Rubidium-82 generator yield and efficiency for PET perfusion imaging: Comparison of two clinical systems

INTRODUCTION: Strontium-82/Rubidium-82 ((82)Sr/(82)Rb) generators are used widely for positron emission tomography (PET) imaging of myocardial perfusion. In this study, the (82)Rb isotope yield and production efficiency of two FDA-approved (82)Sr/(82)Rb generators were compared. METHODS: N = 515 sequential daily quality assurance (QA) reports from 9 CardioGen-82(®) and 9 RUBY-FILL(®) generators were reviewed over a period of 2 years. A series of test elutions was performed at different flow-rates on the RUBY-FILL(®) system to determine an empirical correction-factor used to convert CardioGen-82(®) daily QA values of (82)Rb activity (dose-calibrator ‘maximum’ of 50 mL elution at 50 mL·min(−1)) to RUBY-FILL(®) equivalent values (integrated ‘total’ of 35 mL elution at 20 mL·min(−1)). The generator yield ((82)Rb) and production efficiency ((82)Rb yield/(82)Sr parent activity) were measured and compared after this conversion to a common scale. RESULTS: At the start of clinical use, the system reported (82)Rb activity from daily QA was lower for CardioGen-82(®) vs RUBY-FILL(®) (2.3 ± 0.2 vs 3.0 ± 0.2 GBq, P < 0.001) despite having similar (82)Sr activity. Dose-calibrator ‘maximum’ (CardioGen-82(®)) values were found to under-estimate the integrated ‘total’ (RUBY-FILL(®)) activity by ~ 24% at 50 mL·min(−1). When these data were used to convert the CardioGen-82 values to a common measurement scale (integrated total activity) the CardioGen-82(®) efficiency remained slightly lower than the RUBY-FILL(®) system on average (88 ± 4% vs 95 ± 4%, P < 0.001). The efficiency of (82)Rb production improved for both systems over the respective periods of clinical use. CONCLUSIONS: (82)Rb generator yield was significantly under-estimated using the CardioGen-82(®) vs RUBY-FILL(®) daily QA procedure. When generator yield was expressed as the integrated total activity for both systems, the estimated (82)Rb production efficiency of the CardioGen-82(®) system was ~ 7% lower than RUBY-FILL(®) over the full period of clinical use. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s12350-020-02200-6) contains supplementary material, which is available to authorized users.