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Myocardial uptake of Tc-99m-tetrofosmin and Tc-99m-MIBI

Journal Article · · Journal of Nuclear Medicine
OSTI ID:447738
; ;  [1]
  1. University Hospital Dijkzigt, Rotterdam (Netherlands); and others
Tc-99m-tetrofosmin is an alternative for Tc-99m-MIBI as myocardial perfusion tracer, with easier kit preparation and less liver activity. Dual isotope simultaneous acquisition (DISA) SPECT using Tc-99m-MIBI and 18-FDG is a promising technique for the assessment of myocardial viability. Disturbing scatter from 511 keV photons in the 140 keV channel can be minimized with an activity ratio 18-FDG to Tc-99m-MIBI for DISA, the relative myocardial uptake of both tracers was investigated in neonatal rat myocytes (in medium with 0.2% BSA at 37{degrees}C during 60 min, measurements in triplicate) and in 6 patients at rest, who underwent myocardial perfusion scintigraphy for the evaluation of coronary artery disease. Rest SPECT (high resolution parallel collimators, 360{degrees}, 3{degrees} per step of 30 sec) was performed at least 1 hr after the injection of 370 MBq Tc-99m-tetrofosmin. Rest SPECT with 370 MBq Tc-99m-MIBI was repeated 1 week later. Counts in a fixed circular ROI around the heart in the raw projection images from 40{degrees} RAO to 90{degrees} left lateral were compared for tetrofosmin and MIBI, while images with overlying intestinal or liver activity were omitted. In the rat myocytes the cell associated activity of Tc-99m- MIBI was 0.9 {plus_minus} 0.02% D/10 {mu}g protein after 5 min, 4.73 {plus_minus} 0.09% at 10 min, and 8.76 {plus_minus} 0.19% at 60 min. The cell activity of Tc-99m-tetrofosmin was 0.36 {plus_minus} 0.04% at 10 min, 1.96 {plus_minus} 0.22% at 30 min, and 3.89 {plus_minus} 0.47% at 60 min. The MIBI/tetrofosmin ratio was 2.3 {plus_minus} 0.1. In 3 patients all 41 projection images could be evaluated, in 2 patients 36 images, and in 1 patient only 22. The average counts per ROI ranges from 8577 to 16341 for MIBI and from 8088 to 15375 for tetrofosmin. The individual MIBI/tetrofosmin ratios ranges from 0.97 {plus_minus} 0.03 to 1.31 {plus_minus} 0.04. In vitro, the retention of Tc-99m-MIBI is twice that of Tc-99m-tetrofosmin.
OSTI ID:
447738
Report Number(s):
CONF-960659--
Journal Information:
Journal of Nuclear Medicine, Journal Name: Journal of Nuclear Medicine Journal Issue: Suppl.5 Vol. 37; ISSN JNMEAQ; ISSN 0161-5505
Country of Publication:
United States
Language:
English