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Design, Fabrication And Testing Of A Versatile And Low-Cost Diffuse Optical Tomographic Imaging System

Electronic Theses of Indian Institute of Science

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Title Design, Fabrication And Testing Of A Versatile And Low-Cost Diffuse Optical Tomographic Imaging System
 
Creator Padmaram, R
 
Subject Tomography
Image Processing
Diffuse Optical Tomography (DOT)
Model Based Iterative Image Reconstruction (MOBIIR)
Tissue-Mimicking Phantoms
Diffuse Optical Tompgraphy Breast Scanner/Imager
Diffuse Optical Tomographic Imaging System
Photo Multiplier Tube’s (PMT’s)
Radiology
 
Description This thesis reports the work done towards design and fabrication of a versatile and low cost, frequency domain DOT (Diffuse Optical Tomography) Imager. A design which uses only a single fiber for the source and a single fiber bundle for the detector is reported. From near the source, to diametrically opposite to the source, the detected intensity of scattered light varies by three to four orders in magnitude, depending on the tissue/phantom absorption and scattering properties. The photo multiplier tube’s (PMT’s) gain is controlled to operate it in the linear range, thus increasing the dynamic range of detection. Increasing the dynamic range by multi channel data acquisition is also presented. Arresting the oscillations of a stepper using a negative torque braking method is also adopted in this application for increasing the speed of data acquisition. The finite element method (FEM) for obtaining photon density solution to the transport equation and the model based iterative image reconstruction (MPBIIR) algorithm are developed for verifying the experimental prototype. Simulation studies presented towards the end of this thesis work provide insight into the nature of measurements. The optical absorption reconstructed images from the simulation, verified the validity of implementation of the reconstruction method for further reconstructions from data gathered from the developed imager. A single iteration of MOBIIR to segment the region of interest (ROI) using an homogeneous measurement estimate is presented. Using the single iteration MOBIIR to obtain a relatively more accurate starting value for the optical absorption coefficient, and the reconstruction results for data obtained from tissue mimicking solid epoxy-resin
phantom with a single in-homogeneity inclusion is also presented to demonstrate the imager prototype.
 
Contributor Vasu, R M
 
Date 2009-06-16T07:06:09Z
2009-06-16T07:06:09Z
2009-06-16T07:06:09Z
2007-05
 
Type Thesis
 
Identifier http://hdl.handle.net/2005/530
 
Language en_US
 
Relation G21494