Radiopharmaceutical therapy (RPT) is based on the use of radiolabeled agents affine to antigens overexpressed in tumor cell environments. This type of treatment has the potential to improve outcomes for oncologic patients due to its ability to concentrate radiation in a small environment around the tumor.
This phenomenon is based on the much higher linear energy transfer (LET) of the alphas emitted together with their considerably shorter range as compared to beta emissions. In this work, we studied how the microdosimetric quantities are affected by the displacement of the cell nucleus and variations in its radius. Interestingly, microdosimetry can help in the assessment of the biological effect of these particles to fully take advantage of the features mentioned above.
Previously, an analytic algorithm was developed upon which microdosimetric quantities (yF, yD, zF, zD) were calculated for spherical cells whose membrane acted as uniform source [Bertolet et al. Radiat. Res. (2020)]. Besides exploring the influence of the eccentricity and radius of the nucleus, the analytic model was tested under these conditions.
To calculate the distribution of these microdosimetric quantities, Monte Carlo simulations were run with Geant4-DNA. Our preliminary results show that the microdosimetry quantities are not affected significantly by the cell nucleus position, while the dependence on the nucleus radius is clearly more significant. The analytical method agrees reasonably well with the Geant4 simulations.