Performing temperature feedback controlled tissue photo-coagulation using magnetic resonance thermometry

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to digital@library.tamu.edu, referencing the URI of the item.Includes bibliographical references (leaves 80-85).Issued also on microfiche from Lange Micrographics.Laser photo-coagulation is gaining immense popularity in surgery and medicine because of its minimally invasive nature with very short surgery times. The principal contribution of this thesis is demonstrating the ability of performing temperature controlled photo-coagulation using magnetic resonance imaging as the non-invasive means of temperature feedback. The desired coagulation depth was controlled at a constant temperature of 40 degrees for different amounts of time and the actual coagulation depth observed (lesion size) was measured. The results obtained show that the temperature feedback controlled system developed has the ability to control the temperature at a desired point within the tissue non-invasively and for the desired time length. The system relies on temperature feedback and not on the laser dosage as is the case in uncontrolled coagulation. Thus the heating process is not subject to uncertainties in the laser power density, the optical properties of the tissue, etc. This method of controlled coagulation also reduces the space of the variables to temperature, position and time