Near-infrared spectroscopy (NIRS) systemETG 4000 near-infrared Spectroscopy (NIRS) System

EGI is pleased to offer Hitachi's ETG-4000 Optical Topography System for hemodynamic measurements with near-infrared light. Near-infrared light penetrates brain tissue and is absorbed differentially by hemoglobin and deoxyhemoglobin, providing a non-invasive measure of brain activity. This system is ideal for use with participants and patients of all ages, neonate through adult.

Download Brochure button



About the ETG-4000

These all-in-one systems provide everything you need to get started with NIRS in your laboratory. The system features:

  • Compact and portable design — all components fit onto a wheeled cart, which can be moved easily to accomodate use in one or more laboratories
  • Versatile probe configuration — comfortable probes have a modular design that allows 24, 48, or 52 simultaneous measurements anywhere on the scalp
  • High-performance optical technology — frequency-modulated 695 nm and 830 nm laser diodes provide high sensitivity, even in normal room light
  • Powerful and intuitive software — software includes multimode display capabilities and comprehensive analysis tools, such as principle component analysis (PCA), averaging and statistics, and waveform analysis
  • Multimodal imaging support — the system features several ways to communicate with external devices allowing the synchronization of the ETG-4000 with other modalities, such as EEG, MEG, TMS, external video, etc.

How NIRS works

Near-infrared spectroscopy (NIRS)Near-infrared light is capable of penetrating tissue and bone. Using an emitter laser diode on the scalp, the light reaches 2–3 cm into the skull and cerebral cortex.  In the cerebral cortex, near-infrared light is absorbed by hemoglobin, with any non-absorbed light reflecting back to the surface, where it is measured by a high-sensitivity photodiode.

Oxyhemoglobin and deoxyhemoglobin absorb light differently. By using two different frequency-modulated wavelengths of light (695 nm and 830 nm), one can calculate the ratio between oxy- and deoxyhemoglobin simultaneously.

Contact button




Near-infrared spectroscopy (NIRS)Over 130 research papers have been published using the Hitachi ETG-4000 Optical Topography System in fields such as developmental neuroscience, cognitive neuroscience, multimodal imaging, and clinical research.


ETG-4000 Optical Topography System

Systems are sold as complete packages with everything you will need to start work immediately. Systems include:

  • wheeled cart
  • software
  • computer and monitor
  • probe modules of your choice
  • system manuals
  • 1 year Support Contract


  • neonate/infant probes
  • video system
  • 3-D positioning unit for sensor registration