Investigation of the Mechanisms of Radio-Dynamic Therapy

Abstract

Purpose: Photodynamic therapy (PDT) uses light-activated drugs to treat diseases ranging from cancer to age-related macular degeneration and antibiotic-resistant infections. The fini e penetration depth of light has limited the clinical application of PDT. This work investigates the substitution of light in PDT using Cerenkov light induced by 45MV photon beams from the LA45 therapy accelerator. This new treatment technique has been named radio-dynamic therapy (RDT) and this paper investigates the dosimetric requirement of RDT. Method: Cerenkov light and its spectrum induced by 45MV x-ray beams from a LA45 therapy accelerator, was simulated with the Monte Carlo method. The excitation efficie y of Cerenkov light in RDT was theoretically studied and compared with the excitation efficie y of external laser light in PDT. Experiments were carried out to enhance the excitation efficie y for singlet oxygen production with specific coenzymes as substrates. These results were compared with previous experimental work reported in the literature.