Generation of ozone during irradiation using medical linear accelerators: an experimental study.

Background: Some patients have noted a foul odor during radiation therapy sessions, but the cause of the odor remains unknown. Since we suspected that this phenomenon is due to ozone generated by ionizing radiation, this experimental study measured ozone concentrations in the treatment room and in a coiled polyvinyl chloride (PVC) tube placed within the radiation field.

Methods: We measured ozone concentrations using an ultraviolet absorption method and an ozone monitor.