Radiosensitivity

Radiosensitivity (pronounced: ray-dee-oh-sen-si-tiv-i-ty) is a term used in radiobiology to describe the susceptibility of cells, tissues, or organisms to the harmful effects of ionizing radiation.

Etymology

The term is derived from the Latin radius meaning ray, and the English word sensitivity, referring to the susceptibility or responsiveness to something.

Definition

Radiosensitivity refers to the relative susceptibility of cells, tissues, or organisms to the damaging effects of ionizing radiation. This can vary greatly between different types of cells and tissues within the same organism. For example, rapidly dividing cells, such as those found in the bone marrow, are typically more radiosensitive than slowly dividing cells, such as those found in muscle tissue.

Factors Influencing Radiosensitivity

Several factors can influence radiosensitivity, including the cell cycle stage, oxygen levels, and the ability of the cell to repair DNA damage. Cells are most radiosensitive in the mitotic and late G2 phases of the cell cycle. Oxygen can increase radiosensitivity because it helps to create free radicals that damage DNA. Cells that are proficient in DNA repair are less radiosensitive than cells that are deficient in DNA repair.

Related Terms

Radioresistance: The ability of cells, tissues, or organisms to withstand exposure to ionizing radiation.
Radiobiology: The study of the action of ionizing radiation on living things.
Ionizing radiation: Radiation with enough energy to remove tightly bound electrons from atoms, thus creating ions.
DNA damage (naturally occurring): Damage to DNA that naturally occurs in living organisms.