Medical diagnostic techniques enable the interior of the human body to be investigated. (a) Calculate the Larmor frequency for a hydrogen proton in an MRI scanner that has a magnetic field of 9.4 T, knowing that its gyromagnetic ratio is 42.58 MHZ/T. (2 marks) (b) Both CT and PET medical imaging techniques use a ring of detectors around the patient. Briefly describe how CT and PET work, and explain how the two techniques differ. (3 marks) Page 21 of 24