JPH06109664A - Method and apparatus for reading radioactive image - Google Patents

Abstract

PURPOSE:To prevent a fluctuation in reading sensitivity caused by difference in circumferential speed of a reading position when a radioactive image recording plate is rotated with a constant number of rotations for read-scanning concentrically or spirally. CONSTITUTION:When a radioactive image recording plate is read and scanned on the plate 7 concentrically or spirally by rotation of the radioactive image recording plate 7 by a recording plate rotating means 19 and movement of an application position of excitation light 22 by an excitation light moving means, intensity of the excitation light 22 is the maximum by a modulation circuit 24 when an outermost circumference is scanned in concentric or spiral scanning and becomes weaker as an inner circumference is scanned in proportion to a size of a scanning radius.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation image reading method and apparatus for reading a recorded radiation image from a radiation image recording plate using a phosphor layer which absorbs and stores radiation as a radiation image recording means. More specifically, by utilizing the phenomenon that stimulated emission occurs in the phosphor layer according to the intensity of the accumulated radiation when the phosphor layer is irradiated with excitation light, the phosphor layer of the radiation image recording plate is used. The present invention relates to an improvement of a radiation image reading method and apparatus of a type in which a recorded radiation image is read by scanning the laser beam with excitation light and detecting light emission occurring on the phosphor layer at that time.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional example of an X-ray diffraction apparatus incorporating a radiation image reading apparatus.

In this X-ray diffraction apparatus, an X-ray diffraction optical system 8 for irradiating a sample 5 with X-rays 6 and forming an X-ray diffraction image on a radiation image recording plate 7 utilizing a photostimulable phosphor layer. And a radiation image reading device 9 for reading an X-ray diffraction image formed on the radiation image recording plate 7.

The radiation image recording plate 7 absorbs / accumulates radiation and, when irradiated with excitation light after that, stimulates emission of light according to the intensity of the accumulated radiation.
a, and a radiation image is recorded by the phosphor layer 7a. The phosphor layer 7a is formed by applying a phosphor in a thin film on one surface of a disk-shaped substrate, and the radiation image recording plate 7 has a disk-shaped appearance.

The X-ray diffraction optical system 8 includes an X-ray source 11 for generating X-rays 6, a monochromator 12 for guiding the X-rays 6 generated by the X-ray source 11 to a sample 5, and a collimator 1.
3, a goniometer 14 that rotatably supports the sample 5, a radiation image recording plate 7, and the like are components. The radiation image recording plate 7 is movably supported in the arrow B direction by a moving mechanism (not shown), and the distance to the sample 5 is adjustable.

On the other hand, the radiation image reading device 9 includes the radiation image recording plate 7, a light source 16 for generating the excitation light 15 having a constant intensity, and the excitation light 15 generated by the light source 16 for the radiation image recording plate 7. Of the excitation light reflected by the phosphor layer 7a and the phosphor layer 7a.
An optical system 17 that guides the light emitted by a to a predetermined position, and the phosphor layer 7 that is guided to a predetermined position by the optical system 17.
Emission light detection means (photomultiplier tube) for detecting the emission light of a
18, the recording plate rotating means 19 for rotating the radiation image recording plate 7, and the excitation light 15 on the radiation image recording plate 7 by relatively moving the optical system 17 and the radiation image recording plate 7. Radiation image recording plate 7
Of the excitation light moving means (not shown) for moving in the radial direction (the direction indicated by arrow C in the figure) with respect to the rotation center of the recording plate, and the recording plate rotating means 19 while processing the output signal of the emitted light detecting means 18. And a control unit 20 for controlling the operation of the excitation light moving means.

Here, the optical system 17 has a first light ray reflecting member 17a such as a semi-transmissive mirror, a second light ray reflecting member 17b such as a total reflection mirror, and a condenser lens 17c. The condensing lens 17c in the optical system 17 uses an aspherical lens, and has a role of spot-irradiating the radiation image recording plate 7 with the excitation light 15 with a predetermined beam diameter and light emission caused by the irradiation of the excitation light 15. It plays a role of guiding the reflected light of light or excitation light to the second light ray reflecting member 17b. In addition, the first light reflecting member 17a
Has a property of transmitting the excitation light 15 but reflecting the emitted light on the radiation image recording plate 7. The emitted light guided by the condenser lens 17c and the second light ray reflection member 17b is emitted light detecting means 18 Send to.

Further, the control unit 20 causes the emitted light detecting means 18 to display the radiation image read from the radiation image recording plate 7 on an image display device such as a CRT.
Predetermined processing is performed on the output signal (image information signal) of. Further, the control unit 20 uses the emitted light detection means 18
It also performs processing for sending the image information read via the printer to a printer, a magnetic storage device, or the like.

In the above radiation image reading apparatus 9, the control unit 20 controls the rotation speed of the radiation image recording plate 7 by the recording plate rotating means 19 and the moving speed of the excitation light irradiation position by the excitation light moving means (not shown). By doing so, the surface of the radiation image recording plate 7 (phosphor layer 7
a) Scanning concentrically or spirally with the excitation light 15 on the top, and sequentially detecting the emission intensity of stimulated emission generated on the radiation image recording plate 7 by the scanning by the emission light detecting means 18 at regular intervals. Then, the radiation image recorded on the radiation image recording plate 7 is read out.

According to such concentric or spiral reading scanning, the image recorded on the radiation image recording plate 7 is, for example, an X-ray diffraction image of a crystalline sample or the like, and is generally concentric or not. If you have a similar shape,
Only the circumferential area in which the image is actually recorded (a very small area in comparison with the total area of the recording surface of the radiation image recording plate 7) can be efficiently read, and actually read out. The amount of image information to be processed by the processing can be suppressed to a small amount, and the work time required for the reading processing can be shortened.

[0011]

By the way, in the radiation image reading apparatus 9, the radiation image recording plate 7 is rotated at a constant number of rotations, and the radiation image recording plate 7 is intermittently rotated every one rotation. By concentrically moving the optical system 17 in the radial direction of the radiation image recording plate 7 by a certain distance, concentric reading scanning can be realized, and the optical system 17 can be moved in the radial direction of the radiation image recording plate 7 at a constant speed. If it is moved continuously, the spiral scanning can be realized.

However, on the rotating radiation image recording plate 7, the peripheral speed decreases toward the inner peripheral side. Therefore, when the radiation image recording plate 7 is rotated at a constant number of revolutions to perform concentric or spiral reading scanning, the irradiation area of the excitation light 15 per unit time becomes closer to the inner peripheral side due to the peripheral speed difference. Get smaller. Therefore, the irradiation intensity of the excitation light 15 per unit area on the radiation image recording plate 7 becomes stronger toward the inner periphery side, and even if the accumulated radiation intensity is the same on the inner periphery side and the outer periphery side of the radiation image recording plate 7. The emission intensity increases toward the inner circumference side, resulting in a difference in reading sensitivity.

Therefore, conventionally, in the control unit 20, in order to correct the difference in the reading sensitivity due to the peripheral speed difference, the image information detected by the emitted light detecting means 18 is read at the reading position on the radiation image recording plate 7. Although an arithmetic processing circuit for performing correction processing according to the radius of gyration is provided, the correction processing must be repeated for each read processing performed by the emission light detection means 18, resulting in an enormous amount of arithmetic processing, There have been inconveniences such as a time delay and an increase in the size and cost of the hardware constituting the control unit 20.

As a countermeasure for avoiding such an inconvenience, the radiation image recording is performed so far so that the rotation speed of the radiation image recording plate 7 is variable and the peripheral speed at the reading position is constant. Controlling the rotational speed of the plate 7 has also been considered. However, according to this, in order to maintain the pixel reading accuracy, it is necessary to control the speed of the recording plate rotating means 7 with the necessary accuracy.

The weight of the recording plate rotating means 7 is usually several k.
Since it is more than g and is relatively heavy, it is not always easy to accurately control the rotation speed of the rotor, which causes a problem that the device becomes large and expensive.

The present invention has been made in view of the above circumstances, and is caused by the peripheral speed difference of the reading position when the radiation image recording plate is rotated at a constant number of rotations to perform concentric or spiral reading scanning. It is possible to prevent the fluctuation of the read sensitivity, and therefore, an arithmetic processing circuit for correcting the detected image information for correcting the read sensitivity is unnecessary, which shortens the processing time and downsizes the device and reduces the cost. It is an object of the present invention to provide a radiation image reading method and device capable of achieving the above.

[0017]

According to a first aspect of the present invention, there is provided a radiation image reading method, which absorbs and accumulates radiation, and emits stimulated emission depending on the intensity of the accumulated radiation when excitation light is irradiated thereafter. A radiation image recording plate having a phosphor layer for recording a radiation image by the phosphor layer, a light source for generating the excitation light, and irradiating the phosphor layer with the excitation light generated by the light source, An optical system that guides the excitation light reflected by the body layer and the light emitted by the phosphor layer to a predetermined position; a recording plate rotating means that rotates and operates the radiation image recording plate; and the optical system and the radiation image recording plate. The recording is performed in an environment provided with excitation light moving means for moving the irradiation position of the excitation light on the radiation image recording plate in a radial direction with respect to the rotation center of the radiation image recording plate by moving the recording device in the radial direction. By the operation of moving the irradiation position of the excitation light by the rotation of the radiation image recording plate according to the rotation means and the excitation light moving unit, the radiation image recording plate above is to scan reading concentrically or spirally.

However, the intensity of the excitation light with which the radiation image recording plate is irradiated has a maximum value when scanning the outermost circumference in concentric or spiral scanning, and goes to the inner circumference side in proportion to the size of the scanning radius. Weaken.

According to a second aspect of the radiation image reading apparatus,
The radiation image reading method according to claim 1 is implemented.

Specifically, the phosphor layer has a phosphor layer that absorbs and stores the radiation and emits stimulated emission according to the intensity of the accumulated radiation when irradiated with excitation light after that. A radiation image recording plate for recording an image, a light source for generating the excitation light, and an excitation light generated by the light source for irradiating the phosphor layer, and excitation light reflected by the phosphor layer and emission of the phosphor layer An optical system for guiding the light to a predetermined position, a recording plate rotating means for rotating the radiation image recording plate, and an excitation on the radiation image recording plate by relatively moving the optical system and the radiation image recording plate. And an excitation light moving means for moving the light irradiation position in the radial direction with respect to the rotation center of the radiation image recording plate.

Then, the radiation image recording plate is read and scanned concentrically or spirally on the radiation image recording plate by rotating the radiation image recording plate by the recording plate rotating means and moving the excitation light irradiation position by the excitation light moving means. However, as a means for solving the problem, a semiconductor that is equipped as the light source and outputs a semiconductor laser as excitation light, and the semiconductor is proportional to the size of the scanning radius at the time of concentric or spiral reading scanning. It is equipped with a modulation circuit that directly modulates the intensity of the excitation light output from the semiconductor by controlling the flowing current.

By the direct modulation by the modulation circuit, the intensity of the excitation light with which the radiation image recording plate is irradiated is set to the maximum value at the time of scanning the outermost circumference in the concentric circular or spiral scanning, and the size of the scanning radius is set. Proportionalize and weaken toward the inner circumference.

[0023]

According to the radiation image reading apparatus of the present invention, the radiation image recording plate is rotated at a constant number of rotations by the recording plate rotating means, and the radiation image recording plate is intermittently rotated every one rotation. By moving the optical system in the radial direction of the radiation image recording plate by a certain distance, concentric reading scanning can be realized, and the optical system is continuously moved in the radial direction of the radiation image recording plate at a constant speed. By doing so, the spiral scanning can be realized.

During such concentric or spiral reading scanning, direct modulation by the modulation circuit controls the intensity of the excitation light to decrease toward the inner circumference in proportion to the size of the scanning radius. Thus, the radiation image reading method according to claim 1 is realized.

In the radiation image reading method according to the present invention, the intensity of the excitation light is controlled so as to become weaker toward the inner peripheral side in proportion to the size of the scanning radius, so that the radiation image is recorded on the radiation image recording plate. The irradiation intensity of excitation light per unit area is made uniform, and even when the radiation image recording plate is rotated at a constant number of revolutions to perform concentric or spiral reading scanning, it is caused by the difference in peripheral speed of the reading position. It is possible to prevent variations in reading sensitivity.

Therefore, it is not necessary to correct the image information read from the radiation image recording plate to correct the reading sensitivity, and the processing time can be shortened.

Moreover, the intensity of the excitation light is controlled by using a semiconductor laser as the excitation light, and a simple process of controlling the value of the current flowing through the light source (semiconductor) that outputs the semiconductor laser according to the scanning radius. It is possible to realize the following, and the amount of information processing is significantly reduced compared to the conventional case in which the read image information is corrected to correct the reading sensitivity due to the peripheral speed difference, and the required hardware It is also possible to reduce the size and cost.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of an X-ray diffractometer incorporating a radiation image reading apparatus according to an embodiment of the present invention.

In this X-ray diffraction apparatus, an X-ray diffraction optical system 8 for irradiating a sample 5 with X-rays 6 to form an X-ray diffraction image on a radiation image recording plate 7 utilizing a photostimulable phosphor layer. And a radiation image reading device 21 of one embodiment for reading an X-ray diffraction image formed on the radiation image recording plate 7.

Here, the radiation image recording plate 7 and X
The line diffraction optical system 8 has the same configuration as that of the conventional example shown in FIG.

The radiation image reading device 21 includes the radiation image recording plate 7, a light source 23 for generating excitation light 22,
An optical system that irradiates the phosphor layer 7a of the radiation image recording plate 7 with the excitation light 22 generated by the light source 23 and guides the excitation light reflected by the phosphor layer 7a and the light emitted by the phosphor layer 7a to a predetermined position. System 17, emission light detection means (photomultiplier tube) 18 for detecting emission light of the phosphor layer 7a guided to a predetermined position by the optical system 17, and recording for rotating the radiation image recording plate 7. Plate rotating means 19
By moving the optical system 17 and the radiation image recording plate 7 relative to each other, the irradiation position of the excitation light 22 on the radiation image recording plate 7 is set in a radial direction with respect to the rotation center of the radiation image recording plate 7 (see FIG. Then, excitation light moving means (not shown) for moving in the direction indicated by the arrow C), a modulation circuit 24 for adjusting the intensity of the excitation light output from the light source 23, and an output signal of the emitted light detecting means 18. The recording plate rotating means 19, the excitation light moving means, and the modulation circuit 24.
And a control unit 25 for controlling the operations such as.

Here, the optical system 17 has the same structure as that of the conventional example shown in FIG. 2, and includes a first light ray reflecting member 17a such as a semi-transmissive mirror and a second light ray reflecting member 17b such as a total reflection mirror. The condenser lens 17c and the like are used as constituent elements. The condensing lens 17c in the optical system 17 uses an aspherical lens, and has a role of spot-irradiating the radiation image recording plate 7 with the excitation light 22 with a predetermined beam diameter and light emission caused by the irradiation of the excitation light 22. It plays a role of guiding the reflected light of light or excitation light to the second light ray reflecting member 17b. The first light ray reflecting member 17a has a property of transmitting the excitation light 22 but reflecting the emitted light on the radiation image recording plate 7, and is guided by the condenser lens 17c and the second light ray reflecting member 17b. The emitted light is sent to the emitted light detecting means 18. A semiconductor laser is used for the light source 23. Therefore, the excitation light 22 output from the light source 23 is semiconductor laser light. The semiconductor laser has advantages that it is smaller, more efficient, and more reliable than a solid-state laser or a gas laser, and that the intensity of output light can be directly modulated at high speed by a flowing current. .

In this embodiment, the excitation light moving means (not shown) is a base for supporting the optical system 17, the emitted light detecting means 18, and the light source 23 in a fixed positional relationship, and this base. And a linear movement mechanism for moving back and forth along the surface of the radiation image recording plate 7, and the irradiation position of the excitation light 22 on the phosphor layer 7a is moved in the radial direction by the movement of the base. Let

The modulation circuit 24 is a light source 2 which is a semiconductor.
It is a circuit that directly modulates the intensity of the pumping light 22 by controlling the current flowing through the pump 3.

The control unit 25 determines a predetermined output signal (image information signal) from the emitted light detecting means 18 in order to display a radiation image read from the radiation image recording plate 7 on an image display device such as a CRT. The process of is executed.
The control unit 25 also performs processing for sending the image information read via the emitted light detection means 18 to a printer, a magnetic storage device, or the like. Furthermore, the control unit 25
Controls the operations of the recording plate rotating means 19 and the excitation light moving means, so that the reading scan by the excitation light 22 on the phosphor layer 7a by the excitation light 22 is made concentric or spiral. The rotating operation of the radiation image recording plate 7 by the rotating means 19 and the moving operation of the optical system 17 etc. by the excitation light moving means are interlocked with each other, and at that time, the operation of the modulation circuit 24 is also controlled.

That is, the control unit 25 grasps the scanning radius (distance from the central axis of rotation of the radiation image recording plate 7 to the irradiation position of the excitation light 22) at the time of concentric or spiral reading scanning, and the light source 23 Modulation circuit 24 so that the current flowing through the circuit changes in proportion to the size of the scanning radius.
An operation control signal is output to.

In response to the operation control signal from the control unit 25, the modulation circuit 24 maximizes the intensity of the excitation light 22 with which the radiation image recording plate 7 is irradiated during the concentric circular or spiral scanning. As a value, the direct modulation is performed in proportion to the size of the scanning radius so as to weaken toward the inner circumference side.

In the radiation image reading apparatus 21 of the above-described embodiment, the radiation image recording plate 7 is rotated at a constant rotation speed by the recording plate rotating means 19, and the radiation image recording plate 7 is rotated. The optical system 1 is intermittently provided for each rotation.
By moving 7 in the radial direction of the radiation image recording plate 7 by a constant distance, concentric reading scanning can be realized, and the optical system 17 is continuously moved in the radial direction of the radiation image recording plate 7 at a constant speed. By doing so, the spiral scanning can be realized.

When the concentric or spiral reading scanning is performed with the rotation number of the radiation image recording plate 7 being constant as described above, on the rotating radiation image recording plate 7, the inner circumference side becomes closer. The speed becomes smaller, and the irradiation area of the excitation light 22 per unit time becomes smaller toward the inner peripheral side due to the peripheral speed difference.

However, in this embodiment, the intensity of the excitation light 22 with which the radiation image recording plate 7 is irradiated has a maximum value at the time of scanning the outermost circumference in the concentric circular or spiral scanning, and has a large scanning radius. It is directly modulated by the modulation circuit 24 so that it becomes weaker toward the inner peripheral side in proportion to this.

Therefore, the irradiation intensity of the excitation light 22 per unit area on the radiation image recording plate 7 is constant at any position on any radiation image recording plate 7 within the range of the reading scan, and the circumference of the reading position. It is possible to prevent the fluctuation of the reading sensitivity due to the speed difference. Therefore, it is not necessary to correct the image information detected by the emitted light detecting means 18 to correct the reading sensitivity, and the processing time can be shortened.

Further, the direct modulation of the excitation light 22 by the modulation circuit 24 can be realized by a simple process of controlling the current value flowing through the light source 23 according to the scanning radius, and detected by the emission light detecting means 18. Compared with the conventional case in which image information is corrected to correct the reading sensitivity, the amount of information processing is significantly reduced, and the required hardware can be downsized and the cost can be reduced.

In the present invention, the shape of the radiation image recording plate is not limited to that of the embodiment. The radiation image recording plate 7 of one embodiment has a flat disk shape, but, for example, it is conceivable that the image recording surface of the phosphor layer has a spherical shape with the sample position at the time of image storage processing as the center of curvature. To be The design of the configuration of the optical system 17, the mechanism of the excitation light moving means, etc. may be changed according to the shape of the radiation image recording plate.

[0044]

According to the radiation image reading apparatus of the second aspect, the radiation image recording plate is rotated at a constant rotation speed by the recording plate rotating means, and the radiation image recording plate is rotated every one rotation. If the optical system is intermittently moved in the radial direction of the radiation image recording plate by a constant distance, concentric reading scanning can be realized, and the optical system can be continuously moved in the radial direction of the radiation image recording plate at a constant speed. If it is moved to, the spiral scanning can be realized.

During such concentric or spiral reading scanning, the intensity of the excitation light is controlled in proportion to the scan radius by the direct modulation by the modulation circuit so that the intensity is weakened toward the inner peripheral side. Thus, the radiation image reading method according to claim 1 is realized.

In the radiation image reading method according to the present invention, the intensity of the excitation light is controlled so as to become weaker toward the inner peripheral side in proportion to the size of the scanning radius, so that the radiation image is recorded on the radiation image recording plate. The irradiation intensity of excitation light per unit area is made uniform, and even when the radiation image recording plate is rotated at a constant number of revolutions to perform concentric or spiral reading scanning, it is caused by the difference in peripheral speed of the reading position. It is possible to prevent variations in reading sensitivity.

Therefore, it is not necessary to correct the image information read from the radiation image recording plate to correct the reading sensitivity, and the processing time can be shortened.

Moreover, the intensity of the excitation light is controlled by using a semiconductor laser as the excitation light, and a simple process of controlling the value of the current flowing through the light source (semiconductor) that outputs the semiconductor laser according to the scanning radius. It is possible to realize the following, and the amount of information processing is significantly reduced compared to the conventional case in which the read image information is corrected to correct the reading sensitivity due to the peripheral speed difference, and the required hardware It is also possible to reduce the size and cost.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a conventional radiation image reading device.

[Explanation of symbols]

 7 Radiation Image Recording Plate 7a Phosphor Layer 17 Optical System 18 Emission Light Detection Means 19 Recording Plate Rotating Means 21 Radiation Image Reading Device 22 Excitation Light 23 Light Source 24 Modulation Circuit 25 Control Unit

Claims (2)

[Claims] 1. A radiation image is recorded by the phosphor layer, which has a phosphor layer that absorbs and stores the radiation and emits stimulated emission according to the intensity of the accumulated radiation when irradiated with excitation light after that. A radiation image recording plate, a light source for generating the excitation light, and the excitation light generated by the light source is applied to the phosphor layer, and the excitation light reflected by the phosphor layer and the light emitted by the phosphor layer are emitted. Optical system for guiding to a predetermined position, recording plate rotating means for rotating the radiation image recording plate, and irradiation of excitation light on the radiation image recording plate by relatively moving the optical system and the radiation image recording plate. Excitation light moving means for moving the position in the radial direction with respect to the rotation center of the radiation image recording plate, the rotation of the radiation image recording plate by the recording plate rotating means and the excitation light moving means. A radiation image reading method of reading and scanning the radiation image recording plate in a concentric or spiral shape by moving the irradiation position of the light, and the intensity of the excitation light applied to the radiation image recording plate is a concentric circle. A radiation image reading method characterized in that the maximum value is set at the time of scanning the outermost circumference in the circular or spiral scanning, and the value is weakened toward the inner circumference side in proportion to the size of the scanning radius. 2. A radiation image is recorded by the phosphor layer, which has a phosphor layer that absorbs and stores the radiation and emits stimulated emission depending on the intensity of the accumulated radiation when irradiated with excitation light after that. A radiation image recording plate, a light source that generates the excitation light, and the excitation light generated by the light source is applied to the phosphor layer, and the excitation light reflected by the phosphor layer and the light emitted by the phosphor layer are emitted. An optical system for guiding the radiation image recording plate to a predetermined position, a recording plate rotating means for rotating the radiation image recording plate, and irradiation of excitation light on the radiation image recording plate by relatively moving the optical system and the radiation image recording plate. Excitation light moving means for moving the position in the radial direction with respect to the rotation center of the radiation image recording plate, the rotation of the radiation image recording plate by the recording plate rotating means and the excitation light moving means. A radiation image reading device for reading and scanning the radiation image recording plate in a concentric or spiral shape by a movement operation of an irradiation position of a luminescent light, the semiconductor being equipped as the light source and outputting a semiconductor laser as excitation light. And a modulation circuit that directly modulates the intensity of the excitation light output from the semiconductor by controlling the current flowing through the semiconductor in proportion to the size of the scanning radius during concentric or spiral scanning. By the direct modulation by the modulation circuit, the intensity of the excitation light with which the radiation image recording plate is irradiated is set to a maximum value when scanning the outermost circumference in concentric or spiral scanning, and is proportional to the size of the scanning radius. A radiation image reading device characterized by weakening toward the periphery.