Performance and long-term consistency of five Galliform 68Ge/68Ga generators used for clinical Ga-68 preparations over a 4 year period.

BACKGROUND: Gallium-68 is a positron emitter for PET applications that can be produced without cyclotron by a germanium (Ge-68) chloride/gallium (Ga-68) chloride generator. Short half-life (67.71 min) of Ga-68, matching pharmacokinetic properties of small biomolecules, facilitates isotope utilization in compounding radiopharmaceuticals for PET imaging. The increasing cost of good manufacturing practice-compliant generators has strengthened the need for radionuclide efficient use by planning specific radiopharmaceutical sessions during the week, careful maintenance of the generator and achievement of high labeling yield and radiochemical purity (RCP) of the radiolabeled molecules. METHODS: The aim of this study was to evaluate the annual performance of five consecutive 68Ge/68Ga generators used for small-scale preparations of 68Ga-radiopharmaceuticals. To assess the long-term efficiency of isotope production we measured the weekly elution yield. To assess process efficiency we measured elution yield, labeling yield and RCP of four radiopharmaceutical preparations (68Ga-DOTATOC, 68Ga-PSMA-HBED-CC, 68Ga-PENTIXAFOR and 68Ga-DOTATATE). RESULTS: The annual mean elution yield of the generators was 74.7%, higher than that indicated by the manufacturer, and it never went below 65%. The Ge-68 level in the final products was under the detection limits in all the produced batches (mean value 0.0000048%). The RCP of radiopharmaceuticals determined by high-performance liquid chromatography was 98 ± 0.22%. The mean yield of radiolabelling was 64.68, 68.71, 57 and 63.68% for 68Ga-DOTATOC, 68Ga-PSMA-HBED-CC, 68GaPENTIXAFOR and 68Ga-DOTATATE. CONCLUSION: The ability to prepare in the hospital radiopharmacy high-purity and pharmaceutically acceptable 68Ga-radiolabeled probes on a routine basis facilitates patient access to precision imaging for clinical and research aims.

Radiation dose reduction in myocardial perfusion imaging single-photon emission computed tomography/computed tomography using a dose-tracking software.

OBJECTIVE: We describe our experience with a dose-tracking software (Radimetrics) that was used to optimize, from a dosimetric point of view, the single-photon emission computed tomography/computed tomography protocols used in myocardial perfusion imaging. PATIENTS AND METHODS: We extracted and assessed the major dosimetric indices as the administered activity, the computed tomography dose index, the dose length product and the size-specific dose estimates for a large sample of patients before and after an optimization process. We also evaluated both the effective and the equivalent dose to organs for all the procedures. RESULTS: We achieved a reduction in administered activity by 17.8 and 4.5% for 2- and 1-day protocols, respectively; moreover size-specific dose estimates related to a single computed tomography acquisition was reduced by 50%. The organs that received the highest equivalent dose were the heart and the breast, and with the new protocols, these values were almost halved.The average single-photon emission computed tomography/computed tomography myocardial perfusion imaging effective dose decreased from 21.9±2.5 to 15.6±1.4 mSv for the 2-day protocol and from 17.8±1.7 to 13.6±1.5 mSv for the 1-day protocol. This meant that with a simple but targeted action on acquisition protocols, it was possible to achieve considerable dosimetric reduction.The adoption of a dose-tracking software represented an easy approach to optimization. Furthermore, we could easily calculate the main dosimetric indices and check their trends day by day to perform the necessary corrective actions in real timeVideo abstract: http://links.lww.com/NMC/A135.