Summary
Aim: This study deals with the effect of the non-uniform attenuation correction 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-153 line sources after administration of 400 MBq Tc-99m-tetrofosmin. Results: In non-corrected (NC) stress studies the lowest count rates were found in the inferior segments with mean differences in count rates between maxima and minima of 35.8 ± 10.8%. In attenuation corrected (AC) 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 dependent, but independent of body mass on average. Conclusion: AC using the above technique significantly reduces the variability of count rate distribution in normal subjects and improves the preconditions for accurate diagnostic evaluation of coronary artery disease using SPET.
Attenuation correction of myocardial SPECT by scatter-photopeak window method in normal subjects