최근 도입된 FFF 빔을 활용하는 방사선치료는 flattening filter에서 비롯되는 빔의 감쇠를 막을 수 있어 치료효율을 높일 수 있지만, 불균일한 단면적 선량분포에 대하여 정확한 정도관리가 구축되어 있지 않은 실정이다. 이에 본 연구에서는 광도전체 물질 HgI2 기반의 곡면 선량계를 제작하였으며, 성능을 검증하기 위하여 6 MV 광자에너지에서 재현성 및 선형성을 평가하였다. 또한 곡면 계측의 유용성을 나타내기 위하여 아크릴 필터를 적용한 FFF beam에서 평면 기판과 곡면 기판 상에서 계측되는 신호를 비교하였다. 그 결과 Unit cell 선량계의 재현성은 SE 0.613%, 선형성은 R-sq 0.9999로 나타났으며, line array 곡면 선량계의 유용성 평가는 평면 기판에서 23.337%, 곡면 기판에서 12.264%로 11.073%p 감소된 신호 차이를 보였 다.

Radiation therapy using flattening filter free beam can prevent beam attenuation caused by flattening filter and can improve treatment efficiency. However, accurate dose control is not established for nonuniform iso dose distributions. In this study, curved dosimeter based on photoconductive material HgI2 was fabricated and its reproducibility and linearity were evaluated at 6 MV photon energy to verify its performance. In order to show the usefulness of the curved measurement, the signals measured on the flat substrate and the curved substrate were compared in the flattening filter free beam using the acrylic filter. As a result, the reproducibility of the unit cell dosimeter was evaluated as SE 0.613%, and the linearity was evaluated as R-sq 0.9999. The usability evaluation of the array curve dosimeter demonstrated its usefulness by indicating a curvature error rate of 11.073%p and a reduced error rate.

ABSTRACT
 Ⅰ. INTRODUCTION
 Ⅱ. MATERIAL AND METHODS
 Ⅲ. RESULT
 Ⅳ. DISCUSSION & CONCLUSION
 Reference
 요 약

• Moojae Han(Department of Radiation Oncology, Collage of Medicine, Inje University/Department of Medical Imaging Research Institute, Inje university) | 한무재
• Yohan Shin(Department of Radiation Oncology, Collage of Medicine, Inje University/Department of Medical Imaging Research Institute, Inje university) | 신요한
• Jaehoon Jung(Research for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital) | 정재훈
• Seunguk Heo(Research for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital) | 허승욱
• Kyotae Kim(Korea Institute of Radiological and Medical Sciences) | 김교태
• Yeji Heo(Department of Medical Imaging Research Institute, Inje university) | 허예지
• Heunglae Cho(Department of Radiation Oncology, Busan Paik Hospital, Inje University) | 조흥래
• Sungkwang Park(Department of Medical Imaging Research Institute, Inje university/Department of Radiation Oncology, Busan Paik Hospital, Inje University) | 박성광 Corresponding Author