JP2000029153A - Radiation image information reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To acquire image information by which a radiation image whose S/N is improved can be reproduced by reading the recorded image information from both surfaces of a stimulable phosphor sheet and arithmetically processing it. SOLUTION: A linear laser beam L made incident on the sheet 50 stimulates a stimulable phosphor layer in the condensing area of the sheet 50, so that stimulated luminescences M and M' having emitted light intensity in accordance with the radiation image information accumulated and recorded are respectively emitted from the front surface and the back surface of the sheet 50. The stimulated luminescence M is made parallel beams by a 1st Selfoc(R) lens 15, passes through a dichroic mirror 14 and it is condensed on the light receiving surface of a photoelectric conversion element 21 constituting a line sensor 20 by a 2nd Selfoc(R) lens array 16. In such a case, the laser beam L somewhat coexisting in the luminescence M and reflected on the surface of the sheet 50 is cut by a stimulating light cut filter 17. The luminescence M received by the element 21 is photoelectrically converted into an image signal S and inputted in an information reading means 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a radiation image information reading apparatus, and more particularly to a radiation image information reading apparatus which reads stimulated emission light emitted from a stimulable phosphor sheet by a line sensor.

[0002]

2. Description of the Related Art When radiation is irradiated, a part of this radiation energy is accumulated, and thereafter, when irradiated with excitation light such as visible light or laser light, a stimulable phosphor that emits stimulated light in accordance with the accumulated radiation energy. (Photostimulable phosphor) is used to temporarily accumulate and record radiation image information of a subject such as a human body on a sheet-shaped stimulable phosphor sheet formed by laminating a stimulable phosphor on a support. Excitation light such as laser light is deflected and scanned for each pixel to generate stimulated emission light sequentially from each pixel, and the obtained stimulated emission light is photoelectrically sequentially read by photoelectric reading means to obtain an image signal. A radiation image recording / reproducing system that emits erasing light to the stimulable phosphor sheet after reading the image signal and emits radiation energy remaining on the sheet is widely used in practice.

An image signal obtained by this system is subjected to image processing such as gradation processing and frequency processing suitable for observation and interpretation, and the image signal after these processings is applied as a diagnostic visible image. Filmed or high-definition CR
It is displayed on T and used for diagnosis by a doctor or the like. on the other hand,
The stimulable phosphor sheet from which the residual radiant energy irradiated with the erasing light has been released can store and record radiation image information again, and can be used repeatedly.

Here, in the radiation image information reading apparatus used in the above-mentioned radiation image recording / reproducing system,
From the viewpoint of shortening the reading time of the stimulated emission light, downsizing the apparatus and reducing the cost, a fluorescent lamp, a cold cathode fluorescent lamp, an LED array or Using a line light source such as a broad area laser, as a photoelectric reading unit, a line sensor in which a large number of photoelectric conversion elements are arranged along the length direction of a linear portion of a sheet irradiated with excitation light by the line light source. A configuration has been proposed that includes a scanning unit that uses the line light source and the line sensor relative to a sheet and moves the line light source and the line sensor in a direction substantially perpendicular to the length direction of the linear portion (Japanese Patent Application Laid-Open No. H10-157572). No. 60-111568, No. 60-236354,
JP-A-1-101540).

[0005]

In the above-described radiation image recording / reproducing system, the presence of radiation quantum noise is recognized in the step of storing and recording a radiation image on a stimulable phosphor sheet.

[0006] This noise is finally superimposed on the image signal read by the radiation image information reading apparatus. Therefore, in order to improve the S / N of the radiation image reproduced by the obtained image signal, these noises are required. Must be effectively removed, and the need to remove this noise is the same in the radiation image information reading apparatus using the above-described line light source and line sensor.

The present invention has been made in view of the above circumstances, and has been made in consideration of the above circumstances, and has been made capable of acquiring image information capable of reproducing a radiation image with an improved S / N ratio, using a line light source and a line sensor. It is an object to provide an image information reading device.

[0008]

A radiation image information reading apparatus according to the present invention is a radiation image information reading apparatus using a line light source and a line device, wherein images recorded on both sides of a stimulable phosphor sheet are recorded on the sheet. Read the information,
The obtained image information from both sides is arithmetically processed.

That is, a first radiation image information reading apparatus of the present invention comprises a line light source for linearly irradiating excitation light to a part of a stimulable phosphor sheet on which radiation image information is stored and recorded; A line sensor in which a large number of photoelectric conversion elements are linearly arranged, receiving a photostimulated light emitted from a linearly irradiated portion, and performing photoelectric conversion, the line light source, the line sensor, and the sheet A scanning means for relatively moving the scanning means, and a reading means for reading an output signal of each of the photoelectric conversion elements constituting the line sensor for each movement position by the scanning means, The sheet emits the stimulating light from both surfaces thereof, and the line sensor includes:
The reading unit is provided on each side of the sheet, and the reading unit performs arithmetic processing on image information read from both sides of the sheet by associating pixels on the front and back of the sheet. It is assumed that.

Here, a line light source is a fluorescent lamp, if it irradiates the sheet surface with one-dimensional excitation light.
The light source itself is not limited to a linear light source such as a cold cathode fluorescent lamp or an LED array, but may be a broad area laser (not limited to a broad area semiconductor laser) or an EL (Ele).
ctroluminescence) elements and the like. More preferably, an LED array or a broad area laser is applied, and the excitation light emitted from these light sources becomes linear excitation light on the sheet surface. ), A cylindrical lens, a slit, and a selfoc lens (trademark; or a rod lens) that suppress the spread of the excitation light in a direction (short axis direction) orthogonal to
It is desirable to employ a configuration further using an excitation light guiding means including an array, a fluorescent light guiding sheet, an optical fiber bundle, a hot mirror, a cold mirror, or a combination thereof. When the optimal secondary excitation wavelength of the stimulable phosphor sheet is around 600 nm, the fluorescent light guide sheet may be one in which the activator of the phosphor is Eu3 + (emission center) and is a glass or polymer medium. desirable.

The excitation light emitted from the line light source may be emitted continuously, or may be pulsed light emitted in a pulse shape in which emission and stop are repeated. From the viewpoint of reduction, it is desirable that the light is a high-output pulsed light.

The length of the irradiation area in the major axis direction on the stimulable phosphor sheet by the linear excitation light emitted from the line light source is longer than one side of the image effective area of the stimulable phosphor sheet. It is desirable that they have the same length.
If the length is longer than one side, the side of the sheet may be irradiated with the excitation light obliquely.

The sheet that emits the stimulating light from both sides thereof is supported such that the stimulating light excited by the excitation light irradiated from at least one side is emitted from both sides of the sheet. A sheet whose body or the like is transmissive to stimulated emission light, wherein a line light source is arranged separately on both sides of the sheet, or a second or third radiation image information reading apparatus of the present invention described later. like,
In a configuration in which the sheet is sequentially excited one by one, it is necessary that the support of the sheet is not only capable of transmitting stimulated emission light but also capable of transmitting excitation light. Further, in a configuration in which each surface of the sheet is separately excited, an excitation light shielding layer may be provided as an intermediate layer.

Regardless of the configuration for exciting only from one side of the sheet or the configuration for exciting simultaneously or sequentially from both sides,
A sheet in which a stimulating light emission area of a sheet is subdivided into a number of microcells by an excitation light reflective partition member extending in the thickness direction of the sheet (a so-called anisotropic storage phosphor sheet; JP-A-59-202100, JP-A-62-36599, and JP-A-2-129600 can also be used, and the sharpness of an image based on an image signal obtained by photoelectric conversion can be increased.

As the line sensor, an amorphous silicon sensor, a CCD sensor, a back-illuminated type CCD, a MOS image sensor, or the like can be used. The length of the line sensor is longer than or equal to one side of the image effective area of the sheet. Desirably, it is a length.

The fact that a large number of photoelectric conversion elements are linearly arranged is not limited to the fact that a large number of photoelectric conversion elements are arranged in a straight line in the longitudinal direction.
An array extending in the major axis direction as a whole is intended to include a staggered array arranged in a zigzag shape.

The size of the light receiving surface of each of the photoelectric conversion elements constituting the line sensor is suitably from 10 to 4000 μm, particularly preferably from 100 to 500 μm. Conversion element array number is 1000
It is desirable that this is the case.

Further, a selfoc lens (registered trademark; hereinafter abbreviated) array or a rod lens array is formed between the sheet and the line sensor by an imaging system in which the object plane and the image plane correspond one-to-one. A stimulating luminescence light guiding means comprising a gradient index lens array, a cylindrical lens, a slit, an optical fiber bundle, a hot mirror, a cold mirror, etc., or a combination thereof may be further provided.

Further, an excitation light cut filter (a sharp cut filter, a band-pass filter) that transmits the stimulated light but does not transmit the excitation light is provided on the optical path of the stimulated light between the sheet and the line sensor. Therefore, it is preferable to prevent excitation light from being incident on the line sensor.

Moving the line light source and the line sensor relative to the sheet means that the line light source and the line sensor may be moved relative to the sheet, or vice versa. May also be moved. When the line light source and the line sensor are moved, they are moved integrally.

The moving position is a position at which photoelectric detection is performed by the line sensor, and does not mean a position at which the signal passes instantaneously during the movement.

The line sensor in the first radiographic image information reading apparatus of the present invention is not limited to the above-described one in which the photoelectric conversion elements are arranged in a single row. Alternatively, a plurality of photoelectric conversion elements may be arranged in a direction (short axis direction) orthogonal to the arrangement direction of the photoelectric conversion elements. In this case, the plurality of photoelectric conversion elements may be arranged in a matrix in which the photoelectric conversion elements are arranged in a straight line in any of the long axis direction and the short axis direction, or are arranged in a straight line in the long axis direction. There are various arrangements, such as zigzag arrangement in the short axis direction, zigzag arrangement in the short axis direction but zigzag arrangement in the long axis direction, and zigzag arrangement in both axis directions. can do.

In the case where a line sensor having a configuration in which a plurality of photoelectric conversion elements are arranged also in the short-axis direction described above is employed. In a configuration in which the number of photoelectric conversion elements is increased so as to be affected by the transfer rate, By providing a memory element corresponding to each photoelectric conversion element, temporarily storing the charge accumulated in each photoelectric conversion element in each memory element, and reading out the charge from each memory element during the next charge accumulation period, The configuration may be such that the charge accumulation time is not shortened due to the increase in the transfer time.

The operation processing corresponding to the pixels on the front and back of the sheet means that the image information of the corresponding pixels on the front and back of the sheet is subjected to simple addition, weighted addition or other operation processing. Such a process is called a superimposition process (see Japanese Patent Application Laid-Open No. 56-11399, etc.), which greatly reduces the noise that occurs randomly within the effective image area of the sheet. Clear observation is possible, that is, detection ability can be greatly improved.

The above description also applies to the second and third radiation image information reading apparatuses of the present invention described below.

While the first radiation image information reading apparatus of the present invention has line sensors provided on both sides of a sheet, the second radiation image information reading apparatus of the present invention has It is provided only on one side of the sheet, and after reading the image information on the one side, the sensor is moved to the other side to read the image information on the other side.

That is, a second radiation image information reading apparatus of the present invention comprises a line light source for linearly irradiating excitation light to a part of a stimulable phosphor sheet on which radiation image information is stored and recorded, and a line of the sheet. A line sensor in which a large number of photoelectric conversion elements are linearly arranged, receiving a photostimulated emission light emitted from a portion irradiated in a shape, a line sensor, and the line light source and the line sensor and the sheet A scanning unit that relatively moves the sheet, and a reading unit that reads an output signal of each of the photoelectric conversion elements constituting the line sensor for each movement position of the scanning unit. Emits the stimulating light from both surfaces thereof, and after the reading of the stimulating light from one surface of the sheet is completed, the line sensor is turned on the sheet. Further comprising a sensor moving means for moving the sheet to the other side, wherein the reading means performs arithmetic processing on image information read from both sides of the sheet by associating pixels on the front and back of the sheet. It is assumed that.

The sensor moving means may move the line light source together with the line sensor toward the other surface.

The second radiographic image information reading apparatus of the present invention reads the image information on the other side of the sheet by moving the line sensor to the other side of the sheet. In the third radiation image information reading apparatus, the image information on the other surface side of the sheet is read by turning the sheet upside down without changing the line sensor.

That is, a third radiation image information reading apparatus of the present invention comprises a line light source for linearly irradiating excitation light to a part of a stimulable phosphor sheet on which radiation image information is accumulated and recorded; A line sensor in which a large number of photoelectric conversion elements are linearly arranged, receiving a photostimulated light emitted from a linearly irradiated portion, and performing photoelectric conversion, the line light source, the line sensor, and the sheet A scanning means for relatively moving the scanning means, and a reading means for reading an output signal of each of the photoelectric conversion elements constituting the line sensor for each movement position by the scanning means, The sheet emits the stimulating light from both sides thereof, and after reading the stimulating light from one surface of the sheet, the sheet is turned upside down. Further comprising the door reversal means, said reading means, the image information read from both sides of the sheet, characterized in that in which arithmetic processing in correspondence with the front and back of the pixel of the sheet.

In each of the radiation image information reading apparatuses of the present invention, when the line light source and the line sensor are arranged on the same surface side of the sheet, the optical path of the excitation light from the line light source to the sheet is: It is desirable from the viewpoint of making the apparatus compact that the optical path of the photostimulated emission light from the sheet to the line sensor is at least partially overlapped. In particular, the present invention is more useful in a configuration in which line sensors are separately provided on both sides of a sheet (the first radiation image information reading apparatus of the present invention). In the configuration in which the line light sources are also separately provided on both sides of the sheet, the effect of compactness can be obtained by partially overlapping the optical path on at least one sheet side. In any of the above cases, the optical paths can be partially overlapped to further reduce the size.

In a configuration in which one line sensor reads both sides of a sheet (the second and third radiation image information reading apparatuses of the present invention), the line sensor and the line light source are located on the same side of the sheet. In this case, the size of the optical path can be reduced by partially overlapping the optical paths.

[0033]

According to the radiation image information reading apparatus of the present invention, the image information is read from both sides of the sheet by the line sensors and arithmetic processing is performed in correspondence with the front and back pixels, so that the random number can be obtained within the effective image area of the sheet. Can be greatly reduced, and even a slight difference in radiation absorption of the object can be clearly observed in the final image, that is, the detectability can be greatly improved.

According to the line sensor in the radiation image information reading apparatus of the present invention, wherein the photoelectric conversion elements are arranged in a plurality of rows, the light receiving width of each photoelectric conversion element (meaning the width of the line sensor in the short axis direction). Is smaller than the light beam width of the stimulated emission light, the entire line sensor can receive light over substantially the entire line width of the stimulated emission light, so that the light receiving efficiency can be increased.

It should be noted that the radiation image information reading apparatus of the present invention employs a configuration in which a line sensor is used as a photoelectric reading means, in comparison with a conventional radiation image information reading apparatus which uses a photoelectric reading means other than a line sensor. Accordingly, it is also possible to reduce the reading time of the stimulated emission light, to reduce the size of the apparatus, and to reduce the cost by reducing the mechanical scanning optical parts and the like.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the radiation image information reading apparatus of the present invention will be described with reference to the drawings.

FIG. 1A is a perspective view showing an embodiment of the first radiation image information reading apparatus according to the present invention, and FIG. 1B is a perspective view showing the radiation image information reading apparatus shown in FIG. It is sectional drawing which shows a line cross section.

The illustrated radiation image information reading apparatus has a stimulable phosphor sheet (hereinafter, referred to as a phosphor sheet) on which radiation image information is accumulated and recorded.
Conveying belts 40A and 40B for carrying 50 in the direction of arrow Y on which a sheet 50 is placed, with a line width of approximately 100 μm and an oscillation wavelength of 600 to
A broad area semiconductor laser (hereinafter, referred to as BLD) 11 that emits a 700 nm linear laser beam L substantially parallel to the surface of the sheet 50, a collimator lens for condensing the linear laser beam L emitted from the BLD 11, and one direction. An optical system 12 composed of a combination of toric lenses that expands the beam only at an angle of 45 degrees with respect to the surface of the sheet 50 so as to reflect the laser light L and transmit the photostimulated light M described later. The set dichroic mirror 14, the linear laser light L reflected by the dichroic mirror 14 is
The laser beam L is condensed in a linear shape (line width of about 100 μm) extending in the direction of the arrow X (parallel to the edge of the sheet), and the linear laser light L is condensed on the surface of the sheet 50 (the upper surface in FIG. ), A gradient index lens array (a lens in which a number of gradient index lenses are arranged, and a plurality of gradient index lenses are arranged. The first self-focal lens array 15) and the photostimulated light M that has been converted into a parallel light beam by the first self-focal lens array 15 and has passed through the dichroic mirror 14 The second selfoc lens array 16 condensed on the light receiving surface of the conversion element 21, and the laser light reflected on the surface of the sheet 50 slightly mixed with the stimulated emission light M transmitted through the second selfoc lens array 16. An excitation light cut filter 17 that cuts the light L and transmits the stimulating light M, and a line on which a number of photoelectric conversion elements 21 that receive the stimulating light M transmitted through the excitation light cut filter 17 and perform photoelectric conversion are arranged. sensor
20, the laser light L condensed and cut through the sheet 50 and the laser light L slightly emitted from the back surface together with the stimulating light M 'emitted from the back surface (the lower surface in the figure) of the sheet 50 The excitation light cut filter 17 'that transmits the stimulated emission light M' and the stimulated emission light M 'that has passed through the excitation light cut filter 17 are received by the photoelectric conversion elements 21' constituting the line sensor 20 'described later. A third selfoc lens array 16 'for condensing light on the surface, and a large number of photoelectric conversion elements 21' for receiving the photostimulated light M 'transmitted through the third selfoc lens array 16' and photoelectrically converting the photostimulated light M 'are arranged. An image obtained by reading signals output from the line sensors 20 ′ and the photoelectric conversion elements 21 ′ constituting each of the line sensors 20 and 20 ′ and performing a predetermined weighted addition process in correspondence with pixels on the front and back surfaces of the sheet 50. Information reading means 3 0 is provided.

Here, the sheet 50 used in the radiation image information reading apparatus of the present embodiment is formed by laminating a stimulable phosphor layer on a support layer, and the support layer is formed by photostimulated light. Is formed of a material that can transmit light.

The first selfoc lens array 15 has an effect on the dichroic mirror 14 as an image plane for forming an emission area of the photostimulated light M on the sheet 50 in a one-to-one size. The second selfoc lens array 16 has a dichroic mirror on the light receiving surface of the photoelectric conversion element 21.
The image of the photostimulated light M on the image 14 has an image plane for forming a one-to-one image. The third selfoc lens array 16 'is provided with a photoelectric conversion element 21' of the line sensor 20 '. Of the photostimulated light M 'on the back surface of the sheet 50 is formed as an image surface on which a one-to-one image is formed.

The line sensors 20 and 20 '
As shown in FIG. 2, a large number (for example, 10
(00 or more) photoelectric conversion elements 21 or 21 ′ are arranged. Each of the photoelectric conversion elements 21 or 21 ′ constituting the line sensors 20 and 20 ′ has a light receiving surface having a size of about 100 μm in length × 100 μm in width. Vertical at the surface 1
It is a size that receives stimulated emission light M emitted from a portion of 00 μm × 100 μm in width. The photoelectric conversion element 21,
Specifically, an amorphous silicon sensor, a CCD sensor, a MOS image sensor, or the like can be used as 21 '. The line sensors 20 and 20 'are the same, and are assigned different numbers for convenience of explanation.

Next, the operation of the radiation image information reading apparatus of this embodiment will be described.

First, by moving the transport belts 40A and 40B in the direction of arrow Y, the sheet 50 on which the radiation image information is stored and recorded is mounted on the transport belts 40A and 40B.
In the direction of arrow Y. The conveying speed of the sheet 50 at this time is equal to the moving speed of the belts 40A and 40B,
The moving speeds of A and 40B are input to the image information reading means 30.

On the other hand, the BLD 11 emits a linear laser beam L having a line width of approximately 100 μm substantially parallel to the surface of the sheet 50, and the laser beam L is transmitted through a collimator lens and a toric provided on the optical path. The beam is converted into a parallel beam by an optical system 12 composed of a lens, is reflected by a dichroic mirror 14, and travels in a direction perpendicular to the surface of the sheet 50.
Linear shape extending along the arrow X direction on 50 (line width d _L approximately 100
μm).

Here, the linear laser light L incident on the sheet 50 excites the stimulable phosphor layer in the condensing area of the sheet 50, and responds to the radiation image information stored and recorded in this phosphor layer. The stimulated emission light M and M 'having the emission intensity are emitted from the front and back surfaces of the sheet 50, respectively.

Stimulated light M emitted from the surface of the sheet 50
Is converted into a parallel light beam by the first selfoc lens 15, passes through the dichroic mirror 14, and is condensed by the second selfoc lens array 16 on the light receiving surface of each photoelectric conversion element 21 constituting the line sensor 20. You. At this time, the second
Stimulated light M transmitted through the SELFOC lens array 16
Light L reflected on the surface of the sheet 50 slightly mixed
Is cut by the excitation light cut filter 17.

The stimulated emission light M that has passed through the filter 17
Represents a number of photoelectric conversion elements 21 constituting the line sensor 20.
, And is converted into each image signal S by photoelectric conversion. These image signals S obtained by photoelectric conversion are input to the image information reading means 30.

On the other hand, the stimulated emission light M ′ emitted from the back surface of the sheet 50 passes through the excitation light cut filter
To the SELFOC lens array 16 '. Here, the laser light L transmitted through the sheet 50 is also slightly emitted from the back surface of the sheet 50 together with the stimulated emission light M ', and this laser light L is cut by the excitation light cut filter 17'.

The stimulated emission light M 'transmitted through the excitation light cut filter 17 is condensed on the light receiving surface of each photoelectric conversion element 21' constituting the line sensor 20 'by the third selfoc lens array 16'. You. The stimulated emission light M 'collected by the photoelectric conversion element 21' is received by each photoelectric conversion element 21 ', and is converted into each image signal S' by photoelectric conversion. These image signals S 'obtained by photoelectric conversion are converted into image information reading means 30.
Is input to

The image information reading means 30 to which the image signal S is inputted from the line sensor 20 and the image signal S 'is inputted from the line sensor 20' respectively converts the inputted image signals S and S 'to the transport belt. The pixels are associated with the pixels of the sheet 50 corresponding to the displacement amounts of 40A and 40B, and the image signals S and S 'on the front and back of the sheet associated with the same pixels are weighted and added at a predetermined addition ratio.

With the above operation, according to the image information reading apparatus of the present embodiment, the addition signal obtained by adding the front and back image signals for each pixel is a noise generated randomly on the front and back surfaces of the sheet 50, respectively. Is dispersed in the image effective area of the sheet 50, so that the noise component can be made inconspicuous as a whole of the sheet 50, and furthermore, the stimulated emission light, which is a signal component emitted from each of the front and back surfaces of the sheet 50, Since the light is condensed on each surface, the light condensing efficiency is improved, and as a result, the S / N is greatly improved.

The radiation image information reading apparatus of the above-described embodiment employs a configuration in which the optical path of the laser light L and the optical path of the stimulating light M emitted from the surface of the sheet 50 partially overlap. Thus, the apparatus is made more compact. However, the present invention is not limited to such a configuration. For example, as shown in FIG. 3, the optical path of the laser light L and the optical path of the stimulated emission light M completely overlap. It is also possible to apply a configuration that does not. In the embodiment shown in FIG. 3, it is also possible to adopt a configuration in which a line light source is also provided on the back side of the sheet. When employing a configuration in which a line light source is also provided on the back side of the sheet, it is necessary to use a sheet whose support is formed of a material that transmits excitation light.

FIG. 4 is a plan view showing another embodiment of the line sensor used in the first radiation image information reading apparatus of the present invention. The same applies to the line sensor 20 (20 ').
(Omitted) means that a large number of photoelectric conversion elements 21 are arranged along the long axis direction (arrow X direction), and the rows of the photoelectric conversion elements 21 extending in the long axis direction are aligned with the short axis direction ( Three rows (rows 20A, 20B of photoelectric conversion elements)
20C). The photoelectric conversion elements 21 are arranged in a matrix, and are arranged in a straight line in any of the major axis direction and the minor axis direction.

According to the radiation image information reading apparatus using the line sensor 20 in which the plurality of photoelectric conversion elements 21 are arranged also in the short axis direction, the effect of the radiation image information reading apparatus of the above-described embodiment is obtained. The same effect as described above can be obtained, and the light receiving width of each photoelectric conversion element 21 (meaning the width in the short axis direction of the line sensor 20) is equal to the light beam width of the stimulated emission light (in FIG. Even when the line sensor 20 is shorter than the distribution width shown in the light intensity distribution diagram, the entire line sensor 20 can receive light over substantially the entire width of the stimulating light, the light receiving efficiency can be further improved. . Thus, for example approximately equal beam width d _L and the light-receiving width of the photoelectric conversion element arrays 20B laser beam L (FIG. 5 (1) refer) sheet 50
And then diffuses inside the sheet 50 to spread the light beam width d _L
Exciting the wider region (width d _M ) than the photostimulated emission light M having a light beam width d _M wider than the light receiving width of the photoelectric conversion element array 20B
(FIG. 3 (3) shows an intensity distribution), and even when light is emitted (see FIG. 2 (2)), the stimulated emission light M having a wide light beam width can be efficiently received.

As shown in FIG. 6, the line sensor 20 in which a plurality of photoelectric conversion elements 21 are arranged in the short axis direction as shown in FIG. In the arrangement in which the photoelectric conversion elements 21 are arranged in a straight line but in the long axis direction in a zigzag manner, or as shown in FIG. Arrays can also be employed.

As shown in FIG. 8A, a stimulable phosphor layer 54 is laminated on the support layer 52, and the stimulable phosphor 53 in the stimulable phosphor layer 54 is arranged in the thickness direction of the sheet 50. A sheet 50 (a so-called anisotropic sheet) having a structure that is subdivided into a large number of micro-chambers C by an excitation light-reflective partition member 51 extending in the direction can be used. The sheet 50 has a cross section having the structure shown in FIG. 2B or FIG. 3C. The sheet 50 shown in FIG. The structure excluding the surface thereof is surrounded by a reflective partition member 51 and a support layer 52 having photostimulable emission light transmissivity. The structure shown in FIG. The obtained micro-chamber C is surrounded by only the excitation light-reflective partition wall member 51 except for the surface thereof. The excitation light reflective partition member 51 is a member formed of a material that reflects the laser light L and transmits the stimulating light M, and suppresses the diffusion of the laser light L in the direction in which the sheet surface spreads. Accordingly, the light collection efficiency of the line sensor is improved, and the sharpness of an image based on a signal obtained by photoelectric conversion can be increased.

FIG. 9 (1) is a perspective view showing an embodiment of the second radiation image information reading apparatus of the present invention, and FIG. 9 (2) is a sectional view of the radiation image information reading apparatus II shown in FIG. 9 (1). It is sectional drawing which shows a line cross section.

The illustrated radiographic image information reading apparatus includes conveying belts 40A and 40B for mounting a sheet 50 on which radiographic image information is stored and conveyed in the directions of the arrows Y and -Y, a line width of approximately 100 μm, and an oscillation wavelength of approximately 100 μm. BLD11, BLD that emits a linear laser beam L of 600 to 700 nm almost parallel to the surface of the sheet 50
An optical system 12 composed of a combination of a collimator lens for condensing the linear laser light L emitted from 11 and a toric lens for expanding the beam only in one direction, which is disposed at an angle of 45 degrees with respect to the surface of the sheet 50 In addition, a dichroic mirror 14 set so as to reflect the laser light L and transmit a stimulated emission light M described later, and the linear laser light L reflected by the dichroic mirror 14 is placed on the sheet 50 in the direction of the arrow X ( A line (almost 1 line width) extending along the sheet edge
First, the photostimulated light M emitted from the surface of the sheet 50 on which the linear laser light L is condensed and corresponding to the accumulated and recorded radiation image information is converted into a parallel light flux. The stimulated emission light M which has been converted into a parallel light beam by the selfoc lens array 15 and the first selfoc lens array 15 and has passed through the dichroic mirror 14 is collected on the light receiving surface of each photoelectric conversion element 21 constituting the line sensor 20. The laser light L reflected on the surface of the sheet 50, which is slightly mixed with the stimulated emission light M transmitted through the second selfoc lens array 16 and the second selfoc lens array 16, is cut to emit stimulated light M A line sensor 20 in which a large number of photoelectric conversion elements 21 for receiving and stimulating and converting the stimulating light M transmitted through the excitation light cut filter 17 and a sheet 50 are arranged. After the reading of the stimulated emission light M from the upper surface (in the drawing), the light guide optical system including the line sensor 20 and the line light source 11 is moved to the back side of the sheet 50 by the moving means 60, and the line sensor 20 is used to move the sheet. An image information reading means 30 is provided which receives input of image information S and S 'read from the front surface and the rear surface, respectively, and performs a predetermined weighted addition process in correspondence with pixels on the front and back of the sheet 50.

Here, the sheet 50 used in the radiation image information reading apparatus of the present embodiment has two surfaces, one on the front side and the other on the back side, with a support layer formed of a material that blocks transmission of excitation light therebetween. It is formed by stacking stimulable phosphor layers.

Next, the operation of the radiation image information reading apparatus of this embodiment will be described.

First, when the transport belts 40A and 40B move in the direction of arrow Y, the sheet 50 on which the radiation image information is stored and recorded is mounted on the transport belts 40A and 40B.
In the direction of arrow Y. The conveying speed of the sheet 50 at this time is equal to the moving speed of the belts 40A and 40B,
The moving speeds of A and 40B are input to the image information reading means 30.

On the other hand, the BLD 11 emits a linear laser beam L having a line width of approximately 100 μm substantially parallel to the surface of the sheet 50, and the laser beam L is transmitted through a collimator lens provided on the optical path and a toric laser beam. The beam is converted into a parallel beam by an optical system 12 composed of a lens, is reflected by a dichroic mirror 14, and travels in a direction perpendicular to the surface of the sheet 50.
The light is condensed on the surface 50 in a linear shape extending along the arrow X direction.

Here, the linear laser light L incident on the sheet 50 excites the stimulable phosphor layer on the surface side of the light-condensing area of the sheet 50, and the radiation image information stored and recorded in this phosphor layer Stimulated emission light M having an emission intensity corresponding to the intensity of light is emitted from the surface of the sheet 50. At this time, since the laser beam L does not pass through the support layer, it does not excite the phosphor layer on the back surface side of the sheet 50, and therefore no stimulating light is emitted from the back surface of the sheet 50.

The stimulated emission light M emitted from the surface of the sheet 50
Is converted into a parallel light beam by the first selfoc lens 15, passes through the dichroic mirror 14, and is condensed by the second selfoc lens array 16 on the light receiving surface of each photoelectric conversion element 21 constituting the line sensor 20. You. At this time, the second
Stimulated light M transmitted through the SELFOC lens array 16
Light L reflected on the surface of the sheet 50 slightly mixed
Is cut by the excitation light cut filter 17.

The stimulated emission light M that has passed through the filter 17
Represents a number of photoelectric conversion elements 21 constituting the line sensor 20.
, And is converted into each image signal S by photoelectric conversion. These image signals S obtained by photoelectric conversion are input to the image information reading means 30.

When the reading of the image signal S from the entire surface of the sheet 50 is completed, the moving means 60 moves the light guide optical system including the line sensor 20 and the line light source 11 to the back side of the sheet 50.

The conveyor belts 40A and 40B are turned over and the arrow -Y
Then, the sheet 50 placed on the transport belts 40A and 40B is transported in the direction of the arrow -Y. The BLD 11 moved to the back side of the sheet emits a linear laser beam L having a line width of about 100 μm substantially parallel to the back side of the sheet 50, and the laser beam L is provided on a collimator provided on the optical path. The beam is converted into a parallel beam by an optical system 12 composed of a lens and a toric lens, is reflected by a dichroic mirror 14 and travels in a direction perpendicular to the surface of the sheet 50. Is condensed in a linear shape extending along the arrow X direction.

Here, the linear laser light L incident on the sheet 50 excites the stimulable phosphor layer on the back surface side of the condensing area of the sheet 50, and the radiation image information stored and recorded on this phosphor layer Stimulated emission light M ′ having an emission intensity corresponding to the intensity of light is emitted from the back surface of the sheet 50.

The stimulated emission light M ′ emitted from the back surface of the sheet 50 is converted into a parallel light flux by the first selfoc lens 15, passes through the dichroic mirror 14, and is transmitted to the line sensor by the second selfoc lens array 16. Light is condensed on the light receiving surface of each photoelectric conversion element 21 constituting 20. At this time, the laser light L reflected on the surface of the sheet 50 slightly mixed with the stimulated emission light M transmitted through the second selfoc lens array 16 is cut by the excitation light cut filter 17.

The stimulated emission light M 'having passed through the filter 17 is received by a number of photoelectric conversion elements 21 constituting the line sensor 20, and is converted into image signals S' by photoelectric conversion. These image signals S 'obtained by photoelectric conversion are input to the image information reading means 30.

The image information reading means 30 receives the image signal S input from the line sensor 20 when the front side of the sheet 50 is irradiated with the laser light L and the line signal 20 when the back side is irradiated with the laser light L. The input image signals S 'are respectively associated with the pixels of the sheet 50 corresponding to the displacement amounts of the conveyor belts 40A and 40B, and further, the image signals S and S' on the front and back of the sheet associated with the same pixels. At a predetermined addition ratio.

With the above operation, according to the image information reading apparatus of the present embodiment, the addition signal obtained by adding the image signals of the front and back sides for each pixel is noise generated randomly on the front and back sides of the sheet 50, respectively. Is dispersed in the image effective area of the sheet 50, so that the noise component can be made inconspicuous as a whole of the sheet 50, and furthermore, the stimulated emission light, which is a signal component emitted from each of the front and back surfaces of the sheet 50, Since the light is condensed on each surface, the light condensing efficiency is improved, and as a result, the S / N is greatly improved.

The radiation image information reading apparatus of the above-described embodiment employs a configuration in which the optical path of the laser beam L and the optical path of the stimulating light M emitted from the surface of the sheet 50 partially overlap. Thus, the apparatus is made more compact. However, the present invention is not limited to such a configuration. For example, as shown in FIG. 10, the optical path of the laser light L and the optical path of the stimulated emission light M completely overlap. Alternatively, a configuration in which the line light source 11 and the line sensor 20 are disposed on different surfaces of the sheet 50 as shown in FIG. 11 can be adopted.

In each of the embodiments of the second radiographic image information reading apparatus of the present invention, a plurality of rows of line sensors shown in FIGS. 4, 6 and 7 and an anisotropic sheet shown in FIG. Can be applied.

FIG. 12A is a perspective view showing an embodiment of the third radiation image information reading apparatus of the present invention, and FIG. 12B is a sectional view of the radiation image information reading apparatus shown in FIG. It is sectional drawing which shows a line cross section.

The illustrated radiation image information reading apparatus differs from the apparatus of the second radiation image information reading apparatus according to the second embodiment of the present invention shown in FIG. Sheet inverting means 70 for inverting the front and back of the sheet 50 after the reading of the photostimulated light M from the
It has the same configuration except that it is provided with.

That is, the radiation image information reading apparatus of this embodiment irradiates the surface of the sheet 50 with the laser beam L to condense the stimulated emission light M emitted from the surface side. Is input to the image information reading means 30, the sheet reversing means 70 reverses the front and back of the sheet 50, and the conveyance direction of the conveyance belts 40A and 40B is reversed. The stimulated emission light M ′ emitted from the back side by irradiating the laser light L is collected, and the stimulated emission light M ′ is collected.
Is input to the image information reading means 30.

The image information reading means 30 receives the image signal S inputted from the line sensor 20 when the front side of the sheet 50 is irradiated with the laser light L and the line signal 20 when the back side is irradiated with the laser light L. The input image signals S 'are respectively associated with the pixels of the sheet 50 corresponding to the displacement amounts of the conveyor belts 40A and 40B, and further, the image signals S and S' on the front and back of the sheet associated with the same pixels. At a predetermined addition ratio.

With the above operation, according to the image information reading apparatus of this embodiment, the addition signal obtained by adding the front and back image signals for each pixel is a noise generated randomly on the front and back surfaces of the sheet 50, respectively. Is dispersed in the image effective area of the sheet 50, so that the noise component can be made inconspicuous as a whole of the sheet 50, and furthermore, the stimulated emission light, which is a signal component emitted from each of the front and back surfaces of the sheet 50, Since the light is condensed on each surface, the light condensing efficiency is improved, and as a result, the S / N is greatly improved.

The radiation image information reading apparatus according to the above-described embodiment employs a configuration in which the optical path of the laser beam L and the optical path of the stimulated emission light M emitted from the surface of the sheet 50 partially overlap. Thus, the apparatus is made more compact. However, the present invention is not limited to such a configuration. Also in this embodiment, a plurality of lines of line sensors shown in FIGS. The anisotropic sheet shown in FIG. 8 can be applied.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a first radiation image information reading apparatus of the present invention.

FIG. 2 is a main part plan view showing a relationship between a line sensor 20 and a sheet 50 and a moving direction.

FIG. 3 is a sectional view of a main part showing another embodiment of the first radiation image information reading apparatus of the present invention (part 1);

FIG. 4 is a plan view showing another embodiment of the line sensor in the radiation image information reading apparatus shown in FIG. 1 (part 1);

FIG. 5 is a diagram showing the relationship between the beam width of laser light and the beam width of stimulated emission light.

FIG. 6 is a plan view showing another mode of the line sensor in the radiation image information reading apparatus shown in FIG. 1 (part 2);

FIG. 7 is a plan view showing another mode of the line sensor in the radiation image information reading apparatus shown in FIG. 1 (part 3);

FIG. 8 shows a so-called anisotropic sheet.

FIG. 9 is a configuration diagram showing an embodiment of a second radiation image information reading apparatus of the present invention.

FIG. 10 is a configuration diagram showing another embodiment of the second radiation image information reading apparatus of the present invention (part 1).

FIG. 11 is a configuration diagram showing another embodiment of the second radiation image information reading apparatus of the present invention (part 2).

FIG. 12 is a configuration diagram showing an embodiment of a third radiation image information reading apparatus of the present invention.

[Explanation of symbols]

11 Broad area semiconductor laser (BLD) 12 Optical system consisting of collimator lens and toric lens 14 Dichroic mirror 15, 16, 16 'Selfoc lens array 17, 17' Excitation light cut filter 20, 20 'Line sensor 21, 21' Photoelectric Conversion element 30 Image information reading means 40A, 40B Conveying belt 50 Storage phosphor sheet L Laser light M, M 'Stimulated emission light

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenji Takahashi 798, Miyadai, Kaisei-cho, Ashigara-gun, Kanagawa F-Term (in reference) 2F013 AC03 AC05 5C072 AA01 BA17 CA02 CA06 DA03 DA04 DA06 DA09 EA08 HA02 NA01 NA04 RA10 VA01

Claims (8)

[Claims] 1. A line light source for linearly irradiating a part of a stimulable phosphor sheet on which radiation image information is stored with excitation light, and a stimulus emitted from a linearly irradiated part of the sheet. A line sensor in which a large number of photoelectric conversion elements are linearly arranged to receive the emitted light and perform photoelectric conversion; a scanning unit configured to relatively move the line light source and the line sensor and the sheet; and the scanning. A radiation image information reading device comprising: reading means for reading an output signal of each of the photoelectric conversion elements constituting the line sensor, for each movement position by means, wherein the sheet emits the stimulating light from both surfaces thereof. Wherein the line sensors are respectively disposed on both sides of the sheet, and the reading means reads the image information read from both sides of the sheet. A radiation image information reading apparatus for performing arithmetic processing by associating pixels on the front and back sides of the radiation image information. 2. The radiation image information reading apparatus according to claim 1, wherein the line light sources are separately provided on both sides of the sheet. 3. A line light source for linearly irradiating a part of a stimulable phosphor sheet on which radiation image information is stored and recorded with excitation light, and a stimulus emitted from the linearly irradiated part of the sheet. A line sensor in which a large number of photoelectric conversion elements are linearly arranged to receive the emitted light and perform photoelectric conversion; a scanning unit configured to relatively move the line light source and the line sensor and the sheet; and the scanning. A radiation image information reading device comprising: reading means for reading an output signal of each of the photoelectric conversion elements constituting the line sensor, for each movement position by means, wherein the sheet emits the stimulating light from both surfaces thereof. Further comprising a sensor moving means for moving the line sensor to the other surface side of the sheet after reading the stimulating light from one surface of the sheet. , The reading means, the image information read from both sides of the sheet, read radiation image information, characterized in that the arithmetic processing in correspondence with the front and back of the pixels of the seat device. 4. The radiation image information reading apparatus according to claim 3, wherein the sensor moving means moves the line light source together with the line sensor to the other surface of the sheet. 5. A line light source for linearly irradiating a part of a stimulable phosphor sheet on which radiation image information is stored and recorded with excitation light, and a stimulating light emitted from the linearly irradiated part of said sheet. A line sensor in which a large number of photoelectric conversion elements are linearly arranged to receive the emitted light and perform photoelectric conversion; a scanning unit configured to relatively move the line light source and the line sensor and the sheet; and the scanning. A radiation image information reading device comprising: reading means for reading an output signal of each of the photoelectric conversion elements constituting the line sensor, for each movement position by means, wherein the sheet emits the stimulating light from both surfaces thereof. Further comprising sheet reversing means for reversing the front and back of the sheet after reading the stimulated emission light from one surface of the sheet, wherein the reading means comprises: A radiographic image information reading apparatus for performing arithmetic processing on image information read from both sides of the sheet in correspondence with pixels on the front and back of the sheet. 6. The method according to claim 1, wherein a plurality of rows of the photoelectric conversion elements constituting the line sensor are arranged in a direction orthogonal to an arrangement direction of the photoelectric conversion elements. 6. The radiation image information reading device according to any one of items 5. 7. The light-emitting region of the sheet for stimulated emission light,
The radiation image information according to any one of claims 1 to 6, wherein the radiation image information is subdivided into a large number of microcells by an excitation light reflective partition member extending in a thickness direction of the sheet. Reader. 8. When the line light source and the line sensor are arranged on the same surface side of the sheet, an optical path of the excitation light from the line light source to the sheet, and the line sensor from the sheet. The radiation image information reading apparatus according to any one of claims 1 to 7, wherein an optical path of the stimulated emission light reaching at least a part thereof is overlapped.