An in vitro hemodynamic phantom model for near infrared spectroscopy

Determination of hemodynamic parameters, including blood flow changes, in the tumor tissue will be helpful for tumor prognosis and therapy monitoring. The goal of this thesis is to develop an in vitro hemodynamic tissue phantom model to study the flow variations using Near Infrared Spectroscopy (NIBS). Two types of hemodynamic phantoms were designed, implemented, and tested using both single- and multi-tubes. At the first stage of the development, a single tube representing a group of vessels was embedded to pass through a cylindrical glass holder filled with tissue-like solution. At the second stage, the imbedded single tube was replaced by multiple small tubes that were distributed throughout the holder to more realistically resemble the tissue vasculature.; A single-channel, broadband, LAIRS system with a tungsten light source and a CCD-array spectrometer was used to quantify the changes in optical density (OD) of the dynamic tissue phantoms with variations in flow rate and absorber concentration. The dynamic studies were conducted by passing through the tubes a mixture of Intralipid and ink solution as an external perturbation to determine the dynamic variations in OD. In the multi-tube phantom experiments, animal blood was also used to study the dynamic variations in OD during oxygenation cycles. A single-exponential curve fit was applied to determine the time constant (tau) from the change in OD so as to estimate the flow rate. The dynamic phantom was extended to study the oxygenation consumption by utilizing oxygen-permeable tubes. The data given in this study shows the feasibility of using such dynamic phantoms to characterize the flow of tumor tissue using NIBS.