Abstract

A system designed for more safely administering natural or induced light radiation to the skin of a subject, and having a control system adapted to monitor the instantaneous intensity of the ultraviolet light received by a subject being treated, wherein the instantaneous intensity is integrated and converted to a digital pulse output. The pulse rate is proportional to the instantaneous intensity. The pulses are counted to accumulate the total ultraviolet energy per unit area received by the subject. The apparatus is so controlled that when the total energy received by the subject reaches a predetermined preset value, the subject or doctor is alerted or notified either audibly or visually, e.g., when an ultraviolet lamp source is employed the lamp or lamps may automatically be turned off. In an improved embodiment a minute timer is provided in the circuit and has a switch to turn off the lamps after a predetermined period of time has elapsed as a safety precaution in case of failure of the ultraviolet light sensor and integration system. Additional safety features are provided to turn off lamps if fault occurs or when the ultraviolet sensor is accidentally obscured by the hand of the subject. In further improved embodiments, a manual switch is provided for turning the lamps on momentarily for measuring the intensity of the ultraviolet light acting on the photoelectric cell prior to treatment, and a reset circuit is provided for preventing identical dosages from being given inadvertently to successive patients.