Activity determination of ¹⁸F using liquid scintillation beta-efficiency extrapolation and non-extrapolation methods.

Area of Science:

• Nuclear physics and instrumentation
• Radiochemistry and metrology

Background:

• Accurate determination of radionuclide activity is crucial for medical imaging and research.
• ¹⁸F is a widely used positron-emitting isotope in Positron Emission Tomography (PET).

Purpose of the Study:

• To determine the absolute activity of ¹⁸F using two distinct liquid scintillation coincidence counting methods.
• To compare the results and uncertainty budgets of the extrapolation and non-extrapolation techniques.
• To establish an ionization chamber factor for inter-laboratory comparisons.

Main Methods:

• Absolute activity measurement of ¹⁸F via 4πβ-γ liquid scintillation coincidence counting with beta-efficiency extrapolation.
• Determination of an ionization chamber factor for SIRTI comparison.
• Application of a non-extrapolation method using detection efficiency analysis and double-phototube coincidence counting.

Main Results:

• Both the beta-efficiency extrapolation and the non-extrapolation methods provided results for ¹⁸F absolute activity.
• Detailed uncertainty budgets for each method were calculated and presented.
• An ionization chamber factor was determined, enabling participation in SIRTI comparisons.

Conclusions:

• The study successfully determined ¹⁸F absolute activity using two advanced scintillation counting techniques.
• Comparison of the methods provides valuable data for quality assurance in radionuclide metrology.
• The findings contribute to the accuracy and reliability of ¹⁸F measurements in nuclear science and medicine.