title: Comparison between two absolute methods used for 177Lu activity measurements and its standardization.
abstract: A (177)Lu primary standard was developed at the ENEA-INMRI in the frame of an international comparison organized by BIPM and piloted by NIST (USA). The CIEMAT/NIST method with (3)H standard source as tracer was used for standardizing a solution of (177)Lu. The activity value was compared also with the measurements of the same mother solution carried out by the 4πγ integral counting method. Particular efforts were made to identify and quantify the long-lived (177m)Lu impurity in the mother solution. The results obtained by the two methods are in good agreement within their standard uncertainties. The arithmetic mean of the two values is in good agreement with the Comparison Reference Value (CRV). By the new primary standard two well-type ionization chambers (ICs), one fixed and the other one portable, were calibrated with an uncertainty lower than 2%. These ICs are used for routinely applications in the activity measurements of short-lived radionuclides particularly useful for medical applications.
authors.affiliation: ENEA Istituto Nazionale di Metrologia delle Radiazioni Ionizzanti (INMRI), Centro Ricerche Casaccia, I-00123 Rome, Italy. marco.capogni@casaccia.enea.it
authors.forename: M
authors.initials: M
authors.lastname: Capogni
authors.forename: M L
authors.initials: ML
authors.lastname: Cozzella
authors.forename: P
authors.initials: P
authors.lastname: De Felice
authors.forename: A
authors.initials: A
authors.lastname: Fazio
mesh_terms: D006207:Half-Life; D038622:Internationality; D008187:Lutetium / Q000032:analysis* / Q000592:standards*; D011829:Radiation Dosage; D011868:Radioisotopes / Q000032:analysis* / Q000592:standards*; D011874:Radiometry / Q000592:standards*; D012015:Reference Standards; D012016:Reference Values
chemical_list: D011868:Radioisotopes; D008187:Lutetium