Comparison of Intensity Modulated Radiation Therapy Dose Calculations with a PBC and AAA Algorithms in the Lung Cancer

폐암의 세기조절방사선치료에서 PBC 알고리즘과 AAA 알고리즘의 비교연구

  • Oh, Se-An (Department of Physics, Yeungnam University) ;
  • Kang, Min-Kyu (Department of Radiation Oncology, Yeungnam University College of Medicine) ;
  • Yea, Ji-Woon (Department of Radiation Oncology, Yeungnam University College of Medicine) ;
  • Kim, Sung-Hoon (Department of Radiation Oncology, Yeungnam University College of Medicine) ;
  • Kim, Ki-Hwan (Department of Radiation Oncology, Chungnam National University Hospital) ;
  • Kim, Sung-Kyu (Department of Radiation Oncology, Yeungnam University College of Medicine)
  • 오세안 (영남대학교 이과대학 물리학과) ;
  • 강민규 (영남대학교 의과대학 방사선종양학교실) ;
  • 예지원 (영남대학교 의과대학 방사선종양학교실) ;
  • 김성훈 (영남대학교 의과대학 방사선종양학교실) ;
  • 김기환 (충남대학교병원 방사선종양학과) ;
  • 김성규 (영남대학교 의과대학 방사선종양학교실)
  • Received : 2012.02.03
  • Accepted : 2012.03.03
  • Published : 2012.03.31

Abstract

The pencil beam convolution (PBC) algorithms in radiation treatment planning system have been widely used to calculate the radiation dose. A new photon dose calculation algorithm, referred to as the anisotropic analytical algorithm (AAA), was released for use by the Varian medical system. The aim of this paper was to investigate the difference in dose calculation between the AAA and PBC algorithm using the intensity modulated radiation therapy (IMRT) plan for lung cancer cases that were inhomogeneous in the low density. We quantitatively analyzed the differences in dose using the eclipse planning system (Varian Medical System, Palo Alto, CA) and I'mRT matirxx (IBA, Schwarzenbruck, Germany) equipment to compare the gamma evaluation. 11 patients with lung cancer at various sites were used in this study. We also used the TLD-100 (LiF) to measure the differences in dose between the calculated dose and measured dose in the Alderson Rando phantom. The maximum, mean, minimum dose for the normal tissue did not change significantly. But the volume of the PTV covered by the 95% isodose curve was decreased by 6% in the lung due to the difference in the algorithms. The difference dose between the calculated dose by the PBC algorithms and AAA algorithms and the measured dose with TLD-100 (LiF) in the Alderson Rando phantom was -4.6% and -2.7% respectively. Based on the results of this study, the treatment plan calculated using the AAA algorithms is more accurate in lung sites with a low density when compared to the treatment plan calculated using the PBC algorithms.

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