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RadNet HAZARDOUS MATERIALS BUSINESS PLAN MRI Manual / Regulatory Affairs Original Effective Date: April 28, 2021 APPENDIX B - EMERGENCY RESPONSE PLAN Cryogen Safety and Magnet Quenching A superconductive magnet uses cryogens to super-cool the electrical conductor that creates the magnetic field. Cryogens are liquids with a normal boiling point below -130 F°. Liquid helium is typically used in MRI systems. Temperatures as low as -452°F are achieved. When a cryogen boils, its volume increases by a factor of 700. This can result in high pressures that may cause explosions. Thus, it is crucial to learn proper handling techniques. Typical use of cryogens creates three lethal hazards 1. The cold can cause cold burns, even frostbite, and hypothermia. 2. The boil-off can displace oxygen in the room, leading to asphyxiation. 3. The boil-off can build up pressure in a sealed container, leading to an explosion. Exposure to frostbite or hypothermia can be caused by: 1. Directly touching the liquid with your skin. 2. Indirectly touching something cooled by the cryogenic liquid, like a metal transfer line. 3. Indirectly by exposure of skin or eyes to the cold gas coming out of the pressure relief valve at the end of the transfer line. Exposure to asphyxiation can be caused by: 1. Working in a room without a properly working ventilation system. 2. Standing in or around the white "fog cloud"that is emitted from the pressure relief valve end of a transfer line, or above a spill. Explosions can be caused by: 1. Sealing any pressure relief valves on a cryogenic system or dewar (a double walled metal tank with a vacuum between the walls that is used to hold liquids at a temperature well below the tank's surroundings). 2. Leaving LHe or LH2 dewar transfer valve open such that as the initial boil-off decreases, air can get into the dewar and freeze solid, resulting in a plug inside the dewar. This prevents the pressure relief valves from working, resulting in a slow build- up of pressure. Warning signs of a damaged dewar or cryostat: 1. Continuous venting from a vent valve is not normal. It could mean there is dirt in the vent valve or it is damaged. 2. Sweat or frost at the bottom or sides of a dewar or cryostat is an indication of a faulty or damaged vacuum jacket. If you discover a dewar or cryostat in this state, contact the MRI equipment vendor immediately. Emergency Response When the cyrogens escape from the scanner, it is known as a QUENCH. A quench is indicated by a loud noise and/or warning message. In the event of a quench, all personnel and patients must be immediately evacuated from the MRI system scan room as quickly and as safely as possible. Failure to follow this precaution can result in serious injury (e.g.: asphyxiation, frostbite, or injuries due to panic) or death. 8