Radiolabelled puromycin analogues will allow the quantification of protein synthesis through nuclear medicine-based imaging. A particularly useful application could be the non-invasive longitudinal visualisation of mycobacterial activity through direct quantification of puromycin binding. This study assesses the value of [68Ga]Ga-DOTA-puromycin in the visualisation of mycobacteria through positron emission tomography combined with magnetic resonance imaging (µPET/MRI). The radiopharmaceutical was produced by previously published and validated methods. [68Ga]Ga-DOTA-Puromycin imaging was performed on severe immunodeficient mice infected with Bacille Calmette-Guérin-derived M. Bovis (BCG). Acute and chronic infection stages were examined by µPET/MRI. A follow-up group of animals acted as controls (animals bearing S. aureus-derived infection and sterile inflammation) to assess tracer selectivity. [68Ga]Ga-DOTA-puromycin-µPET/MRI images revealed the acute, widespread infection within the right upper shoulder and armpit. Also, [68Ga]Ga-DOTA-puromycin signal sensitivity measured after a 12-week period was lower than that of [18F]FDG-PET in the same animals. A suitable correlation between normalised uptake values (NUV) and gold standard histopathological analysis confirms accurate tracer accumulation in viable bacteria. The radiopharmaceutical showed infection selectivity over inflammation but accumulated in both M. Bovis and S. Aureus, lacking pathogen specificity. Overall, [68Ga]Ga-DOTA-puromycin exhibits potential as a tool for non-invasive protein synthesis visualization, albeit without pathogen selectivity.

• Keywords
• Fluorodeoxyglucose, Gallium-68, Molecular imaging, Mycobacterium tuberculosis, Positron emission tomography/magnetic resonance imaging,
• MeSH
• Heterocyclic Compounds, 1-Ring chemistry   MeSH
• Magnetic Resonance Imaging * methods   MeSH
• Mycobacterium bovis * MeSH
• Mycobacterium Infections diagnostic imaging   microbiology   MeSH
• Mice, SCID MeSH
• Mice MeSH
• Organometallic Compounds MeSH
• Positron-Emission Tomography * methods   MeSH
• Radiopharmaceuticals * chemistry   MeSH
• Gallium Radioisotopes * MeSH
• Tuberculosis diagnostic imaging   microbiology   metabolism   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Heterocyclic Compounds, 1-Ring MeSH
• Organometallic Compounds MeSH
• Radiopharmaceuticals * MeSH
• Gallium Radioisotopes * MeSH