MRI In Practice 5th edition - Chapter 10 - Safety questions and detailed verified answers pass guaranteed.

Who ultimately determines if a patient can undergo an MRI procedure - correct answer Radiologist Give 3 examples of accidents around an MRI scanner - correct answer Metal being pulled into the MRI scanner, Burns from RF coils, Contrast reaction What are the 3 components of magnetic resonance imaging that potentially could cause harm to an individual - correct answer The main magnetic field, RF pulse, Gradients Which year did the ACR guidelines (White Paper) first get published? - correct answer 2002 What does the ACE White Paper offer - correct answer Guidelines for safe and effective operation of the MR imaging facility In reference to the Static Magnetic Field, which zone is the MRI Scanner in ? - correct answer Zone 4 In reference to the static magnetic field, who is allowed to let people into zone 3 & 4 - correct answer A trained MR personnel In reference to the Static Magnetic Field, who needs to be "screened" before entering zone 3 & 4? - correct answer Everyone What are the two websites in the book dealing with MRI safety issues? - correct answer , If an item is tested at 1T and deemed safe, then it is OK to take that item into a .5T scanner - correct answer False What 4 tings are required to create an MR image? - correct answer Static magnetic field, Radio Frequency Field, Gradient Field, and a body to image What are some potential side effects from exposure to an RF irradiation? - correct answer Heating of tissue, RF antennae effects, Thermal injuries How is the side effects from RF irradiation measured? - correct answer Specific absorption units (SAR), in units of watts per kilogram (w/kg) and temperature (core body & peripheral body temperature) What are some of the potential injuries resulting from the gradient Magnetic Field? - correct answer Peripheral nerve stimulation, Magneto-phosphenes, Acoustic noise What does TVMF stand for and why are we concerned about it in MRI - correct answer Time varying magnetic fields, the potential exists for induction of voltage within a conductor, Induced currents are proportional to the materials conductivity and rate of change of the magnetic fields, in MR this is determined by pulse duration, wave shape, repetition pattern and distribution of the current in the body. What is the magnetic field strength of the earth? - correct answer 0.6G How many Gauss is 1T - correct answer 10,000 What does quench stand for? - correct answer The venting of the cryogen from around the magnet to release the magnetism of the wires or de-magnetizing a magnet What is typically used to maintain the superconductivity of the MR magnet? - correct answer Liquid helium What is the typical temperature of the cryogen bath? - correct answer -269C (-450F) How many liters of helium gas has to be compressed to fill a typical cryogen bath of 1,500 liters? - correct answer Over 1,000,000 liters of helium gas IF a scanner quenches, where does all the helium go? - correct answer Through the quench pipe to the outside environment What is the potential to anyone in the room if the quench pipe fails? - correct answer Freezing to death, asphyxiation, breaking of the windings of the magnet What are the 2 forces within the MR environment from the static magnetic field, and why are we concerned about them? - correct answer Translational forces: is responsible for ferromagnetic objects being violently attracted into the MR scanner. Rotational forces: is responsible for an aneurysm clip moving or twisting when entering the bore of the magnet. Define "Fringe Field" - correct answer This is the magnetic field outside the bore of the magnet What is the term for a flying object into the bore of the magnet - correct answer Missile affect Define the 4 zones in a typical ACE designed MR facility - correct answer Zone 1: Includes all areas that are freely accessible by the general public Zone 2: The interface between zones 1 and the strictly controlled zone 3, This area all personnel are permitted into and there should be a locked door leading into zone 3 Zone 3: All access to this zone should be strictly limited and only level 2 personnel should be the one to allow access to this zone.