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

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.

Rubidium-82 Generator Yield and Efficiency for PET Perfusion Imaging: Comparison of Two Clinical Systems (Preprint)

UNSTRUCTURED 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) to RUBY-FILL® equivalent values (integrated ‘total’ of 35 mL elution at 20 mL/min). 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. 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.

PROJECTILE FRAGMENTATION OF 36,40Ar INDUCED REACTIONS

Fragment yields for Z ≥ 5 from projectile fragmentation using primary beams of 36,40Ar at 50 MeV/nucleon on 64 Ni target have been measured in RIBLL fragment separator. We compare the fragment cross sections with the predictions of the empirical EPAX parametrization of fragmentation cross-sections and Statistical Abration-Ablation model (SAA) by considering the RIBLL separator transmission rate. Isotope yield ratios between these two reactions were calculated and isoscaling parameters α and β are extracted, their dependences on fragment atomic number Z and neutron number N were presented.

PROJECTILE FRAGMENTATION OF 36,40Ar INDUCED REACTIONS

Fragment yields of projectile fragmentation reactions using primary beams of 36,40Ar at 50 MeV/nucleon on 64 Ni target have been measured. Fragment yields of different isotopes were obtained for Z ≥ 5 in RIBLL fragment seperator. We compare the extracted yields to the predictions of the empirical parametrization of fragmentation cross-sections(EPAX) and Statistical Abration-Ablation model(SAA) considering the RIBLL separator transmission rate. Isotope yield ratios between these 2 reactions were calculated, isoscaling parameters α and β, their dependence on fragment atomic number Z and neutron number N were calculated.

INFLUENCES OF THE ISOSPIN-DEPENDENCE OF IN-MEDIUM NUCLEON–NUCLEON CROSS-SECTION AND MOMENTUM DEPENDENT INTERACTION ON ISOSCALING PARAMETER

Influences of the isospin-dependent in-medium nucleon–nucleon cross-section [Formula: see text] and momentum-dependent interaction (MDI) on the isoscaling parameter α are investigated for two central collisions 40 Ca + 40 Ca and 60 Ca + 60 Ca . These collisions are with isospin dependent quantum molecular dynamics in the beam energy region from 40 to 60 MeV/nucleon. The isotope yield ratio R21(N, Z) for the above two central collisions depends exponentially on the neutron number N and proton number Z of isotopes, with an isoscaling. In particular, the isospin-dependent [Formula: see text] and MDI induce an obvious decrease of the isoscaling parameter α. The mechanism of the decreases of α by both [Formula: see text] and MDI are studied respectively.