Speaker
Description
Authors (affiliation): Virginia Peyrés 1, Miguel Roteta 1, Marcos Mejuto 1, Nuria Navarro 1, Eduardo Romero 2
1 Laboratorio de Metrología de Radiaciones Ionizantes, CIEMAT, SPAIN;
2 Unidad de Aplicaciones Biomédicas y Farmacocinética, CIEMAT, SPAIN.
177Lu is the first nuclide approved by the US Food and Drug Administration for peptide receptor radionuclide therapy. It decays by beta minus emission (4 branches) to 177Hf. In the deexcitation process, 6 gamma lines are emitted with energies between 71 and 321 keV. This paper describes the standardization and half-life determination of this nuclide.
Its half-life has been determined by following the decay rate with two measurement systems:
A well-type ionization chamber IG11 with digital registering of the ionization current for time intervals up to 5 half-lives.
An extended-range coaxial HPGe detector from CANBERRA with a digital acquisition system configured to periodically register the spectrum area in an energy region from 40 to 400 keV.
The combination of six results gives a preliminary value of T1/2= 6.643 (4) d, very similar to the DDEP recommended value of 6.647 (4) d.
This radionuclide has also been standardised by three techniques: Liquid scintillation counting (LSC) with Triple to Double Coincidence ratio (TDCR) method (using a custom built system and a commercial TDCR counter); 4πγ counting with a large NaI (Tl) well detector (17.8 × 17.8 cm.) and coincidence techniques.
