Dataset Information

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

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.

SUBMITTER: Ahmadi A

PROVIDER: S-EPMC7599151 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature

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Publications

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

Ahmadi Ali A Klein Ran R Lewin Howard C HC Beanlands Rob S B RSB deKemp Robert A RA

Journal of nuclear cardiology : official publication of the American Society of Nuclear Cardiology 20200520 5

<h4>Introduction</h4>Strontium-82/Rubidium-82 (<sup>82</sup>Sr/<sup>82</sup>Rb) generators are used widely for positron emission tomography (PET) imaging of myocardial perfusion. In this study, the <sup>82</sup>Rb isotope yield and production efficiency of two FDA-approved <sup>82</sup>Sr/<sup>82</sup>Rb generators were compared.<h4>Methods</h4>N = 515 sequential daily quality assurance (QA) reports from 9 CardioGen-82<sup>®</sup> and 9 RUBY-FILL<sup>®</sup> generators were reviewed over a perio ...[more]

PMID: 32436115

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Project description:BackgroundChanges in renal perfusion may play a pathophysiological role in hypertension and kidney disease, however to date, no method for renal blood flow (RBF) determination in humans has been implemented in clinical practice. In a previous study, we demonstrated that estimation of renal perfusion based on a single positron emission tomography/computed tomography (PET/CT) scan with Rubidium-82 (82Rb) is feasible and found an approximate 5% intra-assay coefficient of variation for both kidneys, indicative of a precise method.This study's aim was to determine the day-to day variation of 82Rb PET/CT and to test the method's ability to detect increased RBF induced by infusion of amino acids.MethodsSeventeen healthy subjects underwent three dynamic 82Rb PET/CT scans over two examination days comprising: Day A, a single 8-minute dynamic scan and Day B, two scans performed before (baseline) and after RBF stimulation by a 2-hour amino acid-infusion. The order of examination days was determined by randomization. Time activity curves for arterial and renal activity with a 1-tissue compartment model were used for flow estimation; the K1 kinetic parameter representing renal 82Rb clearance. Day-to-day variation was calculated based on the difference between the unstimulated K1 values on Day A and Day B and paired t-testing was performed to compare K1 values at baseline and after RBF stimulation on Day B.ResultsDay-to-day variation was observed to be 5.5% for the right kidney and 6.0% for the left kidney (n = 15 quality accepted scans). K1 values determined after amino acid-infusion were significantly higher than pre-infusion values (n = 17, p = 0.001). The mean percentage change in K1 from baseline was 13.2 ± 12.9% (range - 10.4 to 35.5) for the right kidney; 12.9 ± 13.2% (range - 15.7 to 35.3) for the left kidney.ConclusionDay-to-day variation is acceptably low. A significant K1 increase from baseline is detected after application of a known RBF stimulus, indicating that 82Rb PET/CT scanning can provide a precise method for evaluation of RBF and it is able to determine changes herein.Clinical trial registrationEU Clinical Trials Register, 2017-005008-88. Registered 18/01/2018.

Project description:BackgroundChanges in renal blood flow (RBF) may play a pathophysiological role in hypertension and kidney disease. However, RBF determination in humans has proven difficult. We aimed to confirm the feasibility of RBF estimation based on positron emission tomography/computed tomography (PET/CT) and rubidium-82 (82Rb) using the abdominal aorta as input function in a 1-tissue compartment model.MethodsEighteen healthy subjects underwent two dynamic 82Rb PET/CT scans in two different fields of view (FOV). FOV-A included the left ventricular blood pool (LVBP), the abdominal aorta (AA) and the majority of the kidneys. FOV-B included AA and the kidneys in their entirety. In FOV-A, an input function was derived from LVBP and from AA, in FOV-B from AA. One-tissue compartmental modelling was performed using tissue time activity curves generated from volumes of interest (VOI) contouring the kidneys, where the renal clearance of 82Rb is represented by the K1 kinetic parameter. Total clearance for both kidneys was calculated by multiplying the K1 values with the volume of VOIs used for analysis. Intra-assay coefficients of variation and inter-observer variation were calculated.ResultsFor both kidneys, K1 values derived from AA did not differ significantly from values obtained from LVBP, neither were significant differences seen between AA in FOV-A and AA in FOV-B, nor between the right and left kidneys. For both kidneys, the intra-assay coefficients of variation were low (~ 5%) for both input functions. The measured K1 of 2.80 ml/min/cm3 translates to a total clearance for both kidneys of 766 ml/min/1.73 m2.ConclusionMeasurement of renal perfusion based on PET/CT and 82Rb using AA as input function in a 1-tissue compartment model is feasible in a single FOV. Based on previous studies showing 82Rb to be primarily present in plasma, the measured K1 clearance values are most likely representative of effective renal plasma flow (ERPF) rather than estimated RBF values, but as the accurate calculation of total clearance/flow is very much dependent on the analysed volume, a standardised definition for the employed renal volumes is needed to allow for proper comparison with standard ERPF and RBF reference methods.

Dataset Information

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

Introduction

Methods

Results

Conclusions

Publications

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

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