Fuente: PubMed "nature biotechnology" EJNMMI Radiopharm Chem. 2026 Apr 1;11(1):22. doi: 10.1186/s41181-026-00442-2.ABSTRACTBACKGROUND: Current methods for assessing radiopharmaceutical uptake are based on scintillation counting (e.g., γ-counting) or imaging techniques, such as positron emission tomography (PET) and single photon emission computed tomography (SPECT), which evaluate the average radiopharmaceutical uptake in biological samples. Single-cell analysis of radiopharmaceutical uptake and biodistribution would provide a better understanding of the possible heterogeneous uptake in cellular populations and organs, with the potential to improve current dosimetry and toxicity assessments. In this proof-of-concept study, we evaluate the use of mass cytometry (CyTOF) as an analytical tool to study the uptake of non-radioactive radiopharmaceutical surrogates at the single-cell level.RESULTS: The preclinical immunoconjugate DOTA-cAC10, targeting CD30 (a receptor overexpressed in lymphomas), was labeled either with radioactive lutetium-177 (177Lu) resulting in the [177Lu]Lu-DOTA-cAC10 radioimmunoconjugate, or stable lutetium-175 (175Lu), yielding the surrogate [175Lu]Lu-DOTA-cAC10. For CyTOF experiments, cells were incubated with the stable surrogate and an iridium DNA intercalator (Cell-ID™) to enable concurrent determination of immunoconjugate uptake and cell identification. CyTOF analysis of the surrogate was performed in three T-cell lymphoma cell lines with varying CD30 expression (Karpas 299, Myla and Jurkat) and compared to γ-counting data obtained for the radioimmunoconjugate. Radioimmunoconjugate [177Lu]Lu-DOTA-cAC10 cellular uptake studies by γ-counting showed receptor-dependent accumulation, with Karpas 299 cells exhibiting the highest uptake levels (32.5 ± 1.6% of total added activity), followed by Myla (20.0 ± 1.0%) and Jurkat cells (15.7 ± 1.2%). Mass cytometry enabled analysis of the stable surrogate [175Lu]Lu-DOTA-cAC10 uptake at single-cell resolution, revealing median signal intensities of 175Lu of 32.2, 14.0, and 2.94 a.u. for Karpas 299, Myla, and Jurkat cells, respectively.CONCLUSIONS: The sensitivity of CyTOF enabled discrimination of uptake between cell models even at low metal-to-antibody stoichiometric ratios. It also revealed intercellular variability in uptake that can only be captured with single-cell methods. Overall, we showed that CyTOF is a robust, high-throughput, multiplexed approach for characterizing the cellular uptake of stable radiopharmaceutical surrogates at single-cell resolution, paving the way for future studies.PMID:41920435 | DOI:10.1186/s41181-026-00442-2