Clinical evaluation of a precision-controlled rubidium-82 elution system for PET myocardial perfusion imaging

Objectives Positron emission tomography (PET) myocardial perfusion imaging (MPI) with rubidium-82 (Rb-82) has been more widely adopted due to its superior diagnostic accuracy and its availability without the need for an onsite cyclotron. For patient safety, optimal MPI and added myocardial blood flow quantification, the eluted Rb-82 activity must be accurate, precise, reproducible, and delivered at a constant rate of activity over a short period of time, without breakthrough of the long-lived parent isotope strontium-82 (Sr-82). We evaluated the performance of a pre-commercial Rb-82 elution system using constant-activity-rate infusions for PET MPI.

Methods The performance of an investigational Rb-82 elution system (JDI Ruby-Fill) was evaluated at one site over a 6 month period. N=300 patients underwent rest-stress MPI (600 scans) with constant-activity-rate infusions of 10 MBq/kg, using a standard 30s ‘slow-bolus’ infusion was to allow for routine flow quantification using 3D dynamic PET imaging. Precision of the Rb-82 yield and Sr-82 breakthrough detection limit values was estimated from daily automated quality control (QC) measurements. For the patient scans, the requested vs. delivered activity (MBq) and elution time (s) were recorded to determine bias and precision.

Results Daily QC values of Rb-82 yield and Sr-82 breakthrough detection limit had excellent measurement precision of only ±0.1%. Patient eluted activity values had a very small positive bias of 0.9±0.8%, with >99% of cases having <3% bias in the delivered vs. requested activity. Patient elution times also had a small bias of 3.0±1.0s, with 98% of the delivered elution times within 6s of the standard 30s time requested.

Conclusions The Rudy-Fill Rb-82 elution system is highly accurate and precise, with performance that is suitable for high-throughput clinical PET perfusion imaging. RESEARCH SUPPORT: Clinical trial #NCT02117284 supported by Jubilant DraxImage Inc.