title: Comparative feasibility of separate or simultaneous rest thallium-201/stress technetium-99m-sestamibi dual-isotope myocardial perfusion SPECT.
abstract: Separate or simultaneous rest 201Tl/stress 99mTc-sestamibi dual-isotope SPECT are potentially efficient myocardial perfusion imaging protocols which combine the use of a high-resolution 99mTc tracer for stress perfusion assessment and 201Tl, the current single-photon agent of choice, for viability assessment.
  
  
  METHODS
  To investigate the feasibility of dual-isotope myocardial perfusion SPECT protocols using rest 201Tl and stress sestamibi, 201Tl crosstalk into the 99mTc acquisition window (Group 1, n = 26 patients) and 99mTc crosstalk into 201Tl windows (Group 2, n = 25) were studied. For Group 1, treadmill exercise with sestamibi injection and poststress SPECT ("virgin" sestamibi images) were performed, followed by rest 201Tl injection and SPECT acquisition using dual-isotope windows (contaminated or "dual" images). For Group 2, the order was reversed: rest 201Tl SPECT (virgin 201Tl images) was performed first, followed by exercise sestamibi injection and dual-isotope SPECT.
  
  
  RESULTS
  The contribution of 201Tl scatter to the dual sestamibi images (Group 1) was measured to be 2.9% +/- 2.1%, while 99mTc crosstalk contributed 26.7% +/- 13.0% to the dual 201Tl images (Group 2). Image quality was considered good to excellent in 92% of the sestamibi (virgin and dual) images and 88% of the virgin 201Tl SPECT, but only in 23% of the dual 201Tl studies.
  
  
  CONCLUSIONS
  Technetium-99m crosstalk into 201Tl windows is substantial; therefore, simultaneous dual-isotope protocols, which involve assessment of 201Tl images contaminated by 99mTc, are not recommended. On the other hand, because of the small amount of 201Tl crosstalk into the 99mTc window, a separate acquisition dual-isotope approach employing the rest 201Tl (virgin)/stress sestamibi sequence is acceptable.
authors.affiliation: Department of Imaging (Division of Nuclear Medicine), Cedars-Sinai Medical Center, Los Angeles, California 90048.
authors.forename: H
authors.initials: H
authors.lastname: Kiat
authors.forename: G
authors.initials: G
authors.lastname: Germano
authors.forename: J
authors.initials: J
authors.lastname: Friedman
authors.forename: K
authors.initials: K
authors.lastname: Van Train
authors.forename: G
authors.initials: G
authors.lastname: Silagan
authors.forename: F P
authors.initials: FP
authors.lastname: Wang
authors.forename: J
authors.initials: J
authors.lastname: Maddahi
authors.forename: D
authors.initials: D
authors.lastname: Berman
mesh_terms: D000368:Aged; D003327:Coronary Disease / Q000000981:diagnostic imaging; D005080:Exercise Test; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D012146:Rest; D017256:Technetium Tc 99m Sestamibi; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D013794:Thallium Radioisotopes; D017256:Technetium Tc 99m Sestamibi