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Radiolysis of intracellular water by ionizing radiation creates peroxides, which are relatively stable precursors to hydroxyl radicals. 60%–70% of cellular DNA damage is caused by hydroxyl radicals, [3] yet hydroxyl radicals are so reactive that they can only diffuse one or two molecular diameters before reacting with cellular components.
When radiation deposits enough energy in organic tissue to cause ionization, this tends to break molecular bonds, and thus alter the molecular structure of the irradiated molecules. Less energetic radiation, such as visible light, only causes excitation, not ionization, which is usually dissipated as heat with relatively little chemical damage ...
Otto Warburg postulated this change in metabolism is the fundamental cause of cancer, [8] a claim now known as the Warburg hypothesis. Today, mutations in oncogenes and tumor suppressor genes are thought to be responsible for malignant transformation , and the Warburg effect is considered to be a result of these mutations rather than a cause.
Ionizing radiation may be used to treat other cancers, but this may, in some cases, induce a second form of cancer. [74] Radiation can cause cancer in most parts of the body, in all animals, and at any age, although radiation-induced solid tumors usually take 10–15 years, and can take up to 40 years, to become clinically manifest, and ...
Radiation therapy sources can cause beta burns during exposure of the patients. The sources can be also lost and mishandled, as in the Goiânia accident, during which several people had external beta burns and more serious gamma burns, and several died. Numerous accidents also occur during radiotherapy due to equipment failures, operator errors ...
Two properties are crucial regarding photoionization. On the one hand, the ionization energy (also called ionization potential, IP), refers to the energy necessary to remove one electron from a molecule; the lowest IP, corresponding to the ejection of a first electron, is the most biologically relevant factor. On the other hand, the ...
Microwave and other radio frequencies cause heating, and this can cause burns or eye damage if delivered in high intensity, [38] or hyperthermia as with any powerful heat source. Microwave ovens use this form of radiation, and have shielding to prevent it from leaking out and unintentionally heating nearby objects or people.
AHTRs occur within 24 hours of the transfusion and can be triggered by a few milliliters of blood. The reaction is triggered by host antibodies destroying donor red blood cells. AHTR typically occurs when there is an ABO blood group incompatibility, and is most severe when type A donor blood is given to a type O recipient. [1] [2] [3]