Clinical experience with technetium 99m teboroxime

Abstract

Technetium 99m teboroxime is a boronic acid adduct of technetium dioxime complex, a neutral lipophilic technetium-containing myocardial perfusion imaging agent with high myocardial extraction, rapid myocardial washout, and entero-hepatic excretion. Early "redistribution" occurs, and, based on preliminary animal data, appears to be due to differential washout alone since there is no reuptake of teboroxime into the heart; however, for practical purposes two injections of tracer, at stress and at rest, are used clinically. Due to the high photon flux of technetium, diagnostic images can be acquired in the narrow time window between the end of blood clearance and peak hepatic uptake. To begin an acquisition within 2 minutes of tracer injection, the patient must be moved rapidly from the treadmill to a camera that is set and ready to count. A complete set of planar images can be completed in less than 5 minutes. Optimal single photon emission computed tomography (SPECT) imaging requires a continuously counting single detector camera or a three-headed camera to complete acquisition in less than 10 minutes. The image quality is comparable to thallium 201 and the imaging time is a fraction of the time required to complete SPECT thallium scans. Both left ventricular function (ejection fraction) and planar imaging can be performed in less than 4 minutes, without moving the patient from the treadmill, using the Sim-400 (Scinticor, Milwaukee, WI), a portable high count-rate, multicrystal scintillation camera. Because teboroxime maintains high myocardial extraction at high myocardial flow, it may be uniquely suited to be used in combination with pharmacological stress, which does not require patient movement between stress and imaging. Work is in progress to further refine and optimize imaging protocols using teboroxime.(ABSTRACT TRUNCATED AT 250 WORDS)