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Experimental determination of the dose kernel in high-energy x-ray beams

Ceberg, Crister LU ; Bjärngard, Bengt E. and Zhu, Timothy C. (1996) In Medical Physics 23(4). p.505-511
Abstract
A semiempirical method to characterize the pencil-beam dose kernel is presented. Results from measurements are described by mathematical models of the applicable physical processes. The measurements were made with 6 and 25 MV x-ray beams from a linear accelerator. Broad-beam notations were used consistently, and the pencil-beam quantities were obtained by differentiation. The results were compared to pencil-beam kernels calculated by Monte Carlo techniques. The analysis of the measured data included a number of approximations. It was assumed that all the constituent pencil beams in the field are parallel, i.e., the divergence is ignored. Furthermore, the lateral variations of the incident photon fluence and the energy spectrum were... (More)
A semiempirical method to characterize the pencil-beam dose kernel is presented. Results from measurements are described by mathematical models of the applicable physical processes. The measurements were made with 6 and 25 MV x-ray beams from a linear accelerator. Broad-beam notations were used consistently, and the pencil-beam quantities were obtained by differentiation. The results were compared to pencil-beam kernels calculated by Monte Carlo techniques. The analysis of the measured data included a number of approximations. It was assumed that all the constituent pencil beams in the field are parallel, i.e., the divergence is ignored. Furthermore, the lateral variations of the incident photon fluence and the energy spectrum were disregarded. Monte Carlo calculations, on the other hand, are based on an average energy spectrum over the field, and are free from divergence and variations in the incident photon fluence. Measured and Monte Carlo calculated pencil beams nevertheless agreed well, and the approximations mentioned caused at maximum 2.7% discrepancies for the largest field size at 6 MV. (Less)
Please use this url to cite or link to this publication:
author
publishing date
type
Contribution to journal
publication status
published
subject
in
Medical Physics
volume
23
issue
4
pages
505 - 511
publisher
American Association of Physicists in Medicine
external identifiers
  • pmid:9157261
  • scopus:0029877777
ISSN
0094-2405
DOI
10.1118/1.597807
language
English
LU publication?
no
id
8f9785bf-0133-46b1-ade4-9649269d115e (old id 1110743)
date added to LUP
2008-07-22 09:40:37
date last changed
2017-07-23 04:41:35
@article{8f9785bf-0133-46b1-ade4-9649269d115e,
  abstract     = {A semiempirical method to characterize the pencil-beam dose kernel is presented. Results from measurements are described by mathematical models of the applicable physical processes. The measurements were made with 6 and 25 MV x-ray beams from a linear accelerator. Broad-beam notations were used consistently, and the pencil-beam quantities were obtained by differentiation. The results were compared to pencil-beam kernels calculated by Monte Carlo techniques. The analysis of the measured data included a number of approximations. It was assumed that all the constituent pencil beams in the field are parallel, i.e., the divergence is ignored. Furthermore, the lateral variations of the incident photon fluence and the energy spectrum were disregarded. Monte Carlo calculations, on the other hand, are based on an average energy spectrum over the field, and are free from divergence and variations in the incident photon fluence. Measured and Monte Carlo calculated pencil beams nevertheless agreed well, and the approximations mentioned caused at maximum 2.7% discrepancies for the largest field size at 6 MV.},
  author       = {Ceberg, Crister and Bjärngard, Bengt E. and Zhu, Timothy C.},
  issn         = {0094-2405},
  language     = {eng},
  number       = {4},
  pages        = {505--511},
  publisher    = {American Association of Physicists in Medicine},
  series       = {Medical Physics},
  title        = {Experimental determination of the dose kernel in high-energy x-ray beams},
  url          = {http://dx.doi.org/10.1118/1.597807},
  volume       = {23},
  year         = {1996},
}