MONTE CARLO DOSE DISTRIBUTION CALCULATION AT NUCLEAR LEVEL FOR AUGER-EMITTING RADIONUCLIDE ENERGIES
The distribution of radiopharmaceuticals in tumor cells represents a fundamental aspect for a successful molecular targeted radiotherapy. At microscopic level only a fraction of cells in tumoral tissues incorporate the radiolabel. The most used method to perform cellular dosimetry is the MIRD one, where absorbed doses are calculated for several electron energies, nucleus diameters, and for homogeneous source distributions. However, the radionuclide distribution inside nuclei can be highly non-homogeneous.
The GPSR researchers developed a study to show to what extent a non-accurate cellular dosimetry could lead to misinterpretations of surviving cell fraction vs dose relationship; the modelling of realistic radionuclide localization inside cells (for 99mTc radionuclide), including a inhomogeneous nuclear distribution, revealed that i) a strong bias in surviving cell fraction vs dose relationships (taking into account different radiobiological models) can arise; ii) alternative models might contribute to accurate prediction of the radiobiological effects inherent to specific molecular targeted radiotherapy strategies.