Comment on "Reproducibility study of Monte Carlo simulations for nanoparticle dose enhancement and biological modeling of cell survival curves" by Velten et al [Biomed Phys Eng Express 2023;9:045004].

This comment highlights two methodological issues with the recent article by Velten et al [Biomed Phys Eng Express 2023;9:045004]: First, the approach taken in this work with a local effect model (LEM) in 2D leads to a significant overstimation of the number of radiation-induced lesions. This results in order of magnitude smaller predicted survival rates compared to the conventional LEM. Second, the dose without nanoparticles is used as the 'macroscopic dose' against which cell survival is plotted. However, for the considered gold concentrations, the average absorbed dose under secondary particle equilibrium is between 2 and 20 times higher with nanoparticles than without.