TY - JOUR T1 - Comparative Evaluation of the Biodistribution Profiles of a Series of Nonpeptidic Neurotensin Receptor-1 Antagonists Reveals a Promising Candidate for Theranostic Applications JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1120 LP - 1123 DO - 10.2967/jnumed.115.170530 VL - 57 IS - 7 AU - Jörg Schulz AU - Martin Rohracker AU - Marvin Stiebler AU - Jürgen Goldschmidt AU - Oliver S. Grosser AU - Frank Osterkamp AU - Annette Pethe AU - Ulrich Reineke AU - Christiane Smerling AU - Holger Amthauer Y1 - 2016/07/01 UR - http://jnm.snmjournals.org/content/57/7/1120.abstract N2 - Neurotensin receptor-1 (NTR1) is a promising target for diagnostic imaging and targeted radionuclide therapy. The aim of this study was to evaluate the biodistribution profiles of a series of newly developed diarylpyrazole-based NTR1 antagonists regarding their suitability as diagnostic and potentially radiotherapeutic agents. Methods: 3BP-227, 3BP-228, and 3BP-483 were labeled with 111In and injected intravenously into NTR1-positive HT29 xenograft–bearing nude mice. At 3, 6, 12, and 24 h after administration, SPECT/CT images were acquired or mice were sacrificed for ex vivo determination of tissue-associated radioactivity. Results: High-contrast tumor visualization in SPECT/CT images was achieved using the 3 compounds of this study. Ex vivo biodistribution studies confirmed a high and persistent tumor uptake, peaking at 6 h after injection for 111In-3BP-227 (8.4 ± 3.1 percentage injected dose per gram [%ID/g]) and at 3 h after injection for 111In-3BP-228 (10.2 ± 5.3 %ID/g) and 111In-3BP-483 (1.9 ± 0.8 %ID/g). Tumor–to–normal-tissue ratios obtained with 111In-3BP-227 and 111In-3BP-228 were consistently greater than 1. Conclusion: On the basis of the superior biodistribution profile compared with previously reported radiolabeled NTR1 ligands, 111In-3BP-227 is an ideal candidate for further development as a theranostic tracer. ER -