^<99m>Tc心筋血流SPECT画像におけるButterworth filterの評価

概要

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We assessed cut-off frequency (Fc) of the Butterworth filter in myocardial nuclear imaging. The RH-2 was used as a myocardial phantom. The parameters are nuclides (^201Tl and ^<99m>Tc) and the collimaters (LEGP and LEHR). Radius direction distribution function Pr(n) was applied to SPECT images for frequency space analysis, and NMSE (Normalized Mean Squared Error) method was used for assessment in real space. In both of these method of analysis, the optimal cut-off frequency varies depending on the nuclide and collimator : Fc in use of ^201Tl are 0.245 (cycles/pixel)with LEGP, and 0.250 with LEHR. However, those in use of ^<99m>Tc are 0.25 with LEGP, and 0.27 with LEHR, respectively. The image spectrum varies depending also on the injected dose in ^<99m>Tc. With 185 MBq, the optimal cut-off frequency was less than with 740 MBq. We concluded that the cut-off frequency of the Butterworth filter should be changed in reconstructing images according to the collimator, nuclide, and injected dose.
社団法人日本放射線技術学会の論文
1996-03-01