Abstract:

BACKGROUND: Currently, all the basic and clinical researches of photodynamic therapy (PDT) for cancer are based on experience and qualitative models, which lacked of optical methods to monitor the effectiveness.
OBJECTIVE: To quantitative analyze the results of PDT quantitative mathematic models in cell test, and to explore the possibility of PDT in the treatment of cancer.
METHODS: Human lung cancer cell line A549, a 3W/633 nm semiconductor diode laser and hematoporphyrin derivative Photosan3 were selected. Cells were cultured in clear bottom black 96-hole plate and kept in dark strictly before the different power light treatments. Standard curves and the control groups were set in each plate. The survival ratio of the cell was calculated based on the absorbance and the mathematic models.
RESULTS AND CONCLUSION: The four survival curves was made by the power at 20, 30, 40, and 50 mW, and the eleven illumination energies from 0 to 20 J/cm², with the photosensitizer concentration was 12 g/L. The survival ratio of the cell decreased as the energies increased when the laser power was the same, and the higher the laser power the more surviving the cells when the energy at the same level. The calculated results showed that, if the incident photon ρ was 8.0×10⁵, the initial concentration of photosensitizeron [S₀] was 4.0×10¹⁰, and the initial concentration of singlet oxygenthe [O₃] was 5.9×10¹⁷, the simulative curve was closed to practical curves, illustrating that the cell survival rate was gradually increased with incident photon increasing; under the same incident photon, the cell survival rate was decreased with energy increasing. This is the first study described the feasibility of PDT quantitative mathematic model and proved the coincidence between the calculated value by mathematic model and the experimental results. The simulation results demonstrate the effectiveness of the presented method.