Biological effects of ionizing radiation

From the aspect of physics, ionizing radiation presents a stream of particles or energy. A common effect of all types of radiation is the ionization of the environment through which they pass. According to this trait, the term linear-energy-transfer (LET) was composed for individual types of radiation to describe the transfer of radiation energy to the environment in which it is present. Biological effects of radiation are carried out in two ways; directly and indirectly. The direct radiation effect is a consequence of the disruption of chemical links between biological macromolecules by radiation energy. The indirect radiation effects are a result of free radical formation, which are highly reactive chemical compounds formed by radiolysis of water in cells. Molecular-cell radio lesions, formed as a result of radiation, cause series of molecular reactions that result in either complete reparation or biological damage. Numerous factors determine the consequences of radiation and they can be grouped in factors connected to biological characteristics of molecules or cells and factors associated with radiation. (author)