PMID: 11339759May 8, 2001Paper

Dynamic wedge versus physical wedge: a Monte Carlo study

Medical Physics
R ShihJ C Chu

Abstract

The purpose of this study is to analyze the characteristics of dynamic wedges (DW) and to compare DW to physical wedges (PW) in terms of their differences in affecting beam spectra, energy fluence, angular distribution, contaminated electrons, and dose distributions. The EGS4/BEAM Monte Carlo codes were used to simulate the exact geometry of a 6 MV beam and to calculate 3-D dose distributions in phantom. The DW was simulated in accordance with the segmented treatment tables (STT). The percentage depth dose curves and beam profiles for PW, DW, and open fields were measured and used to verify the Monte Carlo simulations. The Monte Carlo results were found to agree within 2% with the measurements performed using film and ionizing chambers in a water phantom. The present EGS4 calculation reveals that the effects of a DW on beam spectral and angular distributions, as well as electron contamination, are much less significant than those for a PW. For the 6 MV photon beam, a 45 degrees PW can result in a 30% increase in mean photon energy due to the effect of beam hardening. It can also introduce a 5% dose reduction in the build-up region due to the reduction of contaminated electrons by the PW. Neither this mean-energy increase nor su...Continue Reading

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Citations

Mar 23, 2011·Australasian Physical & Engineering Sciences in Medicine·M B KakakhelJ V Trapp
Jul 10, 2014·Radiation Protection Dosimetry·Kwo-Ping ChangYu-Huang Chien
Dec 10, 2009·Medical Physics·Timothy C ZhuUNKNOWN AAPM Therapy Physics Committee Task Group 74
Jun 1, 2011·Radiotherapy and Oncology : Journal of the European Society for Therapeutic Radiology and Oncology·Sigrun Saur AlmbergJomar Frengen
Jan 5, 2002·Medical Physics·J NovotnyT Cechak
Sep 11, 2014·Journal of Applied Clinical Medical Physics·Wei Loong JongAnatoly B Rosenfeld
Dec 5, 2003·Physics in Medicine and Biology·Frank Verhaegen, Jan Seuntjens
Jan 5, 2002·Physics in Medicine and Biology·R ShihW L Hsu
Mar 15, 2020·Radiological Physics and Technology·Tetsuya TomidaMasahiro Hanmura
May 26, 2016·Asian Pacific Journal of Cancer Prevention : APJCP·Mansour ZabihzadehMahbube Fadaei
Jan 5, 2002·Physics in Medicine and Biology·M K FixP Rüegsegger
Jul 22, 2011·Physics in Medicine and Biology·A JoostenR Moeckli

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