Radioassay problems associated with the clinical use of a 82Rb radionuclide generator

Area of Science:

• Nuclear medicine
• Radiopharmaceutical quality control
• Medical physics

Background:

• 82Rubidium (82Rb), a short-lived positron emitter (t1/2 1.27 min), is vital for Positron Emission Tomography (PET) imaging.
• 82Rb is supplied by 82Strontium (82Sr)/82Rb generator systems, where the parent 82Sr (t1/2 25.5d) is produced via molybdenum spallation.
• Generator eluates can contain impurities of long-lived strontium radionuclides, including 85Sr, 89Sr, and 90Sr.

Purpose of the Study:

• To highlight the importance of assaying and controlling strontium radionuclide impurities in clinical 82Rb preparations.
• To discuss the challenges in accurately measuring these impurities.
• To address the implications for patient radiation dose and spectral analysis.

Main Methods:

• Discussion of measurement challenges for long-lived strontium radionuclides.
• Focus on techniques for resolving overlapping peaks with different Full Widths at Half Maximum (FWHM).
• Consideration of radiation dose calculations for patients receiving contaminated radiopharmaceuticals.

Main Results:

• The presence of varying quantities of 85Sr, 89Sr, and 90Sr alongside 82Rb is a significant concern.
• Accurate quantification of these impurities is essential for safe clinical application.
• Spectral peak overlap complicates precise measurement, potentially affecting dose assessment.

Conclusions:

• Strict quality control and accurate assay of strontium impurities in 82Rb generators are imperative.
• Addressing measurement difficulties, particularly spectral interferences, is key to minimizing patient radiation exposure.
• Ensuring the purity of 82Rb is critical for the safe and effective use of this important diagnostic radionuclide.