Monte Carlo investigation of Ge-doped silica fiber detectors for precision small field dosimetry
Year: 2025
Type: article
Abstract: Accurate dosimetry in small radiation fields remains a critical challenge in modern radiotherapy due to high dose gradients and limited detector spatial resolution. This study investigates the dosimetric performance of Ge-doped silica fiber radioluminescence (RL) detectors for small field measurements through Monte Carlo simulations using the TOPAS tool. Reference data from IAEA database were utilized for implementation of small radiation fields and validation, by comparing experimental beam profile and depth dose measurements for various field sizes. Quality dependence factors (QDFs) were calculated based on the formalism of the IAEA-AAPM working group, considering a Varian Clinac iX linear accelerator with a 10×10 cm 2 reference field and various small fields of 0.5×0.5 cm 2 , 1×1 cm 2 , 2×2 cm 2 and 4×4 cm 2 . The study explored different fiber detector diameters from 125 μm to 2 mm to optimize spatial resolution for small field dosimetry. Simulated electron spectra in various situations were analyzed in both water and fiber volumes to understand reasons behind detector response variations. Notably, the detector diameter significantly influenced quality dependence, with competing effects between energy dependence and a field size dependent spectral discrepancy leading to an optimal balance at a 0.5 mm fiber diameter. Calculated QDFs aligned well within the range reported for other detector types, supporting the applicability of Ge-doped silica fiber RL detectors for precise dose measurements in small radiation fields, offering a potential alternative for advanced radiotherapy applications.
Source: Radiation Measurements
Language: English
Subfield: Radiation
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,690
Funders: Google, Telekom Malaysia Berhad
Awards: G2225160598, G7136930602
OpenAlex ID: W4415727022