Seminar & Colloquium
[세미나: 7월 18일(화), 오전 10시 30분] 가천대학교, 김경남 교수
Title
Optimizing Radio-Frequency Coils for Ultra-High Field MRI: Importance of Electromagnetic Simulations using Biological Virtual Models
Speaker
가천대학교, IT융합대학 의공학과, 김경남 교수
Experience & Education
- 2011 공학박사 (전자공학), 뒤스부르크-에선 대학교
- 2011 - 2012 박사 후 연구원, 가천대학교 뇌과학연구원
- 2012 - 2015 전문연구원, 삼성전자 종합기술원
- 2015 - 2016 연구교수, 가천대학교 뇌과학연구원
- 2016 - 현재 부교수, 가천대학교 의공학과
| Date | Thuesday, July 18th, 2023
| Time | 10:30 ~
| Venue | 33동 315호 (관해 세미나실)
온라인 강의 (https://snu-ac-kr.zoom.us/j/5563427047)
ID: 556 342 7047
[Abstract]
Magnetic Resonance Imaging (MRI) is an essential medical imaging technique that provides detailed visualization of internal body structures. It is a non-invasive, safe diagnostic tool that utilizes a strong magnetic field, radio waves, and a computer to generate images of the body's internal structures. MRI is crucial in diagnosing and monitoring a wide range of medical conditions, including cancer, neurological disorders, joint and bone problems, and cardiovascular disease. It is also used in research to study brain function, tissue properties, and disease mechanisms.
However, the development of ultra-high magnetic field systems of 7 Tesla or more presents a fundamental problem: as the strength of the main magnetic field increases, the wavelength of the high frequency applied to the human body becomes shorter. This leads to non-uniform distribution of the high frequency field in the image area, resulting in low-quality images with non-uniform contrast and signal-to-noise ratio. Additionally, the complexity of the human body's internal structure, as well as the varying dielectric constants and conductivities, can cause constructive and destructive interference of fields, leading to further image quality deterioration. These challenges must be addressed to fully realize the potential of ultra-high field MRI.
Recent research has focused on optimizing multi-channel transmission/reception coils for parallel transmission systems, as well as developing traveling wave coils to overcome limitations in field distribution in ultra-high frequency magnetic resonance imaging systems of 7 Tesla or more. Various types of antennas, such as dipole, monopole, patch, and Yagi-uda are being studied as potential coils for MRI. Unlike loop coils, traveling wave coils maintain the characteristics of the traveling wave, improving the penetration depth of radiofrequency (RF) and obtaining high-quality deep-body images. However, the length of the traveling wave coil increases with the resonant frequency, which can lead to a decrease in signal-to-noise ratio due to external noise. To address this limitation, various coils have been proposed to increase the homogeneity of the magnetic field.
Before fabricating an RF coil, electromagnetic field analysis based on a 3D biological body model is required to optimize the coil structure, analyze the magnetic field distribution, and assess any harmful effects on the human body. The use of biological virtual models in electromagnetic simulations provides a more realistic representation of the human body and its electromagnetic properties. A detailed biological model should provide segmented organs with corresponding permittivity and conductivity values for the frequency of operation. In multi-channel transmission coils, it is crucial to analyze the electromagnetic field characteristics of each element and evaluate the multi-channel modeling and magnetic field characteristics based on transmission efficiency. On the other hand, for reception coils, the performance for parallel imaging can be assessed by examining the feasible acceleration factor, the signal-to-noise ratio, and the g-factor of the multi-channel coil.
The main aim of this study is to demonstrate the importance of electromagnetic simulations in the design of radio-frequency coils for use in MRI systems, with a specific focus on the use of biological virtual models. This approach is crucial to optimize the design of the RF coil, improve image quality, and ensure patient safety in ultra-high field MRI systems.
| Host | 김상국 교수(02-880-5854)