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Optical and Electromagnetic Tracking Technology for OEM Medical Device Integration

NDI is the recognized global leader and industry pioneer of Optical and Electromagnetic tracking technology.

What is Optical and Electromagnetic Tracking?

Both NDI Technologies track surgical instruments with a high level of accuracy, but each has their own set of advantages.

Optical Tracking

See how NDI’s Optical tracking technology uses infrared Optical Trackers to precisely track surgical instruments in real-time.

Electromagnetic Tracking

Discover how NDI’s Electromagnetic technology enables 6D tracking without line-of-sight requirements.

Optical Tracking – Principles of Operation

The Polaris Vega and Polaris Lyra optical navigation solutions work by using near-infrared (IR) light to wirelessly detect and track navigation markers attached to OEM surgical instruments. They do so over a large measurement volume and with exceptional tracking accuracy and precision. Optical measurement technology is also known—and trusted—for its reliable tracking performance.

Illustration of a hand placing optical markers onto a surgical tool.

Optical markers (passive or active) are attached to surgical tools.

Illustration of an optical tracker emitting infrared light.

The Polaris® Optical Tracker floods the measurement volume with infrared (IR) light

Illustration of optical markers reflecting infrared light for tracking.

Passive markers reflect IR light emitted by the tracker, while active markers emit IR light that the tracker detects.

Illustration of an optical marker with its position calculated in 3D coordinates: x, y, and z.

The optical tracker detects the markers and calculates the tool’s position and orientation in 3D space.

Illustration of a surgical tool with optical markers and associated coordinates.

Coordinates are mapped to patient images, creating a real-time view of the tool’s location relative to anatomy.

Illustration of a computer displaying the spine and the position of a tracked surgical tool.

Real-time tracking data is sent to the navigation software for surgical guidance.

Electromagnetic Tracking – Principles of Operation

Aurora® electromagnetic (EM) tracking works by generating a defined EM field in which EM micro-sensors are tracked. Sensors can be embedded into OEM medical instruments such as catheters, endoscopes, guidewires, and needle tips. Using the sensors’ tracking data, the OEM image-guided surgery system can localize and visualize the instrument as it’s navigated through anatomical tracts to target and reach treatment areas.

Illustration of a hand holding a medical instrument with an embedded sensor.

Sensors can be embedded into an OEM medical instrument, where they serve as localization points for the instrument in 3D space.

Illustration of a field generator emitting an electromagnetic field.

The Field Generator emits a low-intensity, varying EM field that establishes the measurement volume.

Illustration of a sensor within an electromagnetic field.

Small currents are induced inside the sensors when they enter the EM field.

Illustration of a sensor interface unit processing signals.

These currents are relayed to the Sensor Interface Unit (SIU), where they’re amplified and digitized as signals.

Illustration of a system control unit displaying sensor coordinates.

The signals are transmitted to the System Control Unit (SCU), which calculates each sensor’s position and orientation as a transformation.

Illustration of a computer displaying a heart model.

Tracking data are communicated to the OEM host application interface for real-time navigation of instruments relative to patient image sets.

Choosing the Right Technology

Optical Tracking

Ideal for procedures where instruments remain visible, providing submillimeter accuracy even in environments where metal interference is present.

  • 4+ Optical Tracker configurations and 3+ marker options
  • Sub-millimetre accuracy across surgical and research applications
  • Ready-to-use tools for research and development.

Electromagnetic Tracking

Ideal for tracking flexible or rigid instruments inside the body where line of sight is obstructed.

  • Sensors as small as 0.3 × 2.5 mm
  • Track up to 32 sensors simultaneously
  • Plug & Play tools available for research and development

Key Differences at a Glance: Compare Optical and Electromagnetic Tracking

Optical TrackingElectromagnetic Tracking
Line of sightRequires line of sightNo line of sight required
Instrument TypeExternal rigid instrumentsInternal flexible instruments
EquipmentOptical Trackers & MarkersElectronic Units, Field Generators & Sensors
Advantages Large measurement volumeSensors as small as 0.3 × 2.5 mm
Product LinePolaris®Aurora®

Polaris® Optical Product Suite

The complete Polaris® Optical tracking system relies on two primary components working together: an optical tracker and optical markers.

Robotic surgical arm performing a knee procedure, with a tracking reference frame on the patient’s leg and a monitor displaying knee X-ray imaging.

OEM Applications

The capabilities of NDI’s Optical technology make it ideal for integration into OEM robotic and computer-assisted surgical navigation systems in cranial, spine, and orthopaedic surgery.

Cranial

Supports OEM navigation systems used in neurosurgical and neuromodulation procedures involving the brain and skull.

Orthopaedics

Supports OEM systems used in orthopaedic procedures involving bone resection and implant placement.

Spinal

Supports OEM systems used for positioning and placement of spinal stabilization hardware.

The Aurora® and 3D Guidance® Electromagnetic Product Suite

NDI offers two electromagnetic tracking platforms, depending on system and integration requirements.

Aurora® Electromagnetic Product Suite

The complete Aurora® Electromagnetic tracking system relies on three primary components working together: Electronics Units (System Control Unit & Sensor Interface Unit), a Field Generator and Sensors.

ENT procedure using EM field generator and probe.

3D Guidance® Electromagnetic Product Suite

The complete 3D Guidance® Electromagnetic tracking system relies on three primary components working together: an Electronics Unit, a Transmitter and Sensors.

EM navigated thyroid procedure using ultrasound and navigated needle.

OEM Applications

NDI’s electromagnetic tracking technology provides position and orientation data designed for integration into OEM navigation systems incorporating instruments such as endoscopes, guidewires, catheters, and needle tips. 

Cardiology

Supporting OEMs developing systems for cardiac electrophysiology and catheter-based interventional workflows.

ENT

Supporting OEMs developing navigation systems for endoscopic and skull base procedures involving the cranial structures and neighboring soft tissues.

Pulmonology

Supporting OEMs that focus on diagnostics and therapeutic procedures in the lung.

Urology

Supporting OEMs that focus on diagnostic and therapeutic procedures in the prostate and surrounding regions.

Interventional Oncology

Supporting OEMs that focus on procedures using CT, Ultrasound or image fusion to guide a biopsy needle or ablation probe to a target lesion.

Exploring Optical or Electromagnetic Tracking for Your Medical Device?

Connect with our Product Integration team to compare NDI tracking technologies and identify the right configuration for your navigation system.