JPS6093425A - Reader of radiation picture information - Google Patents

Abstract

PURPOSE:To improve the resolution of a read image and to make the correction of variance of luminance of accelerated light unnecessary, by providing an exciting light with an exciting light propagating means. CONSTITUTION:The exciting light, for example, a beam-shaped laser light which is generated from an exciting light generating means 21 is reflected on a fixed mirror 30 and is condensed by a lens 22 and is made incident to the optical rotation center of a rotary mirror 34 and is made incident vertically to incidence end faces of plural optical fibers 32 successively. Thereafter, the light is propagated in cores of optical fibers while total-reflecting and is discharged to irradiate a phosphor sheet 3, and the phosphor sheet 3 is carried in the direction of an arrow A to scan the overall face of the phosphor sheet 3. Thus, the resolution of images is improves because the laser light is not scattered by dust or the like in air. The laser light is irradiated at the same angle to individual parts of the phosphor sheet 3, and it is unnecessary to correct the variance of luminance of the accelerated light.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention provides a method for producing radiation [Technical background of the invention and problems thereof] from a phosphor sheet having a photostimulable phosphor that absorbs radiation transmitted through an object. ] First, the configuration of a radiographic apparatus, for example, a digital radiograph, that uses a phosphor sheet having a photostimulable phosphor is
As shown in the figure. X-rays emitted from an X-ray tube 1 pass through a subject 2 and are accumulated in a phosphor sheet 6 made of a stimulable phosphor formed into a sheet.

This phosphor sheet 6 was passed through the radiation image information reading device 4K, and the image information was read out as a signal), and was once recorded in the recording means 7, and the image processing means 5 performed appropriate image data processing. Thereafter, the image is printed on a film 8 in a fourth image recording stage 6, and an X-ray photograph 10 is obtained via an automatic developing means 9. Control during this time is performed by the computer 11.

Next, the configuration of the radiation image information reading device 4 is shown in FIG. The laser beam emitted from the laser tube 21 is focused by a lens 22 and narrowed down to a narrow beam of about 100 μm, and is scanned on the phosphor sheet 3 on which radiographic image information has been accumulated by the scanning rotary reflection 1!1!23. . This phosphor sheet 3 is placed on the bell 124 which is running by the rotating drive 5 of the rollers 25, 25, and is moved, for example, in the direction of the arrow in synchronization with the scanning of the laser beam. In this way, the entire surface of the phosphor sheet B is uniformly scanned by the laser beam. When the phosphor sheet is irradiated with laser light, the phosphor sheet generates photostimulated light. This photostimulable light collecting means 26 collects the light, and the photomultiplier tube (P) collects the light.

After being changed into an electrical signal by M) 27, it is output as radiographic image information to, for example, the image processing device 5 (FIG. 1).

By the way, in the conventional apparatus, a rotating reflecting mirror 26 is used to scan the phosphor sheet 6 with a laser beam.

However, since the irradiation angle of the laser beam is different between the central part and the peripheral part of the phosphor sheet 3, the light energy received from the laser beam is different. As a result, the luminance of the stimulated light changes in a manner other than the image information, making it impossible to accurately read the radiation 1 image information.

Therefore, in the conventional apparatus, a method has been adopted in which brightness changes other than image information caused by differences in the irradiation angle of the laser beam are compensated for programmatically in the image processor 5 shown in FIG. However, this program requires a large amount of memory, making the device expensive, and the image processing speed slows down due to the amount of time it takes to process the corrections. Ta.

Furthermore, since the laser light reflected by the rotating reflector 26 propagates through the living air and reaches the phosphor sheet 6, the laser light is scattered by dust, lumps, etc. in the air, and as a result,
A problem has arisen in that the resolution of the obtained image is reduced.

Furthermore, since the phosphor sheet 6 is scanned from end to end by the rotating reflector 26, a predetermined distance must be maintained between the rotating reflector 23 and the phosphor sheet 6. This spacing makes it difficult to downsize the device.

[Purpose of the invention]

The present invention was made in view of these circumstances, and
In order to achieve the above object, the present invention aims to improve image resolution, eliminate the need for correction of luminance changes of photostimulated light, and provide accurate image information. In a radiation image information reading device that scans with excitation light generated from an excitation light generation means in the form of a phosphor sheet and reads radiation image information accumulated in a photostimulable phosphor, the device rotates at a predetermined speed and generates excitation light. A rotary reflecting means for reflecting the excitation light generated by the means to the surroundings, and one end disposed at a position where the excitation light reflected to the surroundings by the rotary reflecting means can be sequentially incident, and the excitation light that is sequentially incident is illuminated. The excitation light transmitting means is characterized in that the other end of the excitation light transmitting means is arranged at a position on the light sheet where it can be sequentially irradiated at the same irradiation angle.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. □ FIG. 6 is an explanatory diagram showing the configuration of the radiation image information reading device according to the present invention. 21 shows an excitation light generating means, which is a fixed mirror that reflects the excitation light, for example a beam-shaped light, in a predetermined direction, and is fixed at a predetermined position by a fixing means (not shown). The beam-shaped loser light reflected by the fixed mirror 30Kj is focused by the lens 22 and then enters the rotating mirror 31. This rotating mirror 61
For example, the shaft of the motor 66 rotates at S foot speed due to the rotational drive of the motor 33, and the lens 22?
: Reflects the laser light that enters through it to the surrounding area. In this sense, this rotating mirror 31 and the motor 6
6 is referred to as a rotating reflection means 67. On the optical path of the laser beam reflected by the rotation @61, at a position equidistant from the optical rotation center 64 of the rotating mirror 310, excitation light transmitting means, for example, a plurality of original fibers 62 (among them One end (input end) of the plurality of original fibers 32 (indicated by &32a) is arranged, and the laser light reflected by the rotating mirror 31 is sequentially incident on the negative end of the plurality of original fibers 32. There is.

Here, the diameters of the core and cladding constituting the optical fiber 32aIk are determined as follows. That is, the beam spot diameter d of the laser beam is, for example, d if the focal length f of the lens 22 is 80 mm and the beam spread angle θ of the laser beam generated by the excitation light generating means 21 is 0.5 mrad.
From the relationship of =f and θ, it becomes 40 μm. Therefore, if the diameter and cladding diameter of the original fiber 62-I are set to 50 .mu.yn and 100 .mu.m, respectively, all of the laser light generated by the excitation light generating means 21 can be incident on the core of the optical fiber 62.

Further, the other ends (output ends) of the plurality of optical fibers 32 receive the laser beams that have sequentially entered from one end of the plurality of original fibers 32.
For example, they are arranged in a horizontal line so that the phosphor sheet 6 containing the stimulable phosphor is sequentially irradiated at the same irradiation angle.

It should be noted that there is a conveyance means for conveying the phosphor sheet 3 in the direction of the arrow, a condensing means for condensing the photostimulated light generated from the phosphor sheet 6, and image information based on the photostimulated light condensed by the condensing means. Since the processing and the like are the same as those of the conventional device, the explanation thereof will be omitted.

Next, the operation of the apparatus configured as described above will be explained. Excitation light, such as a beam-shaped laser beam, generated by the excitation light generation means 21 is reflected by a fixed mirror 30, and after the beam is focused by a lens 22, it enters a rotating mirror 64.

The laser light incident on the rotating mirror 34 is reflected so as to be incident on one end of the plurality of original fibers 32 one after another. That is, as shown in FIG. 4, the laser light incident on the optical rotation center 64 of the rotating mirror 34, which rotates at a predetermined speed due to the rotational drive of the motor 66, is perpendicular to the input ends of the plurality of original fibers 320. They are incident sequentially.

In this way, the V-thermal light that has sequentially entered one end of the plurality of original fibers 62 propagates through the core of each original fiber while being totally reflected, and then sequentially exits from the other end and travels on the phosphor sheet 6. irradiate. The irradiation field on this phosphor sheet 6 is
It is determined by the distance between the original fiber 32 and the phosphor sheet 3. For example, as shown in FIG. 5, when the outer diameter of the cladding 36 of the optical fiber 32 is 100 μm, the irradiation diameter is
Can be expanded to μm. Further, since the output ends of the optical fibers 32 are arranged in a horizontal line from end to end of the phosphor sheet 6, when the phosphor sheet 3 is conveyed in the direction of arrow A, the phosphor sheet 6 can be scanned.

In this way, when the laser beam generated by the excitation light generating means 21 is propagated through the original fiber 32, the laser beam cannot be scattered by dust, clumps, etc. in the air, so that the resolution of the image is improved. Further, since the irradiation angle of the laser light emitted from the output end of the original fiber 62 and irradiated onto the phosphor sheet 6 is the same regardless of the periphery of the center 2 of the phosphor sheet 6, the irradiation angle is the same. There is no need to correct changes in brightness of light.

Furthermore, an optical fiber with a cladding outer diameter of about 100 μm has a curvature of 10-1IIIfL and can be bent very small. Not restricted. Therefore, the entire device can be made compact.

It goes without saying that the present invention is not limited to the above-mentioned embodiments, and can be modified and implemented as appropriate within the scope of the gist of the present invention.

For example, in the embodiment described above, the laser beam generated by the excitation light generating means 21 is fixed at FILL! Although the configuration is such that the light is reflected at 30 and enters the rotating mirror 61, the configuration is not limited to this, and the configuration may be such that the light is directly incident on the rotating mirror 31.

〔Effect of the invention〕

According to the present invention described above, since the excitation light is propagated by the excitation light propagation means, scattering of the excitation light cannot occur,
Therefore, the resolution of the read image is improved, and
Since the irradiation angle of the excitation light during scanning of the phosphor sheet is always the same, there is no need to correct changes in the brightness of the stimulated light, which was done in conventional devices. In addition, since the excitation light is propagated by the excitation light propagation means which is easily curved, the present invention can provide a radiation image information reading apparatus which exhibits excellent effects such as a small IIK structure for the entire apparatus.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of digital radiography, and FIG. 2 shows the configuration of a conventional radiation image information reading device included in the device shown in FIG. 1. The operation of the device shown in FIGS. 6 and 4. It is an explanatory diagram for explaining.

Claims (1)

[Claims] In a radiation image information reading device that scans a phosphor sheet having a photostimulable phosphor with excitation light generated by an excitation light generating means and reads radiation image information accumulated in the photostimulable phosphor, a predetermined a rotary reflecting means that rotates rapidly and reflects the excitation light generated by the excitation light generating means to the surroundings; and one end is disposed at a position where the excitation light reflected to the surroundings by the rotary reflecting means can be sequentially incident, and , and an excitation light transmitting means, the other end of which is arranged at a position where the excitation light is sequentially incident on the phosphor sheet at the same irradiation angle. Device.