| 摘要 |
PURPOSE:To eliminate a position signal having a large error, and to raise a space resolution of a picture, by detecting a fact that light emission and an ionized layer expand by Compton scattering, etc., and inhibiting an output of the position signal in that case. CONSTITUTION:gamma-rays generated from an RI (radioactive isotope) integrated in a specified internal organ of an object 11 are made incident to a scintillator 13 through a collimator 12, and generate scintillation. This scintillation light is led to each of many photoelectric multipliers 15 through a light guide 14, is converted to an electric signal, and is amplified by a preamplifier 16. Its output passes through a position calculating weight resistance 17, is added in a position calculating circuit 18, and thereafter, is divided by an energy signal Z and a position signal X is obtained. The signal X reaches a memory through a gate 27 which uses an output signal of a subtracter 26 as a gate signal, and a gate 28 which uses an output signal of a pulse height discriminator 21 as a gate signal. |
