These limits are updated periodically based on current scientific knowledge. The public may occasionally be exposed to radiation, but has usually no knowledge of danger of radiation and risk. Trainees under 18 years have a special consideration due to age. Monitoring Radiation Exposure Radiation must be monitored to assess the level of exposure of occupationally exposed individuals. Monitoring is used to maintain individuals under the maximum permissible dose and to investigate new ways to reduce exposure in a given work place.
Film badges are the most common way to monitor radiation exposure.
Film badges must be worn during working time at the level of the chest. They are worn outside of the lead apron, but under a lead thyroid shield. The film badge contains film and several types of thin metal strips. The film is developed once a month or quarterly and exposure is calculated based on film exposure. A record of previous radiation exposure must be kept to insure correct and updated information.