In this study we report a comparison of the three 9 9 m Tc myocardial perfusion imaging agents: Cardiolite , Myoview and Technescan Q12. The three agents were compared for ease of preparation, quality control (QC) analysis and shelf life after reconstitution under a variety of 9 9 m Tc activity levels. Myoview was the easiest agent to prepare, the QC method for Cardiolite was the most straightforward and Technescan Q12 showed the greatest stability over time. All three agents gave >90% radiochemical purity within the manufacturers specifications for use.