Radiation Oncology Journal

The Korean Society for Radiation Oncology (대한방사선종양학회)
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Measurement of Dose Distribution in Small Beams of Philips 6 and 8 MVX Linear Accelerator

Philips LINAC 6 MV와 8 MV X선 소조사연에 대한 선량분포 측정

  • Suh Tae-suk (Department Of Radiology, Catholic University Medical College) ;
  • Yoon Sei Chul (Department Of Radiology, Catholic University Medical College) ;
  • Shinn Kyung Sub (Department Of Radiology, Catholic University Medical College) ;
  • Park Yong Whee (Department Of Radiology, Catholic University Medical College)
  • 서태석 (가톨릭 의과대학 방사선과학교실) ;
  • 윤세철 (가톨릭 의과대학 방사선과학교실) ;
  • 신경섭 (가톨릭 의과대학 방사선과학교실) ;
  • 박용휘 (가톨릭 의과대학 방사선과학교실)
  • Published : 1991.06.01
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Abstract

The work suggested in this paper addresses a method for collecting beam data for small circular fields. Beam data were obtained from philips 6 and 8 MV LINAC at Dept. Radiation Therapy at Gainesville Incorporated and Shands Teaching Hospital. Specific quantities measured include tissue maximum ratio (TMR), off-axis ratio (OAR) and relative output factor (ROF) In small field irradiation, special collimators were used to produce circular fields of 1 cm to 3 cm diameter in 2 mm steps, measured at SAO (soura axis distance) of 100 cm. Diode detector was chosen for primary beam measurement and compared with measurements made with photographic film and TLD dosimeters. The measured TMRs and OARs were formulated from limited measurements to generate basic beam data for reference set-up. The empirical formula were later, extended and generalized for any possible set-up using the trends of fitting parameters. The measured TMRs and OARs were well represented by the fitting formula developed.

본 논문에서는 소조사면에 대한 X-선의 선량분포를 일반실험식으로 계산될 수 있도록 beam 측정 데이타를 종합 처리하는 방법에 대하여 기술하고 있다. Beam 데이타는 philips LINAC 6 MV, 8 MV X-ray에 대하여 측정 되었으며, 측정된 요소는 tissue maximum ratio (TMR), off-axis-ratio (OAH), 그리고 relative output factor (ROF)를 포함한다. 소조사면에 의한 방사선 치료를 위하여 isocenter에서 지름이 1 내지 3cm되도록 실린더 형태의 특수 collimator가 2 mm 간격으로 제작되었다. 본 측정을 위하여 다이오드 detector가 이용되었으며 Film 및 TLO 측정기로 측정된 값과 비교검토 되었다. 제한된 조사면으로 측정된 TMR, OAR data로부터 beam 데이타를 나타내는 실험식을 유도하였으며 이 실험식은 임의의 Set-UP조건에 따른 측정값을 예상할 수 있는 일반 실험식으로 확장되었고 측정된 TMR과 OAR 값들은 잘 일치되었다.

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