The current widely accepted relationship between LET and RBE is based on the DNA structure. However, when we want to inactivate an RNA virus such as SARS-CoV-2 with different particles (and different LETs), this model would not be valid as in the case of DNA, the model is based on 20 Angstrom separation between strands and the density of ionization events (attached figure). So, the question is whether a linear model is more appropriate for RNA? I mean, whether higher LET radiations cause higher RBEs in a linear model?
A widely known relationship between LET and RBE is based on cellular clonogenic survival (mostly at 10% survival dose), rather than DNA damage itself, although irreparable DNA damage (complex clustered DNA damage in particular) plays a pivotal role in cytocidal effects.
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For low-LET radiation, extremely high dose (>10 kGy) is reportedly needed to inactivate SARS-CoV and MERS-CoV. As such, ionizing radiation including high-LET radiation does not possess high efficiency for such purposes.
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https://pubmed.ncbi.nlm.nih.gov/30860018/
https://pubmed.ncbi.nlm.nih.gov/26190637/
Ionizing radiation-induced RNA damage was briefly discussed, and Dr Alexandros G. Georgakilas may have additional thoughts.
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Dear Professor Nobuyuki Hamada Thank you for your thoughtful answers. As you mentioned, extremely high doses (tens of kGy) are needed to inactivate SARS-CoV -2. However, we plan to use Geant-DNA to evaluate the potential damages in virus spikes and RNA. So the basic question is whether the Geant-DNA considers the relationship between LET and RBE based on DNA damage or as you wrote, based on other parameters?