⁶⁸Ga activity calibrations for nuclear medicine applications in Cuba

Area of Science:

• Nuclear physics
• Metrology
• Radiochemistry

Background:

• Accurate activity measurement is crucial for radionuclide applications, especially in nuclear medicine.
• Gallium-68 (⁶⁸Ga) is a key positron-emitting radionuclide for Positron Emission Tomography (PET).
• Establishing reliable activity standards ensures consistency and comparability of measurements.

Purpose of the Study:

• To implement and disseminate a ⁶⁸Ga activity measurement unit in Cuba.
• To calibrate the activity concentration of ⁶⁸Ga solutions using the TDCR method.
• To validate the measurement uncertainty and transfer the ⁶⁸Ga standard to other calibrators.

Main Methods:

• Implementation of the Triple to Double Coincidence Ratio (TDCR) method for liquid scintillation counting.
• Utilized a Hidex™ commercial liquid scintillation counter and a custom FORTRAN code for efficiency calculations.
• Validation performed using a ²²Na standard traceable to NIST.

Main Results:

• The TDCR method yielded a ⁶⁸Ga activity concentration with a relative expanded uncertainty of 2% (k=2).
• Validation with ²²Na showed a difference of 0.16% compared to the NIST traceable reference value.
• Successful transfer of the ⁶⁸Ga activity standard to secondary calibrators, including those used in clinical PET settings.

Conclusions:

• The TDCR method is a reliable technique for the accurate determination of ⁶⁸Ga activity concentration.
• The established ⁶⁸Ga activity measurement unit in Cuba meets metrological requirements.
• The dissemination of this standard supports the quality assurance of ⁶⁸Ga radiopharmaceuticals for PET imaging.