Cluster effects within the local effect model

Area of Science:

• Radiation Biology
• Radiobiology
• Medical Physics

Background:

• The local effect model (LEM) is crucial for predicting relative biological effectiveness (RBE) in radiation therapy.
• Accurate RBE prediction requires precise modeling of DNA damage, particularly double-strand breaks (DSBs).
• Existing models may not fully capture nanoscale DNA damage complexities.

Purpose of the Study:

• To extend the local effect model by incorporating nanoscale cluster effects of single-strand breaks (SSBs).
• To improve the accuracy of RBE predictions for different ions and cell lines.
• To enhance the understanding of DNA damage-induced cell lethality.

Main Methods:

• Utilized experimental photon data for SSB and DSB yields.
• Employed a Monte Carlo method to simulate DNA damage distribution.
• Defined and scored clustered SSBs (within 25 bp) as additional DSBs.
• Derived a modified cell survival curve accounting for SSB cluster effects.

Main Results:

• The extended LEM, including SSB cluster effects, demonstrates improved agreement with experimental data.
• The model shows enhanced accuracy in predicting cell survival compared to the original LEM.
• Incorporating nanoscale cluster effects refines RBE predictions.

Conclusions:

• The extended local effect model provides a more accurate prediction of RBE by accounting for SSB clustering.
• This enhancement improves the simulation of cell lethality based on DSB induction.
• The improved model offers greater precision for radiation therapy planning and research.