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Experimental verification of dose enhancement effects in a lung phantom from inline magnetic fields

Journal Article


Abstract


  • Background and purpose

    To present experimental evidence of lung dose enhancement effects caused by strong inline magnetic fields.

    Materials and methods

    A permanent magnet device was utilised to generate 0.95 T–1.2 T magnetic fields that encompassed two small lung-equivalent phantoms of density 0.3 g/cm3. Small 6MV and 10MV photon beams were incident parallel with the magnetic field direction and Gafchromic EBT3 film was placed inside the lung phantoms, perpendicular to the beam (experiment 1) and parallel to the beam (experiment 2). Monte Carlo simulations of experiment 1 were also performed.

    Results

    Experiment 1: The 1.2 T inline magnetic field induced a 12% (6MV) and 14% (10MV) increase in the dose at the phantom centre. The Monte Carlo modelling matched well (±2%) to the experimentally observed results. Experiment 2: A 0.95 T field peaked at the phantom centroid (but not at the phantom entry/exit regions) details a clear dose increase due to the magnetic field of up to 25%.

    Conclusions

    This experimental work has demonstrated how strong inline magnetic fields act to enhance the dose to lower density mediums such as lung tissue. Clinically, such scenarios will arise in inline MRI-linac systems for treatment of small lung tumours.

Publication Date


  • 2017

Citation


  • Oborn, B. M., Gargett, M. A., Causer, T. J., Alnaghy, S. J., Hardcastle, N., Metcalfe, P. E. & Keall, P. J. (2017). Experimental verification of dose enhancement effects in a lung phantom from inline magnetic fields. Radiotherapy and Oncology, 125 (3), 433-438.

Scopus Eid


  • 2-s2.0-85030471376

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers1/1232

Number Of Pages


  • 5

Start Page


  • 433

End Page


  • 438

Volume


  • 125

Issue


  • 3

Place Of Publication


  • Ireland

Abstract


  • Background and purpose

    To present experimental evidence of lung dose enhancement effects caused by strong inline magnetic fields.

    Materials and methods

    A permanent magnet device was utilised to generate 0.95 T–1.2 T magnetic fields that encompassed two small lung-equivalent phantoms of density 0.3 g/cm3. Small 6MV and 10MV photon beams were incident parallel with the magnetic field direction and Gafchromic EBT3 film was placed inside the lung phantoms, perpendicular to the beam (experiment 1) and parallel to the beam (experiment 2). Monte Carlo simulations of experiment 1 were also performed.

    Results

    Experiment 1: The 1.2 T inline magnetic field induced a 12% (6MV) and 14% (10MV) increase in the dose at the phantom centre. The Monte Carlo modelling matched well (±2%) to the experimentally observed results. Experiment 2: A 0.95 T field peaked at the phantom centroid (but not at the phantom entry/exit regions) details a clear dose increase due to the magnetic field of up to 25%.

    Conclusions

    This experimental work has demonstrated how strong inline magnetic fields act to enhance the dose to lower density mediums such as lung tissue. Clinically, such scenarios will arise in inline MRI-linac systems for treatment of small lung tumours.

Publication Date


  • 2017

Citation


  • Oborn, B. M., Gargett, M. A., Causer, T. J., Alnaghy, S. J., Hardcastle, N., Metcalfe, P. E. & Keall, P. J. (2017). Experimental verification of dose enhancement effects in a lung phantom from inline magnetic fields. Radiotherapy and Oncology, 125 (3), 433-438.

Scopus Eid


  • 2-s2.0-85030471376

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers1/1232

Number Of Pages


  • 5

Start Page


  • 433

End Page


  • 438

Volume


  • 125

Issue


  • 3

Place Of Publication


  • Ireland