Numerical safety study of currents induced in the patient during rotations in the static field produced by a hybrid MRI-LINAC system

Trakic, Adnan, Liu, Limei, Sanchez Lopez, Hector, Zilberti, Luca, Liu, Feng and Crozier, Stuart (2014) Numerical safety study of currents induced in the patient during rotations in the static field produced by a hybrid MRI-LINAC system. IEEE Transactions Biomedical Engineering, 61 3: 784-793. doi:10.1109/TBME.2013.2289924


Author Trakic, Adnan
Liu, Limei
Sanchez Lopez, Hector
Zilberti, Luca
Liu, Feng
Crozier, Stuart
Title Numerical safety study of currents induced in the patient during rotations in the static field produced by a hybrid MRI-LINAC system
Journal name IEEE Transactions Biomedical Engineering   Check publisher's open access policy
ISSN 0018-9294
1558-2531
Publication date 2014-03-01
Year available 2013
Sub-type Article (original research)
DOI 10.1109/TBME.2013.2289924
Open Access Status
Volume 61
Issue 3
Start page 784
End page 793
Total pages 10
Place of publication Piscataway, NJ, United States
Publisher Institute of Electrical and Electronics Engineers
Collection year 2014
Language eng
Abstract MRI-LINAC is a new image-guided radiotherapy treatment system that combines magnetic resonance imaging (MRI) and a linear particle accelerator (LINAC) into a single unit. Moving (i.e., rotating or translating) the patient inside the strong magnetic field of the split MRI-LINAC magnet can potentially induce high levels of electric fields and corresponding current densities in the conducting tissues. The prediction and assessment of patient safety in terms of electromagnetic field exposure have received very little attention for a split cylindrical MRI magnet configuration, especially in the vicinity of the gap region. In this novel numerical study, based on the quasi-static finite-difference method, rotation-induced electric fields and current densities are calculated considering a split 1-T magnet and a tissue-accurate 2-mm-resolution human body model. The patient was modeled in both axial and radial orientations relative to the magnet gap in a number of treatment/imaging scenarios. It was found that rotating the patient in the radial orientation produced an order of magnitude larger field exposure in the central nervous system than when the patient was rotated in the axial orientation. Also, rotating the patient with periods lower than about $T_{rm rot}$ = 43.3 s may result in field exposures above the limits set out in the international safety guidelines. The novel results of this investigation can provide useful insights into the safe use of the MRI-LINAC technology and optimal orientations of the patient during the treatment.
Keyword Body model
Electric field
Current density
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2014 Collection
School of Information Technology and Electrical Engineering Publications
 
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Created: Thu, 27 Feb 2014, 10:02:22 EST by Dr Hector Sanchez Lopez on behalf of Centre for Medical Diagnostic Technologies in Qld