Principle of the radiotherapy for the nonneoplastic diseases

Irradiation the nonneoplastical lesions and degenerative diseases lead to increase circulation of blood, tissues trophy and fagocitosis, improve function of the vegetative innervation, diminishes of hyperemia, edema, pain.

Factors, which influence efficiency of radiotherapy of malignant tumor

Radiobiologists and experts of radiotherapy aspire to the fullest destruction of tumoural elements and minimal damage of surrounding healthy tissues. Radiotherapy of malignant tumors are based upon destroying action of radiation towards cancer cells and tissues.

The most effective dose which can destroy completely epithelial tumor without expressed damage of surrounding healthy tissues.

Significance of irradiated tissues volume

The biological reaction depends on irradiated tissues volume. Раterson achieved a 5 years survival in the 54 % patients if had been irradiated the small volume of tissues, and the 5-years survival 38 % if had been irradiated a big tissues volumes. It testifies that optimal dose should be irradiated of optimum tissues volume (an optimum dose should be different for radiation exposure of greater and small tissues volumes).

For irradiation tumors they are necessary to know the anatomic features of irradiated area and especially the features of regional lymph outflow. The volume of irradiated tissues should be defined by localization, histological structure, character of growth, prevalence of malignant tumor, the general habitus of the patient. In some cases the surgical operation are necessary. Radiotherapy in all cases should be carried out in optimum conditions for the patient. It is necessary to estimate risk associated with cancer process and to define, that represents greater danger-passivity of therapeutic actions or active treatment too. The radiotheraputic method should provide the maximal dose to pathological area but minimal adjacent tissues irradiation.

Dependence of therapeutic effect from a kind of radiation

Biological efficiency depends on the density of ionization (number of ions pairs per track length of ionizing ray) - densely ionizing radiations cause greater biological effect, than radiation with low ionizing density.

Significance of a rhythm and fractionation radiation exposures

Single radiation exposure do not cause of all tumor cells destroyed. On the one part the fractional radiation exposure (ordinary fractionation - 2 Gy) protects the stroma and surrounded healthy tissues from destroyed, on the other part fractionating promotes to the most effective destruction of tumor cells. Fractionating and protragivity (applied the low power irradiation for elongated period) doses increase probability of radiodamaged of tumor elements.

Mechanism of anti-inflammatory, antisensitizing, antispastic and analgetic action of ionizing radiations.

As a result of action of ionizing radiations there is reduction of edema of tissues, the function of organ gets better, circulation of blood rises. In the first time after the radiation exposure there is expansion of capillaries, rise of permeability of vascular wall, exudation increases, migration into the tissue of elements of blood with subsequent their disintegration and formation biologically of active matters. Lymphatic capillaries is widen that leads to the strengthening of outflow from an inflammatory focus, as a result interstitial pressure is decreased and pain is diminished. Fagocitic leucocytes activity rises, acydosis changes into alkalosis (this factor leads to decrease the pain intensity).

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