RESOURCES

Selecting an EMI Filter for Downlight Installation in an MRI Room

   Back to Blog Listings

Electromagnetic compatibility (EMC) in health care facilities is essential for protecting patients, personnel and equipment. This requirement is especially important in exam rooms, where the amount of electromagnetic interference (EMI) in the space can damage diagnostic equipment and increase the risk of patient injury.

This guide to selecting an EMI filter for MRI rooms will help your facility determine which filtering product best meets your needs. 

Why Are EMI Filters Important for MRI Rooms?

Man-made electromagnetic noise can interfere with MRI functionality, potentially reducing scan accuracy and putting patients at risk. This noise can come from various sources, including lighting systems and your MRI machine itself.

EMI filters protect other systems within a space from unwanted signals. That's why installing EMI filters in your MRI room is critical for:

  • Patient safety: Internal medical devices like pacemakers and cochlear implants are highly sensitive to EMI from other machines, such as MRIs. Without EMI shielding or filters, patients with these devices cannot safely receive MRI scans.
  • Equipment protection: EMI generated from downlights and any other electrical system in the MRI room can cause damage to sensitive equipment components and interfere with the MRI signal.
  • Regulatory compliance: EMI filtration devices are essential for compliance with the International Electrotechnical Commission (IEC) 60601-1-2, which defines the safety standards for medical power supplies in various applications.

Properly installed EMI filters can also ensure device compatibility, as allowing unfiltered EMI to pass between them can damage or fail them.

Understanding EMI in MRI Environments

An EMI filter is a critical component for any MRI room due to the amount of sensitive equipment within. The main sources of EMI in MRI rooms include:

  • MRI machines: MRI machines are one of the greatest sources of electromagnetic noise in medical settings, so it's important to minimize the EMI they transmit to other devices. 
  • Lighting: Downlights, which are small lights embedded into ceiling recesses, provide additional visibility in exam rooms such as MRI suites. These lighting systems also generate radiated electromagnetic noise that can interfere with MRI function. 
  • Power lines: EMI signals from external sources, such as power lines, can interfere with MRI function in severe cases.
  • Other medical devices: While MRI rooms can only contain MRI-safe equipment and materials, devices in other rooms may be able to affect MRI machines without proper shielding.

Before purchasing and implementing EMI filters, you must consider the factors that will impact the amount of noise you will encounter during normal operations.

The Role of EMI Filters in Downlight Installations

EMI filters block both incoming and outgoing signals to ensure safe EMC between devices. These are the most important parts of the role EMI filters play in medical downlight installations:

Attenuation of EMI

EMI filters significantly reduce the effect electromagnetic noise can have on other devices and systems. 

Because electromagnetic noise travels predominantly on power lines, it's essential to block those signals from radiating into a space like an MRI room. Filters stop this noise from entering specific devices and damaging their sensitive electronic components. 

Types of EMI Filters

Choosing the correct filter type will ensure your investment lasts for long periods of time. An experienced engineer can help you determine which of the two main filter types will work best in your application:

  1. Passive filters: Passive filters separate incoming signals, allowing only desired low-frequency current to enter the space. This category includes LC filters, Pi filters and T filters.
  2. Active filters: Active filters monitor for and cancel out noise while generating an opposing signal to reduce the overall EMI level on the line. This category includes hybrid filters and active compensation filters.

EMI Filter Design and Purpose

Medical-grade EMI filters from a reliable manufacturer are the safest option for most health care facilities. These filters are designed to meet current requirements for medical applications in a wide variety of settings, from large hospitals to private clinics. 

Three-phase EMI filters can also be effective for operations of this scale, as their complex filtering system can block high levels of noise in high-power applications such as medical devices and test equipment.

Depending on your facility's specific requirements, you may need a custom solution. Working with a company that offers both turnkey and custom designs can help you ensure your EMI filters can withstand the demands of your typical operations.

02-medicalgrade-emi-filters-from-a-reliable-manufacturer

Choosing EMI Filters for Downlights

Installing filters that meet your MRI room's shielding requirements and device specifications is critical for protecting patients and adhering to essential regulations.

Here's a brief overview on how to choose an EMI filter for an MRI room:

1. Understand EMI/EMC Requirements

Selecting the proper EMI filter for downlight installations requires a thorough understanding of the typical electromagnetic signals your MRI room encounters during normal operation.

Because MRI machines give off EMI, they can impact other devices in the room — this is why MRI rooms are typically free of other electrical devices. Due to design variances, different MRI machine models emit varying levels of EMI. You will need to determine the specific requirements of your MRI machine before selecting a filter.

If you are still unsure which filter will be most suitable for your MRI room, consider consulting with an experienced engineer to discuss your facility's specific needs.

2. Consider Factors That Can Affect Filters

It's crucial to minimize the risk of disturbances that can interfere with filter function, as unfiltered noise can introduce serious electrical hazards into your testing environment. Some examples of those disturbances include:

  • Lightning strikes
  • Voltage surges
  • Voltage distortion
  • High ripple currents
  • Temporary overvoltage
  • Overcurrent

These hazards can damage an EMI filter's capacitors and insulation system, potentially leading to catastrophic failure. Consulting with an expert can help you ensure the solution you install can withstand these disturbances and any others you may encounter in everyday tasks.

3. Select Specially Designed Downlights

Downlights intended for medical exam rooms are typically made with non-ferromagnetic metals, which minimize the risk of the lights interfering with the MRI machine's magnetic field. 

Because medical applications have stringent regulatory requirements for patient and personnel safety, pairing these lights with a robust EMI filter is essential for mitigating risk effectively. 

03-astrodyne-tdi-can-help-you-find-the-right-emi-filter-for-your-mri-room

Astrodyne TDI Can Help You Find the Right EMI Filter for Your MRI Room

Regardless of your facility's size or specialty, partnering with a company that has extensive knowledge of the medical industry is key for finding the correct filters for your space.

Astrodyne TDI has decades of experience in designing and manufacturing EMI/EMC filters for various industries, including health care. We offer both off-the-shelf and custom solutions to ensure your EMI filters seamlessly integrate into your facility.

Choose a reliable source for EMI filters in MRI and other medical exam rooms. Contact us today for more information or to request a quote.