Laser dosimetry planning tool for colonoscopic tumor resection

Abstract

Gastrointestinal tumoral pathologies are quite common nowadays. Diseases such as gastric antral vascular ectasia (GAVE) or actinic proctitis may require endoscopic surgery. Argon Plasma Coagulated (APC) or radiofrequency are usually employed. However, they present disadvantages, such as the reduced treated area, magnetic resonance incompatibility, or an uncontrolled ablation depth. Optical surgery could avoid these problems and contribute to a better and controlled treatment result, either ablative or coagulative, in a minimally invasive, non-contact and non-ionizing way. The treatment area could also be increased by adequate optical fiber probe design. In this work laser surgery is analyzed for resection of colonic tumors. A Monte Carlo model is employed to study optical propagation, and an optical ablation approach allows the estimation of the resected volume. The ablation approach is based on plasma-induced ablation, particularly taking into account the freeelectron density generated in the tissue by the pulsed optical source. Several wavelengths, radii and malignant tissue types are considered, either healthy, adenomatous or even coagulated tissues. Optimum source parameters as a function of tumor geometry can be estimated for treatment planning.