How Dangerous are magnetic objects near an MRI Magnet

What is the primary cryogen used in modern superconducting MRI magnets to maintain superconductivity?. Liquid Nitrogen. Liquid Oxygen. Liquid Helium. Compressed Air.

At what temperature must liquid helium be maintained to keep the magnet coils in a superconducting state?. $0^{\circ}C$. $-100^{\circ}C$. $-269^{\circ}C$ (approximately $4\ K$). $-452^{\circ}C$.

Which of the following best describes an MRI "quench"?. The process of cooling the magnet during installation. A sudden loss of superconductivity leading to rapid cryogen boil-off. A scheduled software update for the gradient coils. The act of cleaning the bore with specialized chemicals.

If a quench occurs and the venting system fails, what is the most immediate life-threatening risk to people inside the scan room?. Magnetic pull. Asphyxiation due to oxygen displacement. Radiation exposure. Hearing loss from the alarm.

Why might a quench cause the scanning room door to become impossible to open?. The magnetic field locks the electronic latch. The cold temperature freezes the hinges. Rapidly expanding helium gas creates extremely positive pressure against an inward-swinging door. The emergency alarm system automatically bolts the door for security.

What is the expansion ratio of liquid helium when it converts to a gaseous state at room temperature?. 1 to 50. 1 to 100. 1 to 700. 1 to 2000.

In what specific emergency scenario should a technologist manually initiate a quench?. A patient is having a mild allergic reaction to contrast. A small fire is detected in the breakroom. A person is pinned to the magnet by a large ferrous object and is in a life-threatening situation. The image quality is poor due to artifacts.

What is a potential "fire hazard" associated with a quench, even though helium itself is not flammable?. Helium gas acts as a fuel for flames. The extreme cold can cause atmospheric oxygen to liquefy on surfaces, creating an oxygen-enriched environment. The quench button creates an electrical spark. Static electricity increases significantly during boil-off.

If a technologist is trapped in the scan room during a quench and the door will not open, what should their first action be to equalize pressure?. Wait for the helium to settle. Try to unscrew the door handle. Break the control room window (observation window). Call the service engineer on a cell phone.

After a quench has been completed, when is it safe for personnel to re-enter the scanning room?. Immediately after the visible cloud disappears. As soon as the magnet stops button is reset. Only after the room has been ventilated and oxygen levels are confirmed safe by qualified personnel. Once the patient has been moved to the hallway.