The Larmor frequency (precession frequency of hydrogen protons) in a 3 Tesla MRI scanner is approximately:
- A 42.58 MHz
- B 63.87 MHz
- C 127.74 MHz ✓
- D 170.32 MHz
Correct answer: C. 127.74 MHz
Explanation
The Larmor equation states that ω = γ × B0, where γ (gyromagnetic ratio for hydrogen) is 42.58 MHz/T. At 3 Tesla, the Larmor frequency is 42.58 × 3 = 127.74 MHz. Option A is the value at 1 Tesla, and option B is approximately the value at 1.5 Tesla.
Reference: MRI in Practice, 5th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.