NONUNIFORM ATTENUATION CORRECTION FOR MYOCARDIAL SPET USING 2 GD-153 LINE SOURCES

Aim: This study deals with the effect of the non-uniform attenuation c orrection method on myocardial tomograms of normal subjects. Method: A total of 35 patients (20 female, 15 male) without evidence of cardiac disease underwent SPET with and without attenuation correction using a dual head camera and transmission data obtained by two scanning Gd-1 53 line sources after administration of 400 MBq Tc-99m-tetrofosmin. Re sults: In non-corrected (NCI stress studies the lowest count rates wer e found in the inferior segments with mean differences in count rates between maxima and minima of 35.8 +/- 10.8%. In attenuation corrected IAC) images the respective segmental differences averaged only 20.9 +/ - 3.3% and the images did not show significant count deficiency in the inferior segments. The effects of correction revealed to be sex depen dent, but independent of body mass on average. Conclusion: AC using th e above technique significantly reduces the variability of count rate distribution in normal subjects and improves the preconditions for acc urate diagnostic evaluation of coronary artery disease using SPET.