||How are people exposed to radiation?
Radioactive exposure is traditionally subdivided into external and internal types. A person is exposed to external radiation when radiation passes through the body. Ionizing radiation is either in the form of waves (gamma-ray and X-ray radiation) or micro-particles (alpha-particles, beta-particles, and neutrons). Each type of ionizing radiation affects the body differently. The external alpha-radiation is practically harmless except when it passes through the cornea, because alpha-particles do not penetrate the outer layer of skin. Beta- particles penetrate through the skin, and gamma-rays pass through the entire body.
Fig. 3: The penetrating power of radiation
Internal irradiation occurs when radioactive substances are ingested with food and water, or passed through the respiratory tract or an open wound. Any external and internal can damage living cells.
Fig 4: Pathways of radiation to the body