Authors: MERVE TÜRKER BURHAN, SERHAT TOZBURUN

Abstract: The mucosa layer, the innermost layer of the gastrointestinal (GI) system, is of great importance in carcinogenesis since most cancerous tissues occur as superficial lesions. Although various treatment strategies exist, the main difficulty in eradicating lesions is unintentional damage to healthy tissues with the uncontrolled depth of treatment. This study proposes a computer modeling approach for simulating depth-resolved photothermal (laser) mucosal coagulation therapy. Computer modeling mimics the thermal dynamics of mucosal tissue to characterize the total heat energy required for successful superficial coagulation, which can be controlled by the scan rate, scan time, output power, and beam diameter of the applied laser. It consists of three steps: 1) Monte Carlo simulation to generate a laser energy distribution profile. 2) Heat transfer simulation to calculate the resulting tissue temperature. 3) Thermal damage estimation based on the calculated dead cell ratio. This computer modeling was performed for a laser wavelength of 1500 nm. Transient temperature profiles and a corresponding thermal damage map were generated as functions of laser scanning speed, power, and beam diameter. The guide map estimates that mucosal coagulation can be achieved with the accurate depth limits at 1500 nm laser wavelength, 1 mm beam diameter, 0.33-0.43 W/cm2 irradiation range, and 1-3 mm/s scanning speeds. This computing approach may hold promise in determining optimal therapy parameters for depth-resolved adequate coagulation in a single session with further development.

Keywords: Computer modeling, Monte-Carlo method, photothermal mucosal coagulation, mucosal lesions

Full Text: PDF