Dosimetric properties of radiophotoluminescent glass rod detector in high‐energy photon beams from a linear accelerator and Cyber‐Knife

Abstract

A fully automatic radiophotoluminescent glass rod dosimeter (GRD) system has recently become commercially available. This article discusses the dosimetric properties of the GRD including uniformity and reproducibility of signal, dose linearity, and energy and directional dependence in high-energy photon beams. In addition, energy response is measured in electron beams. The uniformity and reproducibility of the signal from 50 GRDs using a 60Co beam are both +/- 1.1% (one standard deviation). Good dose linearity of the GRD is maintained for doses ranging from 0.5 to 30 Gy, the lower and upper limits of this study, respectively. The GRD response is found to show little energy dependence in photon energies of a 60Co beam, 4 MV (TPR20(10)=0.617) and 10 MV (TPR(20)10=0.744) x-ray beams. However, the GRD responses for 9 MeV (mean energy, Ez = 3.6 MeV) and 16 MeV (Ez = 10.4 MeV) electron beams are 4%-5% lower than that for a 60Co beam in the beam quality dependence. The measured angular dependence of GRD, ranging from 0 degrees (along the long axis of GRD) to 120 degrees is within 1.5% for a 4 MV x-ray beam. As applications, a linear accelerator-based radiosurgery system and Cyber-Knife output factors are measured by a GRD and compared with those from various detectors including a p-type silicon diode detector, a diamond detector, and an ion chamber. It is found that the GRD is a very useful detector for small field dosimetry, in particular, below 10 mm circular fields.

Dosimetric properties of radiophotoluminescent glass detector in low‐energy photon beams

“…[3][4][5] In some studies, the RGD has been evaluated using high energy radiotherapy photon beams. 4,[7][8][9] Tuda et al reported that its reproducibility of dose for high-energy x rays was 0.82% in coefficient of variance (CV), which is comparable to that of a TLD. As for energy dependence of the dose response, the mass energy absorption coefficient of the RGD, silveractivated metaphosphate, is several times higher than that of the TLD, LiF, for low-energy photons around 25 keV.…”

Dosimertry characteristics and performance comparisons: Environmental radiophotoluminescent glass dosemeters versus thermoluminescent dosemeters

“…When these centers receive 337.1 nm pulsed ultraviolet laser beam of the readout system, they will be excited. They will return to a stable energy level after emitting an orange radiophotoluminescent (RPL) (Piesch et al, 1986(Piesch et al, , 1990Araki et al, 2004). The luminescent intensity of an ultraviolet pulse excitation is proportional to the exposure dose of the radiation.…”

Risk of a second cancer from scattered radiation in acoustic neuroma treatment

“…The advantages of the RPLGD compared to the thermoluminescence dosimeter (TLD) include good reproducibility of 1% and relatively low energy dependency at energies higher than 200 keV [8][9][10]. In addition, the RPLGD has a relatively small incident-beam-angle dependency and a low toxicity inside a human body compared to the TLD or the optically-stimulated luminescence dosimeter [11][12][13].…”