Search results
Results From The WOW.Com Content Network
The oxygen enhancement ratio (OER) or oxygen enhancement effect in radiobiology refers to the enhancement of therapeutic or detrimental effect of ionizing radiation due to the presence of oxygen. This so-called oxygen effect [ 1 ] is most notable when cells are exposed to an ionizing radiation dose .
In biochemistry, the oxygen effect refers to a tendency for increased radiosensitivity of free living cells and organisms in the presence of oxygen than in anoxic or hypoxic conditions, where the oxygen tension is less than 1% of atmospheric pressure (i.e., <1% of 101.3 kPa, 760 mmHg or 760 torr).
As ions' damage is direct, OER (Oxygen Enhancement Ratio) is 1, so the effect of oxygen it is not important. An important approach of hypoxia-related treatment interventions is a procedure called dose painting, in which a higher radiation dose is targeted to hypoxic subvolumes of tumor. [ 37 ]
Oxygen enhancement ratio, effect magnitude of ionizing radiation due to the presence of oxygen; Oxygen Evolution Reaction, the formation of oxygen by electrochemical reduction of water; Owner’s Equivalent Rent, an economic metric for housing prices often used in the calculation of market baskets
The relative biological effectiveness for radiation of type R on a tissue is defined as the ratio R B E = D X D R {\displaystyle RBE={\frac {D_{X}}{D_{R}}}} where D X is a reference absorbed dose of radiation of a standard type X , and D R is the absorbed dose of radiation of type R that causes the same amount of biological damage.
Oxygen equivalent compares the relative amount of oxygen available for respiration at a variable pressure to that available at SATP.As external respiration depends on the exchange of gases due to partial pressures across a semipermeable membrane and normally occurs at SATP, an oxygen equivalent may aid in recognizing and managing variable oxygen availability during procedures such as ...
The rationale is that tumours containing hypoxic cells (cells with enough oxygen concentration to be viable, yet not enough to be X-ray-radiosensitive) and cells deficient in oxygen are resistant to killing by X-rays. Thus, the lower Oxygen Enhancement Ratio (OER) of neutrons confers an advantage.
External beam radiation therapy (EBRT) is a form of radiotherapy that utilizes a high-energy collimated beam of ionizing radiation, from a source outside the body, to target and kill cancer cells.