MIMC-β: microdosimetric assessment method for internal exposure ofβ-emitters based on mesh-type cell cluster model

Area of Science:

• Radiation dosimetry
• Nuclear medicine
• Radiobiology

Background:

• Monte Carlo (MC) simulations with mesh-type cell models accurately assess beta-emitter cellular dose but are time-consuming.
• Existing methods face efficiency challenges in evaluating complex cellular dose distributions.

Purpose of the Study:

• To develop a rapid and accurate method for assessing cellular dose and relative biological effectiveness (RBE) from beta-emitters using mesh-type cell cluster models.
• To mitigate the computational time associated with traditional MC simulations for internal exposure dosimetry.

Main Methods:

• Proposed a Microdosimetric assessment method for Internal exposure of β-emitters based on Mesh-type Cell cluster models (MIMC-β).
• Applied MIMC-β to evaluate doses in human bronchial epithelial (BEAS-2B), liver (L-O2), and small intestine (FHs74Int) cells exposed to various β-emitters.
• Utilized microdosimetric quantities from cell cluster models to estimate RBE.

Main Results:

• MIMC-β accurately and rapidly predicts cellular doses from different β-emitters, with discrepancies below 5% compared to PHITS simulations.
• Cellular cluster overall S-values showed minimal deviation (1.35% minimum).
• RBE estimations based on lineal energy for Cs-134, Cs-137, and I-131 were close to C-14, indicating negligible differences in average lineal energy.

Conclusions:

• MIMC-β significantly improves efficiency for cellular dose assessment of β-emitters compared to direct MC simulations.
• The method provides accurate RBE estimations, offering insights into radiobiological damage from internal β-emitter exposure.
• MIMC-β is extendable to diverse cell types and β-emitters, with applications in radiation protection and radioligand therapy.