Near Infrared Optical Detection System Of Early Knee Osteoarthritis

Osteoarthritis (OA) is a kind of chronic joint diseases that is common in elderly people. It causes pains and disabilities which would seriously affect the sufferers’life. At present, the conventional imaging methods, such as X-ray, are difficult to fulfill early OA detection daily. Near infrared spectroscopy (NIRS) can detect concentration changes of articular cartilage in early OA lesion. The purpose of this paper is to develop a set of safe, noninvasive, low cost system that can realize early KOA detection real-time and in vivo.Firstly, the development and application status of NIRS were tracked in this paper. The calculation model of water content of cartilage in knee joint was built on the basis of modified Lambert-Beer law.Secondly, rabbit KOA models were obtained with mechanical method. The changes of near infrared spectrum were studied in its OA lesions. Monte carlo (MC) simulation result of the photon propagation path in the knee joint was discussed. Sensing probe was designed. The KOA detection system includes a sensor probe, hardware circuits and software modules. The sensor probe equips with2different wavelength LED.Finally, no-load test and simple light test were carried out to verify the stability of the system. Left and right knee joints of10volunteers were measured. The measured result was con sistent with theoretical derivation result, which provides preliminary basis for judgment of subsequent actual detecting results.