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

J Nucl Cardiol. 2020 Oct;27(5):1728-1738. doi: 10.1007/s12350-020-02200-6. Epub 2020 May 20.

Abstract

Introduction: Strontium-82/Rubidium-82 (82Sr/82Rb) generators are used widely for positron emission tomography (PET) imaging of myocardial perfusion. In this study, the 82Rb isotope yield and production efficiency of two FDA-approved 82Sr/82Rb 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 82Rb 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 (82Rb) and production efficiency (82Rb yield/82Sr parent activity) were measured and compared after this conversion to a common scale.

Results: At the start of clinical use, the system reported 82Rb 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 82Sr 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 82Rb production improved for both systems over the respective periods of clinical use.

Conclusions: 82Rb 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 82Rb production efficiency of the CardioGen-82® system was ~ 7% lower than RUBY-FILL® over the full period of clinical use.

Keywords: Myocardial perfusion imaging; daily quality assurance; positron emission tomography; rubidium-82 generator.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Heart Diseases / diagnostic imaging*
  • Humans
  • Myocardial Perfusion Imaging / instrumentation*
  • Positron-Emission Tomography / instrumentation*
  • Quality Assurance, Health Care
  • Radionuclide Generators / instrumentation*
  • Retrospective Studies
  • Rubidium Radioisotopes*
  • Strontium Radioisotopes*

Substances

  • Rubidium Radioisotopes
  • Strontium Radioisotopes
  • Strontium-82
  • Rubidium-82