasing light is provided in the conveyance path between the image reading unit 20 and the IP tray 30 so that the radiation energy remaining in the IP 10 after reading the image signal is almost completely emitted. It can also be taken.
[0054]
Since the IP tray 30 can store a plurality of IP10s, the IP tray 30 remains attached to the apparatus 100 until a predetermined number of IP10 after image reading is completed. After being removed and the stored IP 10 is discharged, it is attached to the apparatus 100 again.
[0055]
The CRT monitor 70 displays on the display surface a visible image corresponding to the image signal S ″ after the signal processing input from the image processing unit 50, and the operator observes this display to determine the degree of signal processing. Judging the necessity of correction and range specification change.
[0056]
Further, in the image output unit 60, the sheet means 63 sucks a large number of dry films 61 accommodated in the magazine 62 one by one and carries them into the printer 60, and the conveying means 64 thermally transfers the dry films 61. The thermal head device 65 heats the visible image corresponding to the image signal S ″ on the transported dry film 61 based on the image signal S ″ input from the image processing unit 50. Record. More specifically, in this thermal recording, the control means controls the driving of the cooling fan and the planar heater to adjust the temperature of the thermal head body, thereby recording a gradation image.
[0057]
The dry film 61 in which a visible image is recorded is output from the film discharge port 93 to the outside of the apparatus 100. The film discharge port 93 is positioned so that when the operator stands up and operates the apparatus, the dry film 61 on which a visible image is recorded is easy to be noticed by the operator. It is also possible to prevent forgetting to remove the used film.
[0058]
As described above, according to the radiation image information reading and recording apparatus 100 of the present embodiment, the image signal is separated into signals for each pixel without using expensive components such as a conventional laser light source, laser scanning system, and photomultiplier. Therefore, the manufacturing cost can be greatly reduced compared to the conventional apparatus, thereby reducing the price of the apparatus and spreading the apparatus.
[0059]
In the radiation image information reading apparatus according to the present embodiment, an explanation will be given of the application of BaFC1 as the IP10 storage phosphor, and the pulse light lighting time by the timing control means is 1 μsec, and the CCD storage time is 10 μsec. However, the radiation image information reading apparatus of the present invention is not limited to this mode, and is a response delay time from the start of irradiation of excitation light to the time when the stimulated emission light shows the maximum intensity, which is peculiar to IP10 storage phosphors. Rather than setting or controlling the irradiation time of the excitation light to be shorter and controlling the CCD so that the stimulated emission light due to the response delay in the period immediately after the irradiation of the excitation light can be read. Any form and embodiment can be adopted.
[0060]
Further, in the present embodiment, the mode in which the pulsed light is turned on only once has been described. However, since the irradiation is performed for an extremely short time, the case where the output of the stimulated emission light is small is also conceivable. In such a case, the operations of turning on the pulsed light, resetting the CCD, turning off the pulsed light, and accumulating / transferring the CCD are repeated a plurality of times, and the sum of the image signals S ′ obtained each time may be used.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an embodiment of a radiation image information reading apparatus of the present invention.
2 is a diagram showing a radiological image information reading / recording apparatus having a configuration in which the radiological image information reading apparatus shown in FIG. 1 is partially provided as an image reading unit;
FIG. 3 is a schematic diagram showing an arrangement state of an incident end face and an exit end face of an optical fiber bundle.
FIG. 4 is a diagram showing the relationship between the emission end face of the optical fiber bundle and the photoelectric conversion element of the CCD 25
FIG. 5 is a graph showing afterglow characteristics of a stimulable phosphor
FIG. 6 is a graph in which afterglow characteristics of the stimulable phosphor, the control timing of the light source and the CCD, and the accumulation state of the CCD are arranged in time series.
FIG. 7 is a block diagram showing another embodiment of the radiation image information reading apparatus of the present invention.
[Explanation of symbols]
10 Storage phosphor sheet (IP)
20 Image reader
21 line light source
22 Optical fiber bundle
22a Incident end face
22b Output end face
22i optical fiber
24 Condensing optical system (condensing lens etc.)
25 CCD
26 Reference table
27 Reconfiguration means
28a, 28b Conveyor belt
29 Timing control means
100 Radiation image information reading and recording device

Claims (4)

A line light source for linearly irradiating excitation light on a part of a stimulable phosphor sheet on which radiation image information is accumulated and recorded, a portion of the sheet irradiated with the excitation light and / or a back surface of the irradiated portion The stimulated emission light corresponding to the radiation image information emitted from the portion is divided into pixels in the length direction of the irradiated portion, and a plurality of pixels obtained by the pixel division are photoelectrically expressed in a two-dimensional array. Radiation image information reading apparatus comprising: a pixel division photoelectric reading unit that reads; and a scanning unit that moves the line light source, the pixel division photoelectric reading unit, and the sheet in a direction substantially orthogonal to the length direction. Because
The pulse of the excitation light whose emission time is shorter than the response delay time from the start of irradiation of the excitation light of the stimulable phosphor contained in the stimulable phosphor sheet until the stimulated emission light shows the maximum intensity Light,
The radiation image information reading apparatus, wherein the pixel-divided photoelectric reading means reads the stimulated emission light due to the response delay in a period after the end of emission of the pulsed light. The pixel-divided photoelectric reading means is
Photoelectric conversion means in which a large number of photoelectric conversion elements are arranged two-dimensionally;
Each incident end face is arranged so as to be aligned in the length direction of the linear irradiation portion so as to face the portion where the photostimulated emission light of the sheet is emitted, and each emission end face is arranged on the photoelectric conversion element different from each other. An optical fiber bundle composed of a large number of optical fibers arranged to face each other;
A reference table in which the correspondence between each optical fiber and each photoelectric conversion element on the incident end face is set in advance,
Reconstructing means for reconfiguring each electric signal detected by each photoelectric conversion element into an arrangement corresponding to the arrangement of the optical fibers on the incident end face based on the correspondence set in the reference table. The radiographic image information reading apparatus according to claim 1, wherein The radiological image information reading apparatus according to claim 1, wherein the response delay time is 1 μsec or more. The radiation image information reading apparatus according to claim 1, wherein the stimulable phosphor contains BaFCl.

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