Objective:

To simulate RBE patterns in two cancers and one normal tissue for neutrons and protons, addressing the inverse relationship between dose and RBE attributed to hypoxia, which may have significant implications for treatment strategies.

Key Findings:

• Three distinct RBE responses were fitted for normal skin and two cancer types, with specific metrics indicating the degree of variation.
• Overall RBE initially follows the oxic curve but shifts to the hypoxic curve with increasing dose, suggesting a critical threshold.
• Similar RBE changes were observed for protons, but not solely from the dose rate effect, indicating other influencing factors.

Interpretation:

The study suggests that the observed RBE patterns in neutron studies can be simulated by considering hypoxic and oxic compartments, with significant implications for optimizing proton therapy strategies.

Limitations:

• The model's complexity may limit its practical application without further experimental validation, particularly in clinical settings.
• Further research is needed to confirm RBE effects of protons at similar dose ranges, which could influence treatment protocols.

Conclusion:

The findings indicate potential for hypo-fractionated proton therapy applications, warranting further experimental research.