Tissue equivalent conversion of silicon-based microdosemeters in hadron therapy

Area of Science:

• Medical Physics
• Radiation Dosimetry
• Materials Science

Background:

• Silicon microdosimeters offer advantages like small sensitive volumes and low power consumption.
• Accurate tissue dose assessment requires converting silicon's energy response to tissue-equivalent response.
• Existing spectral conversion methods need refinement for silicon-based microdosimetry.

Purpose of the Study:

• To develop and validate a method for converting microdosimetric energy deposition spectra from silicon to tissue.
• To assess the accuracy and limitations of the proposed spectral conversion technique.
• To identify areas for improvement in silicon microdosimetry for radiation applications.

Main Methods:

• Scaled Fourier transformation and geometric scaling factor for spectral conversion.
• Validation using previously reported spectral conversion data from diamond to tissue.
• Analysis of discrepancies between converted and actual spectra in different regions of the Bragg curve.

Main Results:

• The scaled Fourier transformation method demonstrated proper accuracy in converting silicon microdosimetry spectra to tissue-equivalent spectra.
• Inconsistencies were observed, primarily due to silicon's inherent poor tissue equivalence.
• Discrepancies were attributed to the plateau region (tissue equivalence) and proximal region (spectral shape differences).

Conclusions:

• The developed method is applicable for tissue-equivalent conversion of silicon microdosimetry data.
• Silicon's limited tissue equivalence is a key factor affecting the accuracy of the conversion.
• Further corrections for spectral shape differences are necessary to enhance the method's practicality.