Clinical value of triple-energy window scatter correction in simultaneous dual-isotope single-photon emission tomography with I-123-BMIPP and Tl-201

To improve the image quality in simultaneous dual-isotope single-photon emission tomography (SPET) with iodine-123 labelled 15-(p-iodophenyl)-3-methylpentadecanoic acid (BMTPP) and thallium-201, we applied the triple-energy window method (TEW) for correction of the cross-talk and scatter artifact. Seventy-one patients with coronary artery disease were included. Tl-201 cross-talk into the I-123 acquisition window (group I, n = 30) and I-123 cross-talk into the Tl-201 window (group 2, n = 41) were studied. Tn group 1, I-123 images were first obtained (single-isotope images), followed by Tl-201 injection and SPET acquisition using dual-isotope windows (dual-isotope images). In group 2, the order was reversed, The dual-isotope SPET images with and without TEW were compared with the single-isotope images. Qualitative evaluation was performed by scoring the segmental defect pattern. Detectability of the mismatched fatty acid metabolism on dual-isotope SPET was evaluated by receiver operating characteristic (ROC) curve analysis. Segmental defect pattern agreement between dual and corrected single images was significantly improved by TEW correction (P<0.01). The agreement was particularly improved in segments with absence of uptake, There was no significant difference between TEW-corrected dual-isotope SPET and corresponding single-isotope SPET with regard to either % defect count or background activity. Mismatched fatty acid metabolism depicted by dual-isotope SPET predicted abnormal wall motion more accurately with TEW than without TEW. With TEW, a practical method for scatter and cross-talk correction in clinical settings, simultaneous dual I-123-BMIPP/Tl-201 SPET is feasible for the assessment of myocardial perfusion/metabolism mismatch.