In what unit is precessional frequency measured?

Precessional frequency, which is a key concept in the context of magnetic resonance imaging (MRI), is typically measured in megahertz (MHz). This measurement reflects the frequency at which protons in a magnetic field precess around the direction of the magnetic field. The precession occurs due to the torque exerted by the magnetic field, and the frequency of this rotation is a critical parameter in MRI since it determines the resonance conditions for imaging.

In MRI, the magnetic field strength affects the precessional frequency; higher magnetic field strengths lead to higher frequencies. For example, a clinical MRI system with a magnetic field strength of 1.5 Tesla typically results in a precessional frequency around 63.87 MHz for hydrogen protons. Understanding that the precessional frequency is commonly expressed in megahertz helps in interpreting the operation and optimization of MRI systems effectively, especially when considering different field strengths and their implications for imaging quality and resolution.

While hertz (Hz), kilohertz (kHz), and gigahertz (GHz) are also units of frequency, they are less appropriate for this context. Hertz is the basic unit of frequency and typically used for much lower frequencies. Kilohertz is used for frequencies in a range