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1 - - 2016 9 23 e-mail: : Pencil BeamMonte Carlo 2016 2 (PDD, , ) TPS FaizM. Khan, The Physics of Radiation Therapy F. H. Attix, Introduction to Radiological Physics and Radiation Dosimetry K. R. Hogstromand P. R. Almond, Review of electron beam therapy physics Phys. Med. Biol. 51 (2006), R455. Perez and Brady s Principles and Practice of Radiation Oncology chapter 7 electron -Beam Therapy: Dosimetry, Planning, and TechniquesAAPM TG 105: Issues associated with clinical implementation of Monte Carlo-based photon and electron external treatment planning(2007) b a a >> a : Soft a : Hard (Knock-On) << a : b a b >> a.

2 Soft collision b a : Hard collision b << a : Soft collision X Bethe-Bloch M llercross section Boltzmann transport equation 1941 Fermi: [Ref.]

3 ] B. Rossi, K. Greisen, Rev. Mod. Phys. 13, 265 (1941)1948 Eyges: Fermi [Ref.] L. Eyges, Phys. Rev. 74, 1534 (1948) 1981 Hogstrom: Fermi-Eyges TPS CT [Ref.] Phys. Med. Biol. 26, 445 (1981) Hogstrom [Ref.] K. Kawachi, Phys. Med. Biol. 20, 571 (1975)1970 Hogstrom Hogstrom [Ref.

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5 ] Hogstromet al., Dosimetricevaluation of a pencil-beam algorithm for electrons employing a two-dimensional heterogeneity correction IJROBP, 10, 561 (1984)SSD = 100 cmSSD = 110 cm SSD=100 cm Heterogeneity[Ref.] K. R. Hogstromet al., Dosimetricevaluation of a pencil-beam algorithm for electrons employing a two-dimensional heterogeneity correction IJROBP, 10, 561 (1984) Hogstrom Fermi-Eyges (a) (b) (c) Central-axis (CAX) (a)(b)(c)[Ref.

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8 (scattering foil) Virtual SSD Sigma theta-x Virtual SSDS igma theta-x: (80% - 20% ) FWHM FWHM=0 cm (d) SSD=100 cm Virtual SSD (VSD = 100 d)90 SSDP innacle CT 1) 2) 3) CAX SSD MU Monte Carlo Monte Carlo 2 1 4 [Ref.]

9 ] M. K. Fix et al, Phys. Med. Biol. 58, 2841, 2013 Fermi-Eyges Monte Carlo Monte Carlo 2001 MDS Nordion( Nucletron) Monte Carlo TPS Kawrakow VMC++ (VoxelMonte Carlo C++ ) 2004 Varian Eclipse eMC Neuenschwander Macro Monte Carlo Varian 2010 Elekta-CMS XiOeMCfor electron beams VMC Elekta Monaco Kawrakow VMC Monte Carlo Monte Carlo Monte Carlo(EGS) Macro Monte Carlo (MMC)[Ref.

10 ] H. Neuenschwander, E. J. Born, PMB 37 (1), 107 (1992)Voxel Monte Carlo (VMC, XVMC for photon )[Ref.] I. Kawrakowet al., Med. Phys. 23, 445 (1996)AAPM TG 105 Macro Monte Carlo (MMC) Primary electron Eclipse WaterWaterBoneAir e e Eclipse eMCOriginal MMCV oxelMonte Carlo (VMC) VMC 1 - 30 MeV, 1 3 g/cm3 2 X ( , energy range 30 MeVand water-like materials )