Radiation image read-out method and apparatus

A radiation image read-out apparatus, comprising:

• i) a line light source for irradiating stimulating rays linearly along a main scanning direction and onto 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,
• ii) a line sensor for receiving light, which is emitted from the linear area of the stimulable phosphor sheet exposed to the linear stimulating rays, and performing photoelectric conversion of the received light, the line sensor comprising a plurality of photoelectric conversion devices arrayed along the main scanning direction,
• iii) sub-scanning means for moving the stimulable phosphor sheet with respect to the line light source and the line sensor and in a sub-scanning direction different from the main scanning direction, and
• iv) read-out means for successively acquiring output signal components from the photoelectric conversion devices of the line sensor in accordance with the movement, and thereby performing an operation for reading out the radiation image from the stimulable phosphor sheet, wherein the improvement comprises the provision of:
• a) a reference light source for projecting reference light onto the line sensor,
• b) sensitivity signal component, acquiring means for acquiring sensitivity signal components from the outputs of the photoelectric conversion devices of the line sensor having received the reference light, which is produced by the reference light source,
• c) reference signal component storing means for storing the sensitivity signal components, which have been acquired in an initial state by the sensitivity signal component acquiring means, as reference signal components,
• d) correction signal component calculating means for comparing sensitivity signal components, which have been acquired by the sensitivity signal component acquiring means at a stage immediately before the operation for reading out the radiation image from the stimulable phosphor sheet is performed, and the corresponding reference signal components, which have been stored in the reference signal component storing means, with each other in order to obtain sensitivity correction signal components for making a correction for variations in sensitivity among the photoelectric conversion devices of the line sensor, and
• e) correction means for making a correction of the output signal components, which are acquired from the photoelectric conversion devices of the line sensor at the time of the operation for reading out the radiation image from the stimulable phosphor sheet, by use of the sensitivity correction signal components.

A radiation image read-out apparatus, comprising:

• i) a line light source for irradiating stimulating rays linearly along a main scanning direction and onto 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,
• ii) a line sensor for receiving light, which is emitted from the linear area of the stimulable phosphor sheet exposed to the linear stimulating rays, and performing photoelectric conversion of the received light, the line sensor comprising a plurality of photoelectric conversion devices arrayed along the main scanning direction,
• iii) sub-scanning device that moves the stimulable phosphor sheet with respect to the line light source and the line sensor and in a sub-scanning direction different from the main scanning direction, and
• iv) read-out circuit that successively acquires output signal components from the photoelectric conversion devices of the line sensor in accordance with the movement, and thereby performing an operation for reading out the radiation image from the stimulable phosphor sheet, wherein the improvement comprises the provision of:
• a) a reference light source for projecting reference light onto the line sensor,
• b) sensitivity signal component acquiring circuit that acquires sensitivity signal components from the outputs of the photoelectric conversion devices of the line sensor having received the reference light, which is produced by the reference light source,
• c) reference signal component storage that stores the sensitivity signal components, which have been acquired in an initial state by the sensitivity signal component acquiring circuit, as reference signal components,
• d) correction signal component calculating circuit that compares sensitivity signal components, which have been acquired by the sensitivity signal component acquiring circuit at a stage immediately before the operation for reading out the radiation image from the stimulable phosphor sheet is performed, and the corresponding reference signal components, which have been stored in the reference signal component storage, with each other in order to obtain sensitivity correction signal components for making a correction for variations in sensitivity among the photoelectric conversion devices of the line sensor, and
• e) correction circuit for making a correction of the output signal components, which are acquired from the photoelectric conversion devices of the line sensor at the time of the operation for reading out the radiation image from the stimulable phosphor sheet, by use of the sensitivity correction signal components.