Characteristics of bremsstrahlung in electron beams

T. C. Zhu, I. J. Das, B. E. Bjärngard

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Most electron beam algorithms ignore the bremsstrahlung components. This becomes increasingly important for high energies and for small fields. The difficulty of modeling lies with the lack of knowledge of the bremsstrahlung component. Bremsstrahlung is produced in the head (scattering foils, etc.), in the cerrobend or lead cutout, and in the tissue. These components were separated using measurements in water with variable collimation (diameter 0 - 5 cm) by 12-cm thick Lucite or by cerrobend blocks for clinical electron beams (6 - 22 MeV). Bremsstrahlung from the head dominates and increases with beam radius. Bremsstrahlung from cerrobend decreases with increasing radius because the amount of cerrobend intersecting beam is decreased. EGS4 Monte-Carlo simulation confirms that the bremsstrahlung from tissue is less than 1.5% of the total electron dose for 22 MeV monoenergenic electrons. The energy of the bremsstrahlung is softer than x-ray beams of corresponding nominal energy since the latter is hardened by the flattening filter. The effective attenuation coefficient was 0.057, 0.050, and 0.043 cm-1 and the depth of maximum dose 0.5, 1.7, and 2.8 cm for the 6, 12, and 22 MeV electrons, respectively. The lateral dose distribution is more forward-peaked for higher electron energy. Since the main contribution of bremsstrahlung is from the head, it is not accounted for in all state-of-art electron dose-calculation algorithms, such as Voxel Monte Carlo. This can be overcome by calculating separately for electrons and bremsstrahlung photons. The bremsstrahlung component can also be described by data from a set of simple measurements.

Original languageEnglish (US)
Title of host publicationAnnual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings
EditorsJ.D. Enderle
Pages2498-2501
Number of pages4
Volume4
StatePublished - 2000
Externally publishedYes
Event22nd Annual International Conference of the IEEE Engineering in Medicine and Biology Society - Chicago, IL, United States
Duration: Jul 23 2000Jul 28 2000

Other

Other22nd Annual International Conference of the IEEE Engineering in Medicine and Biology Society
CountryUnited States
CityChicago, IL
Period7/23/007/28/00

Fingerprint

Electron beams
Electrons
Tissue
Polymethyl Methacrylate
Metal foil
Photons
Lead
Scattering
X rays
Water

Keywords

  • Bremsstrahlung
  • Electron beam
  • Radiotherapy

ASJC Scopus subject areas

  • Bioengineering

Cite this

Zhu, T. C., Das, I. J., & Bjärngard, B. E. (2000). Characteristics of bremsstrahlung in electron beams. In J. D. Enderle (Ed.), Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings (Vol. 4, pp. 2498-2501)

Characteristics of bremsstrahlung in electron beams. / Zhu, T. C.; Das, I. J.; Bjärngard, B. E.

Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings. ed. / J.D. Enderle. Vol. 4 2000. p. 2498-2501.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Zhu, TC, Das, IJ & Bjärngard, BE 2000, Characteristics of bremsstrahlung in electron beams. in JD Enderle (ed.), Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings. vol. 4, pp. 2498-2501, 22nd Annual International Conference of the IEEE Engineering in Medicine and Biology Society, Chicago, IL, United States, 7/23/00.
Zhu TC, Das IJ, Bjärngard BE. Characteristics of bremsstrahlung in electron beams. In Enderle JD, editor, Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings. Vol. 4. 2000. p. 2498-2501
Zhu, T. C. ; Das, I. J. ; Bjärngard, B. E. / Characteristics of bremsstrahlung in electron beams. Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings. editor / J.D. Enderle. Vol. 4 2000. pp. 2498-2501
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