Photodynamic therapy (PDT) employs light activation of tissue-localized photosensitizer in an oxygen-dependent process which initiates oxidative stress, inflammation, and cell death. Laser systems, which are mostly used in PDT as light sources can be costly and oversized. light-emitting diodes (LEDs) equipment has a high potential to simplify technical part of phototriggered therapies and to reduce its costs. We develop the LED-based system that includes the control and irradiation units. The system provides the same power density at any irradiation point. Among the advantages of the device is a possibility to change the irradiation area and tune the irradiation dose. PDT experiments with cancer cells in vitro treated with two different photosensitizers demonstrated a possibility to use the developed LED-based system as a low-cost light source in PDT.
In the paper we explored the possibility of monitoring oxygenation of the tumor tissue through the registration of light diffuse reflectance. This method can also be helpful for assessment the effectiveness of PDT, defining the level of vascular damage and the degree of the tumor oxygenation. We also propose the modification of PDT procedure by using a modulated laser that enables to better maintain the necessary parameters for the PS activation and oxygen generation in irradiated tissues simultaneously allowing to reduce the light dose required for tumor treatment.
Photodynamic cancer therapy is used as an alternative or in combination with conventional treatments. PDT involves three key components: a photosensitizer, a light source and tissue oxygen. The combination of these three components leads to the chemical destruction of any tissues which have either selectively taken up the photosensitizer or have been locally exposed to light. In our research we used Charge-coupled device (CCD) spectrometers to measure intensity of the fluorescence signal. Devices allow receiving and processing signal in a CCD structure at a wide range of wavelengths. We have established a system for measuring the fluorescence of tumor tissue. These results are important for determining the dose of laser radiation and optimal time for laser action without damaging healthy tumor.
In this study we propose a new version of photodynamic therapy performed by laser scanning. The method consists in tumor treatment by a light beam of a small cross section which incrementally moves through the chosen area with a defined delay at each point and repetitively re-scans a zone starting from the initial position. Experimental evaluation of the method in vitro on murine tumor model showed that despite the dose, applied by scanning irradiation mode, was 400 times lower, the tumor inhibition rate conceded to attained with continuous irradiation mode by only 20%.