This paper describes RTBioT, one of the first Internet of Things (IoT) healthcare platforms based on spatially resolved near infrared (NIR) spectroscopy to support non-invasively quantify chromophores in biological tissue. Bluetooth Low Energy (BLE) is used as the primary communication protocol, an IR-enhanced Si PIN photodiode is for a light-receiving element, and a compact fiber-stub type beam combiner is employed as a multiple wavelengths light-emitting source. Most of all, a lock-in amplifier is to retrieve the low noise signal from photodiode which enables accurate measurement of small modulated signals in the presence of noise interference orders of magnitude greater than the signal amplitude by using phase-sensitive detection technique (PSD). The sampling rate of the RTBioT is up to 33Hz, so that it can directly measure mayer wave oscillation, respiration, and cardiac cycle from the raw data. However, it is necessary to approach to the statistical analysis to quantify the concentration of tissue chromophores. First, we determine the optical absorption and scattering properties in the tissue from the locked-in received signal by using the algorithm composed of least square method and diffusion equation. Then, inverse-matrix equation with absorption, reduced scattering and extinction coefficients is solved by the algorithm with respect to chromophores. We conducted an experiment through phantoms simulating human tissue and human subjects to demonstrate its feasibility for the IoT healthcare platform. The experimental results show that it is possible to monitor the biological signals and the concentrations of chromophores in a human subject in near real time fashion.
This paper presents a safe, affordable, and noninvasive approach to estimate subcutaneous fat thickness by using a multi-distance
near infrared (MD-NIR) interactance-based wireless sensing platform. In order to perform the simultaneous
measurements at several distances, two light sources with different wavelengths are located at one end of a line followed
by seven photo diodes. Bluetooth Low Energy are adopted as their primary communication protocol as a wireless
communication. The measured data from the MD-NIR interactance sensors are wirelessly transmitted to a smartphone or
a tablet for analysis. The feasibility of the approach and wireless platform is demonstrated using the ex vivo pig fat layer
phantoms.
Many biomedical applications require an efficient combination and localization of multiple discrete light sources. In this paper, we present a compact six-channel combiner of optical sub-assembly type that couples the output of independent solid-state light sources into a single 400 μm diameter optical fiber. It is equipped with six discrete laser diodes, 658, 690, 705, 785, 830, and 850 nm for the measurement of the tissue optical properties from optical spectroscopy and imaging. We demonstrate coupling efficiencies ≥ 77% and output optical power ≥ 20 mW for each of the 6 laser diodes installed into the prototype. The design supports the use of continuous wave and intensity modulated laser diodes (with bandwidth ≥ 3 GHz). The developed light source could be used to construct custom multi-wavelength sources for tissue oximeters, diffuse optical imaging, and molecular imaging technologies.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.