© 2020 Northern Digital Inc - All Rights Reserved
The Polaris Vega® and Polaris Vicra® optical measurement 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 in almost any clinical environment.
Every advancement of the Polaris® product suite represents new opportunities for medical device OEMs to innovate ever-more-complex surgical navigation systems and approaches. Where today’s technology breakthroughs become tomorrow’s standard of care. It’s why the Polaris solutions have been integrated into the workflows of OEM surgical navigation systems for more than 20 years.
Passive Marker Sphere
How Optical Measurement Works*
The Polaris® optical measurement solution consists of two core components that work together: the optical tracker (sometimes known as a ‘camera’) and navigation markers; e.g. passive marker spheres, Radix Lenses, retro-reflective discs. The optical tracker uses IR light to pinpoint and triangulate the real-time X-Y-Z coordinates of the instruments (via the markers) in 3D space. Tracking occurs within a pre-calibrated measurement volume, as reported in the Polaris’ global coordinate system.Coordinate data are calculated as transformations; i.e. positions and orientations. Similar in concept to vehicle GPS navigation, tracking data can be used to visualize the surgical instrument’s location relative to patient image sets, and to plan and navigate the instrument’s path to the target/treatment site. Each instrument has a unique array of markers that distinguishes one instrument from another within the OEM surgical navigation interface.
- Markers can be attached to OEM surgical instruments.
- The Polaris optical tracker floods the measurement volume with infrared (IR) light.
- This light is reflected from the markers back to IR sensors on the Polaris optical tracker.
- The points where the light intersects are used to triangulate the markers’ 3D (X-Y-Z) coordinates within the measurement volume.
- Coordinate data are mapped to the associated instrument and used to calculate the transformations (poses) of the instrument.
- Tracking data are communicated to the host application for real-time visualization and navigation of instruments relative to patient image sets.
Polaris Vega® and Polaris Vicra® Comparison
The Polaris Vega and Polaris Vicra share the same trusted optical measurement performance; where they differ is their size and accuracy. The larger Polaris Vega provides tracking of larger OEM surgical instruments within a larger measurement volume. It has a measurement rate that is—at a minimum— triple that of the Polaris Vicra (depending on the Polaris Vega model). The volumetric accuracy of the Polaris Vega is also two times more accurate than the Polaris Vicra.
However, the small size and small measurement volume of the Polaris Vicra makes it a powerful optical measurement solution for tracking smaller tools within confined areas. The compact form factor of the Polaris Vicra also allows it to be mounted almost anywhere on the OEM medical system or within the operative suite.
Polaris Vega XT
Pyramid Volume (RMS)
Vicra Volume (RMS)
|Volumetric Accuracy1,2||0.12 mm||0.25 mm|
|95% Confidence Interval1,2||0.20 mm||0.50 mm|
|Maximum Frame Rate||250 Hz||20 Hz|
Extended Pyramid (optional)
Polaris Vega XT
|Dimensions (LxWxH)||591 x 103 x 106 mm||273 x 69 x 69 mm|
|Weight||1.7 kg||0.8 kg|
|Mounting||Four M4 x 0.7 mm pitch x 10 mm deep threaded holes, rear mount||¼” thread tripod mount or secured via three M3 x 0.5 mm pitch x 9.0 mm deep threaded holes, rear mount|
Polaris Vega XT
|Tool Types||Passive||Passive, Active Wireless|
|Maximum Number of Tools||Load up to 25 tools (maximum of 6 active wireless)||Load up to 15 tools; simultaneously track up to 6 passive and 1 active wireless|
|Maximum Number of Markers per Tool||6 single-face/20 multi-face||6 single-face/20 multi-face|
Polaris Vega XT
|Data Communication||Gigabit Ethernet||USB|
|Network Synchronization||Precision Time Protocol (PTP)||Precision Time Protocol (PTP)|
|Data/Power Interface||Ethernet, RJ45||Host USB Convertor|
*Example of an original equipment manufacturer’s use of Polaris in its medical device system.
1Based on a single marker stepped through more than 900 positions throughout the measurement volume using the mean of 30 samples at each position at 20°C.
2Accuracy stated based on overall volume.
Compare our Electromagnetic Tracking and Optical Measurement Solutions.
NDI tracking and measurement products are general metrology components that can be integrated into customer products, research experiments, and/or as components of medical devices that require precision measurement and tracking. While NDI components and technology can be integrated into original equipment manufacturer (OEM) medical devices, they are not specifically intended for a given application and, as such, have not been developed or manufactured in accordance with medical device standards. It remains the responsibility of the OEM customer or end-user to determine and test the suitability of NDI components and technology for their intended use, including performing any required ethics approval, verification, and validation required to demonstrate suitability and compliance. System-level testing, certification, and validation are the responsibility of the original equipment manufacturer or the applicable end-user and should be completed prior to the use of NDI products or technologies in any application.