Design of Multi-wavelength Near Infrared Probe to Detect Risk Areas in Diabetic Foot

Diabetic foot diseases are the most common problem among people with diabetes mellitus (DM) that lead to lower body amputation. Loss of sensation (neuropathy) at the foot areas, peripheral arterial disease, and poor microcirculation at foot are the major risk factors which suppress the oxygen availability to the tissues, leading to ulcerations. Different methods are applied for noninvasive measurement of tissue oxygenation. Though there was an immense interest and rigorous research in this area for the last two decades, presently there is no suitable device to assess the tissue oxygenation noninvasively at foot sole. Near infrared (NIR) spectroscopy aids in examining the tissue oxygenation levels in noninvasive manner and also helps in evaluating the values of tissue oxygenation levels at specific region in the foot sole. In this chapter, a noninvasive multi-wavelength (740/850, 740/940) NIR probe was developed using light-emitting diodes (LED) to assess the tissue-oxygenation parameters by using the reflective characteristics of skin tissue in the plantar surface of patient foot, along with the tissue hardness, and temperature at the foot sole areas were obtained. From this study, diminished tissue oxygenation is observed at the area where the tissue hardness and foot sole temperature is high. In conclusion, a proposed optical-based multi-NIR wavelength method can be used to avoid the damages in lower extremity peripheral nerves and to identify the risk areas in the foot at an early stage before it leads to ulceration.