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Abstract
The purpose of our study is to establish an efficient quality assurance (QA) procedure using a transmission-type detector (IBA, Stealth chamber), a reference signal detector, as a field chamber. Relative dosimetry items, including monitor unit linearity, output constancy based on dose rate and field size, and output factor were measured and compared with results obtained from the Farmer-type chamber (IBA, Wellhofer, FC65-G). Moreover, output for each field size was measured to assess its applicability to small fields. Results using the Stealth chamber were in good agreement with the FC65-G within 1.0%, except for output constancy according to gantry angle, which had a 1.1% error rate for the Stealth chamber and 2.7% for the FC65-G. Differences of up to - 6.26% output factor were observed for the Stealth chamber and up to - 0.56% for the CC-13 ionization chamber (IBA) in the 3 × 3 cm2 field. Our study confirmed the possibility of using Stealth chambers for relative dosimetry measurement in QA.

Affiliations

Dong Hyeok Choi 1 2 3, Jin Sung Kim 1 2 3, Rena Lee 4, So Hyun Ahn 5, Woo Sang Ahn 6
1Department of Medicine, Yonsei University College of Medicine, Seoul, South Korea.
2Medical Physics and Biomedical Engineering Lab (MPBEL), Yonsei University College of Medicine, Seoul, South Korea.
3Department of Radiation Oncology, Yonsei Cancer Center, Heavy Ion Therapy Research Institute, Yonsei University College of Medicine, Seoul, South Korea.
4Department of Biomedical Engineering, School of Medicine, Ewha Womans University, Seoul, South Korea.
5Ewha Medical Research Institute, School of Medicine, Ewha Womans University, Seoul, South Korea. mpsohyun@gmail.com.
6Department of Radiation Oncology, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, South Korea. anidol@ulsan.ac.kr.