Characteristics of TLD and PSLD Films for Photon and Electron Dose Measurements
C Kurokawa1*, A Urushiyama2, T Nishio3, S Sugimoto1, (1) Juntendo University, Tokyo, ,(2) St. Pauls (Rikkyo) University, Toshima-ku, Tokyo, (3) National Cancer Center, Kashiwa, 277-8577,SU-E-T-119 Sunday 3:00PM - 6:00PM Room: Exhibit Hall
Purpose: To evaluate the feature of our tissue-equivalent Thermoluminescense and Photoluminescense films for dose distribution measurements of photon and electron, and proton beams.
Methods:Thermal and light fading, repeatability, and dose linearity (dose proportionality) were evaluated for our tissue-equivalent Thermoluminescense (TLD) and Photo-Stimulated luminescense (PSLD) films, which has 18 x 40 cm2 dimension and 0.09 mm thickness. These effects were examined at room temperature and under fluorescent light after irradiation by 6 MV photon. Three-dimensional dose distributions for photon, electron, and proton beams were also measured. Before the measurements of dose distributions, the irradiation was done to calibrate the response of each film. The readout was performed by 180 oC for TLD and blue LED lights for PSLD films, and generated light was detected with a CCD camera which has 1024 x 1024 pixels (FLIML 1001E-2, Finger Lakes Instrument).
Results:After the irradiation, the fading of signals was 1-5% in one hour. It was observed that the variation for 10 sequent dose measurements at 200 cGy using 6 MV photons was less than 5%. Dose profiles for photon and electrons were obtained as smooth curve after the calibration. For photon measurements, PDDs with the TLD films well reproduced the results with ionization chamber, except for the surface region. The measured dose with TLD at surface is around 15%, which is lower more than 30% comparing to the dose with ionization chamber. Although obtained electron PDDs with TLD showed good agreement with that of ionization chamber, PDDs with PSLD showed slightly deviations from the chamber due to the contamination of high Z material.
Conclusion:The characteristics of TLD and PSLD films were evaluated in order to make precise measurements. It is shown that they have the potential to measure the 3D dose distribution including low dose at surface.
Funding Support, Disclosures, and Conflict of Interest: This work was supported by JSPS KAKENHI Grant Number 23791450.