MRSO EXAM PREP |Question and Answers| #Latest Version

MRSO EXAM PREP |Question and Answers| #Latest Version Zero Boil-Off *Ans* System that reduces/eliminates the need to recharge Helium in a magnet. Quench *Ans* 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 *Ans* Resistance that is equal to Voltage divided by the amperage in a wire. V=IR Use of Cryogen reduces/eliminates heating with high voltage and amperage which allows for high magnetic field. Cryogen *Ans* Liquid Helium 42* Kelvin Dual Cryogen System *Ans* Helium Nitrogen (used to keep Helium cold as back-up) Quench Vent *Ans* Used to vent boiled off Helium to the outside. Quench Vent in MRI Room is Zone IV (MRI manufacturer/engineer responsible for inspecting) Quench Vent outside is Zone III (Facility responsible for inspecting) Quench concerns with malfunctioning Quench Vent. *Ans* Dense fog in room. Can rain or snow which can contain Oxygen which is a fire risk. Hypothermia/Frostbite due to lowered room temperature. Aphyxiation Ruptured Ear Drums because of increased pressure in room. Difficulty opening door to Zone III due to increased pressure. May have to break window to release pressure. Magnet doesn't immediately lose its magnetic field. Peripheral Nerve stimulation due to change in magnetic field. Static Magnetic Field Concerns *Ans* Translation/Rotational Force *No adverse effects to patients or fetus have been noted to individuals exposed to up to 8T. Static Magnetic Field Occupational Exposure Limits *Ans* ICNIRP - Head and trunk is limited to a magnetic flux density of 2T - Limits are limited to a magnetic flux density of 8T IEC - Head and trunk is limited to a magnetic flu