| 摘要 |
At least two stimulable phosphor sheets are exposed to at least two kinds of radiation, which have different energy distributions, without an object intervening between the stimulable phosphor sheets and a source of the radiation. The stimulable phosphor sheets are then exposed to stimulating rays, which cause them to emit light in proportion to the amount of energy stored thereon during their exposure to the radiation. The light emitted is photoelectrically detected, and digital image signals are thereby obtained, which are to be used for compensating for nonuniformity in how the radiation is irradiated to the stimulable phosphor sheets. Digital image signals representing radiation images of an object stored with at least two kinds of radiation and the corresponding digital image signals for the compensation are then subtracted from each other, and digital image signals are obtained which are free of noise due to nonuniformity in how at least two kinds of radiation are irradiated to the stimulable phosphor sheets. The digital image signals, which are free of noise, are then subtracted from each other, and a difference signal is thereby obtained which represents the image of only the bones represented by the radiation images. Bone calcium in the bones is quantitatively analyzed by utilizing the difference signal.
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