Study On The Diagnosis And Treatment Of Epithelial Tumor Based On Multiphoton Technique

Cancer has threatened people's health and survival seriously, and it has become one of the most important social problems facing all the countries in the world today. It is well known that more than90%of all cancers arise from the epithelial tissues. In general, it is readily cured if detected and treated in one of the pre-invasive stages. Until now, the detection and treatment of early lesions is challenging. Therefore, the development of "seek-and-treat" tool for early epithelial tumor is of great medical significance.In recent years, multiphoton technique, including multiphoton imaging and multiphoton absorption, has emerged to a feasible and promising approach for diagnosis and treatment of early epithelial tumor. Moreover, this issue has been becoming a hot topic in the field of biomedical photonics. However, the use of multiphoton technique in the diagnosis and treatment of early epithelial tumor has seldom explored because it requires fostering strong collaborations with people who work in different fields. For accelerating the clinical application of multiphoton technique, this thesis focuses on the study of this technique in the diagnosis and treatment of early epithelial tumor as follows:First, to achieve the differentiation of neoplastic and non-neoplastic epithelial lesions, multiphoton imaging was used to investigate two main non-neoplastic epithelial diseases:1) the squamous epithelial tissues—inflammation;2) the columnar epithelial tissues—hyperplastic polyps. A depth-cumulated method is developed to quantify the squamous epithelial redox ratio and stromal collagen quantity. It is found that both inflammatory and dysplastic squamous epithelial tissues display a large decrease in stromal collagen quantity, but have very different epithelial redox ratio, indicating that probing differences in epithelial redox ratio in addition to stromal collagen quantity can serve as quantitative intrinsic indicators for differentiating normal, inflammatory, and dysplastic squamous epithelial tissues. It is also found that multiphoton imaging can provide cellular and subcellular details to the identification of adenomas from hyperplastic polyps. In particular, there is significant difference in the population density of goblet cells among normal columnar epithelial tissue, hyperplastic polyp, and adenoma, providing substantial potential to become a quantitative intrinsic marker for in vivo clinical diagnosis of early columnar epithelial lesions. The related main results have been published in Applied Physics Letters,97,173701,2010(SCI, IF=3.8) and Laser Physics Letters,9,465,2012(SCI, IF=6.0), where the depth-cumulated method is appraised as "a very useful method" by the reviewer of "Applied Physics Letters".Second, the diagnostic features of squamous epithelial tumor stroma and columnar epithelial tumor were investigated thoroughly and in depth by multiphoton imaging. The results show the potential of multiphoton imaging to extract quantitative biomorphologic and biochemical features on collagen-related changes, elastin-related changes, alteration in proportions of matrix molecules, the scattering coefficient of stroma, the important hallmarks of squamous epithelial cancer. The results also suggest that multiphoton imaging can establish the diagnostic features, including the appearance of abnormal cells, the significant loss of collagen, the disorder arrangement of glands, and the distorted and uneven structure of blood vessel, to qualitatively and quantitatively differentiate between normal and cancerous columnar epithelial. These features are essential and significant for the use of multiphoton imaging to perform early diagnosis of epithelial tumor. These findings also fill the gap of studies on "the diagnostic features of squamous epithelial tumor stroma and columnar epithelial tumor". The related main results have been published in Journal of Biomedical Optics Letters,14,020503,2009(SCI, IF=3.1), Lasers in Medical Science,25,911,2010(SCI, IF=2.3) and Gastrointestinal Endoscopy,73,802,2011(SCI, IF=6.0), where the diagnostic features of squamous epithelial tumor stroma is appraised as "an important contribution to new cancer diagnosis" by the reviewer of "Journal of Biomedical Optics Letters" and the diagnostic features of columnar epithelial tumor is appraised as "a novel approach for the early diagnosis of cancer" by the reviewer of "Gastrointestinal Endoscopy, the#1journal among dedicated endoscopy journals".Third, the epithelial tumor progression, including normal case, preinvasive stage, and invasive stage, were investigated thoroughly and in depth by multiphoton imaging. Here, a new approach, combing qualitative, label-free multiphoton imaging and quantitative image analysis, is developed to monitor epithelial tumor progression. It is found that this technique can establish a quantitative link between collagen alteration and squamous epithelial tumor progression. The results show that quantitative characterization parameters derived from collagen image can serve as intrinsic indicators to effectively evaluate squamous epithelial tumor progression, and to locate tumor and determine the margin of tumor regions. It is also found that this technique can visualize information on the biomorphology and biochemistry of columnar epithelial tumor progression. The results also suggest that this technique has the potential in label-freely analyzing the redox ratio of epithelial cells and the changes of basement membranes as new intrinsic markers for columnar epithelial tumor progression. The related main results have been published or accepted in Applied Physics Letters,96,213704,2010(SCI, IF=3.8) and Biomedical Optics Express,2,615,2011(SCI, OSA New Journal), and PLoS ONE,2012(SCI, IF=4.4, In Press), where the quantitative link between collagen alteration and squamous epithelial tumor progression is appraised as "very good" by the reviewer of "Applied Physics Letters".Last, to meet the clinical demand—"detection and treatment of early lesions in epithelial tissue", a novel "seek-and-treat" technique, the combination of multiphoton imaging and absorption, is developed to label-freely detect and ablate preinvasive epithelial tumor. It is found that this technique can label-freely visualize the principal features of nuclear atypia and the differences in collagen density and collagen fiber direction associated with preinvasive epithelial tumor, providing substantial potential to become quantitative intrinsic biomarkers for in vivo clinical diagnosis of preinvasive epithelial tumor. The results also show that the spatial localization of multiphoton absorption can perform targeted ablation of preinvasive cancer cells with micrometer-sized volume precision. This study highlights the potential of this technique as a "seek-and-treat" tool for early lesions in epithelial tissue. The related main results have been published in Applied Physics Letters,100,023703,2012(SCI, IF=3.8) and Journal of Biomedical Optics Letters,16,120501,2011(SCI, IF=3.1). In summary, the achievements and contributions in this thesis have filled the gap of studies on "the use of multiphoton technique in diagnosis and treatment of early epithelial tumor". In this thesis, a novel "seek-and-treat" technique, the combination of multiphoton imaging and absorption, has been developed. The results obtained in this thesis will provide the groundwork to bring the multiphoton device to the bedside and the scientific scheme to achieve the integration of diagnosis and treatment on epithelial tumor.