title: Scaled-up radiolabelling of DOTATATE with 68Ga eluted from a SnO2-based 68Ge/68Ga generator.
abstract: A scaled-up radiolabelling and improved post-labelling purification procedure for [(68)Ga]DOTATATE is reported, using a more than 1 year old SnO(2)-based 1850MBq (68)Ge/(68)Ga generator (initially double-loaded with 3700MBq (68)Ge) as a source of ionic (68)Ga. The elution method of choice comprised elution with 0.6M HCl in a single 4mL fraction, containing up to 95% of the total eluted (68)Ga activity. The unpurified fraction was directly used for labelling after pH adjustment with 2.5M sodium acetate. Labelling efficiencies were determined at 90-95°C at various reaction times and reaction volumes of up to 5.7mL, using either 30μg or 50μg DOTATATE. Only the latter amount resulted in consistently high labelling efficiency in excess of 95%. Post-labelling purification, carried out on Sep-Pak C18, showed that 50% ethanol in saline was a superior desorption eluant than 100% ethanol. The highest and most consistent decay-corrected radiochemical yields (89%) were obtained using 50μg DOTATATE and a 20min reaction time.
authors.affiliation: Radionuclide Production Department, iThemba LABS, PO Box 722, 7129 Somerset West, South Africa. niel@tlabs.ac.za
authors.forename: Daniel D
authors.initials: DD
authors.lastname: Rossouw
authors.forename: Wouter A P
authors.initials: WA
authors.lastname: Breeman
mesh_terms: D005710:Gallium Radioisotopes / Q000737:chemistry* / Q000302:isolation & purification / Q000528:radiation effects*; D007553:Isotope Labeling / Q000379:methods; D009942:Organometallic Compounds / Q000138:chemical synthesis*; D010865:Pilot Projects; D011876:Radionuclide Generators; D017971:Tin Compounds / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D005710:Gallium Radioisotopes; D009942:Organometallic Compounds; D017971:Tin Compounds; C513399:gallium Ga 68 dotatate; C045358:stannic oxide