Wideband Self-Grounded Bow-Tie Antenna for Thermal MR
Artikel i vetenskaplig tidskrift, 2020
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).
self-grounded bow-tie
thermal magnetic resonance
broadband antenna
ultrahigh field MR
thermal intervention
magnetic resonance
radiofrequency antenna
Författare
Thomas Wilhelm Eigentler
Technische Universität Berlin
Helmholtz
Lukas Winter
Helmholtz
Physikalisch-Technische Bundesanstalt (PTB)
Haopeng Han
Helmholtz
Humboldt-Universität zu Berlin
Eva Oberacker
Helmholtz
Andre Kuehne
MRI TOOLS GmbH
Helmar Waiczies
MRI TOOLS GmbH
Sebastian Schmitter
Physikalisch-Technische Bundesanstalt (PTB)
Laura Boehmert
Berlin Institute of Health
Freie Universität Berlin
Helmholtz
Charité Universitätsmedizin Berlin
Humboldt-Universität zu Berlin
Christian Prinz
Charité Universitätsmedizin Berlin
Berlin Institute of Health
Humboldt-Universität zu Berlin
Helmholtz
Freie Universität Berlin
Hana Dobsicek Trefna
Chalmers, Elektroteknik, Signalbehandling och medicinsk teknik
Thoralf Niendorf
Helmholtz
ECRC
MRI TOOLS GmbH
NMR in Biomedicine
0952-3480 (ISSN) 1099-1492 (eISSN)
Vol. 33 5 e4274Ämneskategorier
Energiteknik
Husbyggnad
Annan elektroteknik och elektronik
DOI
10.1002/nbm.4274
PubMed
32078208