EFFECTS OF INHOMOGENEITY CORRECTION ALGORITHMS ON MONITOR UNITS CALCULATION: ANALYSIS OF CLINICAL CASES OF LUNG CANCER

DOI 26 References
  • SUZUKI Minoru
    Department of Radiology, Kinki University, School of Medicine Radiation Oncology Research Laboratory, Research Reactor Institute, Kyoto University
  • OKUMURA Masahiko
    Department of Central Radiological Service, Kinki University, School of Medicine
  • NAKAMATSU Kiyoshi
    Department of Radiology, Kinki University, School of Medicine
  • KANAMORI Shuichi
    Department of Radiology, Kinki University, School of Medicine
  • NISHIMURA Yasumasa
    Department of Radiology, Kinki University, School of Medicine

Bibliographic Information

Other Title
  • 肺癌放射線治療において不均質部補正アルゴリズムが照射線量計算に及ぼす影響

Search this article

Abstract

Purpose: To investigate the effects of inhomogeneity correction algorithms on dose calculations using an inhomogeneity phantom and clinical cases of lung cancer.<BR>Materials and methods: Two inhomogeneity correction algorithms, the Batho (generalized Batho Power Law) and equivalent tissue-air-ratio (ETAR) equipped with Cadplan Helios ver. 6.01, were evaluated in the present study. Using phantoms with 5 and 10 cm cork layers between water density material layers, the central axis depth doses for points beyond the cork layer were measured and compared with the calculated doses, with and without inhomogeneity corrections. Photon beams of 6 and 10 MV were used. We analyzed the values of the monitor unit (MU) of 50 beams calculated with and without correction algorithms using patient data from patients with lung cancer.<BR>Results: In the phantom experiments, the measured doses showed overdoses of 6.7-21.8% compared with the calculated doses without inhomogeneity correction algorithms. The measured doses with the Batho algorithm ranged from 0.938 to 1.003 of the calculated dose. The ETAR algorithm had a tendency to predict lower values than the Batho algorithm. In the patient data analysis, the Batho and ETAR yielded underdosing of 4.2% and 5.6% on average, respectively, compared with the uncorrected doses.<BR>Conclusions: The inhomogeneity correction algorithms, Batho and ETAR, are effective in predicting the doses delivered to points beyond the lung. However, in using these correction algorithms in clinical studies, the underdosing of the tumor doses should be considered compared with the uncorrected doses.

Journal

  • The Journal of JASTRO

    The Journal of JASTRO 15 (4), 271-275, 2003

    Japanese Society for Therapeutic Radiology and Oncology

References(26)*help

See more

Keywords

Details 詳細情報について

Report a problem

Back to top