title: 99mTc myocardial perfusion imaging.
abstract: For more than 15 years, 201Tl has been used for measuring myocardial perfusion and viability although its physical characteristics, which include a photon energy of 68 to 80 keV and a physical half-life of 73 hours, are far from ideal. In early 1991, 99mTc tracers from the group of compounds known as isonitriles and boronic acid adducts of technetium dioximes (BATO) compounds were made available for general use in the United States, with approval by the Food and Drug Administration in late 1990. The uptake of these agents in the myocardium is proportional to regional blood flow. Because these tracers have 99mTc as the radiolabel, they have better physical characteristics--a gamma photon energy of 140 keV and a half-life of 6 hours--than 201Tl. The isonitrile with the best properties for myocardial imaging is 99mTc-hexakis-2-methoxyisobutyl isonitrile (MIBI) (Cardiolite, DuPont, Wilmington, DE). It has transient hepatic uptake and little or no myocardial redistribution, making it an ideal single-photon emission CT tracer. The commercially developed agent of the BATO group is 99mTc-teboroxime (Cardiotec, Squibb, Princeton, NJ). Its extraction fraction by the myocardium is higher than that of 201Tl and 99mTc-MIBI but its washout is very rapid and flow related. Because of the lack of redistribution with 99mTc-MIBI and the rapid washout with 99mTc-teboroxime, two separate injections are necessary for these new tracers to enable them to distinguish ischemia from scar tissue. It is recommended to perform the rest study first, and then to do the exercise study if a 1-day protocol is being used.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Academic Hospital of Maastricht, The Netherlands.
authors.forename: S H
authors.initials: SH
authors.lastname: Braat
mesh_terms: D006328:Cardiac Catheterization; D003325:Coronary Care Units; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000628:therapy; D015609:Organotechnetium Compounds; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D015609:Organotechnetium Compounds