Comparison of the Measurement Uncertainty of Thermoluminescence Dosimeters (TLD-۱۰۰ and GR-۲۰۰) in Clinical Radiotherapy Energies

Background: Accurate determination of individual radiation doses is critical in dosimetry, and international standards emphasize the importance of reporting measurement uncertainties. Neglecting measurement uncertainty undermines the reliability of reported dosimetric values, as emphasized by international standards.Objective: This study aimed to evaluate the measurement of uncertainties in two Thermoluminescent Dosimeters (TLDs)-۱۰۰ and GR-۲۰۰, in the dose range of ۳۰–۱۵۰ cGy.Material and Methods: In this experimental study, we evaluated the measurement of uncertainties in two thermoluminescent dosimeters, TLD-۱۰۰ and GR-۲۰۰, in the dose range of ۳۰–۱۵۰ cGy. The study investigated both random (Type A) and systematic (Type B) uncertainties. Random uncertainties include the non-uniformity of dosimeter sensitivity Element Correction Coefficient (ECC), variability in dosimeter response at zero dose, and repeatability. Systematic uncertainties include the dependence of dosimeter response on radiation energy, radiation angle, nonlinearity of dosimeter response, fading, ambient light effects, and reference calibration errors.Results: The total uncertainty for TLD-۱۰۰ was calculated as ۱۰.۹۹% at a ۶۸% confidence level (۲۱.۹۹% at ۹۵% confidence), while for GR-۲۰۰, it was ۱۳.۶۳% at a ۶۸% confidence level (۲۷.۲۶% at ۹۵% confidence). These values are well below the ۴۲% threshold recommended by the International Atomic Energy Agency (IAEA) for personal dosimetry services. Conclusion: The GR-۲۰۰ exhibits higher sensitivity for low-dose radiation detection; however, its greater uncertainty makes TLD-۱۰۰ more suitable for clinical and personal dosimetry applications, where precision and reliability are paramount.

کلیدواژه ها:

Radiotherapy ، Uncertainty ، Thermoluminescent Dosimetry ، TLD-۱۰۰ ، GR-۲۰۰