Characterization of the Radioluminescence Response of Ge-Doped Silica Fibers for ۶ MV Radiotherapy Beam Profile Dosimetry

Introduction: Accurate radiation dose measurement in both target and non-target tissues is essential in modern external beam radiotherapy. In dosimetry systems, the goal is to deliver the maximum dose to the target volume while ensuring minimal exposure to the surrounding normal cells. Among various medical dosimetry systems like thermoluminescence (TL), optically stimulated luminescence (OSL), and radioluminescence (RL), the RL system offers a real-time monitoring system.Material and Methods: This study aims to characterize the Ge-doped probe in making beam profile measurements using the myDoz® RL/OSL dosimetry system and comparing its accuracy with a CC-۱۳ ion chamber. The RL system utilized a ۳۰-meter PMMA optical fiber with a Ge-doped optical fiber scintillator probe. Beam profiles were measured for ۳ × ۳ and ۱۰ × ۱۰ cm² field sizes at a depth of ۱.۵ cm in solid water, with a source-to-surface distance (SSD) of ۱۰۰ cm, using a ۶ MV photon beam, ۴۰۰ MU/min dose rate, and a total dose of ۳ Gy.Results: The RL readout mechanism enabled instantaneous dose and dose-rate readings. The results showed high consistency and close agreement with the CC-۱۳ ion chamber, with beam profiles displaying uniform central dose, sharp penumbra, and strong symmetry. Larger fields exhibited increased flatness due to photon dispersion. Moreover, the dose distribution out-of-field may still cause low-dose exposure to normal tissues.Conclusion: To sum up, Ge-doped fibers demonstrated excellent real-time, high-resolution performance, making them promising alternatives to traditional dosimeters. Future research should focus on clinical implementation and system optimization for advanced radiotherapy methods.

کلیدواژه ها:

In ، Vivo Dosimetry Radioluminescence Ge ، Doped Silica Fiber Beam Profile Flatness LINAC