Radiant energy – Source with recording detector – Using a stimulable phosphor
Reexamination Certificate
2001-04-19
2003-03-04
Hannaher, Constantine (Department: 2878)
Radiant energy
Source with recording detector
Using a stimulable phosphor
C250S581000, C250S584000
Reexamination Certificate
active
06528813
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to a radiation image readout apparatus, and more particularly to a radiation image readout apparatus equipped with a readout portion, as well as an erasing portion for erasing the radiation energy remaining on a stimulable phosphor sheet after readout has been performed.
2. Description of the Related Art
In the field of radiology, there are in wide use today radiation image readout systems dependent upon radiation image readout apparatuses employing stimulable phosphor sheets, which contain stimulable phosphors that store a portion of radiation energy upon exposure thereto and emit stimulated emissions of a quantity corresponding to the radiation energy stored thereon upon exposure to visible or other stimulating light, to once record the image data of a radiation image obtained by storing a portion of the radiation passing through a subject, such as a human body, etc. on a stimulable phosphor sheet, wherein the stimulable phosphor sheet on which the radiation image has been recorded is scanned by a stimulating light such as a laser, and an image signal is obtained by photoelectrically reading out the stimulated emissions thereof.
According to the radiation image readout systems described above, after readout of the radiation image data, there remains on the stimulable phosphor sheet a quantity of radiation energy that was not completely dissipated during image readout. This energy (remaining radiation energy) originates in the radiation image data that had been stored on the stimulable phosphor sheet, and if it is of a level that cannot be ignored, the next time a radiation image is recorded on the stimulable phosphor sheet, the remaining radiation energy and the previous image are reproduced as noise. Because of this, it is necessary to erase this remaining radiation energy after image readout is performed.
To erase the remaining radiation energy, it can be caused to be emitted and dissipated; for example, a method can be used by which the stimulable phosphor sheet is exposed to ordinary light for a long period of time to dissipate the remaining radiation, or exposed to a high-intensity visible light for a short duration to accomplish the same. If erasable energy is applied to the stimulable phosphor sheet in this way, it is possible to reuse the stimulable phosphor sheet.
Generally, the radiation image readout apparatus employed in the radiation image readout system described above, aside from the readout portion, is also provided with an erasing portion for applying erasing energy to the sheet after readout of the image stored thereon is performed. The readout apparatus is configured so that the stimulable phosphor sheet is set therein and sent to the readout portion, wherein the image data as readout, and is then sent to the erasing portion, wherein the remaining radiation energy is dissipated, and after these continuous operations are complete, the sheet is discharged from the apparatus.
In this way, according to a general radiation image readout apparatus equipped with a readout portion and an erasing portion, after the image is readout from the stimulable phosphor sheet by the readout portion it is always sent to the erasing portion and subjected to erasing; however, because the erasing operation is performed by, for example, continuously exposing the sheet to erasing light for a only a certain period of time, the total time required for performing readout of the image (readout time) and the time required for erasing the remaining radiation energy (erasing time) is the operation time per sheet.
However, when used in conjunction with a group diagnosis, etc., in which radiation images for a large number of patients are readout, when it is necessary to perform readout of the images, from the stimulable phosphor sheets on which photographing has been completed, in a short time, because aforementioned readout and erasing operations are carried out in a continuous manner, a problem arises in that the operation time is excessively long.
On the other hand, there are radiation image readout apparatuses comprising only a readout portion, that is, that are provided with no erasing portion whatsoever. When such apparatuses are used, a method which is the opposite of the operation of the apparatus described above, that is, even for cases in which there is no shortage of time, because only readout is performed, without performing erasing, a sheet from which an image has been read out must be erased by a use of a specialized erasing apparatus, and handling of such an operation is cumbersome.
SUMMARY OF THE INVENTION
The present invention has been developed in consideration of the circumstances described above, and it is a primary objective of the present invention to provide a radiation readout apparatus for performing readout of a radiation image and erasing of remaining radiation in a manner corresponding to the needs of an operators circumstances: when there is a shortage of time, and when there is no shortage of time.
According to the first radiation readout apparatus according to the present invention, by making it possible to select whether or not erasing is to be performed after readout of a radiation image has been completed, readout and erasing operations can be performed in a continuous manner when there are no constraints on the overall operation time, and for cases in which there are constraints on the overall operation time, only the readout operation is given priority and the erasing operation is performed at another time so that the operation time can be shortened, and the apparatus is thereby capable of being employed in a manner suiting the needs of an operator.
That is to say, the first radiation apparatus according to the present invention comprises a readout portion for reading out the radiation image data cumulatively recorded thereon, and an erasing portion for erasing the remaining radiation energy remaining on the sheet after readout of the radiation image has been performed, and is also provided with a mode input means capable of selecting and inputting either the readout-and-erase mode, in which the remaining radiation erasing operation is performed after readout of the radiation image data, or the readout only mode, in which aforementioned erasing operation is not performed immediately after readout of the image data, and a mode control means for controlling at least the erasing portion with regard to whether the erasing operation is to be performed or not.
More specifically, the readout portion scans the stimulable phosphor sheet with a stimulating light, and photoelectrically reads out the quantity of stimulated emission emitted, corresponding to the radiation image data that has been cumulatively recorded on the stimulable phosphor sheet, and the erasing portion causes the radiation energy remaining on the sheet to be dissipated by apply erasing energy thereto. Note that the operation of applying erasing energy may consist of, for example, illuminating the stimulable phosphor sheet with a visible spectrum, etc. erasing light for a predetermined period of time.
In addition, with respect to the readout mode, the expression “erasing operation is not performed” refers not only to carrying out no erasing whatsoever, that is, where no erasing light is emitted, etc. and no erasing energy whatsoever is applied to the sheet, but includes, for example, cases in which, even though no erasing whatsoever is performed, the sheet must be conveyed through the erasing portion, and during only the minimal duration of the interval when the sheet is merely being conveyed through the erasing portion, the sheet is illuminated by erasing light and erasing, though insufficient erasing, is performed. That is to say, for cases in which the remaining radiation energy is erased from a stimulable phosphor sheet by the illumination thereof by erasing light, the erasing energy is prescribed by the product of the intensity and the duration of illumination, and in order to apply sufficient er
Fuji Photo Film Co. , Ltd.
Hannaher Constantine
Moran Timothy J.
Sughrue & Mion, PLLC
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