JPH0380240A - Latent image reading method - Google Patents

Abstract

PURPOSE:To improve efficiency in reading by arranging plural arced accumulative fluorescent screens on the same surface of a cylinder, scanning them with an excitation beam while it is rotated, and thereby reading a latent image. CONSTITUTION:A light guide 3 translates as it rotates; that is, the guide 3 translates along a center axis as it rotates with the center axis of an incoming end 31 having as its rotation center. As it does so, the outgoing end 32 of the light guide 3 passes above the accumulative phospher plates 41 and 42 in that order; the central angle of the circular arc of each of the accumulative fluores cent screens 41 and 42 is about 90 deg.. Since the light guide 3 constantly translates, when the outgoing end 32 comes above the original accumulative fluorescent screen after its one rotation, it is away from the previous reading position a prescribed distance toward the axial direction, and the reading position does not overlap another. Thus, the two accumulative fluorescent screens 41 and 42 are read at a time while the light guide 3 makes one rotation, and efficient reading is achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for reading a latent image from a stimulable fluorescent screen that records the intensity distribution of radiation such as X-rays.

[Prior Art J] To read a latent image recorded on a stimulable phosphor plate, the stimulable phosphor plate is irradiated with excitation light such as a laser beam, and the intensity of the fluorescence generated therefrom is detected. At this time, by scanning the stimulable phosphor screen with laser light, the latent image can be read from the entire surface of the stimulable phosphor screen.

Various methods are known for scanning with laser light, and efforts have been made to read latent images as efficiently as possible in the shortest possible time. By the way, the scanning motion of laser light can basically be considered to be translational reciprocating motion or rotational motion, but when considering the motion drive system, rotational motion has a simpler structure and better stability of motion. ing. The technique of scanning laser light by such rotational movement is, for example,
It is disclosed in Japanese Patent Application Laid-open Nos. 64-6918 and 64-6919.

[Problems to be Solved by the Invention] In the conventional laser beam scanning method described above, only a part of the rotational movement of the laser beam is used for reading the stimulable fluorescent screen, and the remaining rotational movement part is used for accumulating the laser beam. The fluorescent light does not hit the fluorescent screen, and no fluorescence is detected.

Therefore, the reading speed becomes slower.

An object of the present invention is to provide a latent image reading method that can improve reading efficiency in a method of reading a latent image on a stimulable fluorescent screen by irradiating an excitation light beam in a rotational scan manner.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the multiple inventions of this application have in common that a plurality of arc plate-shaped stimulable fluorescent screens are arranged on the same cylindrical surface. The problem lies in reading multiple stimulable fluorescent screens at once.

The invention of claim 1 provides a latent image reading method in which a stimulable phosphor plate on which a latent image is recorded is irradiated with excitation light and fluorescence generated therefrom is detected, in which a plurality of arc-shaped stimulable phosphor plates are arranged in the same cylinder. irradiating the plurality of stimulable fluorescent plates with excitation light sequentially while rotating and scanning them and detecting the fluorescence generated therefrom; The invention of claim 2 is characterized in that the latent image reading method includes a step of moving in the direction of ,
arranging a plurality of arc plate-shaped stimulable phosphor plates on the same cylindrical surface; branching an excitation beam emitted from one excitation beam generator into a plurality of beams; and one of the plurality of beams Under conditions such that when the beam hits one of the plurality of stimulable phosphor plates, the other beams do not hit any of the stimulable phosphor plates,
sequentially irradiating the plurality of stimulable fluorescent plates with the beams while rotating and scanning the plurality of beams and detecting fluorescence generated therefrom; detecting a rotational angular position of the rotational scanning and determining the rotational angle; identifying one stimulable phosphor plate that is hit by the beam from among the plurality of stimulable phosphor plates based on the position; and moving the rotational scanning motion in the axial direction of the cylindrical surface. The invention according to claim 3 is characterized in that a latent image reading method comprises: irradiating a stimulable fluorescent plate on which a latent image is recorded with excitation light and detecting fluorescence generated therefrom;
arranging a plurality of arc plate-shaped stimulable phosphor plates on the same cylindrical surface; branching an excitation beam emitted from one excitation beam generator into a plurality of beams; and one of the plurality of beams Under such conditions that when one of the plurality of stimulable phosphor plates is hitting one of the stimulable phosphor plates, the other beam is also hitting the other stimulable phosphor plate, and the plurality of stimulable phosphor plates are rotated and scanned. irradiating the stimulable phosphor plates with beams in order; detecting the fluorescence generated from the plurality of stimulable phosphor plates as separate fluorescence for each fluorescence corresponding to the plurality of beams; and determining the rotational angular position of the rotational scan. detecting and determining, based on the rotational angular position, which stimulable phosphor plate the separate fluorescence corresponds to; and moving the rotational scanning motion in the axial direction of the cylindrical surface. It is characterized by having.

[Function] In the reading method according to the first aspect, a plurality of arc plate-shaped stimulable phosphor plates are arranged on the same cylindrical surface, and the excitation light beam is irradiated onto these plates by rotating and scanning them. Assuming that there are two stimulable phosphor plates, an excitation light beam hits the first stimulable phosphor plate, and fluorescence is generated therefrom. This is detected by a detector. As the rotational scanning of the excitation light beam progresses, the excitation light beam leaves the first stimulable phosphor screen and hits the second stimulable phosphor screen. In this case as well, the generated fluorescence is detected by a detector.

By moving the rotational scanning motion in the axial direction of the cylindrical surface, the entire surface of the arc-shaped stimulable fluorescent screen can be read. When performing rotational scanning of the excitation light beam, its rotational angular position is detected. By knowing this rotational angular position, it is possible to know which stimulable fluorescent plate the excitation light beam is hitting.

That is, it is possible to know from which stimulable fluorescent plate the detected fluorescence is generated.

Therefore, in the data processing process after fluorescence detection, data can be processed for each stimulable phosphor plate.

According to this invention, one line of each of a plurality of stimulable fluorescent plates can be read while the excitation light beam is scanned one rotation.

In the reading method of claim 2, the excitation light beam is branched into a plurality of beams. The following description will be made assuming that the excitation light beam is split into two beams and these beams are irradiated onto two stimulable fluorescent screens. In this invention, when one of the beams hits either of the stimulable phosphor plates, the other beams do not hit either of the stimulable phosphor plates.

First, the first beam hits a first stimulable phosphor screen, and as the rotational scanning of the beam progresses, this first beam hits the next second stimulable phosphor screen. After the first beam leaves the second stimulable phosphor screen, the second beam now impinges on the first stimulable phosphor screen. Then the second beam continues
This corresponds to a stimulable fluorescent screen. Thereafter, repeat the above operations. In this way, even if two beams are used, only one detection system is required for detecting the generated fluorescence. This is because the beam never hits two stimulable phosphor screens at the same time. As in the first aspect of the invention, it is determined from which stimulable fluorescent plate the fluorescence is generated based on the rotational angular position of the beam.

In this invention, each of a plurality of stimulable fluorescent screens can be read for a plurality of lines (the number of lines equal to the number of branched beams) while the excitation light irradiation system scans one rotation.

The reading method of claim 3 also branches the excitation light beam into a plurality of beams, but unlike the reading method of claim 2, when one of the plurality of beams hits any of the stimulable phosphor plates, the excitation light beam is split into a plurality of beams. The beam also hits other stimulable fluorescent screens. That is, fluorescence is generated simultaneously from two or more stimulable fluorescent screens. Therefore, it is necessary to distinguish between these fluorescences. To do this, the first step is to identify the correspondence between beams and fluorescence. That is, a plurality of fluorescences are detected separately so that it can be determined which beam excited each fluorescence.

In the next step, which stimulable phosphor plate each beam hits is determined based on the rotational angular position of the beam, as in the first aspect of the invention. After all, in this invention, as in the invention of claim 2, each of the plurality of stimulable fluorescent screens is read for a plurality of lines (the number of lines equal to the number of branched beams) while the excitation light irradiation system scans one rotation. However, unlike the invention of claim 2, the beam may hit a plurality of stimulable phosphor plates at the same time, so there are fewer restrictions on the arrangement relationship between the branched beams and the stimulable phosphor plates, and more branched beams and more Many stimulable fluorescent screens can be used.

[Example] Next, embodiments of the invention will be described with reference to the drawings.

FIG. 1 is a perspective view of an embodiment of an apparatus for carrying out the reading method according to claim 1. This reading device includes a laser oscillator 1, a dichroic mirror 2, a light guide 3, a detector 5, and a rotational angle encoder 6, and is configured to read a plurality of arc-shaped stimulable fluorescent plates 41 and 42. . The stimulable fluorescent screens 41 and 42 have the same radius of curvature, the same shape, and are arranged on the same cylindrical surface.

The light guide 3 is composed of a large number of optical fibers, and has one input end 31 and one output end 32. The output end 32 is bent at right angles to the input end 31, and the light guide 3 can rotate around the central axis of the input end 31.

The rotational angle encoder 6 detects the rotational angular position of the rotating light guide 3.

Next, the basic operation of this reading device will be explained. Laser light emitted from a laser oscillator 1 passes through a dichroic mirror 2. The dichroic mirror 2 allows laser light to pass through it, but reflects fluorescence. The laser light that has passed through the dichroic mirror 2 enters the center of the incident end 31 of the light guide 3. The laser light passes through each optical fiber constituting the light guide 3 and emerges from the center of the output end 32 . When the laser light emitted from the emission end 32 hits the portion of the stimulable fluorescent plate 41, 42 where the latent image is recorded, fluorescence is generated. This fluorescence is focused on almost the entire surface of the emission end 32. The focused fluorescence is
The light returns through the light guide 3 and emerges from the entrance end 31. The emitted fluorescence is reflected by a dichroic mirror 2 and enters a detector 5 such as a photomultiplier tube. The analog output of the detector 5 is converted into digital data by an analog-to-digital converter and input to the signal distributor 7. The signal distributor 7 determines whether the output end 32 is scanning the stimulable phosphor screen 41 or the stimulable phosphor screen 42 based on the signal from the encoder 6, and outputs the obtained fluorescence detection data. The identified fluorescence detection data, which characterizes which stimulable phosphor screen is behind, is separated for each stimulable phosphor screen and stored in the memory 81.
is stored in The stored data is transferred to the CPU as needed.
The image is processed in step 82 and displayed on the CRT 83.

The light guide 3 moves in translation while making a rotational movement. That is, while rotating about the central axis of the incident end 31 as a rotation center, it translates along the central axis. Thereby, the output end 32 of the light guide 3 passes over the stimulable fluorescent screens 41, 42 in sequence.

Each stimulable fluorescent screen 41, 42 has a central arc angle of approximately 90
degree (to be exact, it is slightly medium than 90 degrees). Since the light guide 3 is constantly moving in translation, when the output end 32 rotates once and comes to rest on the original stimulable phosphor screen, it is axially separated by a predetermined distance from the previously read position, and the reading There are no duplicate positions.

In this embodiment, two stimulable fluorescent screens can be read at once during one rotation of the light guide 3. If four similar stimulable phosphor plates are arranged on the same cylindrical surface with almost no gaps between them, the four stimulable phosphor plates can be read at once during one rotation of the light guide 3, making it extremely efficient. You can read it visually.

FIG. 2 is a perspective view of an embodiment of an apparatus for carrying out the reading method according to claim 2. In this device, the light guide 3
This device differs from the device shown in FIG. 1 in that the output end of the device is bifurcated into two. The other basic configuration is the same as that of the device shown in FIG. 1, and the same parts are given the same reference numerals.

In this device, the light guide 3 has two exit ends 33,34. That is, the excitation light beam is split into two beams. The two output ends 33, 34 face in opposite directions. That is, they are separated by 180 degrees in rotation angle. To explain the operation of this device, when the light guide 3 rotates, one output end 33 first scans over the first stimulable fluorescent screen 41. Subsequently, the second stimulable fluorescent screen 42 is scanned. When the output end 33 comes off the second stimulable phosphor screen 42, the other output end 34 starts scanning over the first stimulable phosphor screen 41. Thereafter, the same operation is repeated. Fluorescence collected at both emission ends 33 and 34 is detected by the same detector 5.

Which fluorescent light is generated from which stimulable fluorescent plate is determined by the signal distributor 7 based on the signal from the encoder 6, similar to the apparatus shown in FIG.

In this device, two lines of each of the two stimulable fluorescent plates 41, 42 are read during one rotation of the light guide 3, so the reading efficiency is twice that of the device shown in FIG.

FIG. 3 is a perspective view of an embodiment of an apparatus for carrying out the reading method of claim 3. In this device, the light guide 3
It has a very unique configuration, allowing four stimulable fluorescent screens to be read simultaneously using four branched beams.

Note that the same parts as in the apparatus shown in FIG. 1 are given the same reference numerals.

This device uses four arc-shaped stimulable phosphor plates 43.
44, 45, and 46 are arranged on the same cylindrical surface. On the other hand, the light guide 3 is branched into four parts and has four output ends 35, 36, 37, and 38. Since each output end is separated from each other by a rotation angle of 90 degrees, each output end 3
5 to 38 always face any one of the stimulable fluorescent screens 43 to 46. Therefore, while the light guide 3 rotates, the excitation light beam is always available for reading, no matter what rotational angular position it is in.

FIG. 4 shows a rotatable light guide 3 and stationary light guides 931 to 934 for receiving and removing fluorescence from the light guide 3.
FIG. 3 is a cross-sectional view along the axis showing the relationship between the However, the external view of the light guide 3 is shown. The incident end side of the light guide 3 is composed only of a group of optical fibers 91 for laser passage. FIG. 5 is a sectional view taken along the line ■--■ in FIG. 4, and shows the configuration of the optical fiber group 91 for laser passage. This optical fiber group 91 for passing the laser consists of four concentric annular regions 91.
It consists of 1.912.913.914. The laser beam enters the entire optical fiber group 91 for laser passage, and each optical fiber group 911 to 91 forming four annular regions
Laser light is incident on any of the four. It is preferable that the respective intensities of the laser beams incident on the four optical fiber groups 911 to 914 be the same. If the cross-sectional intensity distribution of the laser beam is uniform, the area of the end face of each optical fiber group may be made the same. If the cross-sectional intensity distribution of the laser beam is not uniform, the cross-sectional areas of the optical fiber groups 911 to 914 are appropriately differentiated so that the laser intensity passing through each optical fiber group is the same.

If the optical fiber group 91 for laser passage is divided concentrically in this way on the incident end surface, even if the center of the laser beam is slightly shifted from the center of the incident end, each optical fiber group 911
Advantageously, the laser intensity incident on ~914 does not vary as the light guide rotates.

The diameter of the light guide 3 gradually increases from the input end to the output end, and finally reaches its maximum thickness before the encoder 6. FIG. 6 is a sectional view taken along the line Vl--Vl in FIG. 4, and shows the structure of an optical fiber group 92 for condensing fluorescence disposed outside the optical fiber group 91 for laser passage. This optical fiber group 92 for condensing fluorescence also consists of four concentric annular regions 921, 922, 923, and 924,
Each annular region has the same cross-sectional area.

FIG. 7 shows the four output ends 35, 36, 37 of the light guide 3.
．． 38 is an end view of FIG. FIG. 7(a) is an end view of the output end 35, and the end face of the optical fiber group 911 for laser passage appears at the center of the output end 35. Around it,
The end faces of the optical fiber group 921 for condensing fluorescence are exposed.

Similarly, in FIGS. 7(b), 7(c), and 7(d), the end faces of the optical fiber group 912, 913, 914 for laser passage appear in the center of each output end 36, 37, 38, and the surrounding area , the end faces of optical fiber groups 922, 923, and 924 for condensing fluorescence are exposed. That is, each optical fiber group 911 to 9 forming the optical fiber group 91 for passing the laser at the input end.
14 appears in the center of each output end 35 to 38,
It is configured in the light guide 3.

The fluorescence collected by the fluorescence collection optical fiber group 921 in FIG. 7(a) enters the light guide 931 in FIG. 4. Similarly, the fluorescent light collected by the fluorescent light collecting optical fiber groups 922, 923, and 924 shown in FIGS. enter. The fluorescence entering each of the light guides 931 to 934 is reflected by the dichroic mirrors 21, 22, 23, and 24 in FIG. 3, and detected by the detectors 51, 52, 53, and 54, respectively. Note that the laser light reflected by the stimulable fluorescent screen may return as it is through the group of optical fibers for condensing the fluorescent light, but this laser light is reflected by the dichroic mirrors 21 to 24.
It passes through this without being reflected. Therefore, there is no possibility that this type of laser light will enter the detectors 51-54.

The outputs of the detectors 51 to 54 and the output of the encoder 6 are inputted to the signal distributor 7 in the same way as in the device shown in FIG. 1, and it is determined from which stimulable fluorescent plate the fluorescence detected by each detector comes from. do. In this device, outputs are simultaneously output from the four detectors 51 to 54, so these are time-divided and taken into the signal distributor 7.

Since this device uses four beams to simultaneously read four stimulable phosphor plates, four lines of each of the four stimulable phosphor plates can be read during one rotation of the light guide 3. Therefore, the reading efficiency is eight times that of the apparatus shown in FIG. 1, and four times that of the apparatus shown in FIG.

In this device, the number of output ends of the light guide and the number of stimulable fluorescent screens are four, but these numbers can be set to any number (for example, two, three, five, etc.). In that case, the central angle of the arc plate-shaped stimulable fluorescent screen is changed appropriately.

In the apparatus of FIGS. 1, 2 and 3, the light guide 3 may simply be rotated without being translated. In that case, the stimulable fluorescent screen is translated.

[Effects of the Invention] The invention of claim 1.2.3 both arranges a plurality of arc plate-shaped stimulable fluorescent screens on the same cylindrical surface and scans them with an excitation light beam to read the latent image. Therefore, the reading efficiency is improved compared to the case of reading a single arc plate-shaped stimulable fluorescent screen. That is, when compared with the same rotational scan, the reading is completed faster overall in this invention.

In the invention of claim 2, the excitation light beam is further split into a plurality of beams and used for reading, so the reading efficiency is improved by the number of branched beams compared to the invention of claim 1.

In the invention of claim 3, since the plurality of beams are applied to the plurality of stimulable phosphor plates at the same time, there are fewer restrictions on the arrangement relationship between the branched beams and the stimulable phosphor plates, and the number of branched beams and the number of stimulable phosphor plates can be reduced. can be increased, and the reading efficiency is improved compared to the invention of claim 2.

[Brief explanation of drawings]

Fig. 1 is a perspective view of an apparatus for carrying out the invention of claim 1, Fig. 2 is a perspective view of an apparatus for carrying out the invention of claim 2, and Fig. 3 is a perspective view of an apparatus for carrying out the invention of claim 3. 4 is a sectional view taken along the axis of the light guide used in the device shown in FIG. 3, FIG. 5 is a sectional view taken along the line V-V in FIG. 4, and FIG. FIG. 7 is a cross-sectional view taken along the line Vl-VI in the figure, and FIG. 7 is an end view of the four output ends of the light guide used in the apparatus shown in FIG. 1...Laser oscillator 3...Light guide 5...Detector 6...Rotation angle encoder 41.42...Stormative fluorescent plate

Claims (3)

[Claims] (1) In a latent image reading method in which a stimulable phosphor plate on which a latent image has been recorded is irradiated with excitation light and the fluorescence generated therefrom is detected, a plurality of arc plate-shaped stimulable phosphor plates are arranged on the same cylindrical surface. irradiating the plurality of stimulable fluorescent plates with excitation light sequentially while rotating and scanning, and detecting fluorescence generated therefrom; and moving the rotational scanning motion in the axial direction of the cylindrical surface. A latent image reading method comprising the steps of: (2) In a latent image reading method in which a stimulable phosphor plate on which a latent image has been recorded is irradiated with excitation light and the fluorescence generated therefrom is detected, a plurality of arc plate-shaped stimulable phosphor plates are arranged on the same cylindrical surface. splitting an excitation beam emitted from one excitation beam generator into a plurality of beams; Under conditions such that the beam does not hit any stimulable fluorescent screen,
sequentially irradiating the plurality of stimulable fluorescent plates with the beams while rotating and scanning the plurality of beams and detecting fluorescence generated therefrom; detecting a rotational angular position of the rotational scanning and determining the rotational angle; identifying one stimulable phosphor plate that is hit by the beam from among the plurality of stimulable phosphor plates based on the position; and moving the rotational scanning motion in the axial direction of the cylindrical surface. A latent image reading method characterized by the following. (3) In a latent image reading method in which a stimulable phosphor plate on which a latent image has been recorded is irradiated with excitation light and the fluorescence generated therefrom is detected, a plurality of arc plate-shaped stimulable phosphor plates are arranged on the same cylindrical surface. splitting an excitation beam emitted from one excitation beam generator into a plurality of beams; sequentially irradiating the plurality of stimulable phosphor plates with the beams while rotating and scanning the plurality of beams under conditions such that the beams also hit other stimulable phosphor plates; detecting the fluorescence generated from the fluorescent screen as separate fluorescence for each fluorescence corresponding to the plurality of beams; detecting the rotational angular position of the rotational scanning and detecting the separate fluorescence based on the rotational angular position; A latent image reading method comprising the steps of: specifying which stimulable phosphor plate corresponds to a stimulable fluorescent screen; and moving the rotational scanning motion in the axial direction of the cylindrical surface.