Progress in Medical Physics (한국의학물리학회지:의학물리)

Korean Society of Medical Physics (한국의학물리학회)
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Dosimetric Characteristics of Flexible Radiochromic Film Based on LiPCDA

  • Jung, Seongmoon (Department of Radiation Oncology, Seoul National University Hospital) ;
  • Cho, Jin Dong (Department of Radiation Oncology, Yonsei University College of Medicine) ;
  • Kim, Jung-in (Department of Radiation Oncology, Seoul National University Hospital) ;
  • Park, Jong Min (Department of Radiation Oncology, Seoul National University Hospital) ;
  • Choi, Chang Heon (Department of Radiation Oncology, Seoul National University Hospital)
  • Received : 2021.11.25
  • Accepted : 2021.12.10
  • Published : 2021.12.31
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Abstract

This study aimed to determine the optimal thickness of the active layer and scan mode for a flexible radiochromic film (F-RCF) based on the active lithium salt of pentacosa-10,12-diynoic acid (LiPCDA). F-RCFs of 90, 120, 140, and 170-㎛ thickness were fabricated using LiPCDA. Several pieces of the F-RCFs were exposed to doses ranging from 0 to 3 Gy. Transmission and reflection modes were used to scan the irradiated F-RCFs. Their dose-response curves were obtained using a second-order polynomial equation. Their sensitivity was evaluated for both scanning modes, and the uniformity of the batch was also examined. For both the transmission and reflection modes, the sensitivity increased as the film thickness increased. For the reflection mode, the dose response increased dramatically under 1 Gy. The value of the net optical density varied rapidly as the thickness of the film increased. However, the dose-response curves showed a supralinear-curve relationship at doses greater than 2 Gy. The sensitivity of the reflection scan at doses greater than 2 Gy was higher than that of the reflection scan within 0-2 Gy. The sensitivity steadily decreased with increasing doses, and the sensitivity of the two modes was within 0.1 to 0.2 at 2 Gy and was saturated beyond that. For the transmission scan, the sensitivity was approximately 0.2 at 3 Gy. For the intra-batch test result, the maximum net optical density difference of the intra-batch was 5.5% at 2 Gy and 7.4% at 0.2 Gy in the transmission and reflection scans, respectively. In the low-dose range, film thickness of more than 120-㎛ was proper in the transmission mode. In contrast, the transmission mode showed a better result compared to the reflection mode. Therefore, the proper scan mode should be selected according to the dose range.

Keywords

Acknowledgement

This work was in part supported by Radiation Technology R&D program through the National Research Foundation of Korea funded by the KoreanKorea government (MIST) (2019M2A2B4095126) and by the National Research Foundation of Korea (NRF) and Korean Association for Radiation Application (KARA) as a part of the Radiation Technology Commercialization Project of the Korean Ministry of Science and ICT (NRF-2019M2D3A2060217, Technology Transfer and Commercialization in the Radiation fields).

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