The Journal of Korean Society for Radiation Therapy (대한방사선치료학회지)

Korean Society for Radiation Therapy (대한방사선치료학회)
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A Study on the Improvement of Penumbra and Dose Distribution in the Multileaf Collimator Field Edge

다엽콜리매이터(Multileaf Collimator) 조사야의 반음영 및 선량분포 개선에 대한 연구

  • Kim CW. (Dept. of Radiation Oncology, Catholic University of Korea) ;
  • Kim HN. (Dept. of Radiation Oncology, Catholic University of Korea) ;
  • Lim CK. (Dept. of Radiation Oncology, Catholic University of Korea) ;
  • Ra SK. (Dept. of Radiotechnology, Kim Chon College) ;
  • Park BS. (Dept. of Radiotechnology, Kim Chon College)
  • 김창욱 (가톨릭대학교 강남성모병원 치료방사선과) ;
  • 김회남 (가톨릭대학교 강남성모병원 치료방사선과) ;
  • 임충근 (가톨릭대학교 강남성모병원 치료방사선과) ;
  • 나수경 (김천대학 방사선과) ;
  • 박병섭 (김천대학 방사선과)
  • Published : 1998.12.01
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Abstract

Multileaf collimator is essential equipment in conformal radiation therapy, however the use is limitted by increase of penumbra width and undulating dose distribution at the field edge. The purpose of this study is to improve the penumbra and dose distribution in the multileaf collimator field edge. Measurement were performed with X-omat V film in solid water phantom using 6MV photon beam from Siemens linear accelerator. All the measurement were made along the central axis of $5{\times}5cm,\;10{\times}10cm$ circular field for constant SSD of 100 cm. To improve the penumbra and dose distribution collimator was rotated by 15 degrees from 0 to 90 degrees (collimator rotation method) and center was shifted to the longitudinal direction by fourth of lead width (center shift method). We compare the penumbra and dose distribution at the field edge to alloy block. Dose distribution and penumbra width at the feild edge of MLC showed undulated dose pattern and increased penumbra compared with alloy block. However, in the collimator rotation method and center shift method we abtained simular results with alloy block. Through the study we expected that clinical use of MLC will be increase.

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