The Status of Stress Myocardial Perfusion Imaging Using 99mTc Pharmaceuticals in Japan: Results from a Nationwide Survey

Objective(s): To appropriately use one-day myocardial perfusion imaging(MPI) with 99mTc radiopharmaceuticals (i.e. to avoid shine-throughartifacts), injection doses need to be optimized and dose ratios betweenthe 1st and 2nd scans should be maintained at ≥ 3. However, the current stateof practice in Japan is unclear. Thus, the aim of this study was to clarify thedetails of MPI protocols using 99mTc radiopharmaceuticals in Japan.Methods: A nationwide survey was conducted in June and July 2016.Questionnaires about stress MPI protocols using 99mTc radiopharmaceuticalswere sent to 641 nuclear medicine facilities.Results: Responses were received from 246 facilities. One-day protocolswere used in 97.1% of the facilities. The most common injection dose ratiowas 2.5. Only 18.2% of facilities achieved the recommended injection doseratio. Stress-only protocols were performed in only 1.7% of facilities; theprimary reasons for not performing stress-only protocols were as follows:1) “The reading-physician cannot interpret the image just after the firstscan,” and 2) “Preparation of radiopharmaceuticals and scan arrangementsturn out to be complicated.”Conclusion: Approximately 80% of nuclear medicine facilities do notfollow the recommended injection dose ratio. Stress-only protocols areideal, but are performed at very few facilities. Both optimization andstandardization of stress MPI protocols using 99mTc radiopharmaceuticalsare needed in Japan