| 摘要 |
PURPOSE:To reduce image degradation and improve S/N ratio of measuring current by arranging collimaters of pipe structure between a subject person and a scintillater and arranging the subject person and a scintillater and arranging the surface for receiving radiation in the scintillater perpendicularly to the collimater axis. CONSTITUTION:A collimater 15 of a pipe structure is disposed between a subject 2 and a scintillater 12 and the surface of receiving radiation in the scintillater 12 is disposed perpendicularly to the collimater axis. When an X-ray tube 1 and a detector 3 rotate together around the subject 2, the X-ray fan beam 4 emitted from a focus 5 penetrates the subject 2 and the intensity is lowered. And a unit detection element 3 is so disposed that the beam 4 enters perpendicularly to each incidence surface. When the beam 4 passes through the subject 2, scattered X-ray are produced due to the oblique incidence to the incidence surface of the element 3. However, the scattered rays besides the radiation axes 8 can be attenuated by a meter 15 and only effective X-ray is directed to the scintillater 12. Thus the measurement error due to the scattered rays is eliminated.
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