Lineal Energy or Linear Energy Transfer? A comparative study using an SOI microdosimeter and a Timepix3 detector in a Helium‐ion pristine peak

作者：Yasmin Hamad, Sandra Barna, Tim Gehrke, Andrea Mairani · 发表于：Precision Radiation Oncology · 年份：2026 · DOI：10.1002/pro6.70066 · 研究领域：Radiation Therapy and Dosimetry、Advanced Radiotherapy Techniques、Effects of Radiation Exposure

Characterizing radiation quality in radiotherapy is essential for accurately assessing radiobiological effects, yet it remains a significant challenge. Linear Energy Transfer (LET) is a commonly used metric for quantifying radiation quality. However, microdosimetry offers a valuable alternative, by providing a more precise description of the energy deposition at the cellular level. While microdosimetry has a rich history of experiments in different radiation fields, LET measurements—rather than relying on calculations or simulations—is a novel attempt. This study compares radiation quality assessments performed with two silicon-based detectors with distinct geometries: The mushroom silicon-cylinder microdosimeter developed at the University of Wollongong and the hybrid pixel Timepix3 detector equipped with a 300 µm-thick silicon sensor. Both detectors were irradiated with a monoenergetic 149 MeV/u helium-ion beam. LET probability density distributions and lineal energy spectra were recorded at various depths along the Bragg curve using PMMA slabs. Although both detectors are made of silicon, their differing geometries, sensor thicknesses, and detection principles lead to notable variations in their energy deposition spectra. The results are analyzed with a focus on spectral resolution, energy spectrum shape, and low- and high- tail behavior. Experimental data are supported by Monte Carlo simulations performed using the FLUKA code to validate and interpret the measurements. Th...