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-through artifacts), injection doses need to be optimized and dose ratios between the 1st and 2nd scans should be maintained at ≥ 3. However, the current state of practice in Japan is unclear. Thus, the aim of this study was to clarify the details 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 radiopharmaceuticals were sent to 641 nuclear medicine facilities. Results: Responses were received from 246 facilities. One-day protocols were used in 97.1% of the facilities. The most common injection dose ratio was 2.5. Only 18.2% of facilities achieved the recommended injection dose ratio. Stress-only protocols were performed in only 1.7% of facilities; the primary reasons for not performing stress-only protocols were as follows: 1) “The reading-physician cannot interpret the image just after the first scan,” and 2) “Preparation of radiopharmaceuticals and scan arrangements turn out to be complicated.” Conclusion: Approximately 80% of nuclear medicine facilities do not follow the recommended injection dose ratio. Stress-only protocols are ideal, but are performed at very few facilities. Both optimization and standardization of stress MPI protocols using 99mTc radiopharmaceuticals are needed in Japan.