ZnSe Nanowire Optically Stimulated Luminescence for Accurate Radiation Dosimetry In Radiotherapy
Abstract
Purpose
Accurate radiation dosimetry is critical for patient safety and treatment quality in radiotherapy. Conventional thermoluminescent dosimeters have limitations in re-readability and flexibility. This study aims to explore ZnSe nanowire-based optically stimulated luminescence dosimeters (OSLDs) as a novel solution, leveraging defect-engineered nanostructures to achieve precise, repeatable dose measurements suitable for wearable and adaptable applications in radiotherapy.
Methods
ZnSe nanowires were synthesized using controlled growth techniques to optimize deep-trap formation essential for OSL. These nanowires were integrated into prototype OSLDs fabricated on biocompatible substrates. Experimental characterization was conducted under clinically relevant conditions using an 18 MV photon beam from a Varian TrueBEAM linear accelerator. Optical measurements included steady-state photoluminescence (PL) before and after irradiation to assess trap activation, and time-resolved OSL decay analysis to evaluate luminescence kinetics. Dose–response behavior was quantified across the 0–1 Gy range to determine linearity and sensitivity.
Results
PL spectra revealed a significant increase in the donor–acceptor emission peak at ~630 nm post-irradiation, confirming activation of radiation-sensitive deep traps while near-band-edge emission remained stable. Time-resolved OSL decay curves exhibited bi-exponential behavior with two components: a fast free-carrier term and a slower deep-trap term. OSL lifetimes decreased with increasing dose (≈400 ms to ≈250 ms), indicating dose-dependent kinetics. Moreover, a strong linear correlation between inverse OSL lifetime and dose was observed, validating proportionality and enabling quantitative dose estimation.
Conclusion
Prototype ZnSe nanowire OSLDs demonstrated clear radiation sensitivity, reproducible dose-dependent luminescence, and linear dose–response under clinical photon beams. These findings confirm the underlying mechanism for accurate dose readout and highlight the potential of nanowire-based OSLDs as flexible, re-readable, and precise dosimetry tools for radiation safety and device quality assurance in radiotherapy. Future work will focus on optimizing device architecture and extending testing to broader dose ranges and clinical scenarios.