Singlet oxygen detection and improvement of treatment effect during photodynamic therapy

Photodynamic therapy is a treatment option that can be used in a wide range of applications such as cancer, rheumatoid arthritis and infection treatment. A successful Photodynamic therapy treatment can be attained with the presence of three key components. These are the presence of special wavelenght light, photosensitizier and oxygen. The presence of oxygen in the targeted area directly affects the singlet oxygen concentration required for treatment and is an indicator of Photodynamic therapy dosimetry efficiency. In this thesis; Multimode laser light source and singlet oxygen molecule monitoring system have been developed with a holistic approach. In addition, bacteria-based Photodynamic therapy applications were carried out with developed systems. The presented thesis is divided into 3 main parts. The objectives of the part can be summarized as follows; In the first part, the aim is to develop singlet oxygen detection system and conducting preliminary studies of this system in an electronic based phantom environment. The frequency range of the system is designed to capture the radiation that can occur between 10 ns-15 μs. In the second part, the aim was to develop stable light source with four radiation modes. The system was achieved 0 to 1500 mW ± 1 mW high optical output, wavelength 635 nm ± 1 nm and high temperature stability within the system 15 0C ± 0.2 0C. In the third part, antimicrobial photodynamic therapy application was experimented. The developed multimode laser light source and singlet oxygen detection system was used. SOED (singlet oxygen explicit dosimetry) and SOLD (single oxygen luminescence dosimetry) based dosimetric methods were compared and it was observed that antimicrobial photodynamic therapy can give 3% -10% better results with super pulse mode. The problems discussed in the thesis and the contributions of the thesis to the literature can be summarized as follows: - The application area does not change the temperature-related photophysical parameters during FDT, - Preventing hypoxic environment by providing oxygenation, - Keeping the amount of singlet oxygen luminescence level stable within the pulses, - To be able to track the succes of the treatment with measuring the instantaneous and cumulative singlet oxygen concentration, - Mathematical and measurement based dosimetric method correlation was observed to improve treatment effect.