Patent ID: 7242018
Filing Date: 2007-07-10
Classification: G01T

Abstract:
1. A method of acquiring a radiation image signal, comprising the steps of: i) irradiating stimulating rays, which have been produced by a stimulating ray source and contain red light and infrared rays, to a stimulable phosphor sheet, on which a radiation image has been stored, the stimulating rays causing the stimulable phosphor sheet to emit light in proportion to an amount of energy stored on the stimulable phosphor sheet during exposure of the stimulable phosphor sheet to radiation, and ii) receiving the light, which has been emitted by the stimulable phosphor sheet, with a light receiving device, which comprises photodiodes containing silicon as a principal constituent, via a stimulating ray cut-off filter, which transmits the light emitted by the stimulable phosphor sheet and blocks the red light, the emitted light being subjected to photoelectric conversion performed by the light receiving device, a radiation image signal, which represents the radiation image stored on the stimulable phosphor sheet, being acquired from the photoelectric conversion, wherein the method further comprises the steps of: a) reflecting the stimulating rays, which have been produced by the stimulating ray source, from a reference plate, which has reflection characteristics with respect to the infrared rays approximately identical with the reflection characteristics of the stimulable phosphor sheet with respect to the infrared rays, and which is free from characteristics of emitting light when being exposed to the stimulating rays, b) receiving the stimulating rays, which have been reflected from the reference plate, with the light receiving device via the stimulating ray cut-off filter, the reflected stimulating rays being subjected to photoelectric conversion performed by the light receiving device, an infrared ray image signal, which represents the infrared ray components contained in the stimulating rays, being acquired from the photoelectric conversion, and c) subtracting the infrared ray image signal from the radiation image signal, whereby the radiation image signal is corrected.