Open Scanner Room Door Evacuate personnel from scanner room Announce intention to quench Lift Plastic strike cover on quench button Press and hold Quench button for a count of 3 (The Field should be gone in less than 1 minute) Monitor oxygen level detector for warning Evaluate presence of Magnetic field after Quench Resolve issues leading to quench Notify Siemens and Systems Manager

Scope & application
Overview
definitions
MR safety
Reasons for initiating Quench
Health and Safety Issues
Personnel Qualifications
Location of Systems and Switches
Quench Procedure

1.0 Scope & Application
1.1 This standard operating procedure is for an operator-initiated quench on either the Trio or Sonata MR System. These scanners are housed in the Basement of Rhoads and Founders buildings at the Hospital of the University of Pennsylvania. This SOP will cover:
1.1.1 A short review of safety in MR Environment
1.1.2 Reasons for initiating quench
1.1.3 Location of systems and switches
1.1.4 Actual Quench procedure
1.1.5 Potential issues during quench
1.1.6 Post Quench follow-up

2.0 Overview
2.1 Protecting the health and safety of PENN patients, employees, and students is a top priority. This is why working safely within the MR Research environment is critical.
2.2 The success of this effort relies on the accountability of each individual for their own and others health and safety. This SOP is intended to provide direction and information about an operator-initiated quench. This procedure will rapidly (less than 1 minute) dissipate the existing static field of the MR Magnet.

3.0 Definitions
3.1 Magnet - Super-conducting source of the static field. This field strength 1.5 Tesla for the Sonata and 3 Tesla for the Trio.

3.2 Static Field - This is the field generated by Super-conducting magnet. This field is never turned off unless done by field service or quenched.

3.3 Gauss -The centimeter-gram-second unit of magnetic flux density, equal to one Maxwell per square centimeter. 10,000 Gauss are equal to 1 Tesla.

3.4 Gauss Lines - demarcation lines of specific field strengths

3.5 Oxygen monitor- Sensor inside magnet room that monitors the oxygen level.

3.6 Quench "Operator Initiated" - MR Operator presses the quench switch to rapidly remove the static magnetic field from the MR Suite.

3.7 Spontaneous Quench - The magnet loses the static field without operator initiation. A spontaneous quench can happen if:

3.7.1 Cryogen Levels are allowed to drop past a critical level
3.7.2 A large piece of ferrous material becomes lodged against the magnet
3.7.3 Manual removal of a large ferrous object from the magnet
3.7.4 A cryogenic leak

4.0 MR Safety
4.1 The MR magnetic fields are always on. No ferromagnetic material can be taken inside the scanner room. The ability to know whether a material is ferromagnetic through visual inspection is impossible. Therefore, all equipment containing any type of metal must not be taken into the magnet room. All equipment entering the room must be screened and approved by the Technologist or approved user.
4.2 Personnel must be screened by the MR Technologist or approved user before entering the MRI room.
4.3 Electronic Equipment may not be taken into the scanner room. Electronic equipment often has components that are pulled toward a magnetic field. The safety of the equipment must be determined by the MRI Technologist or CAMRIS member before being taken in the scanner room.
4.4 Safety inspection (6.3) of equipment is done prior to the first procedure. Small ceramic permanent magnets are available at each scanner to evaluate magnetic properties of an object. Ask the Technologist for access to this device.
4.5 Metallic carts are not permitted in the scanning areas.
4.6 All metal must be removed from the animals prior to procedures. (e.g. ID Tags, collars)

5.0 Reasons for Initiating Quench
5.1 Reasons for an operator to initiate the quench sequence are discussed below. Examples are given with each to better illustrate the concepts:

5.1.1 Catastrophic injury :

5.1.1.1 An oxygen tank is brought into the MR Suite. It becomes airborne and pins a person against the magnet.
5.1.1.2 A patient on a wheelchair is brought into the MR Suite. The chair becomes airborne pinning the patient or other personnel against the magnet.

5.1.2 Potential for Catastrophic Injury :

5.1.2.1 A patient on a wheelchair is brought into the MR Suite. The chair is pulled against the magnet while the patient is still in the chair. There is no immediate injury to anyone but the potential for injury is high.
5.1.2.2 An oxygen tank becomes airborne and lodges against the magnet while a patient or personnel are in the room. Again no immediate injury but the large ferrous object is lodged against the magnet presenting an high potential for injury.
5.1.2.3 A fire has erupted in the MR Suite and the arrival of Fire Department and security personnel is imminent.

Our first concern is for the safety of patients and personnel in the MR environment. Stability of ferrous objects lodge on or near the magnet cannot be readily assessed. We must assume that any slight change in their orientation or disposition could have severe consequences. Therefore we want operators of this system to be aware of the quench option and to use it if necessary.

6.0 Health and Safety Issues
6.1 Risks associated with a quench are:
6.1.1 Asphyxia - if the gaseous boil off of the cryogens does not vent properly room air is displaced and persons may asphyxiate.
6.1.2 Cryogenic Burns - If during the boil off some of the magnet cryogens spill out. Personal contact with these substances could cause burns.
6.1.3 Crushing Injuries - as the magnetic field dissipates any objects that were suspended by the magnet will fall and could cause injury.
6.1.4 Increased pressure discomfort - during the quench the pressure in the room may increase causing ear discomfort
6.1.5 Noise Injury - quenches can be very loud and injure hearing

7.0 Personnel Qualifications
7.1 All individuals operating within the MRI environment will be trained Radiologic Technologists or approved users and have reviewed procedural standards of safety. All individuals operating the scanner will have user approval status acquired through CAMRIS.

8.0 Location of Systems and Switches
8.1 The Hup5 magnet is located in the basement of the Founders Building. The quench venting duct of this system is on the roof directly above the small conference room in the Radiologist MR Learning Center. The venting system is checked and maintained by Siemens.
8.2 The quench switches and oxygen sensor for Hup5 are located in the MR suite as shown on the following diagram.

8.3 The Hup6 magnet is located in the basement of the Rhodes Building. The quench venting duct of this system is located directly above the large conference room in the Radiologist MR Learning Center. The venting system is checked and maintained by Siemens.
8.4 The quench switches and oxygen sensor for Hup6 are located in the MR suite as shown in the diagram.

9.0 Quench Procedure
9.1 Open Scanner Room Door - the door of the scanner room should be open during the quench to allow any gases not vented to escape from the room. Improperly vented gas in the MR Suite can cause increased pressure on the door and make it impossible to open. It will also displace breathable air from the room.

9.2 Evacuate personnel from scanner room - the MR Suite and surrounding area should have patients and nonessential personnel removed from the area before the quench when practicable.

9.3 Announce intention to quench - the operator should announce the intention to activate the quench procedure to alert all individuals in the immediate area.

9.4 Lift Plastic strike cover on quench button - the quench switch is covered by a protective plastic cover. It must be lifted up away from the button before the button can be activated.

9.5 Press and hold Quench button for a count of 3 - the quench switch must be pressed firmly and held closed for a short time to ensure the desired quench takes place.

9.6 Monitor oxygen level detector for warning - there is an oxygen sensor in each MR suite mounted at head level. It activates the oxygen alarm outside of the room when oxygen level has reached a level which cannot sustain life.

9.7 Evaluate presence of Magnetic field after Quench - using the gauss meters available at the entrance to each scanner walk into the room and look for evidence of the displacement of the meter's indicator. If the indicator does not move the field is no longer active.

9.8 Resolve issues leading to quench - It is now possible to enter the room with equipment and emergency personnel to retrieve objects or implement activities that are necessary to resolve the issues leading to the quench.

9.9 Notify Siemens Medical and Systems Manager.

9.9.1.1 Hup5 and Hup6 - Norman Butler - 610-209-8438
9.9.1.2 Siemens Medical - 1-800-888-7436