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Lacey Berry's manual on safety training General Information Risks associated with the MRI lab: Used properly, the magnetic resonance imaging equipment contained within the MRI lab is quite safe, however, it poses serious risks to the unwary. Users of the lab should be completely familiar with this manual and with the procedures for protecting others from hazards. To minimize risks to subjects and other members of the research team, only personnel who have successfully completed the full CAMRI safety certification process are allowed access to the MR scan rooms, control rooms or equipment rooms. Observers who have not been safety trained are not permitted to enter the MRI suites without special prior arrangements. The main hazards in the lab are: • The “projectile effect” when heavy, sharp, or dangerous objects are hurled into the instrument. Even seemingly innocuous objects, such as hand tools, can be lethal. • Pacemaker damage. Certain cardiac pacemakers can be damaged by exposure to magnetic fields, causing direct hazards to subjects. Under no circumstances should persons with pacemakers enter the MRI suites at CAMRI. • As in many laboratories, the MRI lab contains wiring and circuitry that operate at dangerous voltages. Under no circumstances should users touch any exposed wiring, or any exposed terminals in the equipment cabinets. • Grossly improper scanner operation could result in excessive heating of the subject due to RF energy being deposited. This is easily avoided by operating the equipment according to the guidelines contained in the user manuals and set by the individual instructors. • Suffocation: in extreme cases, the imaging magnet may release large volumes of helium gas that can rapidly force all air out of the scan room. Normally, the helium gas would be vented through the roof. However, there is a small but significant risk that the venting system could fail. Safe Areas There are no areas in the MR suites that can be considered completely safe. The control rooms, scanner rooms, and equipment rooms all have risks associated with magnetic fields and/or electrical equipment. CAMRI safety certification is required for personnel to enter any of these areas. Reduction of Risks The chief risk exposure in the lab is to entering personnel who are unfamiliar with the equipment and its hazards. Personnel working in the facility must be constantly vigilant of who is entering the console or scan room areas. Especially in emergency situations, you must ensure that no one without proper training enters any of the scanner rooms, and even then, that they have adequately checked themselves for possible hazards such as projectiles. Many objects in the scanner control rooms and equipment rooms are NOT MR compatible and may become projectiles in the MR scanner rooms. You must never move any object from these rooms into the MR scanner rooms unless you are absolutely certain that the object is MR safe. Similarly, some objects in the MR scanner rooms may only be safe when kept at a distance from the MR scanner. Only personnel explicitly authorized to do so should move objects in the scanner room that are labeled “Not MR safe”. Only objects that are not ferromagnetic should be labeled with a “MR safe” label and this safe label should not be in red or orange. Unlabeled objects should be assumed NOT safe to move unless they are clearly non-metallic. Tours and Training Exercises As interesting as the equipment is, please resist the temptation to show visitors the scanner “up close,” as this introduces the unnecessary risk of unwittingly exposing people to potential hazards. Tours or training exercises that would involve having non-safety trained personnel present in the scanners, control rooms or equipment rooms must be authorized in advance by a CAMRI staff member and must be performed in compliance with any special requirements included as part of that authorization. Reporting of safety incidents or near-incidents All incidents or near-incidents must be reported to Krista Runge or Lacey Berry as soon as possible and no more than 24 hours after the incident. 3 Principles of MR Imaging: THE SCANNER IS ALWAYS ON. A serious hazard for MRI safety is allowing object to become attracted to the static magnetic field. This can result in an individual being struck, injured or trapped against the magnet by the object. Equipment can also become damaged by slamming into the magnet or being struck by another object that is accelerating rapidly due to the strong attraction of the magnetic field. There are three main component of the MRI scanner: the static magnetic field, the radiofrequency field, and the gradient or time varying magnetic field. 3.1 Static Magnetic Field The static magnetic field is the main magnetic field that is always present once the scanner is ramped up to the designated field strength. This field is described in units of Tesla (T) or Gauss (1T = 10,000 gauss). Our system uses a 3T static magnetic field, approximately 60,000 times stronger than the earth’s magnetic field that induces a compass to point North. The distance for the magnet that is safe for the general public and to use all objects and devices is denoted as the 5 gauss line. The researcher(s) must be aware of the fringe field, before deciding to take objects into the scanner room. 3.2 Radiofrequency Field The radiofrequency (RF) coil is the heating source within the scanner. This system uses coils as transmitters to excite the MRI signal and as a receiver to detect the MRI signal. It is important to properly use the equipment and accessories of the MRI scanner. 3.3 Gradient/Time varying Magnetic Field The gradient or time varying magnetic field selects the slices and imaging planes. This particular field is superimposed over the static magnetic field, and is the sources of all the acoustic noise. The coils within this system are pulsed on and off to produce linear gradients of the magnetic field for imaging. This allows producing an array of images with different spatial and temporal resolutions, and with different contrast between tissues in the image. Metal Screening Anyone preparing to enter an MR scanner room must complete a metal screening form, and this form must be reviewed before access to the scanner room is granted. Individuals who are safety certified at CAMRI are not required to personally complete a formal written metal screening form about themselves but are responsible for verifying that they are personally safe to enter the scanner room. Before entering the scanner room, subjects and staff must remove all objects from their person that might constitute a risk in the MR environment. It is the investigator’s responsibility to assure that this has been done. Subjects should be asked to turn pockets inside out to demonstrate that no potentially hazardous objects have been overlooked. Silver, gold and platinum jewelry is not ferromagnetic. Nonetheless, subjects should remove jewelry before going in the scanner since these metals can still conduct electricity and therefore pose a risk for burns in the presence of time-varying magnetic fields. Jewelry that forms large loops is particularly hazardous. Screening responses If there are any doubts regarding the metal screening responses, do not allow the individual to enter the scanner room. The fact that the individual has been scanned in an MR scanner previously (even at CAMRI) is never a sufficient basis upon which to conclude that the subject can enter the scanner room safely, since risks vary according to magnetic field strength. Dental fillings and orthodontic braces do not constitute significant risks (though the latter may produce unacceptable artifacts) and do not preclude scanning. Subjects with tattoos or permanent eyeliner should be advised of the small risk of local redness or irritation and asked to report any discomfort immediately. Scanning should be stopped immediately if such discomfort develops. These small risks may be further reduced by applying a damp cloth to the area during scanning. MRI compatible devices Some implanted metal devices have been established as safe for MR scanning. A recent copy of Shellock’s book cataloguing implanted medical devices is available in the MR suite and up-to-date information is always available on the website http://www.mrisafety.com. If, in reviewing these resources, you believe that it is possible to safely scan your subject, you should contact Krista Runge or Lacey Berry to request authorization to scan the subject. Even if you are certain that the implanted metal does not constitute a risk, do not allow the individual into the scanner room unless you have obtained explicit authorization to do so. It is better to ask these questions before your research subject arrives to prevent cancellation at the last minute and inability to scan. Ear Plugs and Headphones Anyone in the scanner room while the scanner is in operation must be provided with and must use hearing protection in the form of earplugs and/or headphones to avoid hearing injury from the acoustic noise generated by the scanner. According to the Trio documentation, hearing protection for subjects should provide a single number rating (SNR) of 10 dB or greater. We provide both ear plugs and headphones in each of our rooms here at CAMRI. Sources of acoustic noise: When the scanner is not acquiring images, the only source of acoustic noise is the chirping of the pump used to circulate cold water. Different studies have report this noise to be in the 65-80 dB range, below the OSHA standard necessitating the use of a hearing protection device (HPD). The time-varying gradient magnetic fields are the primary source of acoustic noise during MR imaging. The rapid rise and fall of currents within the gradient coils in the presence of the static magnetic field create strong Lorentz forces that cause the gradient coils to move against their mountings. The vibration of the coils and the vibration and flexing of their mountings cause the loud tapping and knocking noises during imaging Medical Crash Cart We do not have a MD here at CAMRI and we do not have a medical crash cart. For these reasons individuals that pose a risk for coding or any other safety concern should not be scanned here at CAMRI. Because we have no crash cart we do not do studies that involve contrast. In case of an emergency you should dial 911 and remove the individual from the scanner before they arrive. Squeeze Ball Siemens Squeeze Ball The scanners are equipped with a squeeze bulb that allows the subject to set off an audible alarm to attract the operator’s attention. The squeeze bulb should be made available to subjects unless some alternative method of constant monitoring (e.g., another person in the scanner room) is in effect. Use of the squeeze bulb or some comparable form of continuous subject monitoring is mandatory if you are operating the scanner in “Level 1” mode, which has an increased risk of magnetostimulation or subject heating due to RF energy deposition or if you are scanning a subject who has a tattoo or permanent eyeliner. The squeeze bulb plugs into the red connector at the foot of the bed. You can verify that the squeeze bulb is connected by noting that the squeeze bulb LED lights up when you press the talk button on the intercom. If the subject squeezes the squeeze bulb, a continuous audible alarm is emitted via the intercom and the intercom squeeze bulb LED lights up. Responding to a squeeze bulb alarm 1) If a scan is ongoing, press the “Stop” button on the console using the mouse. Alternatively, you may press the “STOP” button on the Siemens intercom twice (5) to stop the scan immediately. This is especially important if you are scanning in “Level 1” mode rather than standard mode since the subject may have triggered the squeeze ball in response to magnetostimulation or excessive heating. 2) Press the appropriate intercom talk button (11) to stop the audible alarm. 3) While holding down on the intercom talk button, speak to the subject to determine why the squeeze bulb was pressed. Make sure that the volume is turned up so that you can hear the subject’s response. 4) If necessary, enter the room to further investigate and/or correct the problem. Safety Policies Door Security Policy Scan doors should NEVER be left open unattended. Make it a habit to close the door after you. Accurate weight/height input Policy The scanners require that the subject’s height, weight, age and sex be entered before scanning. Accurate information must be provided to ensure that FDA limits for energy deposition are not exceeded. Weights should be correct to within five pounds. Incorrect information should never be entered in an effort to get the scanner to conduct a study that it otherwise would not perform because FDA limits would be exceeded. Temperature Control Policy In regulating energy deposition in the subject’s body in accordance with FDA guidelines, the scanners assume that the ambient temperature in the room does not exceed 72° and that the relative humidity does not exceed 60%. Consequently, the thermostat should never be set for a room temperature higher than 72°. Please note that only cotton, linen or paper should be used for bed covering or blankets since radiofrequency energy may cause heating of synthetic sheets or blankets. Large/Obese subject policy Subjects weighing more than 300 pounds should not be scanned. The Trio 3.0 Tesla scanner bed is designed to support weights up to 440 pounds. Even subjects weighing substantially less than 300 pounds should never be allowed to sit at the distal end of either of the scanner beds, since they are not designed to support the full weight of a large subject applied at full mechanical advantage. To avoid burns or peripheral nerve stimulation, a minimum distance of 5 mm should be maintained between the subject’s body and the wall of the scanner tunnel. MR pads or cotton sheets available in the MR scan rooms can be used to assure this distance is maintained. Children policy Children may only enter the scan rooms as participants in an IRB approved research study of children. Children not involved in the research study (e.g, the child or sibling or a research subject) may not enter the scan room. All safety precautions applicable to adult subjects are applicable and if anything, more important in children. Careful metal screening, accurate entry of age, sex and weight, and use of “Standard Mode” scanning options whenever possible are important steps in minimizing risks to this population . Performing a Routine Scanner Shutdown or Reboot A shutdown or reboot of the MRI scanner initiates a routine electrical shutdown should a situation or problem arise. This takes a few minutes to complete and can be down if any of the following occurs: 1. A notice has been received that there is an electrical outage to the building. 2. There are visible alarms that revealed that the magnet has quenched or that helium levels are low. 3. The scanner table is not responding to controls. 4. An error message has occurred that requires the system to be rebooted. Shut down or Reboot Procedure: 1. Along the top of the system is a bar of various commands. Select “System”. 2. From “System” <End Session>: 3. Then select either, <Shutdown System>, <Restart System>, or <Restart Application> a. Shutdown System will shut down the entire MR system. b. Restart System is only used to reboot the system. c. Restart Application is only used to reboot the software. {i.e. 3D, Spectroscopy Tabs not functioning} To turn on the scanner: 1. Turn the key on control panel to unlock position and press blue scanner on button. Scanner will take about 20 minutes to boot up before you can use it. (you will see a red line at bottom of screen while booting) 2. Once you hear 3 beeps then the scanner is ready to use. (The red line will disappear as well)