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This paper describes the development of an early detection method for probing pathological tissue variations. The
method could be used for classifying various tissue alteration namely tumors tissue or skin disorders. The used approach
is based on light scattering and absorption spectroscopy. Spectral content of the scattered light provides diagnostic
information about the tissue contents. The importance of this method is using a safe light that has less power than the
used in the imaging methods that will enable the frequent examination of tissue, while the exiting modalities have
drawbacks like ionization, high cost, time-consuming, and agents' usage. A modality for mapping the oxygen saturation
distribution in tissues noninvasively is new in this area of research, since this study focuses on the oxygen molecule in
the tissue which supposed to be homogenously distributed through the tissues. Cancers may cause greater vascularization
and greater oxygen consumption than in normal tissue. Therefore, oxygen existence and homogeneity will be alternated
depending on the tissue state. In the proposed system, the signal was extracted after illuminating the tissue by light
emitting diodes (LED's) that emits light in two wavelengths, red (660 nm) and infrared (880 nm). The absorption in these
wavelengths is mainly due to oxyhemoglobin (HbO2) and deoxyhemoglobin (Hb) while other blood and tissue contents
nearly have low effect on the signal. The backscattered signal which is received by a photodiodes array (128 PDs) was
measured and processed using LabVIEW. Photoplethysmogram (PPG) signals have been measured at different locations.
These signals will be used to differentiate between the normal and the pathological tissues. Variations in hemoglobin
concentration and blood perfusion will also be used as an important indication feature for this purpose.
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