Oral cancer is among the top three types of cancers in India which accounts for about 30 percent of all types of cancer. We propose here a portable and cost-effective 3D printed smartphone based bimodal (spectroscopy and imaging) device for detection of oral cancer at an early stage. The device has the ability to perform fluorescence spectroscopy and imaging on a single platform using smartphone as an optical spectrometer and a CMOS camera respectively. A miniature 405 nm laser diode has been used as a source. Fluorescence spectra and images of some known fluorophores such as fluorescein, rhodamine, flavin adenine dinucleotide (FAD) and proto-porphyrin (PpIX) have been recorded using the proposed smartphone-based device for validation. The wavelength resolution of device for spectral measurements is 0.25 nm per pixel in the visible range and for imaging the total area captured at the detector is 1cm2 . Preliminary studies have been performed on patients with oral precancer and cancer to evaluate the efficacy of the proposed system for in-vivo diagnosis of the disease at an early stage.
Epithelial cancers, constituting the majority of human cancer cases, can be identified by alterations in the biochemical and morphological characteristics of the thin epithelial layer (ranging from 100 μm to 500 μm), serving as an initial indication of the disease. Many researchers have utilised spatially resolved fiber optic probes and fluorescence spectroscopy technique to detect subtle variations in the optical properties of the epithelium layer of tissue. This study explores the impact of the incident and different collection configurations on epithelium layer sensitivity for spatially resolved fluorescence. Monte Carlo simulation reveals that a fiber probe with illumination-collection at 45-degree beveled angle in parallel configuration provides maximum fluorescence from the epithelium layer. This configuration is suitable for both in vitro and in vivo settings for epithelial precancer diagnosis. The efficacy of the 45-degree beveled angle fiber probe for measuring spatially resolved sensitivity has also been validated experimentally using two layer solid tissue-mimicking phantoms which demonstrates strong agreement with the results generated from Monte Carlo simulation. These findings suggest that employing an optimum source detector configuration enables the collection of enhanced spatially resolved fluorescence from the epithelium layer.
Cervical cancer ranks as the fourth most prevalent cancer globally, emphasizing the critical need for early detection, which is vital for effective treatment. Traditional diagnostic methods have shown limitations in detecting the progression of the disease. Optical techniques, known for their high sensitivity and specificity, are emerging as reliable tools, especially in cancer-related applications. Among these techniques, fluorescence spectroscopy is one of the highly sensitive approaches for identifying biochemical changes that occur during the advancement of cancer. In our study, fluorescence spectral data was collected from human cervix from a diverse group of individuals using a portable smartphone-based fluorescence spectroscopy device. The spectral signals were processed by initially breaking them down into Fourier Bessel series (FBS) coefficients. Subsequently, the Hessian locally linear embedding (HLLE) based dimensionality reduction method was applied to the FBS coefficients, followed by the implementation of a 1D convolutional neural network classifier. The combination of polarized fluorescence spectra acquired from the device and the proposed classification approach has shown promising results, thus it is proven to be a minimally invasive method with the capability to provide real-time diagnoses for patients
A smartphone-based prototype has been demonstrated and calibrated as a tool to identify the spectral differences from fluorophores during disease progression. Polarized fluorescence is captured through smartphone camera using a 405nm laser source.
Breast cancer arises either in the lobules or the ducts of the tissue. Structural changes occurring with malignancy manifest as refractive index variations inside the tissue. It is crucial to quantify these depth wise variation in refractive index for early cancer detection. In this study, three types of unstained breast tissue sections - fibrocystic, fibroadenoma, and invasive carcinoma have been examined for the ultra-structural changes using `Fourier domain low coherence interferometry'. The resulting interference spectra of the backscattered light from the front and the rear surface of the sample are Fourier analyzed to provide depth correlation function. The subtle small-scale fluctuations in the Fourier analyzed spectra are then evaluated using Discrete Wavelet Transform (DWT). Daubechies-1 wavelet of DWT is used to calculate the high pass and low pass coefficients. The sixth level low pass coefficients of DWT clearly discriminate among normal, benign, and malignant breast tissue. Skewness and kurtosis values for these coefficients are also able to well distinguish the type of tissues.
Most cervical cancers originate from the epithelial layer by an uncontrolled growth of abnormal squamous cells and are known as carcinomas. Early stages of this disease manifest as biochemical and morphological changes in the superficial layer. Such changes can be captured from the spectral behavior of intrinsic fluorophores present in the layered cervical tissue. Fluorescence spectroscopy is thus widely used for detection of pre-cancers, also due to its capability as a fast, non-invasive and quantitative probe. This study focuses on analysis of the spectral information of the fluorophores using spatially resolved fluorescence spectroscopy for diagnosis of cervical cancer at an early stage. An in-house fabricated fiber-optic probe of diameter 1mm, consisting of 77 fibers in approximately five circular rings with very high sensitivity for superficial layer changes, has been used to collect fluorescence spectra from different spatially resolved positions of two layered solid phantoms. The phantoms are prepared by varying the thickness and fluorophore concentration of the upper layer. Optical properties of these layered phantoms have been kept similar to cervical tissue to replicate the subtle changes that occur in the tissue with the growth of abnormality. A 405 nm laser diode source is used to excite the samples with two different fluorophores in the two layers, Flavin Adenine Dinucleotide (FAD) in upper layer and Proto-porphyrin (PpIX) in bottom layer. A `Look-up Table' method is used to finally reconstruct thickness and fluorophore concentrations of upper layer of an unknown phantom by evaluating the peak ratios of fluorophores from spectra obtained at different spatially resolved positions.
Phase contrast images of stromal region of different stages of cervical pre-cancer were captured from tissue sections. A wavelet leader based multifractal analysis was performed on the phase contrast images to estimate multifractal spectrum for each image. Wavelet leaders were calculated through discrete wavelet transform using bi-orthogonal mother wavelets. The derived multifractal parameters, namely, width of singularity spectrum shows good discrimination between different grades of cervical pre-cancer.
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