JPH1138535A - Radiograph erasing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the imparting of excessive erasing energy and to enhance the efficiency of the energy by arranging plural fluorescent lamps in a direction orthogonally crossed to the extending direction thereof and relatively moving the fluorescent lamps and a sheet along in the extending direction of the fluorescent lamps. SOLUTION: This device is provided with the plural twin fluorescent lamps 23 arranged in the direction orthogonally crossed to the longitudinal direction and obtained by concentratedly forming electrodes 22 at one end part in the longitudinal direction and a filter 28 suppressing the transmission of light whose wavelength band is different at a front half part and a back half part in a carrying direction among the erasing light emitted from the respective lamps 23. Then, the stimulable phosphor sheet 11 is placed on a carrying guide belt 12 and carried along in the longitudinal direction of the lamps 23. Thus, since the respective parts of the sheet 11 are passed through parts corresponding to the respective parts of the lamps 23 whose illuminance 15 different, they are almost uniformly irradiated with illumination light along in a scanning direction. Therefore, since the sheet 11 is uniformly irradiated with the erasing light as a whole, the efficiency of the erasing energy is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation image erasing apparatus, and more particularly to a radiation image erasing apparatus using a fluorescent lamp as erasing light.

[0002]

2. Description of the Related Art A recorded radiographic image is read to obtain an image signal, and the image signal is subjected to appropriate image processing.
Reproduction and recording of images are performed in various fields.
In addition, the applicant (X-ray, α-ray, β-ray, γ
A part of this radiation energy is accumulated when irradiated with an electron beam, an electron beam, ultraviolet rays, etc., and thereafter, when irradiated with excitation light such as visible light, a stimulable phosphor (stimulated luminescence) which exhibits stimulated emission according to the accumulated energy. A radiation image of a subject such as a human body is once photographed and recorded on a sheet-like stimulable phosphor using a phosphorescent substance), and the stimulable phosphor sheet is scanned with excitation light such as a laser beam to emit stimulated light. Light is generated, and the resulting photostimulated light is photoelectrically read to obtain image data. Based on the image data, a radiation image of the subject is output as a visible image on a recording material such as a photographic photosensitive material, a CRT, or the like. A radiation image recording / reproducing system has already been proposed (JP-A-55-124).
No. 29, No. 56-11395, No. 55-163472, No. 56-104645
No. 55-116340, etc.).

According to this system, it is possible to obtain a radiation image having a wide latitude and excellent observation and interpretation suitability.

The radiation energy once stored and recorded as image information on the stimulable phosphor sheet is emitted to the outside of the sheet by irradiating the sheet after the image information is read with erasing light from a fluorescent lamp or the like. Therefore, the sheet can be used repeatedly. Therefore, the erasing step of irradiating the sheet with the erasing light must always be performed after the image information reading step, and the radiation image erasing apparatus performing the erasing operation is incorporated as a part of the radiation image information reading apparatus. In general, a straight tube fluorescent lamp is used as an erasing light source, and as shown in FIG. 4A, the sheet is placed in a direction perpendicular to the extending direction (longitudinal direction) of the straight tube fluorescent lamp 21. The entire surface of the sheet is erased by irradiating erasing light from a fluorescent lamp while conveying the sheet.

[0005]

In irradiating the erasing light, it is necessary to apply erasing energy equal to or greater than a predetermined threshold value ETh. Threshold E for some
This is because if there is a portion of erasing energy equal to or less than Th, erasing unevenness occurs and adversely affects reading of image information captured next.

Here, the illuminance in the direction along the extending direction of the fluorescent lamp 21 used in the conventional radiation image erasing apparatus has a distribution as shown in FIG. 4 (2).

That is, the illuminance is the highest at the center in the longitudinal direction of the fluorescent lamp 21 having a straight tube, and the illuminance is low near the electrodes 22a and 22b at both ends.
And because the level of the illuminance is nothing but the magnitude of the erase energy, so that the electrodes 22a indicating the minimum illuminance D _0, the illuminance in the vicinity of 22b, exceeds a threshold DTh in intensity region corresponding to the threshold ETh, fluorescent lamps 21 It is necessary to set the irradiation conditions (irradiation time, illuminance, etc.), but in the center (illuminance Dmax) where the illuminance is originally high, excessive erasing energy is applied conversely, and wasteful energy is consumed.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a radiation image erasing apparatus that suppresses the application of excessive erasing energy and improves energy efficiency.

[0009]

According to the radiation image erasing apparatus of the present invention, a plurality of fluorescent lamps are arranged in a direction perpendicular to the direction in which the fluorescent lamps extend, and the fluorescent lamps and the sheet are positioned relative to each other along the direction in which the fluorescent lamps extend. By moving the sheet, each part of the sheet passes through a part corresponding to each part of the fluorescent lamp having a different illuminance, so that the sheet is irradiated with irradiation light substantially uniformly along the moving direction, while scanning is performed. In the direction orthogonal to the direction, the illuminance is made uniform by arranging a plurality of fluorescent lamps, thereby improving the efficiency of erasing energy.

That is, the radiation image erasing apparatus of the present invention relatively moves a stimulable phosphor sheet on which radiation energy has been stored and irradiates the sheet with erasing light emitted from a fluorescent lamp, thereby irradiating the sheet. In a radiation image erasing device that emits energy to the outside of the stimulable phosphor sheet, a plurality of fluorescent lamps are disposed in a direction perpendicular to a direction in which the fluorescent lamp extends, and a relative position between the fluorescent lamp and the sheet is determined. The moving direction is a direction in which the fluorescent lamp extends.

The above-mentioned fluorescent lamps include, in addition to a straight straight general fluorescent lamp having electrodes at both ends, a twin fluorescent lamp in which the electrode portions are formed concentrated on one end side in the longitudinal direction. A lamp, a twin 2-parallel fluorescent lamp, a U-tube fluorescent lamp, or the like can also be applied.

In the first half of the relative movement with respect to the stimulable phosphor sheet, light containing a short wavelength is transmitted,
It is more desirable to provide a filter that transmits light not including a short wavelength in the latter half of the movement.

The radiation image erasing apparatus of the present invention may have a single configuration in which erasing light is simply emitted to a sheet to emit radiation energy from the sheet, or may be combined with a radiation image information reading apparatus. Alternatively, it may be configured as a radiation image information reading device incorporated as a part of the radiation image information reading device.

[0014]

According to the radiation image erasing apparatus of the present invention,
Since the fluorescent lamp and the sheet are relatively moved along the direction in which the fluorescent lamp extends, each part of the sheet passes through a part corresponding to each part of the fluorescent lamp having a different illuminance. Irradiation light is applied substantially uniformly along the direction, while the plurality of fluorescent lamps are arranged in a direction perpendicular to the extending direction of each fluorescent lamp, so that the illuminance of the sheet in the direction perpendicular to the moving direction is also increased. Uniformity can be achieved, so that the entire sheet can be uniformly irradiated with erasing light, and erasing energy can be made more efficient.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the radiation image erasing apparatus of the present invention will be described.

FIG. 1A is a front sectional view of an embodiment of a radiation image erasing apparatus according to the present invention, and FIG. 1B is a plan view of a main part of the embodiment.

The illustrated radiation image erasing apparatus 20 relatively moves the stimulable phosphor sheet 11 in which radiation energy remains, irradiates the sheet 11 with erasing light emitted from a fluorescent lamp 23, Is a radiation image erasing device that emits the outside of the stimulable phosphor sheet 11, and is provided side by side in a direction perpendicular to the longitudinal direction, and the electrodes 22 are formed concentrated on one end of the longitudinal direction. A plurality of so-called twin fluorescent lamps 23, and a filter 28 that suppresses transmission of light of different wavelength bands in the first half and the second half in the transport direction among the erasing light emitted from each fluorescent lamp 23. ,
The stimulable phosphor sheet 11 extends along the longitudinal direction of the fluorescent lamp 23.
Are placed on the transport guide belt 12 and transported.

The filter 28 performs erasing mainly with light including a wavelength in the UV region in the first half of the erasing light irradiation,
By performing erasure with light including a wavelength in the UV region in the second half, the energy level of the residual radiation is reduced to 1/7 to 1 / compared to erasure using only one of these.
It can be reduced to 10 (see, for example, JP-A-4-1746).

Next, the operation of the radiation image erasing apparatus of this embodiment will be described.

With respect to the illustrated radiation image erasing device 20,
The sheet 11 is placed on the transport guide belt 12 and transported in a direction orthogonal to the arrangement direction of the twin fluorescent lamps 23.

The conveyed sheet 11 is irradiated with erasing light from the twin fluorescent lamps 23 of the radiation image erasing device 20, and the illuminance distribution in the longitudinal direction of the fluorescent lamps 23 at this time is shown in FIG. As shown, the vicinity of the left end electrode 22 is lower than other portions. On the other hand, as shown in FIG. 2B, the illuminance distribution in the direction perpendicular to the sheet conveying direction (scanning direction) is the sum of the illuminance distributions (shown by solid lines in the figure) of the fluorescent lamps. As shown by a broken line in the figure.

As can be understood from the figure, the illuminance distribution in the direction orthogonal to the scanning direction has a smaller and uniform illuminance difference between the maximum illuminance and the minimum illuminance than the illuminance distribution in the scanning direction. .

Therefore, by improving the uniformity of the illuminance,
Efficiency of erasing energy can be improved.

The radiation image erasing apparatus of the present embodiment
Although the embodiment using the twin fluorescent lamp as the erasing light source has been described, the radiation image erasing apparatus of the present invention is not limited to this fluorescent lamp, and a conventional straight fluorescent tube having electrodes at both ends, which has been conventionally used, is used. A lamp may be used. In addition, for example, a U-tube fluorescent lamp shown in FIG.
The twin 2-parallel fluorescent lamp shown in the figure can be applied.

Further, the radiation image erasing apparatus of the present embodiment has been described by way of example in which the sheet is irradiated with erasing light alone to emit radiation energy from the sheet.
It may be configured as a radiation image information reading device combined with the radiation image information reading device or incorporated as a part of the radiation image information reading device.

[Brief description of the drawings]

FIG. 1A is a plan view of a radiation image erasing apparatus according to an embodiment of the present invention, and FIG. 1B is a side sectional view of the embodiment.

FIG. 2 is a view showing (1) the distribution of illuminance along the transport direction of the stimulable phosphor sheet by the radiation image erasing apparatus of the embodiment shown in FIG. 1 (1) In the transport direction of the stimulable phosphor sheet Diagram showing illuminance distribution along orthogonal direction

FIG. 3 is a plan view showing another embodiment of the radiation image erasing apparatus of the present invention.

FIG. 4 is a diagram showing an embodiment of a conventional radiation image erasing apparatus and its illuminance distribution.

[Explanation of symbols]

 11 Storage phosphor sheet 12 Conveyor belt 20 Radiation image erasing device 21, 23 Fluorescent lamp 22,22a, 22b Electrode 26 Main unit 28 Filter

Claims (1)

[Claims] 1. A fluorescent lamp that emits erasing light is relatively moved with respect to a stimulable phosphor sheet on which radiation energy is stored and recorded, and the illuminating light is irradiated to emit the radiation energy to the stimulable phosphor. In the radiation image erasing device to be emitted to the outside of the body sheet, a plurality of fluorescent lamps are disposed in a direction orthogonal to a direction in which the fluorescent lamp extends, and a relative movement direction between the fluorescent lamp and the sheet is A radiation image erasing apparatus, wherein the direction in which the fluorescent lamp extends is provided.