  Organized by the European Radiation Dosimetry Group (EURADOS), a Monte Carlo
code intercomparison exercise was conducted where participants simulated the
emitted electron spectra and energy deposition around a single gold
nanoparticle (GNP) irradiated by X-rays. In the exercise, the participants
scored energy imparted in concentric spherical shells around a spherical volume
filled with gold or water as well as the spectral distribution of electrons
leaving the GNP. Initially, only the ratio of energy deposition with and
without GNP was to be reported. During the evaluation of the exercise, however,
the data for energy deposition in the presence and absence of the GNP were also
requested. A GNP size of 50 nm and 100 nm diameter was considered as well as
two different X-ray spectra (50 kVp and 100kVp). This introduced a redundancy
that can be used to cross-validate the internal consistency of the simulation
results. In this work, evaluation of the reported results is presented in terms
of integral quantities that can be benchmarked against values obtained from
physical properties of the radiation spectra and materials involved. The impact
of different interaction cross-section datasets and their implementation in the
different Monte Carlo codes is also discussed.
