Mrso stuvia - Study guides, Class notes & Summaries

Zero Boil-Off - Answer System that reduces/eliminates the need to recharge Helium in a magnet. Quench - Answer Quickly eliminating the magnetic field. Not immediate, takes 3 to 5 minutes to completely eliminate magnetic field. Loud Noise as Helium rushes out of Quench Vent. Can cause crack in the wire (very costly to repair/replace). Ohm's Law - Answer Resistance that is equal to Voltage divided by the amperage in a wire. V=IR Use of Cryogen reduces/eliminates heating with ...

How do magnetic flux lines travel? A. North to South B. South to North C. East to West D. West to East - Answer A North to South Which of the following can be potential safety concerns to a patient in the static magnetic field? A. Electrically conductive materials B. Ferrous objects C. Magnetic objects D. All of the choices. - Answer D. All of the choices An object that retains its magnetic field when exiting the static magnetic field is call what? A. Paramagnetic B. Diamagnetic ...

What pulse sequence will produce the most patient heating? A. Inverse recovery sequence B. Single shot fast spin echo C. Conventional spin echo D. Gradient Echo - Answer B. Single shot fast spin echo During acquisition, it is noticed that the T wave of the cardiac cycle is elevated. What is this artifact called? A. Magnetohydrodynamic Effect B. Excitation C. Teratogenesis D. Magnetophosphenes - Answer A. Magnetohyrdodynamic Effect When can heating occur in a wire? A. Only in...

All MR medical directors must report incidents to which of the following? a. FDA Medwatch Program b. ACR MR safety board c. None of the choices d. All of the choices - Answer a. FDA Medwatch Program Which of the following is not true? a. Screening process for non-MR personnel and MR personnel should be different. b. Screening process for non-MR personnel and MR personnel should be the same. c. Unscreened patient should not enter zone III. d. Zone IV is the responsibility of the a leve...

Which of the following describe when a non-ferrous object is repulsed by static magnetic field? a. Fourier transformation b. Lenz's force c. Ohm's law d. Larmor equation - Answer b. Lenz's force What is the FDA SAR limit for the whole body in first level controlled operating mode? a. 8 W/kg for 15 mins b. 4 W/kg for 15 mins c. 3 W/kg for 10 mins d. 7 W/kg for 20 mins - Answer b. 4 W/kg for 15 mins Gadolinium contains what kind of magnetism? a. Diamagnetic b. Paramagnetic c....

The quench vent in the MR room should be inspected by who? a. facility engineers b. manufacturer engineers c. MR tech d. MRMD - Answer b. manufacturer engineers The quench vent outside the MR facility is inspected by who? a. facility engineers b. manufacture engineer c. MR tech d. MRMD - Answer a. facility engineers If a cryogen comes in contact with skin, what will happen? a. frostbite/necrosis b. nothing, in its gas form c. explode d. combust - Answer a. frostbite/necrosis ...

Peripheral nerve stimulation can be described by which of the following? a. Faraday's law of induction b. Ohm's law c. Lenz's law d. Planks Law - Answer b. Faraday's law of induction (describes the induction of electrical current in the presence of a changing magnetic field). Lenz's force describes the opposing forces created. Ohm's law deals with the resistance of current along a wire. Gad contrast has been found in the body in what form? Select all that apply. a. Water-solubl...

What is the name of the gradient coil used to produce sagittal and coronal images? a. Transverse coil b. Golay coil c. Maxwell coil d. Receiver coil - Answer b. Golay coil ("saddle coil") Which of the following is able to handle the most RF heating? a. elderly b. adult c. obese adult d. neonate - Answer d. neonate Which of the following techniques can be used to increase the echo spacing? Select all that apply. a. Increase the TR b. Decrease receiving bandwidth c. Increase...

The control room is found where? a. Zone I b. Zone II c. Zone III d. Zone IV - Answer C. Zone III Which of the following describe when a non-ferrous object is repulsed by static magnetic field? a. Fourier transformation b. Lenz's force c. Ohm's law d. Larmor equation - Answer b. Lenz's force Which of the following are recommended by the ACR Guidance document in MR safety 2013 in proper scanning of a patient? I. Metal detector II. Ferromagnetic detection system III. Writte...

Purpose of RF (B1) field - Answer excite hydrogen protons RF energy is absorbed by tissues - Answer within the volume of the RF transmit coil. This is a thermogenic process. Thermogenic process - Answer Results in production of heat. Ex: RF energy absorption MRI local and whole-body tissue heating is due to - Answer magnetic induction Types of RF coil designs - Answer -linearly polarized -circularly polarized (quadrature) Function of coils - Answer -transmit only -receive only ...