Positive tumor resection margins are reported in up to 45% of the patients undergoing surgery for tongue cancer. With the aim to develop a technique that can assess tumor resection margins intraoperatively, we conducted an ex vivo study to evaluate the feasibility of near infrared hyperspectral imaging for distinguishing tumor from healthy tongue tissue.
Fresh surgical specimens of squamous cell carcinoma of the tongue were scanned with a pushbroom camera. The acquired spectral hypercubes contain a measure of the diffuse light reflectance (wavelength range of 900-1700 nm) for each pixel of the hyperspectral image. Spectral bands were selected from the spectrum and used to classify spectra of tumor and healthy tissue. In this, a linear classifier was trained on 80% of the data and its performance in predicting the tissue type of the residual 20% of the data was measured. This was repeated five times and mean accuracy, sensitivity and specificity were used as output for this study.
A total of 463 spectra were obtained from tongue tumor tissue and 421 spectra from healthy tongue tissue. The spectral bands between 1060-1130 nm and 1150-1190 nm were used in the classification analysis. Mean accuracy, sensitivity and specificity were 89%±13, 94%±11 and 87%±21, respectively.
Near infrared hyperspectral imaging can discriminate tongue tumor tissue from healthy tongue tissue in an ex vivo setting by using specific bands of the reflectance spectrum. Further analyses will be done to assess whether using the whole spectrum can improve the classification results.
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