Development of the Australian Standard for Germanium-68 by two Liquid Scintillation Counting methods

Area of Science:

• Nuclear Medicine
• Radiochemistry
• Metrology

Background:

• The use of Germanium-68/Gallium-68 (⁶⁸Ge/⁶⁸Ga) and Gallium-68 (⁶⁸Ga) is growing in nuclear medicine.
• Accurate activity measurements are crucial for reliable diagnostic and therapeutic applications.

Purpose of the Study:

• To conduct an international comparison of activity measurement for ⁶⁸Ge in equilibrium with ⁶⁸Ga.
• To establish traceable standards for ⁶⁸Ge/⁶⁸Ga radioactivity measurements.

Main Methods:

• Standardization of the comparison solution using 4π(Liquid Scintillation)β⁺-γ coincidence extrapolation.
• Utilized Total Detector Efficiency Calculation (TDCR) for efficiency determination.
• Transferred the primary standard to the ANSTO Secondary Standard Ionisation Chamber.

Main Results:

• Excellent agreement was achieved between the two independent measurement methods (4πLSβ⁺-γ and TDCR).
• The primary standard was successfully transferred, enabling secondary standardization.

Conclusions:

• Internationally traceable Australian Certified Reference Materials (ACRMs) of ⁶⁸Ge/⁶⁸Ga can now be produced.
• These ACRMs support various measurement geometries used in nuclear medicine, enhancing measurement consistency and reliability.