| Zugriffsnummer | 44435 |
| Dokumenttyp | Zeitschriftenartikel |
| Peer Review | mit Peer Review |
| Sprache | Englisch |
| Titel | Parallel transmission medical implant safety testbed: Real-time mitigation of RF induced tip heating using time-domain E-field sensors |
| Autor(in); Institution |
Winter, Lukas; 8.1, Biomedizinische Magnetresonanz, PTB-Berlin
Silemek, Berk; 8.1, Biomedizinische Magnetresonanz, PTB-Berlin
Petzold, Johannes; 8.1, Biomedizinische Magnetresonanz, PTB-Berlin
Pfeiffer, Harald; 8.1, Biomedizinische Magnetresonanz, PTB-Berlin
Hoffmann, Werner; 8.1, Biomedizinische Magnetresonanz, PTB-Berlin
Seifert, Frank; 8.1, Biomedizinische Magnetresonanz, PTB-Berlin
Ittermann, Bernd; 8.1, Biomedizinische Magnetresonanz, PTB-Berlin
|
| Quelle/Jahr | Magnetic Resonance in Medicine: 84 (2020), 6, 3468 - 3484 |
| ISSN | 0740-3194 (print) ; 1522-2594 (online) |
| DOI | |
| Verlag | Wiley-VCH |
| Freie Schlagworte | implant safety ; interventional MR ; MR safety ; open source hardware ; orthogonal projection |
| Zusammenfassung | Purpose To implement a modular, flexible, open‐source hardware configuration for parallel transmission (pTx) experiments on medical implant safety and to demonstrate real‐time mitigation strategies for radio frequency (RF) induced implant heating based on sensor measurements. Methods The hardware comprises a home‐built 8‐channel pTx system (scalable to 32‐channels), wideband power amplifiers and a positioning system with submillimeter precision. The orthogonal projection (OP) method is used to mitigate RF induced tip heating and to maintain sufficient urn:x-wiley:07403194:media:mrm28379:mrm28379-math-0002 for imaging. Experiments are performed at 297MHz and inside a clinical 3T MRI using 8‐channel pTx RF coils, a guidewire substitute inside a phantom with attached thermistor and time‐domain E‐field probes. Results Repeatability and precision are ~3% for E‐field measurements including guidewire repositioning, ~3% for temperature slopes and an ~6% root‐mean‐square deviation between urn:x-wiley:07403194:media:mrm28379:mrm28379-math-0003 measurements and simulations. Real‐time pTx mitigation with the OP mode reduces the E‐fields everywhere within the investigated area with a maximum reduction factor of 26 compared to the circularly polarized mode. Tip heating was measured with ~100 μK resolution and ~14 Hz sampling frequency and showed substantial reduction for the OP vs CP mode. Conclusion The pTx medical implant safety testbed presents a much‐needed flexible and modular hardware configuration for the in‐vitro assessment of implant safety, covering all field strengths from 0.5‐7 T. Sensor based real‐time mitigation strategies utilizing pTx and the OP method allow to substantially reduce RF induced implant heating while maintaining sufficient image quality without the need for a priori knowledge based on simulations or in‐vitro testing. |
| Kostenfreier Zugang | Open Access Hybrid |
| Rechteinformation | CC BY 4.0 ; Creative Commons Attribution 4.0 License |
| Themenbereich der Metrologie | Metrologie in der Medizin |
| Forschungsprojekt | 17IND01: MIMAS: Procedures allowing medical implant manufacturers to demonstrate compliance with MRI safety regulations |
| Förderinformationen (1) |
Förderername: European Commission (EC)
Förderer ID: 0000 0001 2242 8989 Förderer ID Typ: ISNI Förderprogramm: EMPIR 2017 Industry Titel der Förderung: 17IND01: MIMAS: Procedures allowing medical implant manufacturers to demonstrate compliance with MRI safety regulations Förderungsnummer: 17IND01 |
Zitierung
Winter, L., Silemek, B., Petzold, J., Pfeiffer, H., Hoffmann, W., Seifert, F., & Ittermann, B. (2020). Parallel transmission medical implant safety testbed: Real-time mitigation of RF induced tip heating using time-domain E-field sensors. Magnetic Resonance in Medicine, 84(6), 3468–3484. https://doi.org/10.1002/mrm.28379