心筋gated SPECTにおけるOSEM法の検討 : 再構成条件の最適化

抄録

In order to use the ordered subsets expectation maximization(OSEM)algorithm for reconstruction of myocardial gated SPECT using ^<99m>Tc myocardial agents, we evaluated the optimal reconstruction parameters in phantom and clinical studies. Since processing time increases in proportion to iteration number, as few iteration numbers as possible is desirable. From the results of left ventricular(LV)volume and normalized mean square error(NMSE)in the phantom study, we concluded that the optimal number of iterations and subsets were 2 and 15, respectively, and the most suitable cutoff frequency of the Butterworth filter was 0.438 cycles/cm. LV volume estimated using the OSEM algorithm was less than that using the filtered back projection(FBP)algorithm. In the clinical study, the correlation coefficients of end-diastolic volume(EDV), end-systolic volume(ESV), and ejection fraction(EF)estimated by the OSEM algorithm were 0.99(p<0.001), 0.97(P<0.001), and 0.96(p<0.001), respectively. A strong correlation was observed between the results of the two methods.