[Use of 99mTc-labeled myocardial perfusion agents in the Kanto-Koshinetsu area]

We sent out a questionnaire to investigate how the 99mTc-labeled myocardial perfusion agents are used in the Kanto-Koshinetsu area. Answers were obtained from 83 laboratories. Examinations using 99mTc-labeled agents were performed more frequently than those using 201T1 only in 10 of 83 laboratories. Main reasons for not using 99mTc-labeled agents were as follows: two injections required in the stress study, superiority of thallium-201 in the assessment of myocardial viability, a large amount of clinical data cumulated in thallium-201 imaging, and problems caused by abdominal uptake of 99mTc-labeled agents. Comparing purposes of the examinations using 201T1 and 99mTc-labeled agents, evaluation of myocardial viability was more common in 201Tl imaging, meanwhile, detection of myocardial ischemia was more common in imaging with 99mTc-labeled agents. It was pointed out that dual isotope imaging using 201Tl and 99mTc-labeled agents and simultaneous evaluation of myocardial perfusion and cardiac function are clinically feasible as new diagnostic procedures.