Numerical investigations of MRI RF field induced heating for external fixation devices.
Background: The magnetic resonance imaging (MRI) radio frequency (RF) field induced heating on external fixation devices can be very high in the vicinity of device screws. Such induced RF heating is related to device constructs, device placements, as well as the device insertion depth into human sub...
| Publicado en: | BioMedical Engineering OnLine Vol. 12; no. 1; pp. 12 - 13 |
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| Autores principales: | , , , , , |
| Formato: | research Journal Article |
| Publicado: |
BioMed Central
2013
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| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=ccm&AN=104260940&site=ehost-live header: @attributes: shortDbName: ccm uiTerm: 104260940 longDbName: CINAHL Complete uiTag: AN controlInfo: bkinfo: dissinfo: jinfo: jid: 1475925X 1CGX jtl: BioMedical Engineering OnLine issn: 1475925X maglogo: N pubinfo: dt: 2013 vid: 12 iid: 1 pid: 24147 pub: BioMed Central artinfo: ui: 104260940 104260940 NLM23394173 2012063956 10.1186/1475-925X-12-12 NLM23394173 PMC3610272 104260940 ppf: 12 ppct: 1 formats: tig: atl: Numerical investigations of MRI RF field induced heating for external fixation devices. aug: au: Liu, Yan Shen, Jianxiang Kainz, Wolfgang Qian, Songsong Wu, Wen Chen, Ji affil: University of Houston, Houston, TX, 77204, USA. jchen18@uh.edu. sug: subj: Orthopedic Fixation Devices Magnetic Resonance Imaging Equipment and Supplies Magnetic Resonance Imaging Methods Radio Frequency Identification Methods Radio Waves Computer Simulation Electromagnetic Fields Heat Human Phantoms, Imaging ab: Background: The magnetic resonance imaging (MRI) radio frequency (RF) field induced heating on external fixation devices can be very high in the vicinity of device screws. Such induced RF heating is related to device constructs, device placements, as well as the device insertion depth into human subjects. In this study, computational modeling is performed to determine factors associated with such induced heating.Methods: Numerical modeling, based on the finite-difference time-domain (FDTD) method, is used to evaluate the temperature rises near external device screw tips inside the ASTM phantom for both 1.5-T and 3-T MRI systems. The modeling approach consists of 1) the development of RF coils for 1.5-T and 3-T, 2) the electromagnetic simulations of energy deposition near the screw tips of external fixation devices, and 3) the thermal simulations of temperature rises near the tips of these devices.Results: It is found that changing insertion depth and screw spacing could largely affect the heating of these devices. In 1.5-T MRI system, smaller insertion depth and larger pin spacing will lead to higher temperature rise. However, for 3-T MRI system, the relation is not very clear when insertion depth is larger than 5 cm or when pin spacing became larger than 20 cm. The effect of connection bar material on device heating is also studied and the heating mechanism of the device is analysed.Conclusions: Numerical simulation is used to study RF heating for external fixation devices in both 1.5-T and 3-T MRI coils. Typically, shallower insertion depth and larger pin spacing with conductive bar lead to higher RF heating. The heating mechanism is explained using induced current along the device and power decay inside ASTM phantom. pubtype: Academic Journal doctype: research Journal Article ougenre: Article language: English refInfo: holdings: @attributes: islocal: N |
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