Speaker
Description
Radiopharmaceutical therapy (RPT) uses radiolabeled agents affine to biomolecules overexpressed in tumor cell environments. This type of treatment has the potential to improve outcomes for oncologic patients due to its ability to target specifically cancerous cells while sparing healthy cells. In radiopharmaceutical research, it is crucial to determine dosimetry for in vitro experiments, and Monte Carlo simulations can assist in achieving this goal.
Within our research group, we have developed a computational tool using the TOPAS Monte Carlo toolkit to model irradiation experiments involving cell layers. We have built a new geometry of a monolayer cell, where the user provides the dimensions of the monolayer and the main geometric features of the cells, assumed as static cylinders in a regular layout. Also, our tool simulates the time evolution of radioactive decays, including the entire decay chain of a given radionuclide. Thus, the computational tool recreates the irradiation conditions by specifying the radionuclide, the initial activity, and the duration of the experiment.
Typically, in-vitro experiments have three separate processes of relevance: the injection of the radionuclide into the culture medium, the binding process of the radiopharmaceutical to a receptor on cell membranes, and internalization process into the cell cytoplasm. Our simulations are correspondingly divided into three static stages: (i) when the radiopharmaceuticals are diluted in the medium, for which we consider uniform distribution of sources; (ii) a second stage when the culture is washed and the medium replaced but no internalization has taken place yet, for which activity comes from cell membranes; and (iii) a final stage with only internalized radioactivity. This approach provides dose and dose rate evolution along the experiment. Future works will aim at including dynamic models of the transitions between these phases.
