Opto-acoustic Tomography And Influnence By Tissue Optical Coefficient

Novel and promising developments in clinical therapies and diagnosis have beenseen in the biomedicine due to the invention of laser, especially in the domain ofbiomedical imaging where the laser plays an important role. Optical coherencetomography and opto-acoustic tomography are two of the most important imagingmodalities recently developed in medical imaging. So, in order to improve theperformance of tomography, the understanding of the influence of laser transmittingthrough the biologic tissue on the performance of tomographic imaging becomes themain instrument. The aim of this thesis is to improve the performance of theopto-acoustic tomography. I first studied how laser light propagating in bio-tissue.And then, I provided some detailed detailed research on opto-acoustic tomographyboth experimentally and theoretically.In chapter one, the history of opto-acoustic technique is reviewed. The merit ofopto-acoustic technique is discussed. Then the applications of opto-acoustic techniquehave been introduced. Among the applications developed so far, the noninvasivemonitoring of blood oxygenation has placed itself an important position.Base on the detection mode of ultrasonic wave, Chapter two discussed thecurrent models in opto-acoustic tomography that can be classified into three maincategories, i.e.: forward model, backward model and sideward model. And theadvantages and disadvantages for each model are detailed. At last, the problems in thecurrent tomography technique are summarized.Chapter three is concerned with computer simulation. In order to obtain thebetter analysis of the experiment results, the computer simulation is done. The historyof Monte Carlo simulation is reviewed. The necessary application of Monte Carlosimulation in tissue optics is shown. And the theory of Monte Carlo simulation isintroduced. As the development of the computer technique, the Monte Carlosimulation shows its great potential.In chapter four, we systematically investigate the influence of absorption andscattering coefficients of tissue on the optoacoustic imaging depth and contrast. Inaddition, we also investigate the influence of spreading photon diffusion in the tissueon its sectioning capability. In the experiments, tissue phantoms were constructed witha range of optical properties. We used the intralipid solution to control the scatteringproperties, and the indocynane green to control the absorption property of thephantom.Last chapter gives the results on optoacoustic tomography of a purpose built highscattering phantom, demonstrating that the system constructed in this work is feasiblein imaging the biological tissues.