RT Journal Article SR Electronic T1 Development of radiopharmaceuticals to target neurotensin receptors based on 68Ga and 177Lu JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1152 OP 1152 VO 56 IS supplement 3 A1 Niculae, Dana A1 Mihon, Mirela A1 Leonte, Radu A1 Silisteanu, Andrei YR 2015 UL http://jnm.snmjournals.org/content/56/supplement_3/1152.abstract AB 1152 Objectives The study aims to develop new theranostic agents for systemic cancer radiotherapy and follow up. The 68 min half-life of the 68Ga matches the pharmacokinetics of neurotensin peptide - rapid diffusion, localization at the target and fast blood clearance. 177Lu is a therapeutic counterpart of 68Ga, giving highly destructive β emissions.Methods The purified eluate from a 68Ge/68Ga generator and a solution of 177LuCl3 respectivelly were used for radiolabelling of neurotensin (DOTA-NT). at pH 4, 950C, in non-ionic buffer. Automated synthesis and postpurification was performed. Analytical testing and biological in vitro and in vivo evaluation of 68Ga/177Lu-DOTA-NT was done in tumor animal models. Real-time quantification of biomolecular interactions was determined: on- and off-rates, affinity of DOTA-NT to tumor cell-surface receptors.Results Nanomoles of DOTA-NT were radiolabelled with a yield of 90% while the radiochemical purity of 68Ga/177Lu-DOTA-NT, after SPE purification was >98%. The biodistribution pattern shows high and stable tumor uptake up to 8.6% ID/g. The blood clearance is fast, the renal elimination is rapid and high tumor to background ratios was observed. Binding to receptors is achieved in the first 3 min of incubation and remains stable for 30 min.Conclusions The radiolabelling with 68Ga and 177Lu of very promising candidates for imaging targets of interest in cancer diagnosis and therapy follow-up such as neurotensin receptors, were successfully adapted on the automated module, reducing reaction time and operator exposure. The biological evaluation of 68Ga/177Lu-DOTA-NT show a high and stable tumor uptake of both compounds.Promising preliminary biological evaluation is recommending further investigations of 68Ga-DOTA-NT1 as potential tracer in PET imaging and 177Lu-DOTA-NT1 as systemic radiotehrapy agent.Research Support The work has been funded by the Sectoral Operational Programme Human Resources Development 2007-2013 of the Ministry of European Funds through the Financial Agreement POSDRU/159/1.5/S/134398 and Partnership Programme in priority areas - PN II, MEN - UEFISCDI, contract 228/2014.