Radiation image information read-out method and system

A radiation image information read-out system for obtaining an image signal representing radiation image information on an object stored on a stimulable phosphor sheet comprising a stimulating light projecting means which exposes the stimulable phosphor sheet to stimulating light thereby causing the stimulable phosphor sheet to emit light in proportion to the amount of energy stored thereon and a photodetector which detects the light emitted from the stimulable phosphor sheet upon stimulation thereof, wherein the improvement comprises

• a sensitivity setting means which sets the sensitivity of the photodetector so that the amount of light emitted from a blank portion on the stimulable phosphor sheet becomes larger than that corresponding to the upper limit of the operable range of the photodetector, and
• a stimulating energy control means which controls the irradiation energy of the stimulating light so that the level of a signal component obtained by the photodetector by reading the light emitted from the blank portion is minimized in the range higher than the upper limit of the read-out signal level range corresponding to the operable range of the photodetector.