Determination of activity meter settings for the PET nuclides 44 Sc and 89 Zr.

Radionuclide activity meters depend on “calibration setting numbers” that are specific for a certain combination of radionuclide, volume and geometry. This work describes their determination for two PET emerging nuclides (44Sc and 89Zr), three commercial activity meters (CAPINTEC CRC15 BETA, ATOMLAB BIODEX 500 and VEENSTRA VDC 405) and two geometries: 1 mL plastic syringes and 5 mL glass vials. For 44Sc, only values for the dial setting for 5 mL ampoules were reported previously and its use for the assayed geometries would lead to significant differences. For 89Zr more data were available in the literature, and results are provided for new geometries. All results rely on the absolute standardisation in activity of solutions of both radionuclides.