Asima Pradhan

Indian Institute of Technology Kanpur | IIT Kanpur · Department of Physics

Cervical cancer is a prevalent malignant tumor within the female reproductive system and is regarded as a prominent cause of female mortality on a global scale. Timely and precise detection of various phases of cervical cancer holds the potential to substantially enhance both the rate of successful treatment and the duration of patient survival. Fl...

Real‐time prediction about the severity of noncommunicable diseases like cancers is a boon for early diagnosis and timely cure. Optical techniques due to their minimally invasive nature provide better alternatives in this context than the conventional techniques. The present study talks about a standalone, field portable smartphone‐based device whi...

In 2020, the number of new cases of cervix uteri was 604,127, i.e., 3.1% of all cancers, and the number of deaths was 341,831 (3.3%) among both sexes. In vivo fluorescence spectroscopy is an emerging optical technology that offers promise for the diagnosis of disease & has the capability to quickly, noninvasively and quantitatively probe the bioche...

Cervical cancer can be treated and cured if diagnosed at an early stage. Optical devices, developed on smartphone-based platforms, are being tested for this purpose as they are cost-effective, robust, and field portable, showing good efficiency compared to the existing commercial devices. This study reports on the applicability of a 3D printed smar...

Objectives: To evaluate the screening potential of portable optical device based on the principle of intrinsic fluorescence spectroscopy to detect the fluorescence of FAD molecules in pre-invasive lesions of cervix and its comparison to conventional screening methods. Methods: A prospective cross-sectional study was conducted on 163 patients, who u...

Progression of oral mucosal lesions is generally marked by changes in the concentration of the intrinsic fluorophores such as collagen, nicotinamide adenine dinucleotide (NADH), flavin adenine dinucleotide (FAD) and porphyrin present in the human oral tissue. In this study, we have probed the changes in FAD and porphyrin by exciting with 405 nm las...

The nonlinear reconstruction problem of quantitative photoacoustic tomography (QPAT) is accomplished by either Jacobian or gradient based schemes; the latter being advantageous w.r.t. computational memory. We report for the first time a 1-step gradient based QPAT reconstruction scheme using frequency domain photoacoustic equation. Numerical results...

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.

An imaging device based on fluorescence for in vivo detection of oral cancer has been developed. Images collected from cancerous patients and normal volunteers have shown a clear difference in fluorescence intensity.

Fiber-optic probes are imperative for in-vivo diagnosis of cancer. Depending on the access to a diseased organ and the mutations one aims to sense, the probe designs vary. We carry out a detailed numerical study of the efficacy of the common probe geometries for epithelial cancer characterization based on spatially resolved reflectance data. As per...

PurposeTo diagnose early cervical neoplasia cervical by use of in vivo handheld probe based on co-polarized and cross-polarized fluorescence spectroscopy and compare the efficacy with colposcopy and histopathology. Methods The cross-sectional observational study was done on 49 patients who came to outpatient department in UISEMH, LLR Hospital betwe...

We propose a gradient-based scheme to solve the fluorescence photoacoustic tomographic (FPAT) problem in a fully nonlinear one-step setting, which aims to reconstruct the map of the absorption coefficient of an exogenous fluorophore from boundary photoacoustic pressure data. Adjoint-based gradient evaluation is presented for the FPAT problem in a f...

Time-resolved Mueller matrix (MM) imaging polarimetry in transmission mode has been implemented in both epithelium and stromal regions of cervical tissues to explore the various polarization dynamics in connection with the diagnosis of cervical precancer. The picosecond-resolved intensity patterns of various MM elements, resulting from the various...

The spatial autocorrelation and correlation map of amplitude and phase anisotropy along with depolarization parameter from the stroma of uterine cervix utilizing their Mueller matrix (MM) images have been reported for early diagnosis of cervical cancer and differentiation of precancerous stages. The comparative results of evaluation of the spatial...

We report detection of cervical pre-cancer through their low coherence images by applying two dimensional multifractal detrended fluctuation analysis. Low coherent backscattered images of pre-cancerous cervical tissue sections were captured using a common path interferometric setup. The captured images contain both depth and lateral information of...

Analysis of spatial frequency of Mueller matrix (MM) images in the Fourier domain yields quantifying parameters of anisotropy in the stromal region in normal and precancerous tissue sections of human uterine cervix. The spatial frequencies of MM elements reveal reliable information of microscopic structural organization arising from the different o...

The mapping of diattenuation, polarizance and retardance vector (normalized Stokes vector) on Poincare sphere, evaluated from Mueller matrix of optically anisotropic stromal region of cervical tissues, is presented for cervical precancer detection and its staging. This reveals that the changes in the polarization states shown by these normalized St...

This paper presents a simple, novel and cost effective process to synthesize MWCNTs and α-Fe2O3 embedded in rGO sheet layers, which is found to be a highly selective and sensitive material for the detection of chloroform vapours in room temperature conditions. The nanocomposite rGO- MWCNT- α-Fe2O3 has showed enhanced chloroform vapour sensing perfo...

In vivo detection of oral precancer has been carried out by a fluorescence-based, in-house-developed handheld probe on three groups: oral squamous cell carcinoma (OSCC), dysplastic (precancer), and control (normal). Measurements have been performed on a total of 141 patients and volunteers of different age groups. Excitation wavelength of 405 nm wa...

Fluorescence optical tomography (FOT) is a well-known imaging technique, where fluorescent biological markers are injected to tag targeted tissues (tumors, proteins), and the absorption coefficient of fluorophore is reconstructed to provide contrast-enhanced images. Conventional FOT is known to have lack of stability to noise and shallow imaging de...

We report the ex vivo results of an in-house fabricated portable device based on polarized fluorescence measurements in the clinical environment. This device measures the polarized fluorescence and elastic scattering spectra with 405-nm laser and white light sources, respectively. The dominating fluorophore with 405-nm excitation is flavin adenine...

In this work we have developed a novel rGO-MWCNT (reduced graphene oxide-multiwalled carbon nanotube) nanocomposite material with Poly-L-Lysine functionalization which can be used for detection of biomolecules with enhanced sensitivity. The reduced GO sheets are found to play a major role as a connector and helps in the assembly of bundles of carbo...

MEMS-based microcantilevers have become an indispensable technique for mass sensing in the last decade. Presently, the need has come to scale down to nanoscale cantilevers for better and faster sensing. Previously, metallic cantilevers were mostly used for biochemical/analyte detection which is more expensive compared to the polymeric ones. Arrays...

We report a significant improvement in the diagnosis of cervical cancer through a combined application of principal component analysis (PCA) and support vector machine (SVM) on the average fluorescence decay profile of Fluorescence Lifetime Images (FLI) of epithelial hyperplasia (EH) and CIN-I cervical tissue samples, obtained ex-vivo. The fast and...

Characterization of inherent reconstruction errors arising from algorithm-parameter choices is becoming an important requirement for photo-acoustic (PA) tomographic systems. In the present work, we derive an estimate of the inherent errors which arise in universal back-projection based photo-acoustic tomography (PAT) because of the filtering of the...

Throat precancer detection using fluorescence from human saliva is reported here. It may be noted that accessing the throat for investigation is cumbersome and use of saliva as a diagnostic medium may ease the process. The study has been conducted on three groups of patients: oral squamous cell carcinoma (OSCC), dysplasia, and normal (control). An...

A systematic study has been conducted on application of wavelet based multifractal de-trended fluctuation analysis (MFDFA) on Mueller matrix (MM) images of cervical tissue sections for early cancer detection. Changes in multiple scattering and orientation of fibers are observed by utilizing a discrete wavelet transform (Daubechies) which identifies...

This contribution proposes a novel extension of the existing ‘Hyper Kurtosis based Modified Duo-Histogram Equalization’ (HKMDHE) algorithm, for multi-objective contrast enhancement of biomedical images. A novel modified objective function has been formulated by joint optimization of the individual histogram equalization objectives. The optimal adeq...

A spatio-temporal map of human cervical tissue is obtained from time-resolved fluorescence images with the dynamic contrast enhanced through Principal Component Analysis (PCA) for clear demarcation of regions of normal and pre-cancerous conditions. Changes in the properties of fluorescence in different environments are captured through fluorescence...

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 ability of fluorescence imaging to identify early physiological changes in tissue places it suitably for use in pre-cancer diagnosis. We have presented a review of the broad classification of tomographic schemes with respect to this problem. We have articulated some of the main motivations, issues, and potential solutions for the use of fluores...

We report here a study on human saliva tested as a diagnostic medium for oral cancer detection on three groups: oral squamous cell carcinoma (OSCC), oral sub mucous fibrosis (OSMF; precancer), and healthy controls (normal). Measurements have been conducted using fluorescence spectroscopy with 350 nm excitation and Stokes shift (SS) spectroscopy (SS...

This volume comprises chapters on the cutting-edge research in photonics undertaken at IIT Kanpur. Photonics requires scientists and engineers to work closely together in addressing challenges which are interdisciplinary in nature. At IIT Kanpur, research is being pursued in several key areas of photonics namely fiber-optics, nanophotonics, quantum...

Microscope images of biopsy samples of cervical precancers conventionally discriminated by histopathology, the current “gold standard” for cancer detection, showed that their correlation properties are segregated into different classes. The correlation domains clearly indicate increasing cellular clustering in different grades of precancer compared...

In fluorescence optical tomography, many works in the literature focus on the linear reconstruction problem to obtain the fluorescent yield or the linearized reconstruction problem to obtain the absorption coefficient. The nonlinear reconstruction problem, to reconstruct the fluorophore absorption coefficient, is of interest in imaging studies as i...

In this contribution, we report the application of higher order statistical moments using decision tree and ensemble based learning methodology for the development of diagnostic algorithms for optical diagnosis of cancer. The classification results were compared to those obtained with an independent feature extractors like linear discriminant analy...

The microfibril angle (MFA) giving the orientation of cellulose chains in hard sclerenchymatous bamboo fibers is one of the most important parameters determining the overall strength of the bamboo culm. In this work, Mueller matrix imaging polarimetry is implemented for determining MFA measured over a transverse section of group of fibers and paren...

A probabilistic robust diagnostic algorithm is very much essential for successful cancer diagnosis by optical spectroscopy. We report here support vector machine (SVM) classification to better discriminate the colon and cervical cancer tissues from normal tissues based on elastic scattering spectroscopy. The efficacy of SVM based classification wit...

THE FLUCTUATIONS OF SPATIAL VARIATION OF BIOLOGICAL TISSUE REFRACTIVE INDEX HAS BEEN ANALYSED BY USING S-TRANSFORM (ST). THIS STUDY USES S-TRANSFORM FOR IDENTIFYING DIFFERENT GRADES OF CERVICAL CANCER OF DIFFERENTIAL INTERFERENCE CONTRAST (DIC) IMAGES OF STROMAL REGION TISSUES. THE SUBTLE DIFFERENCES ARE REFLECTED IN THE SPATIAL FREQUENCY DISTRIBUT...

We propose a one step algorithm to recover the exogenous fluorescent markers concentration from boundary photoacoustic measurements. We numerically validate the proposed scheme in two dimension.

Photo-acoustic tomography is a hybrid imaging modality that combines the advantages of optical as well as ultrasound imaging techniques to produce images with high resolution and good contrast at high penetration depths. Choice of reconstruction algorithm as well as experimental and computational parameters plays a major role in governing the accur...

Synchronous fluorescence spectroscopy is an efficient technique for decoupling fluorophores which are masked in fluorescence spectroscopy due to overlapping of dominant fluorophores. By choosing appropriate offsets between excitation and emission wavelengths during signal acquisition from turbid samples, responses of individual fluorophores are hig...

In this paper, we have carried out the detail studies of pre-cancer by wavelet coherency and multifractal based detrended fluctuation analysis (MFDFA) on differential interference contrast (DIC) images of stromal region among different grades of pre-cancer tissues. Discrete wavelet transform (DWT) through Daubechies basis has been performed for ide...

An optical quantitative histological method in human tissues using spatial frequencies is demonstrated. Optical spatial frequency spectra from different stages of human Cervical Intraepithelial Neoplasia (CIN) tissue are evaluated as a potential quantitative pathological tool. The degree of randomness of tissue structures from normal to different s...

Under the assumption of high scattering and weak absorbing media, diffusion approximation holds in the radiative transport equation to model propagation of light. Diffusion approximation is valid deep inside the medium, not near the boundary. So, we need to implement accurate boundary conditions. Diffuse reflectance close to the source, majorly, de...

In this paper, we have carried out the detail studies of pre-cancer by wavelet coherency and multifractal based detrended fluctuation analysis (MFDFA) on differential interference contrast (DIC) images of stromal region among different grades of pre-cancer tissues. Discrete wavelet transform (DWT) through Daubechies basis has been performed for ide...

Photo-acoustic tomography is a hybrid imaging modality, that combines the advantages of optical as well as ultrasound imaging techniques to produce images with high resolution and good contrast at high penetration depths. Choice of reconstruction algorithm as well as experimental and computational parameters plays a major role in governing the accu...

We present a novel fully non-linear reconstruction scheme for fluorescence optical tomography wherein light propagation is modelled with the SP3 approximation to the radiative transfer equation. We evaluate the Frechet derivative required using an adjoint based approach, and numerically validate it w.r.t a finite-difference calculation. We then pre...

Intrinsic fluorescence spectra of the human normal, cervical intraepithelial neoplasia 1 (CIN1), CIN2, and cervical cancer tissue have been extracted by effectively combining the measured polarized fluorescence and polarized elastic scattering spectra. The efficacy of principal component analysis (PCA) to disentangle the collective behavior from sm...

Spatial frequency spectra from cervical intraepithelial neoplasia (CIN) tissues are used to detect differences among different grades of human cervical tissues. The randomness of the structures of tissues from normal to different stages of CIN tissues is recognized by analyzing the spatial frequency. This study offers a simpler and better way to re...

This paper presents a study on microscopic images to classify cervical precancers by a multifractal analysis. Since internal structure of tissue is non-deterministic, multifractal spectrum is required to characterize such structure. The periodic structure of collagen present in the stromal region of cervical tissue gets disordered with progress in...

Multifractal, a special class of complex self-affine processes, are under recent intensive investigations because of their fundamental nature and potential applications in diverse physical systems. Here, we report on a novel light scattering-based inverse method for extraction/quantification of multifractality in the spatial distribution of refract...

DIC (Differential Interference Contrast Image) images of cervical pre-cancer tissues are taken from epithelium region, on which wavelet transform and multi-fractal analysis are applied. Discrete wavelet transform (DWT) through Daubechies basis are done for identifying fluctuations over polynomial trends for clear characterization and differentiatio...

Differential interference contrast images (DIC) are the direct representation of the refractive index fluctuations of human cervical tissues. These refractive index fluctuations are known to follow self-similar behaviour and in general are multifractal in nature. In this present study, multifractal detrended fluctuation analysis (MFDFA) on refracti...

It is important to detect cervical dysplasia, Cervical Intraepithelial Neoplasia (CIN). CIN is the potentially premalignant and abnormal squamous cells on surface of cervix. In this study, the spatial frequency spectra of pre-cancer cervical tissues are used to detect differences among different grades of human cervical tissues. Seven sets of thick...

The objective of the present work is to diagnose pre-cancer by wavelet transform and multi-fractal de-trended fluctuation analysis of DIC images of normal and different grades of cancer tissues. Our DIC imaging and fluctuation analysis methods (Discrete and continuous wavelet transform, MFDFA) confirm the ability to diagnose and detect the early st...

Quantitative fluorescence spectroscopic Mueller matrix measurements from the connective tissue regions of human cervical tissue reveal intriguing fluorescence diattenuation and polarizance effects. Interestingly, the estimated fluorescence linear diattenuation and polarizance parameters were considerably reduced in the precancerous tissues as compa...

Optical techniques, especially the ones related to light scattering, has been seen to capture morphological changes, such as increase in size and density of nuclei in cells. Mueller imaging of the epithelium and basal layer based on polarized elastic scattering in human cervical tissue sections has been used to identify the dysplastic conditions of...

Spatial frequency spectra from precancer cervical tissue images are presented and used to detect differences among different grades of human cervical tissues.

Spatial frequency spectra from precancer cervical tissue images are presented and used to detect differences among different grades of human cervical tissues.

Mueller matrix polarimetric investigation of normal and diseased human cervical tissue samples in fluorescence scattering yields the possibility of early detection of the disease and a novel probe to monitor morphological changes during disease progression.

Time-resolved fluorescence emission from normal breast tissue, benign and malignant breast tumors were measured using excitation of 100 fs pulses at 310nm. Fluorescence relaxation decay parameters were extracted from the measured temporal emission profiles. The decay times and amplitudes of fast and slow profiles of malignant tissues were different...

We report here a study of confocal microscope images to classify cervical precancers by a multifractal analysis. This study is performed using an inverted confocal microscope with laser scanning fluorescence imaging. The periodic structure of collagen present in the stromal region of cervical tissue gets disordered with progress in grade of dysplas...

The two highest principal components of fluorescence spectra in visible region obtained, using Xenon lamp as an excitation source of normal and dysplastic human cervical tissues are analyzed using scatter plots and probability density functions. These yield significant differences between the tissue types.

Multiresolution analysis on the spatial refractive index inhomogeneities in the epithelium and connective tissue regions of a human cervix reveals a clear signature of multifractality. Importantly, the derived multifractal parameters, namely, the generalized Hurst exponent and the width of the singularity spectrum, derived via multifractal detrende...

Multi-resolution analysis on the spatial refractive index inhomogeneities in the connective tissue regions of human cervix reveals clear signature of multifractality. We have thus developed an inverse analysis strategy for extraction and quantification of the multifractality of spatial refractive index fluctuations from the recorded light scatterin...

To study the diagnostic potential of fluorescence spectroscopy and its comparison with different screening methods, including Pap smear and colposcopy, in detecting early cervical neoplasia. The study was conducted on patients with gynecological complaints. A full gynecological workup of the patients was done along with Pap smear and colposcopy. Ce...

Wavelet transform of polarized fluorescence spectra of human breast tissues is found to localize spectral features that can reliably differentiate normal and malignant tissue types. The intensity differences of parallel and perpendicularly polarized fluorescence spectra are subjected to investigation, since they are relatively free of diffusive bac...

Time-resolved fluorescence emission from normal breast tissue, benign and malignant breast tumors were measured using excitation of 100 fs pulses at 310nm. Fluorescence relaxation decay parameters were extracted from the measured temporal emission profiles. The decay times and amplitudes of fast and slow profiles of malignant tissues were different...

Fluorescence spectroscopy has been demonstrated as a viable tool for noting subtle biochemical changes that occur during early-stage cervical cancer progression. Due to multiple fluorophore contributions, the individual fluorophore activities often get masked due to overlapping spectra of neighboring fluorophores. Recently synchronous fluorescence...

In this work, we report a wavelet based multi-fractal study of images of dysplastic and neoplastic HE- stained human cervical tissues captured in the transmission mode when illuminated by a laser light (He-Ne 632.8nm laser). It is well known that the morphological changes occurring during the progression of diseases like cancer manifest in their op...

Microscopic images from the biopsy samples of cervical cancer, the current "gold standard" for histopathology analysis, are found to be segregated into differing classes in their correlation properties. Correlation domains clearly indicate increasing cellular clustering in different grades of pre-cancer as compared to their normal counterparts. Thi...

The fluctuations in the elastic light scattering spectra of normal and dysplastic human cervical tissues analyzed through wavelet transform based techniques reveal clear signatures of self-similar behavior in the spectral fluctuations. The values of the scaling exponent observed for these tissues indicate the differences in the self-similarity for...