Cell survival responses after exposure to modulated radiation fields

Area of Science:

• Radiobiology
• Cellular Biology
• Radiation Oncology

Background:

• Modulated radiation fields create dose gradients, impacting cell survival both within and outside the primary treatment area.
• Intercellular communication plays a critical role in cellular responses to radiation, particularly in non-uniform dose distributions.

Purpose of the Study:

• To investigate cell survival responses in modulated radiation fields across various human cell lines with differing radiosensitivities.
• To elucidate the role of intercellular communication and radiosensitivity in out-of-field effects.

Main Methods:

• Exposure of primary fibroblast, breast cancer, prostate cancer, and glioma cells to modulated radiation fields.
• Assessment of cell survival in shielded (out-of-field) and unshielded (in-field) regions.
• Inhibition of intercellular communication using blocking agents and pretreatment with bystander signaling inhibitors.

Main Results:

• A significant decrease in cell survival was observed in the out-of-field regions, lower than predicted by the linear-quadratic model.
• Cellular radiosensitivity influenced the magnitude of the in- and out-of-field responses.
• Inhibiting intercellular communication abrogated the out-of-field survival response, which could be increased by blocking bystander signaling pathways.

Conclusions:

• Intercellular communication is crucial for out-of-field effects in modulated radiation fields.
• Radiosensitivity is a key determinant of cellular response in both in- and out-of-field regions.
• Findings may inform the refinement of radiobiological models for advanced radiotherapy planning.