Scaled-up radiolabelling of DOTATATE with 68Ga eluted from a SnO2-based 68Ge/68Ga generator

• Published in: Applied radiation and isotopes Vol. 70; no. 1; pp. 171 - 175
• Main Authors: Rossouw, Daniel D, Breeman, Wouter A P
• Format: Journal Article
• Language: English
• Published: England 01.01.2012
• Subjects: Gallium Radioisotopes - chemistry; Gallium Radioisotopes - isolation & purification; Gallium Radioisotopes - radiation effects; Isotope Labeling - methods; Organometallic Compounds - chemical synthesis; Pilot Projects; Radionuclide Generators; Tin Compounds - chemistry; Tin Compounds - radiation effects
• ISSN: 0969-8043; 1872-9800
• DOI: 10.1016/j.apradiso.2011.07.016

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.