Early diagnosis of cancer using LSS

Thesis (Ph. D.)--Harvard--Massachusetts Institute of Technology Division of Health Sciences and Technology, 2001.Includes bibliographical references.This thesis presents a novel optical technique, light scattering spectroscopy (LSS), developed for quantitative characterization of tissue morphology as well as in vivo detection and diagnosis of the diseases associated with alteration of normal tissue structure such as precancerous and early cancerous transformations in various epithelia. LSS employs a wavelength dependent component of light scattered by epithelial cells to obtain information about subcellular structures, such as cell nuclei. Since nuclear atypia is one of the hallmarks of precancerous and cancerous changes in most human tissues, the technique has the potential to provide a broadly applicable means of detecting epithelial precancerous lesions and noninvasive cancers in various organs, which can be optically accessed either directly or by means of optical fibers. We have developed several types of LSS instrumentation including 1) endoscopically compatible LSS-based fiber-optic system;(cont.) 2) LSS-based imaging instrumentation, which allows mapping quantitative parameters characterizing nuclear properties over wide, several cm2, areas of epithelial lining; and 3) scattering angle sensitive LSS instrumentation (a/LSS), which enables to study the internal structure of cells and their organelles, i.e. nuclei, on a submicron scale. Multipatient clinical studies conducted to test the diagnostic potential of LSS in five organs (esophagus, colon, bladder, cervix and oral cavity) have shown the generality and efficacy of the technique and indicated that LSS may become an important tool for early cancer detection as well as better biological understanding of the disease.by Vadim Backman.Ph.D

Raman Micro Spectroscopy for the Characterisation of Cervical Cancer.

The primary purpose of this study is to evaluate the potential of FTIR and Confocal Raman micro spectroscopy (CRM) in elucidating the biochemical changes occurring in different layers of the cervical epithelium including basal, superficial and the underlying connective tissue known as stroma during the progression of Cervical Intraepithelial Neoplasia (CIN) to cancer. Initially the two techniques were compared and Raman was chosen based on its higher spatial and spectral resolution. The sample preparation and spectral measurement procedures were optimised and all samples were formalin fixed paraffin processed, dewaxed using xylene, and measured on calcium fluoride windows. Raman spectra were recorded using a source wavelength of 785nm and a X100 dry objective lens. Raman micro spectroscopy was able to differentiate the normal region of the cervical tissue sample into three layers including stroma, basal/para-basal and superficial layers on the basis of the spectral features of the collagen, DNA bases and glycogen as well as discrimination of the diseased areas from the normal areas. In particular Raman spectroscopy could describe the biochemical changes in the diseased samples in detail. On moving from normal to abnormal regions of the cervical tissue sample, the characteristic Raman features of the basal layer were observed in the superficial layer and in the stroma. Notably, the normal region of a CIN III sample was found to have biochemical information similar to the abnormal region. This has been indicated by the absence of the collagen Raman spectral bands in the stromal layer as well as absence or minute presence of the glycogen bands in the superficial layer. A comparison of the Principal Components Analysis (PCA) loadings of the HPV negative and positive cell lines (C33A and CaSki), with those of the basal layers of normal and abnormal tissue samples showed no strongly matching Raman signatures which could lead to the identification of signatures of HPV infection in the cervical cancer tissue samples. 3 However, a feature associated with the amide-III beta sheet (1222 cm-1) was found to be consistently present in the PCA loadings contributed by the basal layers of the intermediate and abnormal samples. This was much reduced in intensity in the most extreme abnormal sample and the carcinoma in situ samples. This feature may be considered as an early marker of disease progression, but further investigation is needed to confirm this finding. KMCA indicated the possibility of the migration of basal cells into the superficial and stromal layers and subsequent PCA led to the conclusion that basal cells indicated by high DNA content and lack of glycogen are progressing to the superficial layer due to the progression of the disease. In the case of stroma, the basal like characteristics are actually associated with the biochemical changes in the stromal cells and there is no migration of these cells into the stroma. In addition, during cervical cancer progression, relative to the DNA, collagen has a diminished contribution at some points in the Raman map of the stroma and KMCA recognised the greater similarities with the DNA rich cells of the basal layer. This has been supported by the enhanced expression of p16 protein in the basal and superficial layers rather than in the stroma

Multimodal Optical Imaging for Detection of Cervical Neoplasia

Despite being the most preventable cancer, cervical cancer remains the third leading cause of cancer death worldwide. Over 85% of cervical cancer incidence and mortality occurs in low-resource countries where screening programs for early detection are either inadequate or unavailable. In the developed world, where screening programs are well organized, incidence and mortality rates are greatly reduced. Recent advances in optical imaging have the potential to enable cervical cancer screening at the point-of-care, even in the hands of less experienced providers. High performance optical imaging systems can be constructed at relatively low cost, and image analysis can be automated; thus, these technologies may provide a way to bridge the gap to cervical cancer screening for developing countries. This work focuses on the design, construction, and clinical testing of a novel multimodal optical imaging (combination of wide-field imaging and high-resolution) for early detection of cervical neoplasia. The Multimodal Digital Imager (MDI) acquires in vivo images of cervical tissue in fluorescence, narrow band reflectance, and orthogonal polarized reflectance modes using multiple illumination wavelengths. The High Resolution Microendoscope (HRME) was used to interrogate clinically suspicious areas with subcellular spatial resolution, revealing changes in nuclear to cytoplasmic area ratio. In vivo image data from the wide-field system was combined with image data from a high- resolution microendoscope (HRME) in order to test the effectiveness of the multimodal optical imaging in discriminating between cervical neoplasia and non-neoplastic. Multimodal optical imaging coupled with computer aided diagnostic achieved a sensitivity of 82% and specificity of 85% for discriminating cervical neoplastic from non-neoplastic This work has demonstrated that multimodal optical imaging; combination of wide-field and high-resolution optical imaging of the cervix can assist in the detection of cervical neoplasia and can be implemented effectively in a low-resource setting

Role of Optical Spectroscopic Methods in Neuro-Oncological Sciences

In the surgical treatment of malignant tumors, it is crucial to characterize the tumor as precisely as possible. The determination of the exact tumor location as well as the analysis of its properties is very important in order to obtain an accurate diagnosis as early as possible. In neurosurgical applications, the optical, non-invasive and in situ techniques allow for the label-free analysis of tissue, which is helpful in neuropathology. In the past decades, optical spectroscopic methods have been investigated drastically in the management of cancer. In the optical spectroscopic techniques, tissue interrogate with sources of light which are ranged from the ultraviolet to the infrared wavelength in the spectrum. The information accumulation of light can be in a reflection which is named reflectance spectroscopy; or interactions with tissue at different wavelengths which are called fluorescence and Raman spectroscopy. This review paper introduces the optical spectroscopic methods which are used to characterize brain tumors (neuro-oncology). Based on biochemical information obtained from these spectroscopic methods, it is possible to identify tumor from normal brain tissues, to indicate tumor margins, the borders towards normal brain tissue and infiltrating gliomas, to distinguish radiation damage of tissues, to detect particular central nervous system (CNS) structures to identify cell types using particular neurotransmitters, to detect cells or drugs which are optically labeled within therapeutic intermediations and to estimate the viability of tissue and the prediction of apoptosis beginning in vitro and in vivo. The label-free, optical biochemical spectroscopic methods can provide clinically relevant information and need to be further exploited to develop a safe and easy-to-use technology for in situ diagnosis of malignant tumors

Optical spectroscopy and imaging systems for gynecological cancers: from Ultraviolet-C (UVC) to the Mid-infrared

Optical spectroscopy and imaging has proving to be of diagnostic relevance in many organ sites. We use fluorescence and FTIR spectroscopy to study gynecological organ sites and develop classification algorithms for cancer diagnosis. Ovarian cancer is the deadliest gynecological cancer. The American Cancer Society reports that for the year 20 I 0, there would be 21,880 new cases of ovarian cancer and 13,850 fatalities. This is partly due to the fact that current diagnostic and screening methods for the disease are not very accurate. In this study, we analyze the fluorescence spectra of excised normal and cancerous ovarian tissues at multiple excitation wavelengths. The data includes spectra obtained at the UVC wavelength 270nm and UVB wavelength 300nm. Excitation in the UVC has been especially understudied in spectroscopy for tissue diagnosis. We introduce the application of a novel SVM algorithm for the classification of fluorescence data. This SVM is trained subject to the Neyman Pearson (NP) criterion which allows for a decision rule that maximizes the detection specificity whilst constraining the sensitivity to a high value. This technique allows us to develop a binary classification algorithm that is not biased towards the larger group and this in tum leads to robust classifiers that are more suitable for clinical applications. We obtained sensitivities and specificities greater than 90% for ovarian cancer diagnosis using this algorithm. Also, FTIR is used to analyze cervical tissues. Absorption of light in the mid-IR region by biomolecules show up as peaks in the FTIR spectra, and there is differential absorption in tissue depending on the histopathology. The spectroscopic analysis informed our choosing of a wavelength for the illumination source ofa mid-IR microscope. We then present the design of an imaging system that employs the use ofa mid-IR quantum cascade laser(QCL) which can potentially have clinical use in the future. Finally a reflectance based fiber endoscope imaging system is presented. Cellular imaging is demonstrated with this system that has the potential for use in optical biopsy

Automated image analysis in multispectral system for cervical cancer diagnostic

Uterine cervical cancer is the second most common cancer in women worldwide. The accuracy of colposcopy is highly dependent on the physicians individual skills. In expert hands, colposcopy has been reported to have a high sensitivity (96%) and a low specificity (48%) when differentiating abnormal tissues. This leads to a significant interest to activities aimed at the new diagnostic systems and new automatic methods of coloposcopic images analysis development. The presented paper is devoted to developing method based on analyses fluorescents images obtained with different excitation wavelength. The sets of images were obtained in clinic by multispectral colposcope LuxCol. The images for one patient includes: images obtained with white light illumination and with polarized white light; fluorescence image obtained by excitation at wavelength of 360nm, 390nm, 430nm and 390nm with 635 nm laser. Our approach involves images acquisition, image processing, features extraction, selection of the most informative features and the most informative image types, classification and pathology map creation. The result of proposed method is the pathology map - the image of cervix shattered on the areas with the definite diagnosis such as norm, CNI (chronic nonspecific inflammation), CIN(cervical intraepithelial neoplasia). The obtained result on the border CNI/CIN sensitivity is 0.85, the specificity is 0.78. Proposed algorithms gives possibility to obtain correct differential pathology map with probability 0.8. Obtained results and classification task characteristics shown possibility of practical application pathology map based on fluorescents images

Near-infrared raman spectroscopy for early detection of cervical precancer

Ph.DDOCTOR OF PHILOSOPH