1. A new pencil beam model for photon dose calculations in heterogeneous media
- Author
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M. Nassef, Antoine Simon, Huazhong Shu, Pascal Haigron, R. de Crevoisier, Pengcheng Zhang, Baosheng Li, Centre de Recherche en Information Biomédicale sino-français (CRIBS), Université de Rennes (UR)-Southeast University [Jiangsu]-Institut National de la Santé et de la Recherche Médicale (INSERM), Laboratory of Image Science and Technology [Nanjing] (LIST), Southeast University [Jiangsu]-School of Computer Science and Engineering, Laboratoire Traitement du Signal et de l'Image (LTSI), Université de Rennes (UR)-Institut National de la Santé et de la Recherche Médicale (INSERM), CRLCC Eugène Marquis (CRLCC), Shandong Tumor Hospital, Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Southeast University [Jiangsu]-Institut National de la Santé et de la Recherche Médicale (INSERM), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de la Santé et de la Recherche Médicale (INSERM), and Senhadji, Lotfi
- Subjects
MESH: Photons ,MESH: Radiation Dosage ,Time Factors ,Photon ,[SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging ,Computation ,Physics::Medical Physics ,Monte Carlo method ,Fast Fourier transform ,Biophysics ,General Physics and Astronomy ,MESH: Algorithms ,MESH: Monte Carlo Method ,Radiation Dosage ,Models, Biological ,Spherical shell ,Optics ,Radiology, Nuclear Medicine and imaging ,MESH: Radiotherapy Dosage ,[SPI.SIGNAL] Engineering Sciences [physics]/Signal and Image processing ,MESH: Radiotherapy Planning, Computer-Assisted ,Mathematics ,Photons ,Fourier Analysis ,Phantoms, Imaging ,business.industry ,Radiotherapy Planning, Computer-Assisted ,MESH: Time Factors ,MESH: Models, Biological ,Spherical coordinate system ,Oblique case ,Radiotherapy Dosage ,General Medicine ,Pencil (optics) ,Computational physics ,[SDV.IB.IMA] Life Sciences [q-bio]/Bioengineering/Imaging ,MESH: Phantoms, Imaging ,business ,Monte Carlo Method ,[SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing ,Algorithms ,MESH: Fourier Analysis - Abstract
International audience; The pencil beam method is commonly used for dose calculations in intensity-modulated radiation therapy (IMRT). In this study, we have proposed a novel pencil model for calculating photon dose distributions in heterogeneous media. To avoid any oblique kernel-related bias and reduce computation time, dose distributions were computed in a spherical coordinate system based on the pencil kernels of different distances from source to surface (DSS). We employed two different dose calculation methods: the superposition method and the fast Fourier transform convolution (FFTC) method. In order to render the superposition method more accurate, we scaled the depth-directed component by moving the position of the entry point and altering the DSS value for a given beamlet. The lateral components were thus directly corrected by the density scaling method along the spherical shell without taking the densities from the previous layers into account. Significant computation time could be saved by performing the FFTC calculations on each spherical shell, disregarding density changes in the lateral direction. The proposed methods were tested on several phantoms, including lung- and bone-type heterogeneities. We compared them with Monte Carlo (MC) simulation for several field sizes with 6 MV photon beams. Our results revealed mean absolute deviations
- Published
- 2014