字幕列表 影片播放 列印英文字幕 MRIs use protons, which are abundant in the human body. All protons spin creating a small magnetic charge. When a strong magnetic field is introduced, as is the case in an MRI machine, the protons align with that field. The MRI technician then introduces a radiofrequency pulse that disrupts the proton and forces it into either a 90 degree or 180 degree realignment with the static magnetic field. Since the radiofrequency pulse pushed the proton against its nature, once this pulse is turned off, the protons realign with the magnetic field, releasing electromagnetic energy along the way. The MRI is able to detect this energy, and is able to differentiate various tissues based on how quickly they release energy after the pulse is turned off.
B2 中高級 核磁共振是如何工作的? (How Does an MRI Work?) 198 19 Cheng-Hong Liu 發佈於 2021 年 01 月 14 日 更多分享 分享 收藏 回報 影片單字