What happens to rotational force as one moves away from isocenter?

When considering the behavior of rotational force, or torque, in the context of magnetic resonance imaging (MRI) and the magnetic field configuration, it is essential to understand how distance from the isocenter affects the magnetic environment.

As one moves away from the isocenter of the MRI magnet, the homogeneity of the magnetic field tends to degrade, which can lead to variations in magnetic field strength across the imaging volume. In general, the rotational force that affects how spins align with the magnetic field diminishes as the distance from isocenter increases. This decrease occurs because the magnetic field strength typically weakens further from the central region of the magnet, resulting in less effective torque acting on the magnetic moments of the nuclei being imaged.

In summary, moving away from the isocenter leads to a decrease in the rotational force due to the weaker magnetic field strength, thereby validating the assertion that it decreases.