Characterisation of sensitive Ge-doped silica flat fibre-based thermoluminescence detectors for high resolution radiotherapy dosimetry

10th International Seminar on Medical Physics; 1st AMDI International Oncology Symposium

物理学;医药卫生

Rahim, A. R. Abdul^1 ; Zahaimi, N.A.^1 ; Zin, H.M.^2 ; Bradley, D.A.^3 ; Mahdiraji, G.A.^4 ; Rahman, A. T. Abdul^1,3,5

School of Physics and Material Studies, Faculty of Applied Sciences, Universiti Teknologi MARA, Selangor, Shah Alam

40450, Malaysia^1

Radiotherapy and Oncology Department, Advanced Medical and Dental Institute Malaysia, Universiti Sains Malaysia, Bertam, Penang

13200, Malaysia^2

Centre for Nuclear and Radiation Physics, Department of Physics, University of Surrey, Guildford, Surrey

GU2 7XH, United Kingdom^3

School of Engineering, Taylor's University, Selangor Darul Ehsan, Subang Jaya

47500, Malaysia^4

Institute of Science, Universiti Teknologi MARA, Selangor Shah Alam

40450, Malaysia^5

关键词: Clinical radiotherapy;    Confidence levels;    Photon irradiation;    Radiation dosimeters;    Radiation therapy dosimetry;    Reproducibilities;    Standard error of the means;    Thermoluminescence detectors;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/851/1/012024/pdf
DOI  :  10.1088/1742-6596/851/1/012024

学科分类：卫生学

来源: IOP

【 摘 要 】

Present study focuses on characterisation of SiO2optical fibers as a potential thermoluminescence (TL) system for radiation therapy dosimetry. Irradiations were made using 6 MV photon beams from a linear accelerator. Flat SiO2optical fibers of various dimensions with 8% concentration of germanium doped were used. The dimensions of the flat fibers were 270x60 μm, 360x73 μm, 100x510 μm and 160x750 μm. Flat SiO2optical fibers were characterised for TL dose response in terms of linearity, sensitivity, fading and reproducibility. The uncertainty measured was ±1 standard error of the mean and the coefficient variation was within ±4%, as required for clinical radiotherapy dosimetry. Results shown a good distribution of TL response measured by flat SiO2optical fibers with uncertainties less than 4%. Linearity of TL comes out with a coefficient of determination (r2) of each fibers that is better than 99% which resulted in high percentage of confidence level. The loss of TL response due to fading, for photon irradiation at fixed energy and constant dose was found to be (20.4 ± 0.2)% over a post irradiation period of 30 days. The TL fading well, showing rapid loss in the first seven (7) days (17.8 ± 0.2)% followed by a more linear like loss subsequently the following day (3.2 ± 0.2)%. A perfect selection of fibers can enhance the accuracy of radiation dosimeter in order for better determination and measurement of radiation doses with a linear response over wide range therapeutic dose.