Question

A hypothetical MRI is made having a magnetic field (B0) of 7 Tesla. This uses nitrogen for study. The gyrometric ratio of nitrogen 15 is -4.316. Find the Lamar frequency.

(a) -35.889

(b) – 30.212

(c) 0

(d) -189.812

This question was addressed to me during an internship interview.

My doubt is from MRI topic in portion Diagnostic Investigation via Imaging Techniques of Clinical Science

Answer 1

The correct option is (b) – 30.212

The explanation is: Gyrometric ratio is the ratio of the magnetic moment to the angular moment of the element. Lamar frequency, also called as Lamar precision is the frequency by which the element will undergo a change in orientation when placed in a strong external magnetic field. Lamar frequency is given by the formula:  f = γn x B0/2Π

Here γn/2Π is the gyrometric ratio. Thus,

 f  =  -4.316*7 = -30.212.