Irradiation and contamination:
The two main hazards in radioprotection are those due to irradiation and contamination. Irradiation is caused by X-rays or gamma rays emitted by an external source, against which one can interpose protective screens. Contamination, on the other hand, is the danger posed by the contact, the inhalation or the ingestion or radioactive substances. In that case, the damage come mainly from alpha and beta particles.