Topics
Environmental Issues and how they impact imaging equipment.
EMI (electromagnetic i nterference)VibrationAcoustics
Co-siting of imaging equipmentShielding requirements for imaging equipmentSummary
ENVIRONMENT AL CONCERNSEMI (electromagnetic interference)VibrationsAcoustics (air and structure borne noise)
EMI (electromagnetic interfer ence)Magnetic fields generated by:
Transformers, electrical vaults, air conditioning units, power line, etc. (AC sources)Subways, trams, elevators, automobiles (DC sources).
Problematic for some imaging equipment:
MRI, CTs, and some angiography systems.
Effects of EMI
Can lead to poor quality images.Poor images due to EMI can impact American College of Radiology (ACR) accreditation.
Interference from EMI Normal Image
EMI Solutions
Locate and move Source of EMI.Relocate equipment.Shielding
Passive (steel, aluminum, etc.)Active Shielding (electronic shielding system).
Vibrations
Vibrations created by:Other imaging equipmentMechanical (motors, HVAC, etc.)Street traffic
Problematic for some imaging equipment: MRIs and CTs.
Effects of VibrationsElevated structural vibr ation caused by street traff ic, mechanicals and other sources can result in poor images for CTs and MRIs.
Vibration SolutionsSolutions utilizing spring isolators, dampening pads, or combination of both.Design of isolated and spring isolated slabs.Solutions applied:
On imaging equipmentOn building structureOn mechanicals (HVAC, motors, generators, etc.)
Acoustic Noise
MRIs can generate excessive air and structure borne acoustic noise.Can be disturbing for other facility residents.
structure-borne
airborne
Acoustic SolutionsAir borne:
Proper construction of building elementsTreatment of all penetrations.
Structure borne:Isolated slabsDampening systems
Proper planning can:Guarantee that equipment will function optimally.Reduce installation costs.Reduce service costs.Improve and optimize work flow.Simplify future upgrades.Consultants available to aid in process.
Co-Siting of Imaging Equi pment
Siting multiple MRI systems.
Gauss field intersect creating “crosstalk”between MRI systems.“Crosstalk” can hinder the performance of the magnet.May lead to increased service calls.Will increase magnetic shielding costs.
Siting multiple MRI systems.
Locating a reading room, MRI equipment room, or some other method of separation between the MRIs will reduce the possibility of “crosstalk” between the MRI system and reduce magnetic shielding requirement.
Siting an CT next to an MRILocating equipment like CTs near MRI systems can be problematic without proper planning. CTs can be impacted by elevated magnetic f ields, like those generated by MRIs. The CT requirements wil l drive magnetic shielding requirements in this example.
Imaging equipment using Ionizing Radiation
Smaller Scan roomOccupied spaces in relativel y close proximity of ionizing radiation source (imaging equipment).
Outdoor Parking Lot
Other Imaging (MRI, CT, etc.)
OfficesOffices
Scan Room
Hot Lab Patient Toilet
Injection/Upta
ke
ControlConsole
Door
Office for PET Secretary & Technologist
Door
Storage, Linens
“Typical” Layout
Imaging equipment using Ionizing Radiation
Larger scan room for ionizin g radiation source.Greater distance f rom occupied space (off ices).Remember, distance is your f riend when shielding f or radiation.
Outdoor Parking Lot
Other Imaging (MRI, CT, etc.)
OfficesOffices
Scan Room
Hot Lab Injection/Uptake
Patient Toilet
ControlConsole
Door
Offi
ce fo
r PET
Se
cret
ary
& Te
chno
logi
st
Door
Stor
age,
Li
nens
“Better” Layout
Shielding Requirements
Most imaging equipment requires magnetic, RF, and/or radiation shielding.Shielding is necessary for health and saf ety and/or performance of the imaging equipment.
Radiation Shielding
Necessary to meet health and safety requirements related radiation exposure.Proper layouts can reduce shielding requirements while not impacting functionality or workflow.
MRI Shielding
Magnetic ShieldingFDA recommends five Gauss containment from public areas, but:Consider other imaging equipment in close proximity (ex. CTs, PET, etc.)Consider the current and planned use of surrounding areas (ex. ORs, other tenants, etc.)
MRI Shielding
Radio Frequency (RF) shielding.
Required for all MRI systems.Critical to the performance of the MRI.
Protects MRI f rom RF noise generated in the environment by sources like TV and radio stations.
RF Shielding for MRI
RF “zipper” artifactDeficiencies in RF shield can lead to RF “zipper” artifacts.Note: Not all arti facts are caused by a shielding problem. Some issues can result from poor grounding and peripheral devices in the MRI suite that generate RF noise.
What to consider when siting imaging equipment?
Do you plan to upgrade in the future?
Consider how you may want to use the space in the future and items that can be done during the initial construction to accommodate future upgrades.A focus strictly on cost in the beginning can lead to greater expenses later on.
Consider the cost associated with planning and implementing a site versus benefits to patients, workflow, and alternative site options.
Is there another s ite available?What is the cost associated with implementing the propos ed site?
Are there envi ronmental issues?Are there special shielding considerations?
What works best for patient care, the facility environment, and work flow?
SummaryWhen planning for imaging equipment, remember environmental issues (EMI, vibrations, RF, and acoustics) may be problematic.
Review facility drawings and visually inspect the area around a planned installation to identify possible environmental problems.Typically costs much less to address at time of construction andprevents downtime later on.
Remember that siting imaging equipment in close proximity to each other can create interf erence.
Not only can one piece of imaging equipment have a negative impact on another, but can also impact other functional areas.
SummaryRadiation shielding is necessary to address health and safety requirements.
A refined layout can help reduce the shielding requirements.Facility physicist or consulting physicist can provide the necessary services to identify radiation shielding requirements.
Magnetic shielding is necessary for health and safety requirements. RF shielding is necessary f or MRI performance.
Magnetic: While five Gauss containment is important for pacemakers, more stringent Gauss containment may be nec essary.RF shielding is critical to the image qual ity of an MRI.Shielding consultants are available to aid in identifying shielding requirements and si te planning.Shielding vendors are available to service shields.
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