Low-dose dual-isotope procedure planed for myocardial perfusion CZT-SPECT and assessed through a head-to-head comparison with a conventional single-isotope protocol

purpose of the reportthis study aimed at assessing an original low-dose dual-isotope procedure in which the abnormal stress tc-99m sestamibi spect is followed by rest tl-201 spect, along with a head-to-head comparison with a single-isotope procedure. methods: and resultsone hundred two patients, referred for a low-dose stress-spect with sestamibi (123 ± 20 mbq) on a czt camera and for whom a rest sestamibi spect was warranted, had an additional tl-201 rest-spect (52 ± 5 mbq) between stress and rest sestamibi spect recordings. tl-201 images were processed for spill-over and scatter corrections, and uptake differences with stress sestamibi spect were analyzed: (1) for rest acquisitions from tl-201 (dual-isotope procedure) and from sestamibi (single-isotope procedure) and (2) in segments for which a diagnosis of ischemia, infarct, or normal perfusion was achieved. mean effective dose was 8.3 msv for dual-isotope but would decrease to 5.7 msv for an expected rate of 37% of patients for whom rest-spect is not warranted. after a further background correction of tl-201 images, the rest–stress difference in myocardial uptake was equivalent between dual- and single-procedures for identifying ischemic segments (respective areas-under-curves: 0.83 ± 0.03 and 0.81 ± 0.03). conclusion:this original dual-isotope procedure provides acceptable radiation doses and consistent results, as compared with conventional single-isotope.