Erratum: Determining dose enhancement factors of high-Z nanoparticles from simulations where lateral secondary particle disequilibrium exists (Physics in Medicine and Biology (2019)64 (155016) DOI: 10.1088/1361-6560/ab31d4).
In our paper (Rabus et al 2019) we presented a procedure to determine the dose enhancement factors (DEFs) for gold nanoparticles (GNPs) for an extended photon radiation field from simulations with narrow beam geometries. In the context of different work, it has become evident that there has been an error in the ROOT software routine used for processing the simulation data for the purpose of our article. More precisely, in the command line where the deposited energy obtained from the simulation was converted to the energy density in the spherical shells used for scoring, the volume of the spherical shells was implemented as (Formula Presented) Using integers in the factor 4/3 in the first bracket leads to an integer output, i.e. 1 instead of 1.3333… In consequence, the values shown as simulation results in figure 5 of our paper were enhanced by a factor of 4/3 and so were the values for the dose enhancement factors for an extended photon field in figures 6 and 7. The corrected figures are presented below. Furthermore, we noted the following typos in the article: • A wrong sign in the denominator on the right-hand side of equation (4). The correct expression is (Formula Presented). In producing the data for figures 7 and 9, the correct equation as given above was used, however. • In the paragraph on page 7 below equation (12), it should read ‘… is on the order of 1/3 (µr)2. … z in equation (11) …’ • In the Conclusion, the second recommendation should read ‘… as given in equation (8). …’ Correcting the identified data processing error leads to a reduction of the predicted DEF for GNPs irradiated with an extended field of diagnostic x-rays by a factor of ¾. In consequence, the conclusions of our publication (regarding the magnitude of the DEFs for an extended beam and the limited radial range where significant DEFs occur) remain.(Figure Presented).