| 摘要 |
PURPOSE:To obtain the positron ECT apparatus in which a scattering simultaneous counting operation and an accidental simultaneous counting operation are reduced and whose resolution is enhanced by using positional information regarding a wire which is situated in a collimator part and which is composed of a radiationshielding material. CONSTITUTION:Many radiation detectors 4 are arranged on the circumference of a circle so as to surround a tunnel 3, and a collimator part 6 is arranged so as to surround the tunnel part 3 between the tunnel part 3 and the detectors 4. A collimator is formed in such a way that a wire 7 which is composed of a radiation shielding material is arranged on a cylinder surrounding the tunnel part 3, e.g. around the arrangement central axis of the detectors 4 and that many blind-shaped grids which are in parallel in the direction of the central axis are formed. When it is arranged at the collimator part 6, an opposite radiation 11a (or 11b) is not Compton-scattered (or Compton-scattered) and detected 4a (or 4b) from a positron quenched position 11. Consequently, information on the existence of the collimator on the connection of the detectors 4a to 4b is provided, false information that the position exists on the connection can be removed when an image is reconstituted, and a scattering simultaneous counting operation can be reduced. Also an accidental simultaneous counting operation can be reduced in the same manner.
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