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Wideband Self‐Grounded Bow‐Tie Antenna for Thermal MR
- Source :
- NMR in Biomedicine
- Publication Year :
- 2020
-
Abstract
- The objective of this study was the design, implementation, evaluation and application of a compact wideband self-grounded bow-tie (SGBT) radiofrequency (RF) antenna building block that supports anatomical proton (H-1) MRI, fluorine (F-19) MRI, MR thermometry and broadband thermal intervention integrated in a whole-body 7.0 T system. Design considerations and optimizations were conducted with numerical electromagnetic field (EMF) simulations to facilitate a broadband thermal intervention frequency of the RF antenna building block. RF transmission (B-1(+)) field efficiency and specific absorption rate (SAR) were obtained in a phantom, and the thigh of human voxel models (Ella, Duke) for H-1 and F-19 MRI at 7.0 T. B-1(+) efficiency simulations were validated with actual flip-angle imaging measurements. The feasibility of thermal intervention was examined by temperature simulations (f = 300, 400 and 500 MHz) in a phantom. The RF heating intervention (P-in = 100 W, t = 120 seconds) was validated experimentally using the proton resonance shift method and fiberoptic probes for temperature monitoring. The applicability of the SGBT RF antenna building block for in vivo H-1 and F-19 MRI was demonstrated for the thigh and forearm of a healthy volunteer. The SGBT RF antenna building block facilitated F-19 and H-1 MRI at 7.0 T as well as broadband thermal intervention (234-561 MHz). For the thigh of the human voxel models, a B-1(+) efficiency >= 11.8 mu T/root kW was achieved at a depth of 50 mm. Temperature simulations and heating experiments in a phantom demonstrated a temperature increase Delta T >7 K at a depth of 10 mm. The compact SGBT antenna building block provides technology for the design of integrated high-density RF applicators and for the study of the role of temperature in (patho-) physiological processes by adding a thermal intervention dimension to an MRI device (Thermal MR).
- Subjects :
- Electromagnetic field
Materials science
Radio Waves
Acoustics
Thermometry
Bow tie
Imaging phantom
030218 nuclear medicine & medical imaging
magnetic resonance
self‐grounded bow‐tie
03 medical and health sciences
Electromagnetic Fields
0302 clinical medicine
broadband antenna
Broadband
Dielectric heating
Humans
Computer Simulation
Radiology, Nuclear Medicine and imaging
ddc:610
Wideband
thermal magnetic resonance
Spectroscopy
radiofrequency antenna
ultrahigh field MR
Phantoms, Imaging
Specific absorption rate
Magnetic Resonance Imaging
thermal intervention
Molecular Medicine
Protons
Antenna (radio)
610 Medizin und Gesundheit
030217 neurology & neurosurgery
Subjects
Details
- ISSN :
- 09523480
- Database :
- OpenAIRE
- Journal :
- NMR in Biomedicine
- Accession number :
- edsair.doi.dedup.....9cf9b1f879b1b1c58fd6a782af9aa9e8
- Full Text :
- https://doi.org/10.1002/nbm.4274