An estimation of cell survival in targeted radionuclide therapy using Geant4-DNA and microdosimetric kinetic model

Abstract

  Targeted radionuclide therapy (TRT) with Auger and alpha nuclides is one of a promising radiation therapies. To enhance treatment effects while minimizing radiation exposure for normal tissue, determining adequate dose is essential. Microdosimetric kinetic (MK) model which is used for treatment planning of a heavy ion therapy is also useful for estimating cell survival in TRT The model is based on dosimetry in small regions. To calculate the microdosimetry, we used Geant4-DNA which is a toolkit modeling of early biological damage by ionizing radiation at the DNA scale. Using the MK model and Geant4-DNA, we estimated cell survivals as a function of the time in cases of the ¹¹¹In (Auger) and ²¹¹At (alpha), where a Monte Carlo method with the MK model assumptions dedicated for the TRT was developed. We compared cell survivals between RI remained at cell membrane and nucleus. Also we estimated survivals considering dynamics of radioactive pharmaceuticals based on a compartmental model. In this work, we showed cell survivals in TRT and the effectiveness of ²¹¹At quantitatively. However some compartmental model parameters which should be determined by same experiments and validations of the simulation are needed for the accurate estimations.