@misc{oai:repo.qst.go.jp:00076914,
 author = {Mizuno, Hideyuki and Fukuda, Shigekazu and Nakaji, Taku and Fukumura, Akifumi and Yamashita, Wataru and Takase, Nobuhiro and al., et and Mizuno, Hideyuki and Fukuda, Shigekazu and Nakaji, Taku and Fukumura, Akifumi and Yamashita, Wataru and Takase, Nobuhiro},
 month = {Sep},
 note = {Background and Objectives
Radiophotoluminescent glass dosimeter (RPLD) has been used in Japan as dosimeter of postal dose audit in external radiotherapy. Due to its advantages of compactness, repeatable readout, good precision and small fading1), RPLD become a suitable dosimeter for the audit. In Japan, the permanent auditing system using RPLD for external radiotherapy was launched in 2007. Currently, in multicenter clinical studies conducted in the framework of the Forum for Nuclear Cooperation in Asia (FNCA), the RPLD is also used as a dosimeter for brachytherapy dosimetry audit.

Material
　The glass dosimeter (DOSE ACE, ASAHI TECHNO GLASS CORPORATION; ATG) is silver-activated phosphate glass. Its weight composition is as follows: 11.0% Na, 31.55% P, 51.16% O, 6.12% Al and 0.17% Ag [14]. Its dimensions are 1.5mm in diameter and 12mm in length. A solid-state laser (ultraviolet wavelength) is used for reading. On its reading, 10 to 20 pulses of laser are irradiated per second, and the average value is obtained. In order to suppress variations in light emission amount depending on slight position fluctuation including rotation of the element, sensitive setup of the element is necessary. In addition, the whole reading process is repeated for 5 times, to improve the statistics.
 
Dosimetry audit for external radiotherapy
　RPLD elements are embedded in a solid phantom (Tough water phantom, manufactured by Kyoto Science Co., Ltd.), and it is set to be the reference condition of linear accelerator, and the reference dose (1 Gy) is irradiated. Phantom and RPLD are sent to the radiotherapy hospital according to their request. After irradiation, those are sent back to NIRS to evaluate the dose irradiated to the RPLD.

Dosimetry audit for brachytherapy
　The use of RPLD as a dose auditing tool for image-guided brachytherapy performed as a multicenter clinical study of cervical cancer has been studied. We are planning an end-to-end test that enables validation including the same flow as the actual patient, such as CT acquisition and treatment plan, rather than simple source intensity measurement. Although the beam quality is close to the cobalt irradiation field that calibrates the RPLD, it is affected by the dose gradient caused by the distance from the source close, and it is necessary to consider the volume effect. The phantom photograph produced is shown in the figure below. It was manufactured so that the RPLD element can be inserted into the evaluation points which are clinical dose evaluation points, point A right and left, and representative points of risk organs, bladder and the rectum (ICRU reference point). Currently we are doing Monte Carlo simulation for basic data verification and beam quality correction. 

Conclusion
　RPLD is a useful solid state dosimeter for the external dosimetry audit in radiation therapy., 19th International Conference on Solid State Dosimetry (SSD19)},
 title = {Application of radiophotoluminescent glass dosimeter to radiotherapy dosimetry audit},
 year = {2019}
}