| 摘要 |
PURPOSE:To exactly correct the counting loss by measuring the counting-rate from discriminating output, determining a correction factor based on the counting rate, and correcting the counting in response to the correction factor. CONSTITUTION:Each time an unblank signal is generated, the counting is performed for each position signal. That is, each time a radiation comes in a scintillator 22, the counting is performed for each incidence-position, and an image is formed by the radiation. On the other hand, respective outputs of a photoelectric transducer connected to the scintillator 22 are added, and the added output is discriminated from a noise level. Further, the counting rate is measured from the discriminating output. The counting-rate corresponds to an incidence counting-rate at a ratio of 1:1, and thus the incidence counting- rate can be exactly determined from the measured counting-rate. Next an exact correction factor for the counting-rate of the unblank signal which corresponds to the incidence counting-rate, is determined to correct the counting for each incidence-position. In this time, since the amount to be added is determined by the correction factor corresponding to the unblank signal, the counting loss can be exactly corrected even when the incidence counting-rate becomes high.
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