RT Journal Article SR Electronic T1 Cyclotron-Produced 132La as a PET Imaging Surrogate for Therapeutic 225Ac JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1012 OP 1015 DO 10.2967/jnumed.120.255794 VO 62 IS 7 A1 Eduardo Aluicio-Sarduy A1 Todd E. Barnhart A1 Jamey Weichert A1 Reinier Hernandez A1 Jonathan W. Engle YR 2021 UL http://jnm.snmjournals.org/content/62/7/1012.abstract AB The aim of this work was to explore 132La as a PET imaging surrogate for 225Ac using a DOTA-based, tumor-targeting alkylphosphocholine (NM600). Methods: 132La was produced on a biomedical cyclotron. For in vivo experiments, mice bearing 4T1 tumors were administered 132La-NM600, and PET/CT scans were acquired up to 24 h after injection. After the last time point, the ex vivo tissue distribution was measured to corroborate the in vivo PET data. The ex vivo tissue distribution in mice was determined at 4 and 24 h after injection of 225Ac-NM600. Results: PET/CT images showed elevated, persistent 132La-NM600 uptake in the tumor. Low bone accumulation confirmed the in vivo stability of the conjugate. Ex vivo biodistribution studies validated the image-derived quantitative data, and the comparison of the 132La-NM600 and 225Ac-NM600 tissue distributions revealed a similar biodistribution for the 2 radiotracers. Conclusion: These findings suggest that 132La is a suitable imaging surrogate to probe the in vivo biodistribution of 225Ac radiotherapeutics.