A sterilization system consisting of a mobile emitter, a sensing subsystem and a data logging subsystem is described. The emitter has one or more UV emitting lamps or devices. The sensing system comprises at least one remote UV sensor and at least one door sensor. The door sensor comprises a safety shut off door detector and may contain an emergency stop detector and arming detector to protect people from being exposed to UV energy. The system has a remote control for starting, stopping and setting system parameters which include but are not limited to: treatment time, dosage, room size, room number, unit number, floor, facility name, operator name, operator identification number, password, default dosage values, dosage, and patient identification number. The number of treatments per unit of time can be maximized because of the use of incident light measurement.