Investigation of the dosimetric characteristics of radiophotoluminescent glass dosimeter for high-energy photon beams

Abstract

The aim of this work was to investigate the dosimetric characteristics of radiophotoluminescent glass dosimeter (RPLGD) for high energy photon beams in both flattening filter mode and flattening filter free (FFF) mode. The dosimetric characteristics of RPLGD model GD-302M were studied in 6 MV photon beams for the reproducibility of dosimeter reader, uniformity and reproducibility of RPLGD, dose linearity (range from 1 to 20 Gy), repetition rate, and angular dependence. In addition, the energy responses were observed in flattening filter mode (6 MV, 10 MV, and 15 MV) from Varian Clinac Cseries and FFF mode (6 MV_FFF and 10 MV_FFF) from Varian TrueBEAM system. The FGD-1000 reader system exhibited stable readout. The entire number of 100 RPLGDs showed good uniformity and reproducibility within ±1.5%. Furthermore, the signal from RPLGD demonstrated a linear proportion to the radiation dose (r = 0.999), and no energy dependence was observed. For repetition rate response of flattening filter mode and FFF mode, the maximum error of relative response to 400 MU/min were 0.977 ±0.006 and 0.986±0.017, respectively. The response of RPLGD reached 1.00 at ±30°g antry angle while at +90°gantry angle, the RPLGD response was 8% lower compared to-90°gantry angle because the attenuation effect was more pronounced. We conclude that the RPLGD is capable to measure radiation dose since it provides desirable dosimetric properties such as good uniformity and reproducibility of RPLGD including the reader system. Besides, RPLGD is available with small active readout area which adds benefit for clinical implementation in radiotherapy, especially for advanced techniques.

Estimated radiation doses to ovarian and uterine organs in breast cancer irradiation using radio‐photoluminescent glass dosimeters (RPLDs)

“…The RPLDs showed 8% of maximum X-ray selfattenuation when the incident beam was parallel to the long axis of the RPLDs. 8 In this study, the correction factors for the directional dependence were negligible for the VMAT plans due to the continuation of the gantry and MLC movement. It is complicated to apply correction factors for partial doses.…”

“…This study utilised RPLDs (GD‐302M, batch number FD7131213‐2) 8 for dose measurement under the same conditions as those used for the IC measurements. The RPLD process was started from the annealing process (400°C for 1 h), radiation exposure, preheat (70°C for 30 min) and signal readout using FGD‐1000 software (AGC Techno Glass Co., LTD, Shizuoka, Japan).…”

“…Only one RPLD was placed in each measured position of the Rando phantom section. The doses were measured only once in one plan for each technique because the RPLD dose–response stability was within 2% 8 …”

“…Radio‐photoluminescence glass dosimeters (RPLDs) are a recent trend in radiation dosimetry. These passive dosimeters offer several benefits, as reported by Oonsiri et al, 8 including small size, high sensitivity, photon energy, dose rate independence, angular independence in the beam direction perpendicular to the longitudinal axis of the RPLD and adequate repeated reading until the detectors become annealed. These advantages make RPLDs more robust than thermoluminescence dosimeters (TLDs) for radiation dosimetry 5,9 .…”

“…The doses were measured only once in one plan for each technique because the RPLD dose-response stability was within 2%. 8 Ovarian and uterine doses in VMAT plans: Rando phantom Five VMAT patient plans of the left breast duplicated MLC movement and MU delivery into the Rando phantom. The RPLDs were used to measure the left breast, which represented the in-field measurements.…”