Optimization of energy parameters for laser-induced photodynamic therapy of cervical tissues using numerical simulation and fluorescent navigation

The main problem in the photodynamic therapy of tumors is insufficient light exposure to tissue depth or the appearance of undesirable surface effects. It is required to investigate the influence of energy density and radiation spot diameter on the photosensitizer photobleaching efficiency by depth. Optimization of energy parameters for laser-induced photodynamic therapy of cervical tissues was conducted using numerical simulation and fluorescent navigation. The laser radiation fluence rate in the near-surface layer of cervical tissue increases relative to the incident radiation fluence rate with increasing spot diameter in the range from 0.2 to 15 mm. The photosensitizer photobleaching increases with an increase in the spot diameter from 5 to 15 mm. The developed method will improve the efficiency of photodynamic therapy by providing a therapeutic effect throughout the entire depth of tumor invasion without superficial thermal damage.