Analysis of Thermally Denatured Depth in Laser Vaporization for Benign Prostatic Hyperplasia using a Simulation of Light Propagation and Heat Transfer

Abstract

Laser vaporization of the prostate is expected as a less invasive treatment by photothermal effect for benign prostatic hyperplasia (BPH). In order to develop safer and more effective laser vaporization of the prostate, it is essential to set optimal irradiation parameters based on quantitative evaluation of temperature distribution and thermally denatured depth in prostate tissue. Therefore, a simulation model with light propagation and heat transfer calculation was constructed, and the vaporized and thermally denatured depths were estimated by the simulation model. The results of the simulation were compared with those of an ex vivo experiment and clinical trial. As the result, the vaporized depth strongly depended on the distance between the optical fiber and the prostate tissue, and it was suggested that contact laser irradiation could vaporize the prostate tissue most effectively. Additionally, it was suggested by analyzing thermally denatured depth comprehensively that laser irradiation at the distance of 3 mm between the optical fiber and the prostate tissue was useful for hemostasis. This study enabled quantitative and reproducible analysis of laser vaporization for BPH and will play a role in clarification of safety and efficacy of this treatment.