Intrinsic fluorescence for cervical precancer detection using polarized light based in-house fabricated portable device

Abstract

An in-house fabricated portable device has been tested to detect cervical precancer through the intrinsic fluorescence from human cervix of the whole uterus in a clinical setting. A previously validated technique based on simultaneously acquired polarized fluorescence and polarized elastic scattering spectra from a turbid medium is used to extract the intrinsic fluorescence. Using a diode laser at 405 nm, intrinsic fluorescence of flavin adenine dinucleotide, which is the dominant fluorophore and other contributing fluorophores in the epithelium of cervical tissue, has been extracted. Different grades of cervical precancer (cervical intraepithelial neoplasia; CIN) have been discriminated using principal component analysis-based Mahalanobis distance and linear discriminant analysis. Normal, CIN I and CIN II samples have been discriminated from one another with high sensitivity and specificity at 95% confidence level. This ex vivo study with cervix of whole uterus samples immediately after hysterectomy in a clinical environment indicates that the in-house fabricated portable device has the potential to be used as a screening tool for in vivo precancer detection using intrinsic fluorescence.

Concentration of FAD as a marker for cervical precancer detection

“…Several groups have worked on diagnosis of cervical precancer using laser-induced fluorescence spectroscopy 14,15 and in combination with reflectance spectroscopy [16][17][18] for comparison and to improve the detection efficacy. Intrinsic fluorescence [19][20][21] has also been extracted to understand the biochemical changes with disease progression through different experimental 22 and simulation-based techniques. [23][24][25][26] The use of different algorithms, such as machine learning, 27 wavelet analysis, 9 and other multivariate algorithms 10,20,28,29 have made detection more effective and robust.…”

“…Hence extraction of intrinsic fluorescence is needed to monitor the relative changes in the concentration of contributing fluorophores. 20,[22][23][24][25][26]34 Earlier, Biswal et al 22 developed an experimental technique to extract the intrinsic fluorescence based on polarized fluorescence and polarized scattering measurements, which is free from absorption and scattering effects. Further ex vivo studies on biopsy samples of the cervix have illustrated the efficacy of this technique.…”

“…Further ex vivo studies on biopsy samples of the cervix have illustrated the efficacy of this technique. 19,20 This has led to the fabrication of a portable device for in vivo detection of cervical precancer. 20 In this study, we report the ex vivo results from the portable device, by using the change in the concentration of FAD as a marker for early cervical cancer detection.…”

“…19,20 This has led to the fabrication of a portable device for in vivo detection of cervical precancer. 20 In this study, we report the ex vivo results from the portable device, by using the change in the concentration of FAD as a marker for early cervical cancer detection. A number of fluorophores contribute to the broad fluorescence spectrum when tissue is excited at 405 nm.…”

“…35 Nelder-Mead method has been utilized to fit the spectral profile with Gaussian to decouple the different bands of contributing fluorophores (FAD and porphyrin). 20,31 The change in concentration of FAD during disease progression manifests in the change in ratio of total area and FWHM of its Gaussian profile. Receiver operating characteristic (ROC) curve analysis has been used to discriminate different grades of cervical precancer by using the ratio as input parameter.…”