TY - GEN
T1 - Performance of a terbium doped gadolinium oxysulphide plastic optical fiber sensor in a flattening filter free setting
T2 - Optical Fibers and Sensors for Medical Diagnostics and Treatment Applications XIX 2019
AU - Alharbi, Majed
AU - Martyn, Michael
AU - Gillespie, Sean
AU - Woulfe, Peter
AU - O'Keeffe, Sinead
AU - Foley, Mark
N1 - Publisher Copyright:
© COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
PY - 2019
Y1 - 2019
N2 - This paper presents an initial investigation into the depth dependence of an inorganic optical fibre sensor (OFS) based on physical measurements and Monte Carlo (MC) simulations, using a 6 MV flattening filter free (FFF) beam. The OFS was fabricated using an inorganic scintillating material (Gd2O2S:Tb), which was embedded in a cavity of diameter 700 μm, in a 1mm plastic optical fibre. Percentage depth dose (PDD) profiles were measured in a solid water phantom for three field sizes: 10×10 cm2, 4×4 cm2 and 2×2 cm2. The OFS results were then compared to an ion chamber and the W1 plastic scintillator. A MC model of an Elekta Versa HD linear accelerator (linac) was developed using the MC software packages BEAMnrc and DOSXYZnrc and then used to simulate the Gd2O2S:Tb and polystyrene scintillators. The OFS measurements over-estimated the dose when compared to the ion chamber and the W1 measurements, across the investigated field sizes, by a maximum of 30%, 20% and 15% for 10×10 cm2, 4×4 cm2 and 2×2 cm2, respectively. The MC simulations of the Gd2O2S:Tb and polystyrene scintillators were in good agreement with the W1 and ion chamber measurements, however, the OFS measurements were found to differ across all field sizes. Our results therefore indicate the need for further investigation into the overall contribution of the stem effect to the discrepancy between the OFS physical measurements and the ion chamber and the W1 measurements.
AB - This paper presents an initial investigation into the depth dependence of an inorganic optical fibre sensor (OFS) based on physical measurements and Monte Carlo (MC) simulations, using a 6 MV flattening filter free (FFF) beam. The OFS was fabricated using an inorganic scintillating material (Gd2O2S:Tb), which was embedded in a cavity of diameter 700 μm, in a 1mm plastic optical fibre. Percentage depth dose (PDD) profiles were measured in a solid water phantom for three field sizes: 10×10 cm2, 4×4 cm2 and 2×2 cm2. The OFS results were then compared to an ion chamber and the W1 plastic scintillator. A MC model of an Elekta Versa HD linear accelerator (linac) was developed using the MC software packages BEAMnrc and DOSXYZnrc and then used to simulate the Gd2O2S:Tb and polystyrene scintillators. The OFS measurements over-estimated the dose when compared to the ion chamber and the W1 measurements, across the investigated field sizes, by a maximum of 30%, 20% and 15% for 10×10 cm2, 4×4 cm2 and 2×2 cm2, respectively. The MC simulations of the Gd2O2S:Tb and polystyrene scintillators were in good agreement with the W1 and ion chamber measurements, however, the OFS measurements were found to differ across all field sizes. Our results therefore indicate the need for further investigation into the overall contribution of the stem effect to the discrepancy between the OFS physical measurements and the ion chamber and the W1 measurements.
KW - Inorganic Scintillator
KW - Monte Carlo
KW - Optical Fibre Sensor
KW - Percentage Depth Dose.
KW - Radiation Therapy
UR - http://www.scopus.com/inward/record.url?scp=85064873496&partnerID=8YFLogxK
U2 - 10.1117/12.2509441
DO - 10.1117/12.2509441
M3 - Conference contribution
AN - SCOPUS:85064873496
T3 - Progress in Biomedical Optics and Imaging - Proceedings of SPIE
BT - Optical Fibers and Sensors for Medical Diagnostics and Treatment Applications XIX
A2 - Gannot, Israel
A2 - Gannot, Israel
PB - SPIE
Y2 - 2 February 2019 through 3 February 2019
ER -