Researchers at the Centre for Earth Science Studies (Kerala, India), led by Dr. Narayanan Subhash, have developed a noninvasive, inexpensive spectral imaging system that could screen for oral cancer in dental and clinical settings. Their system can discriminate healthy oral tissue from premalignant and malignant tissues in real time, with accuracy comparable to histopathology of a biopsy sample.
Related: Practical, sensitive and specific: Applying OCT for oral cancer screening
The core of their novel diffuse reflectance imaging system (DRIS) is an EMCCD camera (Andor Technology's Luca-R), which captures monochrome images of the patient's mouth at 545 and 575 nm. The system also includes the company's Solis software to compute a ratio image (R545/R575) of the area under investigation and generate a pseudo-color map (PCM), where blue designates healthy tissue, red denotes dysplastic/premalignant tissue, and yellow identifies malignant tissue. This allows rapid visual differentiation of oral lesions and identification of regions with premalignant characteristics.
|Diffuse reflectance (DR) imaging set-up and image processing. Schematic of the diffuse reflectance imaging system (DRIS; a) and photo of the oral cavity of a patient with verrucous growth in the left commissure (b). Typical set of monochrome images recorded at 545 (c) and 575 nm (d), computed DR ratio (R545/R575; e) image, and pseudo-color-mapped ratio image (f). Color palette shows the range of median pixel intensity values for lesion discrimination.|
Subhash says that their system also delineates the boundaries of neoplastic changes and locates sites with the most malignant potential for biopsy, thereby avoiding unnecessary repeated biopsies and delay in diagnosis. "What's more, imaging the entire region may also help the surgeons to identify the margins of the lesion that cannot be easily visualized by the naked eye during surgical interventions," he adds.
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