Abstract 4328: Broadband diffuse reflectance spectroscopy noninvasively detected in vivo hemoglobin concentration and oxygen saturation of normal and malignant oral tissues

Abstract

Abstract Tumor physiological properties play an important role in cancer diagnosis and treatments. Diffuse reflectance spectroscopy has emerged as an important technique that provides several unique measurable parameters for characterization of a wide variety of tissue samples. By illuminating visible-NIR light at one location of tissue surface (source position) and collecting diffused light at another location (detection position) using optical fibers, we are able to access tissue physiological properties including total hemoglobin concentration (THC) and oxygen saturation (StO2). The depth of the measured tissue is determined by the source-detection separation that is approximately one third to one half of the separation. In oral cancers, close associations were found between tumor progression and tumor angiogenesis and hypoxia through the molecular markers. However, the prognostic and therapeutic value of these markers is not clearly known. The first goal of this study is to demonstrate the visibility of monitoring tissue THC and StO2 of normal and squamous cell carcinoma (SCC), which represent ∼95% of oral malignancies. Our 2nd goal is to compare these optical measured physiological properties to molecular markers from the same tissues. We have collected data from 25 SCC and 24 non-SCC (hyperplasia and dysplasia) patients at the department of dentistry, Taichung Veterans General Hospital. Adjacent normal sites were measured optically as well in the same patient. Optical measurements were analyzed by employing a physical model of light transport inside the tissue to extract THC and StO2. From all measurements, the THC and StO2 have a range of 25 and 229 uM and of 25 and 100%, respectively, while the source-detection separation at 4 mm (the detection depth 1.3 to 2 mm) was used. SCC did not show significant different THC and StO2 (mean±STD: 117±48 uM and 72±19%, respectively) from the normal site of the same patient (115±61 uM and 69±19%, respectively) and the non-SCC tissues (117±49 uM and 68±22%). While shorter source-detection separation was used (the detection depth was less than 1mm), the results from 7 SCC and 7 non-SCC patients show higher THC than normal and non-SCC tissues (233 uM versus 182 uM). Well oxygenated tissue layers were detected in both SCC, non-SCC, and normal sites with a range of 92 and 100%. The data indicated that both normal and malignant oral tissues are well oxygenated. Increased THC in SCC sites was observed only when the surface layer at the depth less than 1 mm was compared. Further analysis from all tissue sites will be performed to confirm this finding. The results of molecular markers will be compared with these optical measurements and the prognostic and therapeutic value of these markers will be discussed. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4328.