Estudiantes

.  Summary of Radiobiology.


Radiobiology Is the branch of science concerned with effects of light and of ultraviolet and ionizing radiations on living tissue or organisms.

RadiosensitivityDefinicion : Is the properties of cells and tissues to be more or less damaged by exposure to ionizing radiation. In general, the sensitivity to the effects of the radiant energy is greater thegreater the reproductive activity of cells that compose the fabric: in fact one of the cellular macromolecules most vulnerable in this regard is the DNA, of which the radiation inhibit the synthesis,interfering with the division process cellulare.I tissues most radiosensitive are therefore those rich in cellular elements in the division (the lymphoid tissues, the bone marrow, the epithelium of thelining of the intestinal mucosa, the epithelium of the seminal testicular, ovarian follicular structures) and poorly differentiated tissues (such as embryonic tissue), in which the cells have not yetreached the degree of specialization definitive funzionale.The relatively radiosensitive tissues (and radioresistant) are very different elements, such as cells and muscle fibers, nerve cells, elementsepithelial cells of the liver, kidney, pancreas, bone and cartilage cells mature. An intermediate position occupied by the connective tissue, the neuroglia, the cartilage tissue and bone duringaccrescimento. The same phenomenon is observed in tumor tissues, in which the r. depends both on the tissue of origin of the tumor is its degree of cytological and histological differentiation: Thisproperty is exploited practically in the radiotherapy of malignant tumors, with the possibility of success greater, the greater the difference between the r. own tumor tissue and that of the surroundinghealthy tissue (such difference is defined therapeutic range). The vulnerability of the neoplastic cells to ionizing radiation can be increased by increasing the degree of oxygenation of the neoplastic...