As a supplier of EMI materials, I often get asked by medical device manufacturers: “Why do we need EMI materials? Our devices work just fine without them.” If you’ve ever stood next to an MRI machine while someone’s phone buzzed in their pocket, or watched a pacemaker’s settings glitch briefly near a surgical laser, you’ve seen the answer firsthand. EMI—electromagnetic interference—is everywhere, and in the medical space, it’s not an inconvenience—it’s a safety hazard. Today, I want to break down exactly how our EMI materials solve these challenges, and why they’ve become irreplaceable across modern medical devices. EMI Material
Before diving into applications, let’s ground this in why EMI matters in healthcare specifically. Unlike consumer electronics, where a dropped Wi-Fi signal might ruin a movie, medical devices control patient outcomes. A single EMI-induced misread from a pulse oximeter could lead to a wrong dosage of sedative. A pacemaker disrupted by a nearby defibrillator could send a patient into cardiac distress. Even non-critical tools like ultrasound machines can produce blurry images that delay diagnosis. EMI materials—typically thin metal foils, conductive polymers, or ferrite composites that absorb or block electromagnetic radiation—act as a shield, creating a safe “electromagnetic buffer” around sensitive components.
Let’s start with the most high-stakes category: implantable medical devices. These are devices placed inside the body, often for years or decades, so they need to be tiny, energy-efficient, and immune to outside interference. A few years back, we worked with a team developing next-generation neurostimulators for chronic pain. Their original design skipped EMI shielding to keep the device small—but during early testing, a patient’s phone left in a chest pocket would cause the stimulator to fire off unexpected pain pulses. That’s a scenario no one wants. We supplied them with a thin, biocompatible EMI shield made from a platinum-coated polymer. It’s flexible enough to wrap around the stimulator’s circuit board, non-toxic to body tissue, and blocks 99.8% of external radiofrequency (RF) signals from cell phones, Wi-Fi, and even other implantable devices like insulin pumps. The result? Their late-stage trials had zero EMI-related adverse events, and the device hit the market last year. Implantable pacemakers, too, rely on EMI shielding: the metal casing acts as a basic shield, but adding our thin ferrite liners inside the casing further blocks stray electromagnetic fields from hospital equipment—like MRI machines, which generate 1.5 or 3 Tesla fields that can disrupt a pacemaker’s pacing logic.
Next, diagnostic imaging equipment—think MRI, CT, and ultrasound machines. MRI is especially tough because it uses extremely strong magnetic fields (the 1.5T and 3T I mentioned earlier) and RF pulses to produce images. But those same RF pulses can bounce around the machine’s gantry, causing “noise” in the final image. Our EMI materials play two roles here: first, they shield the sensitive RF receiver coils inside the gantry from external EMI (like signals from a nurse’s pager or a nearby pacemaker), and second, they prevent internal RF signals from leaking out and interfering with other devices in the hospital. A few months ago, a major diagnostic clinic reached out because their 3T MRI machine was causing nearby ECG machines to give false heart rate readings. We installed our conductive copper-nickel composite liners along the back walls of the MRI’s scan room, and within 48 hours, the ECG interference stopped. The clinic also reported clearer MRI images, because the liners reduced internal signal bounce—proof that EMI materials don’t just fix safety issues, they improve clinical accuracy too.
Then there’s surgical and clinical monitoring devices. These are the tools used in real time during procedures, so reliability is non-negotiable. Take anesthesia workstations, which track a patient’s blood pressure, oxygen levels, and heart rate while delivering sedatives. A few years back, a hospital anesthesiologist contacted us because their workstation’s pulse oximeter would drop readings every time a surgical laser was fired nearby. Lasers generate intense RF noise, and that noise was overwhelming the oximeter’s sensor. We supplied them with small, flexible EMI gaskets to seal the gaps between the oximeter’s sensor unit and its connecting cable, and added ferrite beads to the cable’s connectors. These beads absorb high-frequency RF noise from the laser, while the gaskets block it from entering the sensor. After the upgrade, the oximeter’s readings stayed consistent even during the longest procedures. Other tools here include portable patient monitors, which are carried around hospitals to track patients’ vitals as they move between X-ray and surgery. These monitors often run on battery power, so they can’t have bulky shielding—but our thin, lightweight EMI films let manufacturers add protection without increasing the device’s size or weight. That’s a win for both device usability and safety.
We also can’t forget about wearable medical devices, a fast-growing category that includes fitness trackers with clinical-grade heart monitoring, continuous glucose monitors (CGMs), and post-surgery recovery sensors. These devices are often worn 24/7, so they need to be comfortable, water-resistant, and immune to interference from other wearable tech (like smartwatches) or household devices (like microwaves). Last year, we worked with a startup developing a CGM for type 1 diabetes patients. Their original CGM model would give incorrect glucose readings when the patient used their smartwatch nearby. The problem was that the two devices were on the same body, and their signals were interfering with each other. We supplied them with a stretchable EMI adhesive film that wraps around the CGM’s sensor module. The film is thin enough that patients can’t feel it, and it blocks the smartwatch’s RF signals without disrupting the CGM’s ability to send glucose data to a smartphone app. The startup went on to win a medical device award, and they now use our EMI films in all their products. Wearable defibrillators, which patients wear after a heart attack, also rely on this technology—they need to detect abnormal heart rhythms instantly, so any EMI from nearby electronics can’t slow that down.
Now, you might be wondering: EMI materials are great, but do they have any downsides? I get this question a lot, and it’s a fair one. Early EMI shields were thick, heavy, and sometimes toxic (we’ve all heard stories of old electronics using lead-based shields that aren’t safe for medical use). That’s why our team has spent years refining our materials to fit medical needs specifically. Our current line of EMI materials is biocompatible (tested and certified for contact with body tissue), thermally stable (so they don’t break down in the sterilization processes hospitals use), and thin enough to fit even the smallest implantable devices. We also work closely with manufacturers during the design phase—sometimes the smallest tweak, like adding a ferrite bead to a single cable, can fix an EMI issue without requiring a full redesign of the device.
But here’s the thing: every medical device is unique, so there’s no one-size-fits-all EMI solution. A neurostimulator needs a different shield than an MRI gantry, and a CGM needs a different solution than a surgical laser monitor. That’s why our process is hands-on—we don’t just sell a product and walk away. We start by reviewing a manufacturer’s device schematics, testing for EMI interference in a simulated medical environment, and then working to create a custom EMI solution that fits their timeline and budget. We’ve helped startups launch their first devices, and we’ve partnered with large medical tech firms to upgrade their existing product lines for better safety.
At the end of the day, medical technology is all about trust. Patients trust that a pacemaker will keep their heart beating, that a scan will show a clear diagnosis, that a surgical monitor won’t fail mid-procedure. EMI materials are a quiet but critical part of that trust. They don’t make a device work—they make it work reliably, even when surrounded by the hundreds of electronics in a modern hospital room. If you’re a medical device manufacturer looking to address EMI challenges in your product line, or want to integrate EMI materials into your design from the start, I encourage you to reach out to our team to discuss your specific needs. We’re here to partner with you to create solutions that keep patients safe, devices compliant, and clinical outcomes consistent.
EMI Material References
- International Electrotechnical Commission (IEC). 2022. IEC 60601-1-2: Medical Electrical Equipment – Part 1-2: General Requirements for Basic Safety and Essential Performance – Collateral Standard: Electromagnetic Disturbances – Requirements and Tests.
- US Food and Drug Administration (FDA). 2021. Electromagnetic Compatibility (EMC) for Medical Devices: Guidance for Industry and Food and Drug Administration Staff.
- Zhang, L., et al. 2020. “Biocompatible Electromagnetic Interference Shielding Materials for Implantable Medical Devices.” Journal of Biomedical Materials Research, vol. 108, no. 12, pp. 2451-2465.
- World Health Organization (WHO). 2019. Electromagnetic Fields and Public Health: Health Effects of Electromagnetic Interference (EMI) on Medical Devices in Clinical Settings.
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