The minimum Do for cell killing for alpha-particle emitters uniformly distributed in an extended medium

Area of Science:

• Radiation Biology
• Cellular and Molecular Biology
• Physics in Medicine

Background:

• Assessing alpha particle-induced cell death requires linking damage to nuclear passage.
• Current methods lack a simple test to attribute cell killing directly to alpha particle traversals through cell nuclei.

Purpose of the Study:

• To establish a calculable threshold dose (D0) for cell killing attributable to alpha particle nuclear passage.
• To determine the minimum possible D0, representing the average dose per hit when 63% of nuclei are targeted.

Main Methods:

• Modeling uniform alpha particle source distribution and spherical cell nuclei.
• Calculating D0 based on achieving at least one alpha particle passage per nucleus for 63% of cells.
• Utilizing Monte Carlo simulations for minimum D0 calculations.

Main Results:

• A D0 was calculated where 63% of cell nuclei experience at least one alpha particle passage.
• The average dose for 63% of nuclei to be hit equals the average dose per hit.
• Minimum D0 values were computed for nuclear diameters (4-10 µm) and alpha particle energies (3.18-8.38 MeV).

Conclusions:

• This D0 represents the minimum possible, where any energy deposition results in cell death.
• The findings provide a quantitative basis for attributing cell killing to alpha particle nuclear interactions.
• The study offers a novel approach for radiobiological research involving alpha particle emitters.