| 摘要 |
<p>PURPOSE:To accurately correct miscounting even if RI(radioactive isotope) is unevenly distributed in a sample by correcting the miscounting of simultaneous coefficient data by coincidence blocks. CONSTITUTION:Many radiation detectors 1 are arrayed in a ring shape and radioactive gamma rays of the RI in the sample in the ring are made incident on the radiation detectors 1. Their outputs are grouped by being passed through respective grouping circuits 2 and counted 3 at the same time by each combination of two groups, so that each simultaneous counting circuit 3 obtain a simultaneous counting output and a random counting output. Then each data gathering circuit 4 calculates a miscounting coefficient by a coefficient generator 41, where the random counting output is sent, in accordance with the counting rate (quantity per unit time) and sends it to a multiplier 42. Here, the simultaneous counting output is multiplied by the miscounting coefficient and the resulting value is added in a memory 43. Thus, values are added after miscounting correction by simultaneous counting events and data in respective memories 43 are reconstituted into an image by a CPU 5.</p> |
