Cross-section-based scaling method for material-specific cluster dose calculations - a proof of concept.

Area of Science:

• Medical Physics
• Radiation Dosimetry
• Computational Biology

Background:

• Track structure simulation software lacks cross-section data for non-water materials.
• Current nanodosimetric quantity transformations rely on water-based data.
• Existing mass-density-based scaling methods yield unrealistic, material-independent cluster dose equations.

Purpose of the Study:

• To develop and validate a new scaling method for nanodosimetric quantity transformation.
• To address the limitations of mass-density-based scaling in track structure simulations.
• To enable accurate cluster dose calculations in heterogeneous materials for radiotherapy.

Main Methods:

• Introduced a novel scaling method using material-specific ionization cross-sections.
• Utilized the mean free path ratio of primary particles and secondary electrons as the scaling factor.
• Performed cluster dose calculations for a carbon ion beam in a realistic head geometry.

Main Results:

• The cross-section-based scaling method produced physically realistic increases in cluster dose for denser materials.
• This contrasts with the previous mass-density-based approach, which showed material-independence.
• Demonstrated improved accuracy for nanodosimetric calculations in heterogeneous environments.

Conclusions:

• The proposed cross-section-based scaling method offers a physically sound approach for nanodosimetry.
• This method is crucial for accurate cluster dose distribution determination in heterogeneous geometries.
• The approach facilitates the integration of nanodosimetry into radiotherapy treatment planning.