Cross Polarized Optical

About

Background Skin cancer accounts for nearly half of all cancers in the United States. More than 2 million cases of non-melanoma skin cancer are found in this country each year. Around 40-50% of Americans who live to the age of 65 will develop skin cancer at least once. Terahertz radiations are known to be safe but due to the lack of commercially available continuous wave terahertz sources, most medical research in terahertz imaging thus far has been focused on terahertz pulsed imaging (TPI). Technology   UMass Lowell researchers have developed a Terahertz/Optical-based imaging system for cancer detection, especially in skin. Continuous wave terahertz imaging (CWT) has the potential to differentiate between nonmelanoma skin cancers and normal skin.  Use of cross-polarized terahertz reflection to enhance contrast helps in to clearly identify the cancerous area of the sample by eliminating Fresnel reflection and imaging deeper into the tissue volume. Combination of Terahertz with Polarized light imaging at optical frequencies allows high sensitivity to cancer tissue provided by terahertz imaging as well as high resolution imaging of tissue morphology and chromophores, afforded by optical imaging techniques. Advantages Optical imaging offers higher resolution, which enables identification tissue morphology. Combining terahertz and optical interrogation of skin lesions shows promise for accurate delineation of skin cancers Significant improvement of the terahertz image quality due to the rejection of Fresnel reflections. Cross-polarized imaging has long been a staple in optical domain, but has never been used in terahertz biomedical imaging, most likely due to erroneous assumption that terahertz radiation does not penetrate into the biological tissue deep enough to make cross-polarized imaging valuable. Significant improvement of terahertz image quality the image quality due to probing deeper into the tissue and collecting signals from larger volumes without contamination of the detected radiation by specular reflection. Terahertz imaging is sensitive to water content and offers intrinsic contrast between normal and cancerous skin.