The high fatality rate associated with the late detection of skin cancer makes early detection crucial in preventing death. The current method for determining if a skin lesion is suspect to cancer is initially based on the patient's and physician's subjective observation of the skin lesion. Physicians use a set of parameters called the ABCD (asymmetry, border, color, diameter) rule to help facilitate diagnosis of potential cancerous lesions. Lesions that are suspicious then require a biopsy, which is a painful, invasive, and a time-consuming procedure. In an attempt to reduce the aforementioned undesirable elements currently associated with skin cancer diagnosis, a novel optical polarization-imaging system is described that has the potential to noninvasively detect cancerous lesions. The described system generates the full 16-element Mueller matrix in less than 70 s. The operation of the system was tested in transmission, specular reflection, and diffuse reflectance modes, using known samples, such as a horizontal linear polarizer, a mirror, and a diffuser plate. In addition, it was also used to image a benign lesion on a human subject. The results of the known samples are in good agreement with their theoretical values with an average accuracy of 97.96% and a standard deviation of 0.0084, using 16 polarization images. The system accuracy was further increased to 99.44% with a standard deviation of 0.005, when 36 images were used to generate the Mueller matrix.

The Mueller matrix describes all the polarizing properties of a sample and, therefore, the optical differences between noncancerous and precancerous tissue that may be present within the matrix elements. A high-speed polarimetry system that generates 16 ͑4 ϫ 4͒ full Mueller matrices to characterize tissues is presented. Feature extraction is done on the Mueller matrix elements resulting in depolarization and retardance images by polar decomposition. These are used to detect and classify early oral cancers and precancerous changes in epithelium such as dysplasia. These images are compared with orthogonal polarization images and analyzed in an attempt to identity useful factors for the differentiation between cancerous lesions and their benign counterparts. Our results indicate that polarimetry has potential as a method for the in vivo early detection and diagnosis of oral premalignancy.

Articles you may be interested inRotatable spin-polarized electron source for inverse-photoemission experiments Rev. Sci. Instrum. 85, 013306 (2014); 10.1063/1.4863097 Anomalous Rashba effect of bismuth(111) thin films studied by high-resolution spin-and angle-resolved photoemission spectroscopy Absolute spin calibration of an electron spin polarimeter by spin-resolved photoemission from the Au(111) surface states Rev. Sci. Instrum. 80, 043904 (2009); 10.1063/1.3115213Electronic structure and magnetic anisotropy of Co/Au(111): a spin-resolved photoelectron spectroscopy study AIP Conf.We have developed a new compact retarding-potential Mott spin polarimeter and achieved an efficiency of 1.9ϫ10 Ϫ4 for gold target operating in 25 keV. A novel design of the retarding field electron optics with 0.59 sr collection solid angle for scattered electrons was adopted based on Monte Carlo calculations for the spin-dependent electron scattering process and electron beam ray-tracing calculations. We have combined the new spin polarimeter with an angle-resolved photoelectron spectrometer and measured the spin-and angle-resolved photoelectron spectra and studied the spin-dependent electronic structure of Ni͑110͒ along the ⌫S line of its surface Brilluoin zone.

Abstract. Early detection of cancer remains the best way to ensure patient survival and quality of life. Squamous cell carcinoma is usually preceded by dysplasia presenting as white, red, or mixed red and white epithelial lesions on the oral mucosa (leukoplakia, erythroplakia). Dysplastic lesions in the form of erythroplakia can carry a risk for malignant conversion of 90%. A noninvasive diagnostic modality would enable monitoring of these lesions at regular intervals and detection of treatment needs at a very early, relatively harmless stage. The specific aim of this work was to test a multimodality approach [three-dimensional optical coherence tomography (OCT) and polarimetry] to noninvasive diagnosis of oral premalignancy and malignancy using the hamster cheek pouch model (nine hamsters). The results were compared to tissue histopathology. During carcinogenesis, epithelial down grow, eventual loss of basement membrane integrity, and subepithelial invasion were clearly visible with OCT. Polarimetry techniques identified a four to five times increased retardance in sites with squamous cell carcinoma, and two to three times greater retardance in dysplastic sites than in normal tissues. These techniques were particularly useful for mapping areas of field cancerization with multiple lesions, as well as lesion margins.C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

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