Room: Exhibit Hall
Purpose: To develop a low-cost scintillation dosimetry system based on a liquid scintillation dosimeter and a CMOS detector of a commercial digital camera.
Methods: The liquid scintillation dosimeter was a solution of anthracene in dichloromethane in a concentration of 0.0153 g/ml. Its scintillation was evaluated in a closed L-shaped system with both arms of 50cm length, in one extremity, the sample is positioned and on the other extremity, the camera is positioned. A mirror was used in the middle of the curvature to redirect the light from the sample to the camera. A Nikon D90 professional camera and a kiloVoltage x-ray generator Magnum Moxtek were used. The linearity of response of the dosimetric system was evaluated, as well as its dependence on the radiation beam dose rate (from 1.0 to 6.7 Gy/min). Two-dimensional analyses of a depth dose deposition in the scintillator were also evaluated for different kilovoltage beams (50kVp, 150kVp, and 160kVp).
Results: The linearity of response was observed as a function of absorbed dose for several beams with different dose rates, being limited by the maximum intensity presented in the images (16 bits images were used). A linear decrease in the sensitivity of the dose-response was observed when increasing the radiation beam dose rate, a value 17.3% smaller was observed when changing the dose rate from 3 to 5 Gy/min. The two-dimensional depth dose distribution curves were obtained and the detected depths of the 50% dose deposition were 0.69; 1.06 and 1.19 cm for the beams with 50, 150 and 160 kVp respectively, confirming the expected higher penetrability of the high energy beams.
Conclusion: This work indicates the potential for dosimetry in two dimensions of the proposed low-cost system. The dosimetric response of the system for high energy beams will be evaluated in a future investigation.