JP2002116515A - Radiation image information reading method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation image information reading method and device which is capable of automatically detecting the degree of the chemical deterioration of stimulus phosphors in a stimulus phosphor sheet during reading of radiation image information and adequately reading image information in accordance with the result thereof or subjecting the sheet to adequate processing. SOLUTION: The display of the sensor of the stimulus phosphor sheet having the sensor to detect and display the degree of moisture absorption is detected before or after reading of the radiation image information and when the display exceeds a specified level, the display is recorded and/or notified as an error or the reading conditions and/or image processing conditions are controlled according to the level of the display or the sheet is subjected to processing to restore the moisture absorption after the reading.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for reading radiation image information stored and recorded on a stimulable phosphor sheet.

[0002]

2. Description of the Related Art When irradiated with radiation such as X-rays, a part of the radiation energy is absorbed and accumulated, and then, when irradiated with electromagnetic waves (excitation light) such as visible light and infrared rays, the accumulated radiation energy is reduced. A stimulable phosphor (accumulative phosphor) having a property of exhibiting stimulable luminescence in response to the stimulable phosphor sheet is used.
Radiation transmitted from the subject or emitted from the subject is irradiated to temporarily accumulate and record the radiation image information of the subject or the subject, and then the sheet is scanned with excitation light such as laser light and emitted sequentially as stimulated emission light. A radiation image recording / reproducing method, which comprises reading out the stimulated emission light photoelectrically and obtaining an image signal, is widely used in practice. After the reading of the sheet is completed, the remaining radiation energy is erased, and the sheet is prepared for the next photographing and used repeatedly.

As another method of the above-mentioned radiation image recording / reproducing method, Japanese Patent Application No. 11-372978 by the present applicant discloses that the radiation absorbing function and the energy storage function of the conventional stimulable phosphor are separated. A stimulable phosphor sheet containing at least a stimulable phosphor (energy storage phosphor) and a phosphor (radiation absorption phosphor) that absorbs radiation and emits light in the ultraviolet to visible region. A radiation image forming method using a combination with a fluorescent screen has been proposed. In this method, radiation transmitted through a subject is first converted into light in an ultraviolet or visible region by a radiation absorbing phosphor of the screen or sheet, and the light is then converted to a radiation image by an energy storage phosphor of the sheet. Store and record as information. Next, the sheet is scanned with excitation light to emit stimulated emission light, and the stimulated emission light is photoelectrically read to obtain an image signal. A stimulable phosphor sheet containing such a phosphor for energy storage,
Included in the present invention.

In the above-described radiation image recording / reproducing method (and radiation image forming method), image processing such as gradation processing and frequency processing can be performed on the obtained image signal, and a large amount of information can be obtained with a small irradiation dose. There is an advantage that a radiographic image can be obtained.

As a method of reading radiation image information emitted as photostimulated light, conventionally, pixel division is performed by scanning with excitation light, and photostimulable light is detected by using a photomultiplier tube having a wide light receiving surface or the like. A method using a light receiving element such as a photoconductive element is known. Then, from the viewpoints of shortening the reading time of the stimulated emission light, reducing the size of the reading device, and reducing the cost, pixel division is performed by a light receiving element such as a two-dimensional solid-state imaging device or a semiconductor line sensor, and the time is controlled by an electric circuit. A method for forming a sequence image signal has been proposed. For example, Japanese Patent Publication No. 5-32945 discloses that a light emitted from a fluorescent lamp or the like is irradiated on a stimulable phosphor sheet through a slit to irradiate excitation light linearly (“line excitation”), An apparatus for detecting emitted photostimulated light by a line sensor including a large number of photoelectric conversion elements arranged opposite to a portion irradiated with excitation light ("line detection") is described.

The stimulable phosphor sheet (also referred to as a radiation image conversion panel) used in the radiation image recording / reproducing method has, as a basic structure, a support and a phosphor layer provided thereon. However, when the phosphor layer is self-supporting, a support is not necessarily required. The phosphor layer usually comprises a stimulable phosphor and a binder containing and supporting the stimulable phosphor in a dispersed state, but does not contain a binder formed by a vapor deposition method or a sintering method. There are also known ones composed only of aggregates of the body and those in which the gaps between the aggregates of the stimulable phosphor are impregnated with a polymer substance. In addition, a protective film is usually provided on the upper surface of the stimulable phosphor layer (the surface not facing the support) to protect the phosphor layer from chemical deterioration or physical impact. ing.

[0007] The stimulable phosphor contained in the stimulable phosphor sheet deteriorates when absorbing moisture or the like in the air and changes its emission characteristics. When the moisture absorption is remarkable, the phosphor itself deliquesces. May be done. In particular, when the phosphor layer is formed by a vapor deposition method, the phosphor is not covered with a binder such as a resin, so that the phosphor easily absorbs moisture and tends to deteriorate. Due to the deterioration of the stimulable phosphor, the stimulable phosphor sheet causes a decrease in sensitivity and a decrease in image sharpness. In order to prevent such stimulable phosphor from being chemically degraded, a protective film made of a synthetic resin or the like is provided on the phosphor layer, or a resin coating film or a spacer is provided on a side surface of the phosphor layer. It is common practice to shield the phosphor layer from the outside air as much as possible. However, while the sheet is used repeatedly over a long period of time, these synthetic resin materials may notably permeate moisture in the air, and water may enter from the joints between the spacer and the support. Therefore, deterioration of the stimulable phosphor cannot be completely avoided. Furthermore, in practice, it is difficult to notice chemical deterioration if the same sheet is used repeatedly, and conversely, if it is left for a long time,
There is a problem that the state of the sheet cannot be determined unless the radiation image information is once accumulated and read and read.

For the purpose of detecting the deterioration of the stimulable phosphor due to moisture absorption, Japanese Patent Application Laid-Open No. Sho 61-239200 discloses that the phosphor layer of the stimulable phosphor sheet is brought into physical contact with the phosphor layer or via air. Thus, it has been proposed to provide an indicating means for indicating a change that can be detected by contact with moisture such as cobalt chloride which indicates a color change. It is stated that the user can directly detect the change in the indicating means to detect the deterioration and determine whether or not the use can be continued.

[0009]

SUMMARY OF THE INVENTION The present invention automatically detects the degree of chemical deterioration of a stimulable phosphor in a stimulable phosphor sheet at the time of reading radiation image information, and furthermore, based on the result, It is an object of the present invention to provide a radiographic image information reading method and apparatus capable of suitably reading image information or performing appropriate processing on a sheet.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a stimulable phosphor sheet provided with a sensor for detecting and displaying the degree of moisture absorption as described above. Automatically detects changes, determines the availability of sheets according to the level of change, records / notifies them, sets optimal reading conditions and image processing conditions, and performs processing for recovery from deterioration. By applying
The purpose is to always obtain a good radiation image and to use the sheet in a better condition. Since the user does not need to visually detect and judge individually as in the past, the burden on the user can be reduced.

[0013] First, the present invention is to move a stimulable phosphor sheet, which has a sensor for detecting and indicating the degree of moisture absorption and on which radiation image information is stored and recorded, in the plane direction of the sheet while moving the sheet. The portion is irradiated with excitation light in a direction different from the moving direction, and stimulated emission light emitted from the excitation light irradiation portion and / or the back surface of the irradiation portion of the sheet is sequentially photoelectrically detected, and the radiation image information is converted into an electrical image. In the method for reading radiation image information, which is obtained as a signal, before or after reading, a display of a sensor of the sheet is detected, and when the display exceeds a certain level, recording as an error and / or notification is performed. The method is characterized by a method for reading radiation image information.

The present invention also provides scanning means for moving a stimulable phosphor sheet on which radiation image information is stored and provided in a plane direction thereof, comprising a sensor for detecting and displaying the degree of moisture absorption, and a part of the sheet. A radiation source comprising: an excitation light source for irradiating excitation light in a direction different from the moving direction; and a photodetector for sequentially and photoelectrically detecting stimulated emission light emitted from an excitation light irradiation portion of the sheet and / or a back surface of the irradiation portion. An image information reading apparatus, comprising: means for detecting a display of a sensor of the sheet; means for recording as an error when the display exceeds a certain level; and / or means for notifying. There is also a radiation image information reading device.

[0013] Second, the present invention relates to a stimulable phosphor sheet having a sensor for detecting and displaying the degree of moisture absorption and having radiation image information stored therein, while moving the stimulable phosphor sheet in the plane direction of the sheet. The portion is irradiated with excitation light in a direction different from the moving direction, and stimulated emission light emitted from the excitation light irradiation portion and / or the back surface of the irradiation portion of the sheet is sequentially photoelectrically detected by a photodetector, and the light detection is performed. In the radiation image information reading method of sequentially reading the output from the container according to the movement of the sheet and obtaining the radiation image information as an electric image signal, before reading, the display of the sensor of the sheet is detected. Controlling a reading condition according to the display level, and / or controlling an image processing condition, and performing image processing on the obtained image signal. That.

The present invention also provides a scanning means for moving a stimulable phosphor sheet on which radiation image information is stored and provided in a plane direction thereof, comprising a sensor for detecting and displaying the degree of moisture absorption, and a part of the sheet. An excitation light source for irradiating the sheet with excitation light in a direction different from the moving direction, a photodetector for sequentially photoelectrically detecting stimulated emission light emitted from an excitation light irradiation portion of the sheet and / or a back surface of the irradiation portion, and the light detection A radiation image information reading apparatus comprising: reading means for sequentially reading an output from a container in accordance with the movement of the sheet and obtaining radiation image information as an electric image signal, wherein a means for detecting a display of a sensor of the sheet is provided. And / or means for controlling reading conditions and / or image processing conditions in accordance with the display level, and / or image processing means. There is also the location.

[0015] Third, the present invention provides a stimulable phosphor sheet having a sensor for detecting and displaying the degree of moisture absorption and storing radiation image information, while moving the stimulable phosphor sheet in the plane direction of the sheet. The portion is irradiated with excitation light in a direction different from the moving direction, and stimulated emission light emitted from the excitation light irradiation portion and / or the back surface of the irradiation portion of the sheet is sequentially photoelectrically detected by a photodetector, and the light detection is performed. In the radiation image information reading method of sequentially reading the output from the container according to the movement of the sheet and obtaining the radiation image information as an electric image signal, the display of the sensor of the sheet is detected before or after the reading. When the display exceeds a certain level, the radiation image information reading method is characterized in that the sheet is subjected to moisture absorption recovery processing after reading.

According to the present invention, there is also provided scanning means for moving a stimulable phosphor sheet on which radiation image information is stored and provided in a plane direction thereof, comprising a sensor for detecting and displaying the degree of moisture absorption, and a part of the sheet. An excitation light source for irradiating the sheet with excitation light in a direction different from the moving direction, a photodetector for sequentially photoelectrically detecting stimulated emission light emitted from an excitation light irradiation portion of the sheet and / or a back surface of the irradiation portion, and the light detection A radiation image information reading apparatus comprising: reading means for sequentially reading an output from a container in accordance with the movement of the sheet and obtaining radiation image information as an electric image signal, wherein a means for detecting a display of a sensor of the sheet is provided. The radiation image information reading apparatus further comprises means for performing a moisture absorption recovery process on the sheet after reading when the display exceeds a certain level.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the radiation image information reading method of the present invention, the stimulable phosphor sheet sensor displays the degree of moisture absorption by a color change. It is preferable to detect by using or by measuring the light reflectance.

Hereinafter, a first radiation image information reading method and apparatus of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram showing an example of a radiation image information reading apparatus according to the present invention. In FIG. 1, a radiation image information reading apparatus includes a scanning belt 40 on which a stimulable phosphor sheet 10 is placed and conveyed in an arrow Y direction, a laser light source 11 that emits excitation light L, and an excitation light L emitted from the laser light source 11. Lens 12 for linearly condensing the light on the sheet 10, a gradient index lens array (a large number of lenses) for condensing the photostimulated light M emitted from the sheet 10 by condensing the excitation light L on the line sensor 13. 13 is a lens in which refractive index distribution type lenses are arranged, and is hereinafter referred to as a SELFOC lens array) 13. Excitation reflected on the surface of the sheet 10 slightly mixed with the stimulating light M transmitted through the SELFOC lens array 13. Excitation light cut filter 14 that cuts light L and transmits stimulated emission light M, Excitation light cut filter 1
4, a line sensor 20 in which a large number of photoelectric conversion elements 21 that receive the photostimulated light M that has passed through the photoelectric conversion element 4 and perform photoelectric conversion are provided, and a signal Q output from the line sensor 20 is processed in accordance with a portion of the sheet 10. Then, the image information reading means 30 for outputting as the electric image signal S, the color discrimination sensor 50 for detecting the color change of the moisture absorption display sensor 5 of the sheet 10, and the error in the recording / notifying means 52 based on the level of the color change. And a recording / notifying unit 52 for controlling recording and / or notification.

FIG. 2A shows a stimulable phosphor sheet 10.
FIG. 2B is a plan view showing the configuration of FIG. 1, and FIG. 2B is a cross-sectional view taken along line II of FIG. In FIG. 2, the stimulable phosphor sheet 10 has a configuration in which a support 1, a phosphor layer 2, and a transparent protective film 3 are sequentially laminated, and a resin coating film 4 is provided on a side end thereof. A sensor 5 for detecting and indicating the degree of moisture absorption is provided at the upper end of the phosphor layer. The moisture absorption display sensor 5 is made of, for example, cobalt chloride and shows a color change upon contact with moisture. The phosphor layer 2 is a layer made of a CsBr: Eu stimulable phosphor formed by a vapor deposition method.

The moisture absorption display sensor 5 has some correlation between the degree of moisture absorption of the phosphor and the color change such that the stimulable phosphor shows a color change as it absorbs moisture. The color change need not be strictly proportional to the amount of moisture absorbed by the phosphor.

A laser light source (LED (light emitting diode) array) 11 is disposed in a direction orthogonal to the arrow Y direction.
The laser light source 11 emits light in the visible region having a wavelength of 630 to 690 nm. The cylindrical lens 12 condenses the light emitted from the laser light source 11 linearly on the sheet 10 in a direction orthogonal to the arrow Y direction.

The selfoc lens array 13 has a light receiving surface of the line sensor 20 that functions as an image plane for forming a light emitting area of the stimulating light M on the sheet 10 in a one-to-one size.

The line sensor 20 has a configuration in which a large number (for example, 1000 or more) of photoelectric conversion elements (CCD, charge-coupled elements) 21 are arranged in a direction orthogonal to the arrow Y direction. Each of the large number of photoelectric conversion elements 21 has a length of 100 μm.
× Has a light receiving surface of about 100 μm wide,
It corresponds to a pixel. Each light receiving surface receives stimulated emission light M emitted from a region of about 100 μm × 100 μm on the surface of the stimulable phosphor sheet 10.

The color discrimination sensor 50 has a red LED, a blue L
The color of the sensor 5 is detected by irradiating the three-color synthesized light from the three light sources of the ED and the green LED to the moisture absorption display sensor 5 of the sheet 10 and how close the color is to the registered color. Is represented by a digital value. The color change of the moisture absorption display sensor 5 and the CsBr: E
The correlation with the deterioration of the u-stimulable phosphor or the change in the image conversion characteristics of the sheet (such as a decrease in image quality such as sensitivity and sharpness) is determined, for example, when the use of the sheet 10 is impossible. The color is determined, and the color is set as a registered color.

The first radiation image information reading method of the present invention can be carried out as follows using the above-described reading device and stimulable phosphor sheet. First, a stimulable phosphor sheet 10 on which radiation image information of a subject is accumulated by being irradiated with radiation such as X-rays transmitted through the subject is placed on a scanning belt 40 and conveyed in the arrow Y direction. Is done. The conveying speed of the sheet 10 is equal to the moving speed of the belt 40, and the moving speed of the belt 40 is input to the image information reading means 30.

At the same time, the excitation light L emitted from the laser light source 11 is condensed on the sheet 10 by a cylindrical lens 12 provided on the optical path in a linear shape extending in a direction orthogonal to the arrow Y direction. You.

The excitation of the linear excitation light L incident on the sheet 10 causes the stimulated emission light M having an intensity corresponding to the accumulated and recorded radiation image information to be emitted from the condensing area of the sheet 10 and its vicinity. . The stimulated emission light M is condensed by the Selfoc lens array 13 on the light receiving surface of each photoelectric conversion element 21 constituting the line sensor 20. At this time, the excitation light L slightly reflected in the stimulated emission light M transmitted through the selfoc lens array 13 and reflected on the surface of the sheet 10 is cut by the excitation light cut filter 14.

The stimulated emission light M received by each photoelectric conversion element 21 is photoelectrically converted, and each signal Q obtained by the photoelectric conversion is input to the image information reading means 30. Each signal Q is processed by the image information reading means 30 in accordance with the position of the sheet 10 based on the moving speed of the scanning belt 40, and is output as image data to an image display device (not shown).

On the other hand, the sheet 10 for which reading has been completed is further conveyed by the scanning belt 40, and a color change of the moisture absorption display sensor 5 of the sheet 10 is detected by the color discrimination sensor 50, and the digital value (for example, 0 to 999) is obtained. And is output to the control means 51.

In the control means 51, based on the digital value output from the color discrimination sensor 50, if the digital value is 950 or more, for example, the recording / notification means 52 makes the above reading as an error in the sheet number, date and time, It is controlled so as to notify that the continuous use of the seat 10 is impossible through recording together with a digital value representing the moisture absorption, emitting a sound such as a buzzer, or turning on or blinking a lamp. . Alternatively, a stamp may be directly applied to a spot (outside the image area) of the sheet 10 that is noticeable, or may be displayed together on a display screen such as a CRT on which a radiation image is displayed. If the digital value is 800 or more, for example, under the control of the control unit 51,
In the recording / notifying means 52, a warning can be issued by sound or blinking of a lamp.

The control from the control means 51 may be further divided into several steps corresponding to the digital value output from the color discrimination sensor 50, or may be performed by the recording / notifying means 52.
Recording and notification according to each step of the control signal. Further, two or more of the above-described recording and notification may be performed in combination. Note that even if the digital value output from the color determination sensor 50 is not equal to or higher than a certain level, the digital value can be recorded and notified as a guide for determining the state of the sheet. Color discriminating sensor 5
The detection of the color change due to 0 may be performed before reading the image information.

Next, a second radiation image information reading method and apparatus according to the present invention will be described in detail by taking the case of using the reader shown in FIG. 3 as an example.

FIG. 3 is a schematic configuration diagram showing another example of the radiation image information reading apparatus of the present invention. In FIG. 3, the radiation image information reading apparatus includes a scanning belt 40 on which a stimulable phosphor sheet 10 is placed and transported in the direction of arrow Y, a laser light source 11 that emits excitation light L, and an excitation light L emitted from the laser light source 11. Lens 12 for condensing light on the sheet 10 in a linear manner, a selfoc lens array 13 for condensing stimulated emission light M emitted from the sheet 10 by condensing the excitation light L on the line sensor 13, and a selfoc lens array An excitation light cut filter 14 that cuts off the excitation light L slightly mixed with the stimulated emission light M that has passed through the light source 13, and a large number of photoelectric conversions that receive the photostimulated emission light M that has passed through the excitation light cut filter 14 and perform photoelectric conversion. The line sensor 20 in which the elements 21 are arranged, and a signal Q output from the line sensor 20 are subjected to arithmetic processing in accordance with a portion of the sheet 10 to obtain an electrical image. Image processing means 31 for the image information reading unit 30, various types of image processing on the image signal S is subjected to output as the signal S, the sheet 1
0, a color discrimination sensor 50 for detecting a color change of the moisture absorption display sensor 5, and the laser light source 1 based on the level of the color change.
1 and / or a control unit 51 for controlling the reading conditions in the line sensor 20 and / or the image processing conditions in the image processing unit 31.

First, prior to reading of the radiation image information, the stimulable phosphor sheet 10 on which the radiation image information of the subject is stored is placed on the scanning belt 40 and conveyed in the arrow Y direction. The color change of the moisture absorption display sensor 5 is detected by the color discrimination sensor 50, represented by a digital value, and output to the control means 51.

The control means 51 controls the laser light source 11 to emit a constant level of strong excitation light if the digital value is 500 or more, based on the digital value output from the color discrimination sensor 50, for example. I do.
Alternatively, control is performed such that the charge accumulation time in each photoelectric conversion element 21 of the line sensor 20 is lengthened. Alternatively, control is performed so that the image processing unit 31 performs appropriate image processing based on the image signal S. Such control by the control means 51 may be divided into several steps corresponding to the digital value from the color discrimination sensor 50, or may be performed simultaneously by combining a plurality of these controls. Good.

Next, the sheet 10 is further conveyed by the scanning belt 40 in the direction of arrow Y. At this time, sheet 1
The transport speed of 0 is equal to the moving speed of the belt 40, and the moving speed of the belt 40 is input to the image information reading means 30.

At the same time, the excitation light L emitted from the laser light source 11 with strong energy under the control of the control means 51
Is a cylindrical lens 12 provided on the optical path.
Accordingly, the light is condensed on the sheet 10 in a linear shape extending along a direction orthogonal to the arrow Y direction.

The excitation of the linear excitation light L incident on the sheet 10 causes the stimulated emission light M having an intensity corresponding to the accumulated and recorded radiation image information to be emitted from the light condensing area of the sheet 10 and its vicinity. . The stimulated emission light M is condensed by the Selfoc lens array 13 on the light receiving surface of each photoelectric conversion element 21 constituting the line sensor 20, and
Excitation light L transmitted through excitation light cut filter 14 and mixed
Is cut.

The stimulated emission light M received by each photoelectric conversion element 21 is photoelectrically converted, and each signal Q obtained by the photoelectric conversion is input to the image information reading means 30. Each signal Q is processed by the image information reading means 30 in accordance with the position of the sheet 10 based on the moving speed of the scanning belt 40, and is output to the image processing means 31 as an image signal S.

In the image processing means 31, under the control of the control means 51, processing for increasing the image sharpness is performed more strongly on the image signal S. Further, in accordance with a change in image conversion characteristics of the sheet due to deterioration of the stimulable phosphor, various image processing in a broad sense including normalization and S value calculation can be performed at a desired level and appropriately combined as necessary. . The image signal S may be further subjected to various known image processing such as gradation processing and frequency processing. The image signal S ′ subjected to the image processing is output to an image display device (not shown).

Next, a third radiation image information reading method and apparatus according to the present invention will be described in detail by taking the case of using the reader shown in FIG. 4 as an example.

FIG. 4 is a schematic configuration diagram showing another example of the radiation image information reading apparatus of the present invention. In FIG. 4, the radiation image information reading apparatus includes a scanning belt 40 on which the stimulable phosphor sheet 10 is placed and conveyed in the direction of arrow Y, a laser light source 11 that emits excitation light L, and an excitation light L emitted from the laser light source 11. Lens 12 for condensing light on the sheet 10 in a linear manner, a selfoc lens array 13 for condensing stimulated emission light M emitted from the sheet 10 by condensing the excitation light L on the line sensor 13, and a selfoc lens array An excitation light cut filter 14 that cuts off the excitation light L slightly mixed with the stimulated emission light M that has passed through the light source 13, and a large number of photoelectric conversions that receive the photostimulated emission light M that has passed through the excitation light cut filter 14 and perform photoelectric conversion. The line sensor 20 in which the elements 21 are arranged, and a signal Q output from the line sensor 20 are subjected to arithmetic processing in accordance with a portion of the sheet 10 to obtain an electrical image. The image information reading means 30 for outputting a signal S, the sheet 1
A color discrimination sensor 50 for detecting a color change of the moisture absorption display sensor 5 of 0, a control means 51 for controlling the moisture absorption recovery means 53 to operate based on the level of the color change, and a moisture absorption recovery means 53 are provided. is there.

The moisture absorption recovery means 53 comprises a heater for heating the sheet 10 at a constant temperature for a constant time. The heating may be performed under reduced pressure. Alternatively, a device that sends warm air to the sheet 10 may be used. The treatment for recovering moisture absorption is not limited to the heat treatment, and any treatment such as a degassing treatment can be performed according to the type of the stimulable phosphor and the structure of the sheet.

First, the stimulable phosphor sheet 10 on which the radiation image information of the subject is stored is placed on the scanning belt 40 and transported in the direction of arrow Y. The conveying speed of the sheet 10 is equal to the moving speed of the belt 40, and the moving speed of the belt 40 is input to the image information reading means 30.

At the same time, the excitation light L emitted from the laser light source 11 is condensed on the sheet 10 by a cylindrical lens 12 provided on the optical path in a linear shape extending in a direction orthogonal to the arrow Y direction. You.

The excitation of the linear excitation light L incident on the sheet 10 causes the stimulated emission light M having an intensity corresponding to the accumulated and recorded radiation image information to be emitted from the condensing area of the sheet 10 and its vicinity. . The stimulated emission light M is condensed by the Selfoc lens array 13 on the light receiving surface of each photoelectric conversion element 21 constituting the line sensor 20, and
Excitation light L transmitted through excitation light cut filter 14 and mixed
Is cut.

The stimulated emission light M received by each photoelectric conversion element 21 is photoelectrically converted, and each signal Q obtained by the photoelectric conversion is input to the image information reading means 30. Each signal Q is processed by the image information reading means 30 in accordance with the position of the sheet 10 based on the moving speed of the scanning belt 40, and output to an image display device (not shown).

On the other hand, the sheet 10 that has been read is further conveyed by the scanning belt 40, and the color change of the moisture absorption display sensor 5 of the sheet 10 is detected by the color discrimination sensor 50, and is represented by a digital value. Is output to

The control means 51 controls the moisture absorption recovery means 53 to operate based on the digital value output from the color discrimination sensor 50 if, for example, the digital value is 800 or more.

In the moisture absorption recovery means 53, under the control of the control means 51, a process is performed in which the sheet 10 is heated at a constant temperature for a predetermined time by a heater to dry the stimulable phosphor in the sheet 10. In the case where the phosphor does not completely return to the original state by the moisture absorption recovery processing, if the image conversion characteristics of the sheet are improved at least to some extent, the above-described second method and the like are used thereafter. This is meaningful because an improvement in image quality can be expected. The control by the control means 51 may be divided into several steps such as changing the heating time and the temperature based on the digital value from the color discrimination sensor 50.

The first, second, and third reading methods described above may be performed separately, but may be performed in an appropriate combination. The reading apparatus shown in FIGS. 1, 3, and 4 may have a configuration in which respective units are combined correspondingly.

Further, the radiation image information reading apparatus of the present invention is not limited to the illustrated embodiment. For example, the color discrimination sensor 50 is adapted to respond to the color change of the moisture absorption display sensor 5 of the stimulable phosphor sheet 10. It may be a means for measuring the light reflectance at the specified wavelength, or if the moisture absorption display sensor 5 indicates another change such as a potential difference, it may be a detecting means corresponding thereto. . Further, the color determination sensor 50 is installed in the apparatus corresponding to a position in the sheet 10 to which the moisture absorption display sensor 5 is attached.

The light source, the condensing optical system between the light source and the stimulable phosphor sheet, the optical system between the sheet and the line sensor, and the line sensor can also employ various known structures. For example, in the above description, the line light source and the line sensor are arranged on the same surface side of the stimulable phosphor sheet, but may be arranged on the opposite surface side of the sheet.

As described above, the line light source itself may be linear, and a fluorescent lamp, a cold cathode fluorescent lamp, or the like may be used. Alternatively, the emitted excitation light may be linear, and a broad area laser or the like may be used. The excitation light emitted from the line light source may be emitted continuously or may be pulsed light. From the viewpoint of noise reduction, it is preferable that the light is a high-output pulse light.

As the line sensor, in addition to the CCD sensor, an amorphous silicon sensor, a CCD with a back illuminator, a MOS image sensor, or the like can be used.

In the above embodiment, the optical system between the stimulable phosphor sheet and the line sensor is set to a 1: 1 image forming system for the sake of simplicity. Good. However, it is preferable to use a unity or magnifying optical system in order to increase the light collection efficiency.

The moving direction of the stimulable phosphor sheet is as follows.
It is desirable that the direction is substantially perpendicular to the length direction of the line light source and the line sensor, but, for example, within a range in which the excitation light can be irradiated uniformly over substantially the entire surface of the sheet,
It may be moved in an oblique direction deviating from the length direction or in a zigzag manner.

Further, in the above description, the image information is read by using a combination of a line light source and a line sensor. However, the image information is read by a combination of a point light source such as a laser and a photomultiplier tube, or a two-dimensional image. A configuration including a combination of the excitation unit and the two-dimensional solid-state imaging device may be employed.
Various image output means for outputting and displaying a visible image represented by an image signal on a CRT, a dry film, or the like, suction means for pulling out the stimulable phosphor sheet contained in the cassette from the cassette, or a sheet after reading is completed. It is also possible to adopt a configuration further provided with an erasing means for appropriately emitting the remaining radiation energy.

The stimulable phosphor sheet to which the method and apparatus of the present invention can be applied is not limited to the configuration shown in FIG. 2, and the moisture-absorbing display sensor may be any sensor as long as its display can be detected from outside the sheet. At a position. However, in order to more accurately detect the degree of moisture absorption of the stimulable phosphor, it is desirable to provide the phosphor in contact with the phosphor layer. Further, the display is not limited to one that can be visually detected such as a color change, and any display may be used as long as it can be detected by any measuring device such as a potential difference. Further, the other configurations of the stimulable phosphor and the sheet are not limited to the CsBr: Eu phosphor and the configuration shown in FIG. 2, and various known stimulable phosphors and configurations can be used. Regarding the configuration of the stimulable phosphor sheet, see, for example,
No. 200 can be referred to.

However, the method and apparatus of the present invention can be advantageously applied to a stimulable phosphor sheet containing an alkali metal halide phosphor represented by the following basic composition formula (I) as a stimulable phosphor. Can be applied.

[0062] The basic formula ^{(I): M I X ·} aM II X '2 · bM III X "3: zA ‥‥ (I) provided that, M ^I is Li, Na, K, from the group consisting of Rb and Cs Represents at least one alkali metal selected,
M ^II is Be, Mg, Ca, Sr, Ba, Ni, Cu, Z
represents at least one kind of alkaline earth metal or divalent metal selected from the group consisting of n and Cd, wherein M ^III is Sc,
Y, La, Ce, Pr, Nd, Pm, Sm, Eu, G
d, Tb, Dy, Ho, Er, Tm, Yb, Lu, A
represents at least one rare earth element or trivalent metal selected from the group consisting of l, Ga, and In;
e, Pr, Nd, Sm, Eu, Gd, Tb, Dy, H
o, Er, Tm, Yb, Lu, Na, Mg, Cu, A
represents at least one rare earth element or metal selected from the group consisting of g, Tl and Bi. X, X 'and X "each represent at least one halogen selected from the group consisting of F, Cl, Br and I. a, b and z
Represents numerical values in the range of 0 ≦ a <0.5, 0 ≦ b <0.5, and 0 ≦ z <0.2, respectively.

It is preferable that M ^I in the basic composition formula (I) contains at least Cs. It is preferable that X contains at least Br. A is particularly preferably Eu or Bi.

[0064]

According to the method and apparatus for reading radiographic image information of the present invention, simultaneously with reading of radiographic image information, the same apparatus is used to reduce the chemical degradation of the stimulable phosphor in the stimulable phosphor sheet. The degree can be automatically detected and notified to the user. Further, according to the degree of the deterioration, optimal reading conditions and image processing conditions can be set, or processing for recovering the deterioration can be performed. This allows
A good radiation image can always be obtained, and the sheet can be used in a better condition, so that the user can use the stimulable phosphor sheet repeatedly for a long period of time with peace of mind. Further, since it is not necessary to visually detect and determine the possibility of using the sheet as in the past, it is possible to reduce the burden on the user.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an example of a radiation image information reading apparatus according to the present invention.

FIG. 2A is a plan view showing an example of a stimulable phosphor sheet used in the present invention, and FIG. 2B is a cross-sectional view taken along line II of FIG.

FIG. 3 is a configuration diagram showing another example of the radiation image information reading apparatus of the present invention.

FIG. 4 is a configuration diagram showing another example of the radiation image information reading apparatus of the present invention.

[Explanation of symbols]

 Reference Signs List 5 Humidity display sensor 10 Storage phosphor sheet 11 Laser light source 12 Cylindrical lens 13 Selfoc lens array 14 Excitation light cut filter 20 Line sensor 21 Photoelectric conversion element 30 Image information reading means 31 Image processing means 40 Scanning belt 50 Color discrimination sensor 51 control means 52 recording / notification means 53 moisture absorption recovery means L excitation light M photostimulated emission light Q signal S image signal

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G21K 4/00 G21K 4/00 L 5C072 H04N 1/04 H04N 1/04 EF term (reference) 2G083 AA03 BB04 BB05 CC02 DD20 EE08 2H013 AC05 AC06 2H108 AA06 CA00 CB01 JA01 5B047 AA17 AB02 BA01 BB02 BC01 BC05 BC12 CA02 CA23 CB11 DB01 DC06 5B057 AA07 BA02 BA03 CA08 CA12 CA16 CB08 CB12 CB16 CE03 DA03 DB06 DC25 5C072 AA01 DA04 BA04

Claims (12)

[Claims] 1. A stimulable phosphor sheet on which a radiation image information is stored and provided with a sensor for detecting and displaying the degree of moisture absorption is moved in a plane direction of the stimulable phosphor sheet while exciting light is applied to a part of the sheet. Irradiation is performed in a direction different from the moving direction, and stimulated emission light emitted from the excitation light irradiation portion and / or the back surface of the irradiation portion of the sheet is sequentially photoelectrically detected to obtain radiation image information as an electric image signal. A radiographic image information reading method, wherein before or after reading, a display of a sensor of the sheet is detected, and when the display exceeds a certain level, the radiographic image is recorded as an error and / or notified. Information reading method. 2. A stimulable phosphor sheet sensor for displaying the degree of moisture absorption by a color change, wherein the color change of the sensor is detected by using a color determination sensor or by measuring light reflectance. The radiation image information reading method according to claim 1. 3. A scanning means for moving a stimulable phosphor sheet on which radiographic image information is stored and provided in a plane direction thereof, comprising: a sensor for detecting and displaying the degree of moisture absorption. Radiation image information reading apparatus comprising: an excitation light source for irradiating light in a direction different from the moving direction; and a photodetector for sequentially and photoelectrically detecting stimulated emission light emitted from an excitation light irradiation portion of the sheet and / or a back surface of the irradiation portion. An apparatus, comprising: means for detecting a display of a sensor on the sheet; means for recording as an error when the display exceeds a certain level; and / or means for notifying. Reader. 4. A stimulable phosphor sheet having a sensor for detecting and displaying the degree of moisture absorption and having radiation image information stored therein is moved in a plane direction thereof while exciting light is applied to a part of the sheet. Irradiation in a direction different from the moving direction, stimulated emission light emitted from the excitation light irradiation portion of the sheet and / or the back surface of the irradiation portion is sequentially photoelectrically detected by a photodetector, and the output from the photodetector is output. In a radiation image information reading method, which sequentially reads in accordance with the movement of the sheet and obtains radiation image information as an electric image signal, a display of a sensor of the sheet is detected before reading, and a level of the display is detected. And / or controlling the image processing conditions to perform image processing on the obtained image signal. 5. A stimulable phosphor sheet sensor displays the degree of moisture absorption by color change, and detects the color change of the sensor by using a color difference sensor or by measuring light reflectance. The radiation image information reading method according to claim 4. 6. The radiation image information reading method according to claim 4, wherein the reading condition is controlled by increasing the energy of the excitation light as the display level of the sensor of the stimulable phosphor sheet increases. 7. The radiation image information according to claim 4, wherein the image processing condition is controlled by applying a process of increasing image sharpness to the image signal as the display level of the sensor of the stimulable phosphor sheet increases. Reading method. 8. Scanning means for moving a stimulable phosphor sheet on which radiation image information is stored and provided in a plane direction thereof, comprising a sensor for detecting and displaying the degree of moisture absorption, and a part of the sheet for exciting light. An excitation light source for irradiating light in a direction different from the moving direction, a photodetector for sequentially and photoelectrically detecting stimulated emission light emitted from an excitation light irradiation portion of the sheet and / or a back surface of the irradiation portion, and a photodetector from the photodetector. A radiation image information reading apparatus comprising: reading means for sequentially reading an output according to movement of the sheet and obtaining radiation image information as an electric image signal, wherein the means for detecting a display of a sensor of the sheet; A radiation image information reading apparatus comprising: means for controlling reading conditions and / or image processing conditions in accordance with a display level; and / or image processing means. 9. A stimulable phosphor sheet having a sensor for detecting and displaying the degree of moisture absorption and having radiation image information stored therein is moved in a plane direction thereof while exciting light is applied to a part of the sheet. Irradiation in a direction different from the moving direction, stimulated emission light emitted from the excitation light irradiation portion of the sheet and / or the back surface of the irradiation portion is sequentially photoelectrically detected by a photodetector, and the output from the photodetector is output. In the radiation image information reading method, which sequentially reads in accordance with the movement of the sheet and obtains radiation image information as an electric image signal, before or after reading, a display of a sensor of the sheet is detected, and the display is performed. A radiation image information reading method, wherein when a predetermined level is exceeded, a moisture absorption recovery process is performed on the sheet after reading. 10. A sensor of the stimulable phosphor sheet displays the degree of moisture absorption by a color change, and detects the color change of the sensor by using a color difference discriminating sensor or by measuring light reflectance. The radiographic image information reading method according to claim 9. 11. The radiation image information reading method according to claim 9, wherein a moisture absorption recovery process is performed by heating the stimulable phosphor sheet. 12. A scanning means for moving a stimulable phosphor sheet on which radiation image information is stored and provided in a plane direction thereof, comprising a sensor for detecting and displaying the degree of moisture absorption. An excitation light source for irradiating light in a direction different from the moving direction, a photodetector for sequentially and photoelectrically detecting stimulated emission light emitted from an excitation light irradiation portion of the sheet and / or a back surface of the irradiation portion, and a photodetector from the photodetector. A radiation image information reading apparatus comprising: reading means for sequentially reading an output according to movement of the sheet and obtaining radiation image information as an electric image signal, wherein the means for detecting a display of a sensor of the sheet; A radiation image information reading apparatus comprising means for performing a moisture absorption recovery process on the sheet after reading when the display exceeds a certain level.