What are the side effects resulting from radiation treatment?

Radiation poisoning can result from accidental exposure to industrial radiation sources. People working with radioactive materials often wear electrometer dosimeters or film "badges" to monitor their total exposure to radiation. These devices are more useful than Geiger counters for determining biological effects, as they measure cumulative exposure over time, and are calibrated to change color or otherwise signal the user before exposure reaches unsafe levels. However, film badge types require the film to be developed, as with photographic film, and are used to measure long-term exposure where brief catastrophic exposures are not expected.