JPH0697328B2 - Radiation image reader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a radiation image recording member using a phosphor layer that absorbs and stores radiation as a radiation image recording means.
The present invention relates to a radiation image reading apparatus for reading a recorded radiation image, and more specifically, when the phosphor layer is irradiated with excitation light, the phenomenon that stimulated emission occurs in the phosphor layer according to the strength of the accumulated radiation A radiographic image reading device of a type in which a recorded radiographic image is read by utilizing the excitation light to scan the phosphor layer of the radiographic image recording member and detecting light emission occurring on the phosphor layer at that time. Related to the improvement of.

[Prior Art] The radiographic image reading device of the above-mentioned type is developed as an alternative to a radiographic method using silver salt in order to avoid problems such as depletion of silver resources. As a conventional example of the apparatus of the type, those described in JP-A-59-13235 and JP-A-59-13236 are known.

The devices described in these publications have a phosphor layer that absorbs and accumulates radiation and emits light according to the intensity of the accumulated radiation when irradiated with excitation light after that. A radiation image recording member for recording an image, a light source for generating the excitation light, and light emitted from the phosphor layer at a position deviated from the path of the excitation light (hereinafter,
(Referred to as emitted light) and configured to include a light emission detection device that detects light emission on the phosphor layer, scans the phosphor layer with excitation light, and emits light at each point of the scanning path during scanning. The radiation image recorded on the radiation image recording member is read by sequentially detecting the state by the light emission detection device.

[Problems to be Solved by the Invention] When scanning the excitation light, it is necessary to devise the shape of the radiation recording member and the method of moving the spot irradiation portion of the excitation light so that the reading can be performed more efficiently. To be done.

In the one described in the above-mentioned publication, the phosphor layer is formed into a cylindrical shape and rotated about its axis, and the phosphor layer and the light source of excitation light are relatively moved in the direction of the axis, or the phosphor layer Has been shown, and the spot irradiation unit is moved vertically and horizontally along the plane.

However, it is necessary to consider the shape of the radiation recording member and the method of moving the spot irradiation portion of the excitation light with respect to the compatibility with the shape of the radiation image recorded on the radiation recording member. If it is not considered together, the problem that unnecessary scanning increases, it takes time to grasp the shape of the read image, and the efficiency of reading work decreases, or the movement of the movable part (moving range) for scanning Becomes larger and the space occupied by the device increases, which is a problem.

The present invention has been proposed to solve such a problem, and in particular, a so-called Laue spot observed when a substance having a crystal structure such as a single crystal or a polycrystal is irradiated with a specific X-ray, Alternatively, when the image is grasped mainly as a concentric circle shape or a similar shape like a diffraction image of a Debye ring or the like, the reading can be efficiently performed, and in the case of the conventional photographic method. It is possible to directly obtain the crystal orientation or crystal grain size from the read image information by performing comparatively simple arithmetic processing on the read image information without making it into a figure like the above. Moreover, it is an object of the present invention to provide a radiation image reading apparatus capable of reducing the movement of the movable portion during scanning in a compact manner and reducing the occupied space of the apparatus. .

[Means for Solving Problems] A radiation image reading apparatus according to the present invention solves the above-mentioned problems by improving the structure and operation of a radiation image recording member. As a radiographic image recording, a phosphor layer is provided which absorbs and accumulates radiation and emits light according to the intensity of the accumulated radiation when irradiated with excitation light afterwards and records a radiation image by the phosphor layer. A member and a light source for generating the excitation light,
And a light emission detection device for detecting light emission on the phosphor layer by receiving light emitted from the phosphor layer at a position deviated from the path of the excitation light, and the phosphor layer of the radiation image recording member is , Has a disk shape and is rotatably provided with its center as a rotation center.

[Operation] In the radiation image reading device according to the present invention, the phosphor layer for recording a radiation image is formed in a disc shape and is rotatably provided. While rotating the phosphor layer, irradiation of excitation light is performed by fluorescence. Scanning is performed by relatively moving the body layer in the radial direction, and the intensity I of the emitted light at each position and the position corresponding to the emitted light represented by, for example, the radius R of the disk and the rotation angle θ are obtained to form an image. It is something to read. In other words, the concentric circles of the phosphor layer are sequentially scanned and read, and if image information having a certain meaning is recorded on the concentric circles, it is not necessary to scan the entire phosphor layer. Without this, it can be read with only one or several rotation scans. For example, when the radiation image is an X-ray diffraction image of a substance having a single crystal or polycrystal structure, if the position or distribution ratio of at least one concentric spot is known, the crystal orientation, crystal grain size, etc. Therefore, it is possible to obtain image information sufficient to obtain orientation information or grain size information by one or several rotation scans without scanning the entire phosphor layer. Also, if you scan over the entire range, you can obtain a large number of direction information and granularity information, average these,
Alternatively, it is possible to perform other processing to accurately determine the orientation, or to obtain other crystal information.

Further, if the disc-shaped phosphor layer is rotated and scanning is performed to relatively move the excitation light in the radial direction of this phosphor layer, the relative movement distance of the excitation light in the radial direction is determined by the radius of the phosphor layer. That is, only half of the range in which the image is recorded, that is, the movement of the movable part involved in scanning can be suppressed compactly, and the space occupied by the device can be reduced.

[Embodiment] FIG. 1 shows an embodiment of a radiation image reading apparatus according to the present invention.

This radiographic image reading device includes a radiographic image recording member 1,
A light source 3 for generating the excitation light 2, a light ray reflection member 4 arranged on the path of the excitation light 2, and a position on the movement path of the excitation light 2 between the light ray reflection member 4 and the radiation image recording member 1. The aspherical lens 5 for condensing and the emission detection device 6 are provided.

The radiation recording member 1 includes a disc-shaped support plate 9 and a phosphor layer 10 that is also layered in the disc shape on the surface of the support plate 9.
And a rotation driving means 11 such as a motor for rotating the support plate 9 around the center thereof. In this recording member 1, the phosphor layer 10 absorbs radiation.
A stimulable phosphor that accumulates and stimulates emission depending on the intensity of the accumulated radiation when irradiated with excitation light 2 is applied in a layered manner with a predetermined thickness. The radiation image 12 (see FIG. 2) of the subject is recorded by irradiating with.

The excitation light 2 indicates visible light, ultraviolet light, infrared light, etc. of electromagnetic radiation, and the radiation indicates X-rays, gamma rays, beta rays, alpha rays, neutron rays and the like.

The light source 3 has a flexible optical fiber 3a protruding from the tip of the main body 3b, and the excitation light 2 is generated from the tip of this optical fiber (which is usually attached with a beam expander or a beam collimator). . The light source 3 generates the excitation light 2 as a beam having an extremely small diameter because the diameter of the hole in the light reflecting member 4 described later is minimized.

The light ray reflection member 4 is located on the path of the excitation light 2,
The emission light 14 from the phosphor layer 10 is separated from the reflected light of the excitation light 2 and sent to the emission detection device 6.
A hole 4a for passing the excitation light 2 is provided in the central portion intersecting with the path of and the mirror surface 4b for total reflection is provided on the surface facing the phosphor layer 10.
Is applied to the total reflection mirror.

The aspherical lens 5 is newly adopted in the present invention. As a condensing lens for spot-irradiating the phosphor layer 10, a spherical lens has been known so far. However, when an aspherical lens is used, the aperture / The focal length can be increased, and the light collection efficiency can be significantly improved.

The light emission detection device 6 detects the light emission by receiving the light emission 14 reflected by the reflection member 4, and when receiving the light, a photomultiplier tube 6a that outputs a predetermined signal according to the intensity of the light. And a filter 6b located in front of the light-receiving surface of the photomultiplier tube 6a for cutting light having a wavelength other than the emitted light 14
And is arranged at a position deviated from the path of the excitation light 2. The output signal of the photomultiplier tube 6a is arithmetically processed or displayed by an image information processing device, a display device or the like (not shown).

The above-mentioned tip portion of the optical fiber 3a, the light beam reflecting member 4, the aspherical lens 5 for condensing, the light emission detecting device 6 and the like are held in a fixed positional relationship by the support frame 16 and integrated. By holding the support frame 16, the light beam reflecting member 4 is caused to emit the excitation light 2
The excitation light 2 is vertically applied to the phosphor layer 10 and the emitted light 14 is reflected in a direction orthogonal to the excitation light 2 while being kept in a state of being inclined by 45 degrees with respect to the path of the excitation light 2.

The support frame 16 is a phosphor layer by a drive mechanism (not shown).
It is made movable in the direction along the surface of 10 (the direction indicated by the arrow A in the figure), and its moving range is approximately the radius of the phosphor layer 10 from the outer peripheral portion of the phosphor layer 10. Further, the moving speed of the support frame 16 can be linked with the rotating speed of the rotation driving means 11.

Now, in the image reading operation by this radiation image reading apparatus, the rotation driving means 11 drives the phosphor layer 10 to rotate, and the support frame 16 is moved at a constant speed every time the phosphor layer 10 makes one rotation. , By scanning the phosphor layer 10 with excitation light 2.

That is, the radiation image recorded on the phosphor layer 10 is read by sequentially detecting the light emission state at each point of the scanning path during scanning by the light emission detection device 6. In this case, if the rotation speed of the phosphor layer 10 is increased toward the center of the phosphor layer 10 so that the scanning speed of the excitation light 2 becomes constant, the image processing after reading is facilitated. be able to.

According to the above configuration, the phosphor layer 10 is formed into a disk shape and is driven to rotate, and the support frame 16 for supporting the tip portion of the light source 3, the light ray reflection member 4, the spherical lens 5, the light emission detection device 6, and the like. By holding it all together and making this support frame 16 movable, control of the movable part during scanning becomes easier,
Further, for example, the movement distance of the support frame 16 is equal to the radius of the phosphor layer 10, that is, half of the range in which an image is recorded, the movement of the movable part is suppressed compactly, and the space occupied by the device is reduced. You can

Further, when the radiation image is an X-ray diffraction image of a substance having a single crystal or polycrystal structure, if the position or distribution ratio of at least one concentrically distributed spot is known, the crystal orientation, crystal grain size, etc. Therefore, it is possible to obtain image information sufficient to obtain orientation information or grain size information by one or several rotation scans without scanning the entire phosphor layer. Moreover, if scanning is performed over the entire range, it is possible to obtain a large number of orientation information / grain size information, which can be averaged, or other processing can be performed to accurately determine the orientation, or other crystals can be obtained. It is also possible to obtain information. Further, since the position information for determining the azimuth is obtained as the radius R and the rotation angle θ of the disk, once the diffraction image is made a visible image and R, θ is read from the visible image as in the conventional photographic method. It is possible to directly obtain the read image information by performing an arithmetic process without the need. Moreover, the calculation processing is remarkably simple compared with the case of other scanning such as vertical and horizontal scanning,
Therefore, the diffraction image of the crystal accumulated in the fluorescent layer is instantly read and the orientation, the crystal grain size and the like are instantly calculated, which makes it practically possible to do what is impossible in the conventional photographic method.

Further, in the radiation image reading apparatus according to this embodiment, a total reflection mirror is used as the light ray reflection member 4, and the excitation light 2 emitted from the light source 3 is a hole provided in the central portion of the total reflection mirror. 4a allows the light to pass through without any refraction, and therefore can prevent the deviation of the irradiation position of the excitation light 2 (focal deviation) due to refraction and the like, and enables precise scanning by accurate spot irradiation. In addition, since the emitted light is efficiently collected by using the aspherical lens, it is possible to read even weak emitted light. Therefore, as in the case of reading the X-ray diffraction image described above, the emitted light is weak because the intensity of the diffraction line is relatively weak, and the accuracy of reading spots in the diffraction image affects the accuracy of direct orientation determination. In such a case, it is a very important advantage, and in combination with the disc-shaped phosphor layer, it is possible to perform X-ray diffraction image analysis very quickly and accurately with high feasibility. Is.

In the above-described embodiment, as the operation for scanning, the phosphor layer 10 can be rotated, and the support frame 16 facing it can be linearly moved along the radial direction of the disk. The support frame 16 side may be fixed, and the phosphor layer 10 side may have a rotational movement and a linear movement in the radial direction thereof.

EFFECTS OF THE INVENTION As is clear from the above description, the radiation image reading apparatus according to the present invention has a phosphor layer for recording a radiation image, which is disc-shaped and rotatably provided. Since the irradiation of the excitation light is performed by relatively moving the phosphor layer in the radial direction of the phosphor layer while rotating the layer, an arbitrary position on the phosphor layer is represented by the radius R of the disk and the rotation angle θ. It is possible to obtain an image mainly by a so-called Laue spot observed when a substance having a crystal structure such as a single crystal or a polycrystal is irradiated with a specific X-ray, or a diffraction image such as a Debye ring. When it is recognized as a concentric circle shape or similar shape, the reading can be efficiently performed, and the read image information is once converted into a graphic as in the case of the conventional photography method. Needless to say, it is possible to directly obtain the crystal orientation or the crystal grain size from the read image information by performing relatively simple arithmetic processing on this, and moreover, the movement of the movable part during scanning can be made compact. There is an excellent effect such that the space occupied by the device can be reduced by suppressing it.

[Brief description of drawings]

FIG. 1 is an overall view of an embodiment of the radiation image reading apparatus according to the present invention, and FIG. 2 is a view of the radiation image recording member in FIG.
It is a II arrow view. 1 ... Radiation image recording member, 2 ... Excitation light, 3 ... Light source, 4 ... Ray reflecting member, 4a ... Hole, 5 ... Aspherical lens, 6 ... Emission detecting device, 10 ... Phosphor Layer, 12 ... Radiation image, 14 ... Emitted light.

Claims (1)

[Claims] 1. Radiation for absorbing and accumulating radiation and having a phosphor layer which emits light according to the intensity of the accumulated radiation when irradiated with excitation light after that, and which records a radiation image by the phosphor layer. An image recording member, a light source that generates the excitation light, and a light emission detection device that receives light emitted from the phosphor layer at a position deviated from the path of the excitation light and detects light emission on the phosphor layer. The radiation image recorded on the radiation image recording member is read by scanning the phosphor layer with excitation light and sequentially detecting the light emission state at each point of the scanning path during scanning by the light emission detection device. A radiation image reading device, wherein the phosphor layer of the radiation image recording member has a disk shape and is rotatably provided with a center thereof as a rotation center.