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www.mcdmag.com May/June 2014 | Medical Construction & Design 39 when siting an MRI and must be consid- ered when evaluating potential locations. An EMI and vibration survey must be performed in the proposed location to con- fi rm the space is within the selected mag- net specifi cations. Elevators and electrical transformers are top EMI contributors, while air handling systems and vehicles in parking garages can cause vibration issues. Most issues can be resolved through EMI shielding, active cancellation, vibration dampening or relocation of the source. All of these will add to the overall project cost so advance planning that takes these items into account upfront will minimize the budget impact later. As modalities and devices are added, the planning complexity grows. RF and radiation shielding must be in place per equipment specifi cations. Devices to be used in rooms with the magnet must be MRI compatible and MRI safe. Protocols must be in place to move them to an acceptable location so as not to interfere with the imaging or become a projectile in the magnetic fi eld. ACOUSTIC AND MAGNET NOISE Acoustic considerations are an important factor in the overall suite design since the MRI magnet can be loud during scan sequences. If the magnet bay is also intended to function as a clinical imaging suite when not needed during surgery, then the OR area needs to be protected from the acoustic noise generated dur- ing MRI scans. This allows both areas to be used simultaneously for more effi cient use of the hospital resources. While there is a fair amount of ambient noise present in an OR, sudden and loud noise from an MRI scan could startle people working in the OR. PATIENT AND PERSONNEL SAFETY Patient safety is the primary concern when designing an iMRI. Maintaining a sterile environment is crucial for the patient. Typically, a positive air pres- sure is maintained in the OR to minimize the possibility of airborne pathogens entering the area. With the larger doors needed for the intra-operative environ- ment, air handling in these areas may require additional planning to ensure proper air pressure in the OR and adja- cent areas. Since minimizing or eliminat- ing pathogens is a primary concern in an OR environment, the RF-shielded door designs used in the iMRI area need to have surfaces and thresholds that may be easily cleaned and minimize fl uid/dirt/ dust collection points. The large magnet bay doors are gen- erally intended to provide magnet safety for the OR personnel and others in the event of an emergency. In the unlikely event of a fi re, for example, the magnet bay doors provide a safety barrier for protecting people who need to be in the same area as the MRI, but may not have experience working around an MRI mag- net. Specialized control systems should be used to provide personnel safety functionality. PREVENTIVE MAINTENANCE Key to the continued successful use of an iMRI theater is the assurance that the equipment and supporting technology are always working at top performance levels. Preventive maintenance should be scheduled and performed on a regular basis. As with any MRI, periodic maintenance is required to check and fi ll helium levels, examine cabling for wear and damage, review image quality through internal diagnostic testing and checking coils and patient tables to ensure they are functioning as expected and are in good condition. The RF-shielding system integral to obtaining the highest quality images is another important component requiring maintenance. iMRI by design requires a higher level of RF-shielding technol- ogy to allow for the best operational fl ow of patients and staff to access the MRI machine. RF doors require frequent cleaning and operational maintenance to ensure continued RF integrity and functional performance. Simulation of a full procedure should be made periodically to confi rm every- thing is working as a system. Researchers and surgeons are con- tinually expanding the use of high-quality iMRI images. Successfully implementing an iMRI suite requires upfront planning by experts to address all aspects of these complex projects. ■ Jim Mueth is the intra-operative product man- ager with ETS-Lindgren. He may be reached by email at Jim.Mueth@ETS-Lindgren.com. Joe Weibler is the director of engineering with ETS-Lindgren. He may be reached by email at Joe.Weibler@ETS-Lindgren.com. Editor's Note: An extended version of this article is available at www.ets-lindgren.com /whitepapers. A marriage of modalities is shown in this surgical suite. The patient remains stationary while a C-Arm scan and MRI may be conve- niently moved to provide images in real-time during surgical procedures and treatments. F d M C D 0 5 1 4 _ 3 8 - 3 9 - i M R I . i n d d 3 9 FdMCD0514_38-39-iMRI.indd 39 5 / 7 / 1 4 1 : 4 0 P M 5/7/14 1:40 PM