JPH01946A - Radiation image reading device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Field of Application) The present invention is directed to the production of radiation images from a stimulable phosphor sheet (imaging plate: abbreviated as IP) that accumulates and stores information about radiation passing through a subject. The present invention relates to a radiation image reading device that reads information.

(Prior art) An IP containing a stimulable phosphor absorbs radiation that has passed through an object such as a human body, accumulates and records the radiation image edge of the object, and later excite this with laser light or the like. Irradiate the light,
There is a known device that reads the stimulated light emitted at that time with a suitable photodetector, converts the read signal into an electrical signal, and then records and reproduces it as a radiation image on photographic film, CRT, etc. (U.S. Patent No. 3.859.527).

This can be explained using the system configuration diagram shown in FIG. 5 as follows. Radiation emitted from the X-ray tube 1 passes through the subject 2 and is recorded on the IP3. The recorded radiation information is read out by the radiation image reading device 4 and sent to the data processing device 5.
After data processing is performed to obtain an image with excellent diagnostic suitability, the image is printed on a film 7 supplied by an image recording device 6, and passed through an automatic processor 8 to form an X-ray photograph 9.

FIG. 6 shows the configuration of a conventional radiation image reading device. A laser beam 10 emitted from a laser oscillator (not shown) is transmitted through a lens 11.
focused at 100 μm Pi! ! The beam is narrowed down to a narrow beam Ii and irradiated onto IPa by the galvanometer 12. IP3 is the roller 13a.

13b on the traveling belt 14, and moves in the direction of the arrow 17 in synchronization with the scanning of the laser beam 10. In this way, the entire area of IP3 will be uniformly scanned.

Stimulated light generated by laser beam irradiation is collected by a condenser 15, photoelectrically converted by a photomultiplier tube 16, and sent to a data processing device 5 shown in FIG.

However, in the conventional device, since the IPa was scanned by reflecting the laser beam with a galvanometer, there is a drawback that positional deviation occurs due to slight vibrations and reading accuracy decreases. Furthermore, if the scan speed is increased, the excitation time of each pixel becomes shorter, and the S/N ratio of the image deteriorates due to a decrease in the amount of stimulated light emitted, so the scan speed cannot be increased. This makes it difficult to shorten the reading time.

Therefore, the applicant first investigated the reading accuracy of radiographic images and the S.
We provide a radiation image reading device that aims to improve the /N ratio and shorten the reading time (patent application 1986-29).
4646>.

This device includes an excitation light irradiation means for simultaneously irradiating one line of an IP containing a stimulable phosphor and storing radiation image information with excitation light, and one line of brightness generated from the IP by the irradiation of the excitation light. It is characterized by having a plurality of photostimulum detection means for each detecting photostimulosis, and a data processing means for processing the detection output of each photostimulum detection means and obtaining image data for one line. This device will be specifically explained below with reference to FIGS. 7 to 15.

As shown in FIG. 7, this device includes excitation light irradiation means 20.
'fN photometric analysis detection means 21A21B, data processing means 29. It has a memory 322 and a display section 33.

The excitation light irradiation means 20 is for simultaneously irradiating one line of IP3 with excitation light, and the photostimulation light detection means 21A and 21B are for detecting the stimulated light generated from IP3 by this excitation light irradiation. The stimulated light detection means 21A and 21B are arranged to sandwich the excitation light irradiation means 20, and include light guides 22A and 22B and a filter 23A, respectively.

23B, and line sensors 24A and 24B. The light guides 22A and 22B are for guiding the stimulated light from IP3, and are formed by arranging a plurality of optical fibers as will be described in detail later. Filter 23A.

23B allows only light in a predetermined wavelength range to pass through,
Line sensors 24A and 24B each have this filter 2.
It converts the light taken in through 3A and 23B into an electrical signal.

The data processing means 29 is the photostimulant detection means 21A.

It processes the detection output of 21B to obtain one line of IP3 image data, and the line sensors 24A and 24B
An A/D (analog-to-digital) converter 25A converts the output of the converter into a digital signal.

25B, switches 26A and 26B that connect and disconnect the transmission path of this A/D conversion output signal, and these switches 26A and 2
Adders 27A and 27B that add data taken in during the ON period of 6B, and a memory 28A that stores the output thereof.
, 28B, an address controller 30 that controls the addresses of the memories 28A, 28B, and the memories 28A, 28B.
The adder 31 adds data read from 8B. The addition output of this adder 31 is sent to a memory 32 disposed at a subsequent stage, and a radiation image read out from IP3 is formed in this memory 32. The image formed in the memory 32 is visualized on the display section 33.

FIG. 8 is a sectional view of the excitation light irradiation means 20, and FIG. 9 is an explanatory view of the main part of FIG. 8 viewed from the direction of arrow 39.

As shown in the figure, this excitation light irradiation means 20 includes a point light source 4
0, an optical system (lens) 41 that converts this point light source light into parallel light, a light guide 35 that guides this parallel light onto IPa and emits it in a line shape, and an optical system (lens) that focuses this emitted light. lens) 36. A halogen lamp is used as the point light source 40. The light guide 35 is
Consists of multiple optical fibers arranged. That is, the plurality of optical fibers are bundled into a circular end face on the parallel light incident side, and arranged in a line on the output side.

The light emitted from the end of the light guide 35 passes through the optical system 36 and passes through a slit 37 with a width of 200 μm.
The excitation light is irradiated onto the IP3 via the excitation light.

Further, each optical fiber 45 constituting the light guide 35 is formed by connecting fibers having different numerical apertures (abbreviated as NA) in series. That is, by applying a fiber with a large NA to the portion indicated by 42 in FIGS. 9 and 10, it is possible to improve the efficiency of receiving parallel light from the optical system 41 and to prevent a decrease in light transmission efficiency at the bent portion. We are trying to

Furthermore, by applying a fiber with a small NA to the portion indicated by 43, the sharpness of the emitted light is improved.

The excitation light irradiation area by the excitation light irradiation means 20 having the above configuration is in the form of a line with a width of 200 μm, as shown in FIG.

Furthermore, the light guide 22A (22B) in the photostimulated photodetection means 21A (21B) has a structure as shown in FIG.
It is formed by arranging a plurality of optical fibers 46 having rectangular end faces of axb. For example, as shown in Figure 13, 1 on IPa
When the pixel is 200 μm x 200 μm, the length of the side a of the fiber 45 is set to 200 μm or less in order to improve the resolution in the direction perpendicular to the scanning direction (Y direction), and on the other hand, the focusing efficiency of stimulated light from IP3 is improved. In order to achieve this, the length of the sides is set to 200 μm or more.

Next, the operation of the above configuration will be explained.

The point light source light from the point light source 40 in FIG. 9 is converted into parallel light by an optical system 41, converted into line light by a light guide 35, and then passed through an optical system 36 and a slit 37 in order on one line of IP3. All pixels are irradiated simultaneously.

Here, the relationship between the absorption characteristics of IP and the excitation light spectrum is as shown in FIG. The most efficient wavelength (
For example, irradiation with excitation light near 600 nm produces stimulated light with an efficiency corresponding to the wavelength.

This device uses excitation light with a wavelength of 6801 m.

This excitation light irradiation generates one line of stimulated light from IP3, and this stimulated light is transmitted to the light guide 22A.

22B and filter 23A.

The signal is transmitted to line sensors 24A and 24B via 23B. Here, FIG. 15 shows the line sensors 24A, 24.
Sensitivity characteristics of B, excitation light spectrum.

As shown in the relationship between the stimulated light spectra, there is a possibility that excitation light may also be detected due to the sensitivity of the line sensor 24A and the 24-direction body. Therefore, filters 23A and 23B having the characteristics indicated by α in the same figure are respectively installed on the line sensor 24.
By arranging it before A and 24B, detection of excitation light is prevented.

The detection outputs of the line sensors 24A and 24B are converted into digital signals by A/D converters 25A and 25B, respectively, and then sent to a switch 26A.

Adder 27A during the on period of adder 26B.

27B respectively. This adder 27A.

27B adds data on the same line one after another, and the contents of memories 28A and 28B are updated. Address control of the memories 28A and 28B is controlled by an address controller 30. Then, the contents stored in the memories 28A and 28B are added by an adder 31, and the addition result is written into the memory 32 as read image data for one line of IP3. The above operation is repeated every time one line is intermittently conveyed in the direction of the arrow 34 of IP3, and a read image is formed in the memory 32.

This image is visualized on the display section 33.

In the addition process of the adder 31 described above, the data to be added must be of the same pixel in IP3. Therefore, if there is a relative positional deviation between the photostimulated light detection means 21A and 21B, the address controller 3
The positional deviation is corrected on the data by address control of 0.

(Problem to be solved by the invention) However, in the apparatus shown in FIG.
The excitation light irradiated from 0 is reflected on the surface of IP3 and becomes scattered light, and this scattered light excites IP3 again, resulting in a new problem in that noise is generated.

That is, as shown in FIG. 4, not all of the excitation light irradiated onto IP3 is absorbed by IP3, and some degree of surface reflection is unavoidable due to the surface properties of IP3. This reflected component is reflected again at the ends of the photostimulated light detection means 22A, 22B, and enters the IP3. When the incident position of this excitation light scattering component (scattered light) is different from the excitation light irradiation position from the excitation light irradiation means 20, stimulated light is generated from unrelated pixels on IPa, which causes noise in the read image. It causes

SUMMARY OF THE INVENTION The present invention aims to eliminate the above-mentioned drawbacks and to provide a radiation image reading device that prevents the occurrence of noise caused by excitation light scattering components.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides an excitation light irradiation means for irradiating excitation light to an IP that stores radiographic image information, and
The radiation image reading apparatus has a photostimulated light detection means for detecting photostimulated light generated by the radiation image reading apparatus, and is provided with a scattered component shielding member that prevents the excitation light scattered components from entering the IP.

(Function) According to the above configuration, it is possible to prevent the excitation light scattering component from entering the IP, and therefore it is possible to suppress the occurrence of noise on the read image.

(Example) Hereinafter, the present invention will be specifically explained with reference to Examples.

This embodiment is an improved version of the device described with reference to FIGS. 7 to 15, and only the points that are different from the device in terms of structure will be explained, and the explanation of other parts will be omitted.

FIG. 1 shows the main parts of an apparatus according to an embodiment of the present invention. As shown in the figure, in the apparatus of this embodiment, a scattered component 11 is provided at the tips of the photostimulated light detection means 22A, 22B.
5A and 35B are provided.

The scattered component shielding members 35A and 35B are for blocking excitation light scattered components (scattered light) from entering the IP3,
They are arranged at a predetermined interval (this interval is approximately equal to the width of the excitation light) so as not to block the excitation light (direct light) irradiated by the excitation light irradiation means 20. FIG. 2 is a perspective view showing how the scattered component shielding member 35A is installed. The scattered component shielding member 35A has a cross section bent in a “V” shape,
Its length in the longitudinal direction is equal to the width of IP3. Also, IP
The portion parallel to the three planes is in contact with IP3, and is configured to relatively slide on IP3 when reading radiation image information. The same applies to the scattered component shielding member 35B.

There are no particular restrictions on the material of the scattered component shielding members 35A and 35B, but their surfaces may be coated with a material that well absorbs scattered light (excitation light scattering component, the wavelength of which is equal to the excitation light), such as black paint. Or something with the same properties is attached.

According to the above configuration, the excitation light scattering component is blocked by the scattering component shielding member 35A or 35B and is not irradiated onto the IP3 surface again. Therefore, noise generation in the read image can be suppressed.

Note that the image information reading operation from IP3 and the processing of the information are similar to the apparatus shown in FIG. 7.

Although one embodiment of the present invention has been described above, it goes without saying that the present invention is not limited to the above-described embodiment, and that various modifications can be made.

To enhance the scattered component removal effect, use the scattered component shielding member 35A.
, 35B must be brought as close to the IP3 plane as possible.

Moreover, the scattered component shielding member 35A.

If the relative movement between IP3 and IP3 is not performed smoothly, reading operation will be hindered. Therefore, as shown in FIG. 3, the scattered component shielding member 35A is attached via a biasing member such as a coil spring, and a material with a small frictional coefficient (for example, a It is preferable to attach a film 36A made of synthetic resin (such as a synthetic resin made by polymerizing ethylene chloride). With this configuration, the reading operation can be performed smoothly and the effect of removing scattered components can be enhanced.

Further, the present invention can also be applied to the conventional device shown in FIG. In this case, a scattered component shielding member may be attached to the tip of the condenser 15. When excitation light is irradiated onto IPa in a dotted manner, a scattering component in a direction perpendicular to the moving direction of IP3 (direction of arrow 17) also becomes a problem. However, it is difficult to remove this. In this regard, when the excitation light is irradiated in a line as in the above embodiment, the linear scattered light distribution becomes substantially uniform, and there is no need to take this into account.

Therefore, the effect of removing scattered components is higher when applied to a device that irradiates excitation light in a line shape, as in the above embodiment, than to a device that irradiates excitation light in a dotted manner.

Furthermore, a slight gap (for example, 50 μm) may be provided without bringing the scattered component shielding member into contact with the IP surface. This is advantageous in terms of smooth reading operation and prevention of scratches on the IP surface. As a method for making the scattered component shielding member float slightly above the IP surface, for example, an air jet hole is provided on the bottom surface of the scattered component shielding member, and air is jetted out from the eye hole toward the IP surface at a constant speed (air curtain method). )
can be mentioned.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide a radiation image reading device that prevents the generation of noise caused by excitation light scattering components.

[Brief explanation of drawings]

@ Figure 1 is an explanatory diagram of the main parts of the device according to one embodiment of the present invention, Figure 2 is a perspective view of the main parts of the same device, Figure 3 is an explanatory diagram of another embodiment, and Figure 4 is the excitation light scattering component (scattered component). FIGS. 5 and 6 are block diagrams and configuration explanatory diagrams of the conventional example, respectively, and FIGS. 7 to 15 are for explaining the device prior to the present invention. The figure is a block diagram of the device,
Figures 8 to 10 and 12 are explanatory diagrams of the main parts, Figure 11 is an explanatory diagram of the excitation light irradiation area on the IP, and Figure 13 is an explanatory diagram of the excitation light irradiation area on the IP.
The figure is an explanatory diagram of one pixel on IP, Figure 14 and Figure 1.
FIG. 5 is a characteristic diagram for explaining the operation of the device. 3... IP (imaging plate), 20... Excitation light irradiation means, 2mA, 21B... Stimulated light detection means, 35A, 35B
...Scattered component shielding member. Agent Patent Attorney Norihiro Kon Kendo Takeshi Kondo Figure 1, 21A, 5PJ3, Figure 4, Figure 5, Figure 11, Figure 22A (22B) / Figure 12, Funeral Figure 13, Waste Forces Stopping Zectrum People φ- Funeral, Figure 15

Claims (4)

[Claims] (1) Radiation image reading having excitation light irradiation means for irradiating excitation light onto an imaging plate that stores radiation image information, and photostimulated light detection means for detecting stimulated light generated from the imaging plate by this excitation light irradiation. A radiation image reading apparatus, characterized in that the apparatus further comprises a scattered component shielding member that prevents excitation light scattered components from entering the imaging plate. (2) The radiation image reading device according to claim 1, wherein the scattered component shielding member is provided at the tip of the photostimulated light detection means. (3) The radiation image reading device according to claim 1 or 2, wherein the excitation light irradiation means irradiates excitation light to one line of the imaging plate simultaneously. (4) The stimulated light detection means detects one line of stimulated light generated from the imaging plate by the excitation light irradiation by the excitation light irradiation means.
The radiographic image reading device described in 2.