Publication
Catalytic activity imperative for nanoparticle dose enhancement in photon and proton therapy.
Journal Paper/Review - Jun 6, 2022
Gerken Lukas R H, Weber Damien C, Plasswilm Ludwig, Meer David, Psoroulas Serena, Schiefer Johann, Gerdes Maren E, David Helena, Starsich Fabian H L, Gogos Alexander, Herrmann Inge K
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PubMed
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Journal
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Issn Electronic
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Brief description/objective
Nanoparticle-based radioenhancement is a promising strategy for extending the therapeutic ratio of radiotherapy. While (pre)clinical results are encouraging, sound mechanistic understanding of nanoparticle radioenhancement, especially the effects of nanomaterial selection and irradiation conditions, has yet to be achieved. Here, we investigate the radioenhancement mechanisms of selected metal oxide nanomaterials (including SiO, TiO, WO and HfO), TiN and Au nanoparticles for radiotherapy utilizing photons (150 kVp and 6 MV) and 100 MeV protons. While Au nanoparticles show outstanding radioenhancement properties in kV irradiation settings, where the photoelectric effect is dominant, these properties are attenuated to baseline levels for clinically more relevant irradiation with MV photons and protons. In contrast, HfO nanoparticles retain some of their radioenhancement properties in MV photon and proton therapies. Interestingly, TiO nanoparticles, which have a comparatively low effective atomic number, show significant radioenhancement efficacies in all three irradiation settings, which can be attributed to the strong radiocatalytic activity of TiO, leading to the formation of hydroxyl radicals, and nuclear interactions with protons. Taken together, our data enable the extraction of general design criteria for nanoparticle radioenhancers for different treatment modalities, paving the way to performance-optimized nanotherapeutics for precision radiotherapy.