I'm currently a rad tech student and we're doing a section on CT and MRI. I'm trying to get my head around the MRI part and I think I have an idea how it works, but thought that I'd run it past the hive mind and find out-
This is intended to be a super basic overview.
So...hydrogen nuclei process. If you apply a sufficiently strong magnetic field, you can excite some of them to switch from a spin-up state to a spin-down state, and cause the net magnetic vector of the tissue to drop to zero. Then when you hit them with an appropriate burst of EM energy you can get them to all process in phase, and cause a rotating magnetic vector that is perpendicular to the machine's magentic field. When the exciting energy is removed this rotating vector can be detected by the current it induces in a coil, and the tissue type can be determined by how quickly the nuclei shed their energy as heat and return to their natural procession, causing the rotating transverse vector (and therefore the induced current) to disappear.
Am I close?
[link] [comments]
source https://www.reddit.com/r/Radiology/comments/y7819m/question_about_mri_physics/
Comments
Post a Comment