Journal article
Effect of transverse magnetic fields on a simulated in-line 6 MV linac
Physics in medicine & biology, Vol.55(16), pp.4861-4869
08/21/2010
DOI: 10.1088/0031-9155/55/16/015
PMID: 20679699
Abstract
The effects of a transverse magnetic field on an in-line side-coupled 6MV linear accelerator are given. The results are directly applicable to a linac-MR system used for real-time image guided adaptive radiotherapy. Our previously designed end-to-end linac simulation incorporated the results from the axisymmetric 2D electron gun program EGN2w. However, since the magnetic fields being investigated are non-axisymmetric in nature for the work presented here, the electron gun simulation was performed using OPERA-3d/SCALA. The simulation results from OPERA-3d/SCALA showed excellent agreement with previous results. Upon the addition of external magnetic fields to our fully 3D linac simulation, it was found that a transverse magnetic field of 6 G resulted in a 45 +/- 1% beam loss, and by 14 G, no electrons were incident on the target. Transverse magnetic fields on the linac simulation produced a highly asymmetric focal spot at the target, which translated into a 13% profile asymmetry at 6 G. Upon translating the focal spot with respect to the target coordinates, profile symmetry was regained at the expense of a lateral shift in the dose profiles. It was found that all points in the penumbra failed a 1%/1 mm acceptance criterion for fields between 4 and 6 G. However, it was also found that the lateral profile shifts were corrected by adjusting the jaw positions asymmetrically.
Details
- Title: Subtitle
- Effect of transverse magnetic fields on a simulated in-line 6 MV linac
- Creators
- J. St Aubin - University of AlbertaS. Steciw - Cross Cancer InstituteB. G. Fallone - University of Alberta
- Resource Type
- Journal article
- Publication Details
- Physics in medicine & biology, Vol.55(16), pp.4861-4869
- Publisher
- Iop Publishing Ltd
- DOI
- 10.1088/0031-9155/55/16/015
- PMID
- 20679699
- ISSN
- 0031-9155
- eISSN
- 1361-6560
- Number of pages
- 9
- Language
- English
- Date published
- 08/21/2010
- Academic Unit
- Radiation Oncology
- Record Identifier
- 9984313093702771
Metrics
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