The performance and magnetic shielding of a 6 MV in-line linac in a parallel linac-MR configuration

• Author / Creator

  Santos, Dan Michael Uson

• To achieve real-time image-guided radiation therapy, the integration of a linear accelerator (linac) with a magnetic resonance (MR) imager has been proposed. This thesis presents work that investigated performance and magnetic shielding of a linac in the presence of parallel magnetic flux densities. This work used computer simulations and numerical techniques such as finite element and particle tracking algorithms. It showed that a linac can operate with only a 17 ± 1 % target current lost and maintain its treatment beam’s symmetry in the presence of 0.011 T parallel magnetic flux densities. Furthermore, the target current lost is the result of the altered electron gun optics when parallel magnetic flux densities are present. Minimal magnetic shielding (such as a 5-mm-thick, 146.5-mm-long passive shield or a pair of active shield coils with 625 and 430 A turns) around the electron gun and waveguide was demonstrated to recover this lost target current.

• Subjects / Keywords

  • Linac-mr
  • Particle simulation
  • Parallel configuration
  • Longitudinal magnetic flux density
  • Magnetic shielding
  • Fringe magnetic flux density

• Graduation date

  Spring 2012

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3X66K

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.