When is Oxygen is effective during radiotherapy?

The inhalation of oxygen during radiotherapy may increase the radiation kill effect on the tumor by counteracting areas of hypoxia-based radioresistance, and thus improve overall survival. Breathing normobaric oxygen before and during radiation therapy could increase the effectiveness of conventional radiotherapy for advanced squamous cell carcinomas of the head and neck. Hyperbaric oxygen is a mode of therapy in which the patient breathes pure, 100-percent oxygen at pressures two to three times greater than normal atmospheric pressure. This hyperoxygenation provides immediate suppo to poorly perfused tumor tissue in areas of compromised blood flow. These include radiation-damaged tissue that has lost blood supply and is oxygen deprived due to scarring and narrowing of the blood vessels within the area treated.