JP2002244237A - Radiation image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation image reader with makes it possible to constitute a filter, which receives light generated by a scan with exciting light and is long in a main scanning direction, without increasing the cost even when a read range of a radiation image stored in a radiation image conversion plate is windened and the main scanning range becomes wider. SOLUTION: This radiation image reader is equipped with a read part which reads radiation image information out of the radiation image conversion plate where the radiation image information is recorded and is further equipped with a filter 21 which has a photodetection surface 21a extending in the horizontal scanning direction so as to receive the light generated as the read part irradiates the radiation image conversion plate with the exciting light over a scan and also absorbs the exciting light; and the filter 21 is composed of long-sized filters 31, 32, and 33 which extend along the photodetection surface 21a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiographic image reading apparatus for reading a radiographic image stored in a radiographic image conversion plate and displaying and storing image information.

[0002]

2. Description of the Related Art Radiation images such as X-ray images are widely used for diagnosing diseases and the like.
After the radiation transmitted through the subject from the X-ray irradiator is absorbed by a stimulable phosphor plate as a radiation image conversion plate, the stimulable phosphor plate is irradiated with laser light (excitation light having a wavelength of about 680 nm, for example) as excitation light. ), The radiation energy (radiation image information) accumulated by the stimulable phosphor plate by the above-mentioned absorption is emitted as fluorescence by excitation while scanning, and the fluorescence is photoelectrically converted to obtain a radiation image signal. A method for reading a radiation image is known (U.S. Pat. No. 3,859,527 and JP-A-55-12144).
Reference).

[0003] Fluorescence generated from the stimulable phosphor plate by the scanning of the excitation light is received by a filter, then condensed via a light guide, and made incident on a photocathode of a photomultiplier (photomultiplier tube). Photoelectric conversion is performed, and a radiation image is read based on the electric signal. Thereafter, the stimulable phosphor plate is irradiated with erasing light from a halogen lamp or the like to erase the afterimage, and the next radiation imaging is performed. In this case, the filter is configured to be long in the main scanning direction, and absorbs excitation light and transmits fluorescence.

By the way, in order to enable radiographing of a wide subject or the like, for example, a stimulable phosphor plate having a width of 17 inches is used instead of a conventional stimulable phosphor plate having a width of 14 inches. It is necessary to widen the main scanning range so as to widen the reading range, but this would make the filter longer. Such a filter that absorbs the excitation light is expensive, and if the filter is longer, its manufacture becomes difficult, which leads to a further increase in cost.

[0005]

SUMMARY OF THE INVENTION The present invention is directed to a main image receiving apparatus that receives light generated by scanning with excitation light even if the reading range of a radiation image stored in a radiation image conversion plate is widened and the main scanning range is widened. An object of the present invention is to provide a radiation image reading apparatus that can easily configure a filter that is long in the scanning direction without increasing the cost.

[0006]

In order to achieve the above object, a radiographic image reading apparatus according to the present invention comprises a radiographic image conversion plate such as a stimulable phosphor plate on which radiographic image information is recorded. A radiation image reading apparatus provided with an image reading means for reading light, wherein the image reading means extends in the main scanning direction so as to receive light generated by irradiating the radiation image conversion plate with excitation light while scanning the radiation image conversion plate. A filter having a surface and absorbing the excitation light is provided, and the filter comprises a plurality of long filters extending along the light receiving surface.

According to the radiation image reading apparatus, since the filter extending in the main scanning direction is constituted by a plurality of long filters, the filter which is long in the main scanning direction can be easily constituted even if the main scanning range is widened. In addition, since a filter having a length that can be easily manufactured can be used, an increase in cost for the filter can be avoided. Further, since a filter corresponding to the main scanning range can be configured regardless of the length of the main scanning range, a change in the main scanning range can be dealt with without considering cost increase.

[0008] In this case, it is preferable that the plurality of long filters are bonded by bonding, and it is preferable that the filters are bonded by an adhesive having a small light transmittance to the excitation light. Further, a filler having a small light transmittance with respect to the excitation light may be arranged along each end of the plurality of long filters without bonding.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing a reading unit of the radiation image reading apparatus according to the embodiment of the present invention, and FIG. 2 is a plan view showing a light receiving system of the reading unit in FIG.

As shown in FIG. 1, a reading section as an image reading means of the radiation image reading apparatus according to the present embodiment is a stimulable phosphor plate which is a radiation image conversion plate in which a radiation image is stored by irradiation of radiation. A scanning optical unit 24 which is excited by irradiating a laser beam 24a having a wavelength of about 680 nm as a scanning light while scanning the laser light 20 and a stimulable phosphor plate 20 which is excited by the laser beam from the scanning optical unit 24 and emits light. Fluorescence of wavelength 405nm 2
A filter 21 having a light receiving surface 21a on which the light 0a is incident and having an optical characteristic of absorbing laser light and transmitting generated fluorescence 20a; a light guide 22 for guiding light emitted from the filter 21; A photomultiplier 23 having a photoelectric surface 23a on which the emitted light is incident.

In FIG. 1, a laser beam from a scanning optical section 24 scans the stimulable phosphor plate 20 in a direction perpendicular to the plane of the drawing and vertically scans the drawing. The filter 21 has a long light receiving surface 21a and is arranged so as to extend in the main scanning direction (a direction perpendicular to the paper surface of FIG. 1 and a horizontal direction X of FIG. 2).

Further, as shown in FIG. 1, the radiation image reading apparatus is provided with an erasing lamp 26, and by irradiating the stimulable phosphor plate 20 after reading the radiation image,
The radiation image information stored in the stimulable phosphor plate 20 is erased, and the next radiation imaging can be performed.

As shown in FIG. 2, in the reading section of the radiation image reading apparatus of FIG. 1, a filter 21, a light guide 22,
The photomultiplier 23 having the photocathode 23a constitutes a light receiving system. In this light receiving system, in order to be able to receive light from a stimulable phosphor plate having a width of, for example, 17 inches, the filter 21 is replaced by a plurality of long filters 31, 32, 33 having the same optical characteristics. It is configured to be longer in the main scanning direction than in the case of inch width. Filter 3
1 and 32 are joined at their end faces by an adhesive 34, and the filters 32 and 33 are joined at an end face by an adhesive 35, respectively.
The light receiving surface 21a of the filter 21 extending in the horizontal direction X (main scanning direction) of FIG. 2 is formed in a planar shape from the light receiving surfaces 31a, 32a, and 33a of the long filters 31 to 33. The adhesives 34 and 35 absorb laser light having a wavelength of about 680 nm emitted from the scanning optical section 24 and have a characteristic of low transmittance of light of that wavelength.

The long filters 31 to 33 as described above.
For example, B-410 manufactured by HOYA can be used, and a synthetic rubber-based adhesive can be used. For example, 1521C manufactured by Three Bond can be used.
It is not limited to these.

The operation of the reading section of the radiation image reading apparatus will be described with reference to FIGS. When the laser beam 24a from the scanning optical section 24 is sub-scanned in the vertical direction in FIG. 1 while main scanning the stimulable phosphor plate 20 in the direction perpendicular to the paper surface of FIG. 1 (horizontal direction X in FIG. 2), the stimulable phosphor plate Light 20 a generated from the body plate 20 is incident on the light receiving surface 21 a of the filter 21. This incident light enters the incident surface 22a of the light guide 22, exits from the exit surface 22b, enters the photoelectric surface 23a,
Photoelectric conversion is performed by the photomultiplier 23. This electric signal is subjected to current-voltage conversion, further amplified and digitally converted,
It is sent to a controller (not shown) to read the radiation image and store it in a storage device. After this reading,
By irradiating the stimulable phosphor plate 20 with erasing light from the erasing lamp 26 so as not to hinder the next radiation image recording, the afterimage of the stimulable phosphor plate 20 is erased.

As described above, the reading section of the radiation image apparatus shown in FIG.
Since the filter 21 is configured to be longer in the main scanning direction than in the related art so as to receive light from the main body, radiation imaging is possible even when the main scanning range is widened and the subject is wide. Further, since the filter 21 which is longer and difficult to manufacture than the conventional one can be configured by using a plurality of filters which are easy to manufacture conventionally, the cost of the filter does not increase. Further, regardless of the length of the main scanning range of the reading unit of the radiation imaging apparatus, a long filter corresponding to the main scanning range can be configured, and the main scanning range can be changed without considering cost increase.

Further, since the end faces of the filters 31 to 33 are joined by the adhesives 34 and 35 having characteristics of absorbing the excitation light and having a low transmittance of the excitation light, the filters 31 to 33 are formed.
The excitation light hardly penetrates at the junction, and the excitation light does not leak from the junction and enter the photocathode 23a of the photomultiplier 23. Therefore, the dark current of the photomultiplier 23 increases. There is no possibility that the photocathode 23a is deteriorated.

Next, with reference to FIGS. 3A to 3C, a modified example of the filter structure that does not adhere will be described. In the example of FIG. 3A, a substantially V or U-shaped groove is formed along each end between the ends of the filters 31 to 33 on the light receiving surface 31 a to 33 a side.
The grooves are arranged so as to be filled with fillers 41 and 42. In the example of FIG. 3B, a substantially V- or U-shaped groove is formed along each end between the ends of the filters 31 to 33 on the side opposite to the light receiving surfaces 31 a to 33 a on the side opposite to the surface 31 b to 33 b. The grooves are arranged so as to be filled with fillers 43 and 44. In the example of FIG. 3C, the light receiving surfaces 31 a to 31 a along the respective light receiving surfaces 31 a to 33 a of the filters 31 to 33 are arranged.
The fillers 45 and 46 are placed on the side 33a. As the filler, silicone or the like having a small light transmittance to excitation light can be used, and for example, KE45B manufactured by Shin-Etsu Chemical Co., Ltd. can be used. 3 (a) to 3 (c)
The same effect as described above can be obtained by such a filter structure that does not adhere.

As described above, the present invention has been described by the embodiments. However, the present invention is not limited to these, and various modifications can be made within the technical idea of the present invention. For example, the filter 21 is replaced with three filters 31 to 3
Although the filter is composed of three filters, the filter may be composed of two filters or four or more filters.
To 33 etc. do not necessarily have to be the same length.

In FIG. 1 and FIG. 2, the filter 21 is provided in front of the incident surface 22a of the light guide 22.
2 may be disposed between the second light exit surface 22 b and the photoelectric surface 23 a of the photomultiplier 23.

[0021]

According to the radiation image reading apparatus of the present invention,
Even if the reading range of the radiation image stored in the radiation image conversion plate is widened and the main scanning range is widened, a long filter for receiving the light generated by the scanning of the excitation light can be easily configured without increasing the cost.

[Brief description of the drawings]

FIG. 1 is a side view showing a reading unit of a radiation image reading apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view showing a light receiving system of a reading unit in FIG.

FIG. 3 is side views (a), (b), and (c) of a filter showing modifications (three examples) of the filter configuration of FIG. 2;

[Explanation of symbols]

REFERENCE SIGNS LIST 20 photostimulable phosphor plate (radiation image conversion plate) 21 filter 21 a light receiving surface of filter 21 31 to 33 plural filters constituting filter 21, adhesive 22, 22 ′ light guide 23 photomultiplier 23 a photomultiplier Photovoltaic surface of pliers 24 Scanning optics

Claims (4)

[Claims] 1. A radiation image reading apparatus comprising an image reading means for reading the radiation image information from a radiation image conversion plate on which the radiation image information is recorded, wherein the image reading means transmits an excitation light to the radiation image conversion plate. A filter having a light receiving surface extending in the main scanning direction so as to receive light generated by irradiating the excitation light, and a filter for absorbing the excitation light, wherein the filter has a plurality of lengths extending along the light receiving surface. A radiation image reading device comprising a scale filter. 2. The radiation image reading apparatus according to claim 1, wherein the plurality of long filters are joined by bonding. 3. The radiation image reading apparatus according to claim 2, wherein an adhesive having a small light transmittance to the excitation light is used. 4. The radiation image reading apparatus according to claim 1, wherein a filler having a small light transmittance with respect to the excitation light is arranged along each end of the plurality of long filters.