WE-FG-BRA-12: Research Work of the Radio-Dynamic Treatment Mechanism.

PURPOSE: The finite penetration depth of Laser light has limited clinical applications for PDT. This present work investigates the activation of photosensitizers using Cerenkov light emission from 45MV photon beams produced in an LA45 cancer therapy accelerator. We have named this new treatment technique Radio-Dynamic Therapy (RDT).

METHODS: Monte Carlo simulations were made on various Cerenkov emission energies and their spectroscopy in excited target areas in order to estimate their photosensitizer inner activation efficiency. The Cerenkov light excitation efficiency used in RDT has been theoretically compared with the exotic excitation efficiency of external Laser light used in PDT. In addition, laboratory tests showed the differences of the excitation efficiencies between a patented catalyst coenzyme added as a substrate, and then without the coenzyme. A specific probe of DMA (Singlet Oxygen fluorescent probe-9, 10-dimethylanthracene) was also used to detect singlet oxygen. Finally, we also compared our results with similar previous experimental work reported in the scientific literature.

RESULTS: Our Monte Carlo results showed that the Cerenkov light intensity induced with 45MV beams from an LA45 is 8 - 10 times the Cerenkov light intensity induced with 6MV beams from conventional accelerators. Furthermore, the patented catalyst coenzyme enhanced the excitation efficiency of photosensitizers by 3-6 times under different conditions. In clinical situations, the new RDT technique also showed favorable outcomes for early and late stages of specific cancers and it is also good at metastatic cancer treatment.

CONCLUSION: Our results indicated that the process of using the Cerenkov light emission to excite photosensitizers from 45MV photons has a similar process and efficiency as the conventional laser in PDT. Comparing the advantages of RDT with a conventional PDT, the RDT may be developed into a potential treatment modality for a wider range of cancers stages as well as for other diseases.