3Interactive 3D demonstration of MRI spin physics.
5**Live: https://concept-collection.github.io/mri-spins/**
7A sample of isochromats (sphere or cube) evolves under the Bloch equations in
8the rotating frame. Apply RF pulses, gradients, and a Larmor frequency offset;
9adjust T1/T2 relaxation; and view the magnetization as vector arrows or
10colored balls. A live trace shows the signal (real and imaginary parts of the
11net transverse magnetization).
13A built-in spoiled gradient echo sequence plays out 16 phase-encoded TRs,
14driving the controls automatically and acquiring signal during the readout
15windows. Optional gradient sounds click like a real scanner.
17## Things to try
19- Apply a 90° pulse: the spins precess at Δf₀ while T2 attenuates the signal
20 and Mz recovers with T1.
21- Turn up Gx to dephase the spins, then apply a 180° pulse to refocus them
22 into a spin echo.
23- Turn on sound and run the spoiled gradient echo.
25Single static page, no build step — three.js is loaded from a CDN. Serve
26locally with any static file server, e.g. `npx serve .`