Development Of Trans-rectal Ultrasound (TRUS) Coupled Diffuse Optical Tomography (DOT) For Prostate Cancer Imaging
Abstract
Prostate cancer is one of the leading causes among cancer deaths in men in the United States. A minimally invasive real time searching tool for cancer need to be developed, which can enhance the odds of cancer detection; Current diagnostic techniques such as Trans-rectal ultrasound (TRUS) suffers from low sensitivity and specificity. The goal of the dissertation is to develop a Trans-Rectal Ultrasound (TRUS) coupled Diffuse Optical Tomography (DOT) probe that can detect and image prostate cancer. To accomplish the task, an optical clip-on probe has been designed that can incorporate the existing ultrasound probe and can pass through the rectum. Next, a multi- step reconstruction technique has been developed by combining the piecewise cluster reconstruction and hard prior reconstruction methods. Optical properties of ex-vivo prostate specimens also have been measured. Finally, Clip-on optical probe is tested by utilizing prostate cancer animal models. The clip-on probe has been successfully tested using computer simulations and laboratory phantoms. In experiments, a hidden absorber without prior location information was reconstructed with a recovery rate of 100% in its location and 95% in its optical property. The result from ex-vivo specimen study indicates cancer tissues carry different optical signatures from the benign tissues. Change in light scattering from benign to cancer tissues is more noticeable or prevailing than that in absorption. Animal study successfully validated the functioning of the clip-on probe by reconstructing the images during gas stimulus.