Calibration of the Capintec CRC-712M dose calibrator for 18F

Primary standardisation was performed on a solution of 18F using the 4πβ–γ coincidence counting efficiency-tracing extrapolation method with 60Co used as a tracer nuclide. The result was used to calibrate the ANSTO secondary standard ionisation chamber which is used to disseminate Australian activity standards for gamma emitters. Using the secondary activity standard for 18F, the Capintec CRC-712M dose calibrator at the Australian National Medical Cyclotron (NMC) Positron Emission Tomography (PET) Quality Control (QC) Section was calibrated. The dial setting number recommended by the manufacturer for the measurement of the activity of 18F is 439. In this work, the dial setting numbers for the activity measurement of the solution of 18F in Wheaton vials were experimentally determined to be 443±12, 446±12, 459±11, 473±15 for 0.1, 1, 4.5 and 9 ml solution volumes, respectively. The uncertainties given above are expanded uncertainties (k=2) giving an estimated level of confidence of 95%. The activities determined using the manufacturer recommended setting number 439 are 0.8%, 1.4%, 4.0% and 6.5% higher than the standardised activities, respectively. It is recommended that a single dial setting number of 459 determined for 4.5 ml is used for 0.1–9 ml solution in Wheaton vials in order to simplify the operation procedure. With this setting the expended uncertainty (k=2) in the activity readout from the Capintec dose calibrator would be less than 6.2%.