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Development of Real-Time Dwell Verifier for HDR Brachytherapy Based On 64 Channels of Scintillation Fiber System

NH KWON1*, JS Kim2, JH Kim3, KP Kim4, GH Jahng5, SH Choi6, DW Kim2, (1) Yonsei University, Seoul, KR, (2) Department of Radiation Oncology, Yonsei Cancer Center, Seoul, KR, (3) CHA Bundang Medical Center, CHA University, Seongnam, Gyeonggi, KR (4) Kyung Hee University, Yongin-si, KR (5) Kyung Hee University Hospital at Gangdong, Seoul, KR (6) Division of Medical Radiation Equipment, Korea Institute of Radiological and Medical Sciences, Seoul, KR


(Sunday, 7/12/2020)   [Eastern Time (GMT-4)]

Room: AAPM ePoster Library

Purpose: high dose rate brachytherapy (HDR-BT), it is very important to bring the radioactive source to the correct dwell position and irradiation in correct dwell time. In this study, we developed and evaluated the real-time dwell verifier system based on scintillation fiber for HDR-BT.

Methods: developed the 64 channels of dwell verifier using plastic scintillation fiber. Each sensor was 1 mm thick and 2 mm long and placed apart around the tandem. The measurement sensor is connected to the read-out system via optical fiber. The data read-out system was based on LabView2012 and photo multiplier tube. We used the 192-Ir source to evaluate the measurement accuracy of dwell position, output linearity and dwell time. In addition, we used 2 clinical treatment plans and a silicon-based human phantom.

Results: compared the difference between the expected and the actual measured dwell position. The results of difference of dwell position were all found to be within 0.65 mm. The difference of dwell time was within 0.01 seconds. And for the linearity, the number of signals of scintillation fiber increased linearly. (635, 1203, 1857, 2477, 3057, and 3716) And the results of validating the clinical treatment plans, the dwell position accuracy was above 99.9% for both. The difference of dwell time was 0.76 ± 1.3 seconds for Patient 1 and 0.44 ± 0.40 seconds for Patient 2.

Conclusion: confirmed that our system can accurately detect the source dwell positions, times and output in real-time. And we confirmed the possibility of application to patient plan. The results of our study satisfied the criteria of AAPM TG-40 and NRC policy. It’ll gives the physician the ability to precisely track the position of each seed as it is placed at real time. We expected applicator could be widely used for real-time verifier for HDR-BT.

Funding Support, Disclosures, and Conflict of Interest: This work was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF- 2018R1D1A1B07050217).


HDR, Brachytherapy, Dosimetry


TH- Brachytherapy: Experimental dosimetry

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