A non-invasive test for oral tumours can return results in under five minutes, claim cancer researchers in India.
The Diffuse Reflectance Imaging System (DRIS) is capable of real-time recognition of healthy oral tissue from pre-malignant and malignant tissues with accuracy claimed to be comparable to the gold standard histopathology of a biopsy sample.
The system comprises an unmodified Andor Luca-R electron multiplying charge coupled device (EMCCD) camera, which captures monochrome images of the patient’s mouth at 545 and 575nm.
Andor, which has its corporate headquarters in Belfast, provided its SOLIS software that calculates a ratio image (R545/R575) of the area under investigation, then generates a Pseudo Colour Map (PCM) where blue indicates healthy tissue, red dysplastic or pre-malignant tissue, and yellow identifying malignant tissue.
Dr Subhash Narayanan, a biophotonics consultant at the Centre for Earth Science Studies in Kerala, India led the research.
He told The Engineer via email that clinical trials have been carried out in patients at the Regional Cancer Centre in Trivandrum, India to evaluate the capability of the R545/R575 ratio to discriminate different types of lesions in vivo.
‘We observed that the diffuse reflectance (DR) ratio has good diagnostic accuracy for detection of tongue cancers as compared to laser induced fluorescence techniques,’ he said. ‘The DR imaging studies presented in BMC Cancer, 2013 were carried out afterwards to screen large lesions in near real time and to identify most malignant sites for biopsy.’
Experienced clinicians are not immune from experiencing difficulties when identifying the most malignant site in a lesion for biopsy, which can lead to multiple biopsies and discomfort for patients.
‘What our device does is to identify the most malignant site in a lesion for biopsy, thereby avoiding repeated biopsies,’ said Dr Narayanan.
The prototype device cost around Rs.15,00,000 (£14,546) to develop, a figure that Dr Narayanan believes can be reduced drastically with more astute design and choice of components.
Dr Narayanan conceded also that the technique is limited in that it does not provide depth resolution like OCT [optical coherence tomography], nor is it useful in accessing tissues deeper than 2mm.
However, he does believe results could be improved by removing the effect of specular reflection from tissues that could be a problem when the tissue is wet or moist.
‘Further, the present system has limitations in accessing all anatomical sites of the oral cavity, which could be improved using imaging fibre probes and the system also could be made more compact and portable,’ he said.