Wearable, Interventional, & Non-Contact Medical Imaging, Sensing and Health Monitoring Technologies
Functional Near-Infrared Spectroscopy (fNIRS) is a non-invasive imaging technology that leverages the unique absorption spectra of oxygenated and deoxygenated hemoglobin in the near-infrared wavelength to monitor brain activity(Fig. 1a). By placing a near-infrared light source and detector on the scalp (forming an optical channel as shown in Fig. 1b), it captures variations in light intensity as the light traverses the scalp and brain. These variations allow fNIRS to detect changes in the concentrations of oxy-hemoglobin (HbO) and deoxy-hemoglobin (HbR), providing valuable insights into cerebral hemodynamics.
Enhancing fNIRS, Diffuse Optical Tomography (DOT) and High-Density DOT (HD-DOT) utilize multiple light sources and detectors for detailed 3D neuroimaging via overlapping spatial sampling, significantly improving spatial resolution and depth accuracy. These advancements have made functional neuroimaging more accessible, portable, and cost-effective, especially valuable in clinical settings where traditional imaging methods are limited. Despite these advances, challenges in achieving full wearability persist, with limitations in data processing, power consumption, motion tolerance, and the weight of wearable components, as fNIRS and its enhanced versions still rely on external systems for data analysis.
To address the challenges of wearability in fNIRS/DOT technologies, we focus on developing a new generation of wearable, modular optical imaging technologies using high-frequency optoelectronics. This advanced system aims to provide precise measurements for both brain and body imaging, including neuroactivity and critical data like blood volume and oxygenation. By integrating various modal monitoring modules and employing advanced wearable electronics, we are working towards a compact, high-resolution imaging device that offers both comfort and functionality. Our goal is to create a fully wearable health imaging system, facilitating continuous, non-invasive monitoring and opening new avenues in personalized healthcare and neurorehabilitation.
Figure 1 Illustration of Functional Near-Infrared Spectroscopy (fNIRS) Principles and Setup. (a) Absorption spectra of Hb and HbO2. The isosbestic point is where the absorption coefficients of Hb and HbO2 are equal. (b) An example of fNIRS measurement on the scalp. A near-infrared light source and a detector are placed on the head, showing the light's path through the scalp and brain.