Terahertz imaging for early screening of diabetic foot syndrome: A proof of concept

Abstract

Most people with diabetes suffer some deterioration of the feet. Diabetic foot syndrome causes ulceration in about 15% of cases and such deterioration leads to amputation in about 2.5% of diabetic patients, diminishing their quality of life and generating extraordinary costs for patients and public health systems. Currently, there is no objective method for the detection of diabetic foot syndrome in its early stages. We propose terahertz imaging as a method for the evaluation of such deterioration. This screening method could aid the prevention and medical treatment of this condition in the future.

Recent advances in terahertz technology for biomedical applications

“…The applicability of THz tissue modelling in a diagnostic context has been recently demonstrated in the screening of diabetic foot syndrome (22). Diabetic foot syndrome causes dehydration of the foot skin, increasing the risk of developing severe ulcers which can eventually necessitate amputation if not treated.…”

“…In extracting these accurate values for different regions, Zaytsev et al proposed a highly accurate algorithm, considering errors from both imaging window aberrations and digital noise (25). Thus, any technique to measure skin hydration level such as the diabetic foot syndrome study presented earlier (22) needs to be carefully calibrated. This is further complicated by the variability in skin hydration between different patients and, if an imaging plate is used, the occlusion properties of the skin.…”

“…The Bruggeman model is also used to estimate the safety thresholds in the THz range of skin and cornea (21). As well as the Bruggeman model, the Landau-Lifshitz-Looyenga EMA has been used to estimate the THz permittivity of human skin (22). For all EMAs, the accuracy of the underlying material permittivity is crucial.…”

“…For all EMAs, the accuracy of the underlying material permittivity is crucial. Researchers have used dehydrated tissue to estimate the biological background (16,22), and Debye theory and finite difference time domain (FDTD) methods have been used to model the THz response of breast (23) and skin (24) tissue.…”

Millimeter-Wave Sensing of Diabetes-Relevant Glucose Concentration Changes in Pigs

“…Specifically, the work presented in [13][14][15] showed a glucose study performed in a rat, where its glucose levels were changed intravenously by injecting glucose and insulin. Finally, the work in [16] used THz waves to detect water content changes in tissue, which can often indicate diabetic foot syndrome (albeit not directly measuring glucose level changes).…”