JP3717638B2 - Radiation image eraser - Google Patents

Description

[0001]
BACKGROUND 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]
[Prior art]
Reading a recorded radiation image to obtain an image signal, subjecting the image signal to appropriate image processing, and then reproducing and recording the image are performed in various fields. In addition, when the applicant of the present invention irradiates radiation (X-rays, α-rays, β-rays, γ-rays, electron beams, ultraviolet rays, etc.), a part of the radiation energy is accumulated, and when irradiated with excitation light such as visible light thereafter, it accumulates. Using a stimulable phosphor (stimulable phosphor) that exhibits photostimulated luminescence according to the received energy, a radiation image of a subject such as a human body is temporarily captured and recorded on a sheet-like stimulable phosphor. The photosensitive phosphor sheet is scanned with excitation light such as laser light to generate stimulated emission light, and the resulting stimulated emission light is photoelectrically read to obtain image data. Based on this image data, a radiographic image of the subject Image recording / reproducing system that outputs a visible image on a recording material such as a photographic photosensitive material or a CRT has already been proposed (Japanese Patent Laid-Open Nos. 55-12429, 56-11395, 55-163472, 56-104645 and 55-116340).
[0003]
According to this system, it is possible to obtain a radiographic image having a wide latitude and excellent observation readability.
[0004]
Also, the radiation energy once stored and recorded as image information on the above-mentioned stimulable phosphor sheet is emitted to the outside of the sheet by irradiating the sheet after the image information is read from a fluorescent lamp or the like. The sheet can be used repeatedly. Therefore, the erasing process for irradiating the sheet with the erasing light must be performed after the image information reading process, and the radiation image erasing apparatus that performs the erasing operation is configured 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 oriented in a direction perpendicular to the direction (longitudinal direction) in which the straight tube fluorescent lamp 21 extends. The entire surface of the sheet is erased by irradiating erasing light from a fluorescent lamp while conveying the sheet.
[0005]
[Problems to be solved by the invention]
By the way, in irradiating the erasing light, it is necessary to give an erasing energy equal to or higher than a certain threshold ETh. This is because even if there is a part of the erasing energy equal to or less than the threshold value ETh, the erasing unevenness occurs and adversely affects the reading of the next image information taken.
[0006]
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.
[0007]
That is, the illuminance is highest at the longitudinal center of the straight fluorescent lamp 21, and the vicinity of the electrodes 22a and 22b at both ends is low. 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 excessive erasing energy is applied to the central portion (illuminance Dmax) where the illuminance is originally high, and wasteful energy is consumed.
[0008]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a radiographic image erasing apparatus in which energy efficiency is improved by suppressing application of excessive erasing energy.
[0009]
[Means for Solving the Problems]
In the radiation image erasing apparatus of the present invention, a plurality of fluorescent lamps are arranged in a direction orthogonal to the extending direction, and the fluorescent lamp and the sheet are relatively moved along the extending direction of the fluorescent lamp. Since each part passes through a part corresponding to each part of a fluorescent lamp having different illuminance, the sheet is irradiated with irradiation light substantially uniformly along the moving direction, while the direction perpendicular to the scanning direction is fluorescent. By arranging a plurality of lamps, the illuminance is made uniform and the efficiency of erasing energy is improved.
[0010]
That is, the radiation image erasing apparatus of the present invention relatively moves the stimulable phosphor sheet on which the radiation energy is accumulated and recorded, and irradiates the sheet with erasing light emitted from a fluorescent lamp, so that the radiation energy is In the radiation image erasing apparatus that discharges to the outside of the stimulable phosphor sheet,
A plurality of fluorescent lamps are arranged in a direction orthogonal to the direction in which the fluorescent lamp extends,
The direction of relative movement between the fluorescent lamp and the sheet is a direction in which the fluorescent lamp extends.
[0011]
As the fluorescent lamp, in addition to a straight general straight tube fluorescent lamp provided with electrodes at both ends, a twin fluorescent lamp or twin lamp in which electrode portions are concentrated on one end side in the longitudinal direction. Two parallel fluorescent lamps or U-tube fluorescent lamps can also be applied.
[0012]
The first half of the relative movement with respect to the stimulable phosphor sheet transmits light including a short wavelength, and the second half of the movement includes a filter that transmits light not including the short wavelength. More desirable.
[0013]
The radiographic image erasing apparatus of the present invention may be a single configuration that simply irradiates the sheet with erasing light and releases the radiation energy from the sheet, or is combined with the radiographic image information reading apparatus or the radiographic image. It may be configured as a radiation image information reading device incorporated as a part of the information reading device.
[0014]
【The invention's effect】
According to the radiation image erasing apparatus of the present invention, the fluorescent lamp and the sheet are relatively moved along the extending direction of the fluorescent lamp, so that each part of the sheet becomes a part of the fluorescent lamp having different illuminance. Since the light passes through the corresponding portions, the irradiation light is irradiated substantially uniformly along the scanning direction. On the other hand, a plurality of fluorescent lamps are arranged in a direction perpendicular to the extending direction of each fluorescent lamp, Also, the illuminance can be made uniform in the direction orthogonal to the moving direction, so that the entire sheet can be irradiated with erasing light uniformly, and the erasing energy can be made more efficient.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, specific embodiments of the radiation image erasing apparatus of the present invention will be described.
[0016]
FIG. 1 (1) is a front sectional view of an embodiment of the radiation image erasing apparatus of the present invention, and FIG. 1 (2) is a view showing a main part plan view of this embodiment.
[0017]
The illustrated radiation image erasing apparatus 20 relatively moves the storage phosphor sheet 11 in which the radiation energy remains, and irradiates the sheet 11 with the erasing light emitted from the fluorescent lamp 23 to store the radiation energy. A radiation image erasing apparatus that emits to the outside of the phosphor sheet 11, and is provided in a row perpendicular to the longitudinal direction, and a plurality of electrodes 22 formed on one end in the longitudinal direction in a concentrated manner The so-called twin fluorescent lamps 23, and a filter 28 that suppresses transmission of light in different wavelength bands in the first half and the second half of the erasing light emitted from each fluorescent lamp 23. The stimulable phosphor sheet 11 is placed on the transport guide belt 12 and transported along the longitudinal direction of the lamp 23.
[0018]
It is to be noted that the filter 28 performs erasing mainly with light including the wavelength in the UV region in the first half of the erasing light irradiation, and erasing with light including the wavelength in the UV region in the second half, so that only one of them is used. Compared with erasing using, the energy level of the residual radiation can be reduced to 1/7 to 1/10 (see JP-A-4-1746, etc.).
[0019]
Next, the operation of the radiation image erasing apparatus of this embodiment will be described.
[0020]
With respect to the radiation image erasing apparatus 20 shown in the figure, the sheet 11 is placed on the conveyance guide belt 12 and conveyed in a direction perpendicular to the arrangement direction of the twin fluorescent lamps 23.
[0021]
The erasing light is irradiated from the twin fluorescent lamp 23 of the radiation image erasing device 20 to the conveyed sheet 11, and the illuminance distribution in the longitudinal direction of the fluorescent lamp 23 at this time is as shown in FIG. The vicinity of the leftmost electrode 22 is lower than the other portions. On the other hand, as shown in FIG. 2B, the illuminance distribution in the direction along the direction orthogonal to the conveying direction (scanning direction) of the sheet 11 is the sum of the illuminance distributions by the fluorescent lamps (shown by solid lines in the figure). As shown by a broken line in the figure.
[0022]
As understood from this figure, the illuminance distribution in the direction orthogonal to the scanning direction has a smaller illuminance difference between the maximum illuminance and the minimum illuminance than the illuminance distribution in the scanning direction, and is made uniform.
[0023]
Therefore, the efficiency of erasing energy can be improved by improving the uniformity of illuminance.
[0024]
Although the radiation image erasing apparatus of the present embodiment has been described with respect to a form using a twin fluorescent lamp as an erasing light source, the radiation image erasing apparatus of the present invention is not limited to this fluorescent lamp, and has been used conventionally. A general straight tube fluorescent lamp having electrodes at both ends can also be applied. For example, a U-shaped fluorescent lamp shown in FIG. 3 (1) and a twin two parallel fluorescent lamp shown in FIG. 2 (2) are applied. You can also
[0025]
In addition, although the radiation image erasing apparatus of the present embodiment has been described with respect to an example of a configuration in which the sheet is irradiated with erasing light alone and radiation energy is emitted from the sheet, the radiation image erasing apparatus is combined with the radiation image information reading apparatus or It may be configured as a radiation image information reading device incorporated as a part of the information reading device.
[Brief description of the drawings]
1 is a plan view of an embodiment of a radiation image erasing apparatus according to the present invention, and FIG. 1 is a side sectional view of the embodiment. FIG. 2 is a radiation image erasing apparatus of the embodiment shown in FIG. (1) A diagram showing the distribution of illuminance along the conveying direction of the stimulable phosphor sheet. (1) A diagram showing the distribution of illuminance along the direction orthogonal to the conveying direction of the stimulable phosphor sheet. FIG. 4 is a plan view showing another embodiment of the radiation image erasing apparatus of the present invention. FIG. 4 is a diagram showing one embodiment of a conventional radiation image erasing apparatus and its illuminance distribution.
11 Storage phosphor sheet
12 Conveyor belt
20 Radiation image eraser
21, 23 Fluorescent light
22,22a, 22b electrode
26 Body
28 Filter

Claims (1)

The fluorescent lamp that emits the erasing light is moved relative to the stimulable phosphor sheet on which the radiation energy is accumulated and recorded, and the erasing light is irradiated to the radiation energy to the outside of the stimulable phosphor sheet. In the radiation image erasing device to be released,
A plurality of fluorescent lamps are arranged in a direction orthogonal to the direction in which the fluorescent lamp extends,
The radiation image erasing apparatus according to claim 1, wherein a direction of relative movement between the fluorescent lamp and the sheet is a direction in which the fluorescent lamp extends.

Images