Abstract:

BACKGROUND: Transmitting law of laser in biological tissues is hard to calculate by mathematical analysis or clinical monitoring. Therefore, numerical simulation is commonly used for its prediction. Monte Carlo simulation is an ideal method for this study.
OBJECTIVE: To establish a light dose mathematical model by Monte Carlo method, and to explore the damage of laser to liver tissues.
METHODS: Light dose mathematical models of normal tissues and tumor with varied optical parameters were established by Monte Carlo method, and the migration trajectory of ponderosus photons was calculated one by one, and the distribution of photon was analyzed.
RESULTS AND CONCLUSION: The decay of photo dose with depth was approximately exponential, and the second peak value will be formed at the verge of the organization. The damage of organization was a process of the threshold value. The dose curved shape was the same as the line of threshold. Using Monte Carlo method, the ransmitting law of laser in tissues of liver tumor was obtained. The results demonstrated that optimal ration of illumination intensity can obtain a shallow but entirely selective depth of tumor necrosis, but to obtain deeper tumor necrosis necessarily means some degree of normal tissue damage．