Radiation therapy

Radiation therapy (radiotherapy) - treatment of ionizing radiation. It is mainly used for influence on tumor order to cure the patient (radical radiation therapy) or temporary relief of his condition (palliative radiation therapy). Radiation therapy may be used in some non-tumorous diseases (inflammatory processes of the type of mastitis, felon, gidradenit and others, eczema, neurodermatitis and others) in cases when other methods of treatment have been unsuccessful.
Sources of ionizing radiation are radioactive isotopes (see), to be applied in the form of specially manufactured drugs (see Radioactive drugs), or radiation generated by the devices (see X-ray machines. Gamma-ray apparatuses, Accelerators of charged particles). Natural radioactive elements (uranium, radium-Mesohori) currently in therapy goals (radium therapy) shall no longer apply.
In the basis of the radiation treatment of malignant diseases is known in radiobiology pattern, indicating different radiosensitivity (see) healthy and tumor tissues. In effect, as a rule, the greater the sensitivity, the tumor with radiation exposure damaged stronger than the surrounding healthy tissue, inevitably fall into the zone of irradiation. The longer the interval in the radiosensitivity of healthy and tumor tissues (therapeutic interval), the easier it is to destroy the tumor by irradiation, without causing significant harm to healthy surrounding tissues. Naturally, the tumor with high radiosensitivity, expand the therapeutic interval. Sufficient to ensure therapeutic interval, as a rule, takes place in cervical cancer, tumors of the breast, tonsils, throat, nose, throat, larynx and some other organs. Radiation therapy can be used as an independent method of treatment (for example, with nasopharyngeal tumors, cancer of the lips and others)Naibolee often, radiation therapy in combination with surgical treatment or chemotherapy (combined radiation therapy). When combined radiotherapy and surgical treatment, radiation therapy can be used in preoperative (preoperative radiation therapy)and postoperative (postoperative, or preventive, radiation therapy) periods. Irradiation of the tumor is conducted primarily to suppress its activity; in cases where it is not possible to remove the tumor in keeping with the principle of ablation (see), the main goal of radiation therapy is to bring the patient in operable condition. When pre - and postoperative radiation therapy radiation is not only the tumor or its container, but a possible area of metastasis. For example, if breast cancer advanced irradiated armpits, supraclavicular, and subclavian region, mediastinum.
There are the following methods of radiation therapy: an application, internal, intracavitary, interstitial, remote.
Application radiation therapy is treatment with β - or g-active drugs, located on a special applicators that keep radioactive sources in a certain place and at proper distance from the surface of the body. Is for the treatment of diseases of the skin or mucous membranes. Applicators as models previously used very widely, now rarely used. Are the so-called flexible beta-applicators, intended for the treatment of superficial diseases - eczema, neurodermatitis, capillary hemangiomas , etc. They are made in the form of flexible plastic plate, containing evenly distributed radioactive phosphorus, thallium or strontium, which is applied on the affected skin for several minutes or even hours. When working beta applicators must carefully monitor the safety of the plastic bag containing the applicator, because otherwise it is possible contamination of the skin of the patient dust particles of radioactive compounds.
Internal radiation therapy is carried out by introducing the organism (per os or directly into the blood stream) radioactive drugs - often I131 (see Iodine, the radioactive), R (see Phosphorus, radioactive), AI (see the Gold, radioactive). Is used in diseases of the thyroid gland, blood disease (e.g., polycythemia, leukemia), chlamydia. Patients receiving radioactive preparations, require isolation in special chambers; their urine and feces within 10 days after receiving the drug is collected in special containers (see Containers radioisotope).
Intracavitary radiation therapy - radiation of tumors of abdominal organs by announcing to them radioactive drugs, most often cobalt-60 (see Cobalt, radioactive). Most often used in the treatment of cancer of the cervix and the uterus, vagina, bladder, rectum, esophagus and nasopharynx. Medications given for a few hours or even a day. The introduction is carried out only in specially equipped premises - radiomonitoring. With the introduction of drugs with the personnel for special lead foil screens.
Patients with radioactive drugs are found in special chambers (see Radiology Department). The peculiarity of care, which is treatment is thorough control and prevention of loss drugs. After extracting drugs, patients may be in the General wards.
Interstitial radiation therapy - radiation of tumors by introducing them needles radioactive cobalt or flashing tumor nylon fibre filled with fine pieces of a wire made of radioactive cobalt, gold or iridium. Most often used for superficial tumors and tumors of the tongue and mouth. Radioactive needle and thread type on a few days, and then remove. Recently, instead of needles and threads in tumor is administered by injection of colloidal solutions of radioactive gold-198 or very small iridium grain. Introduction of grains produced using a special gun, and colloidal solutions - using syringes in a protective lead cases (see Radiological instrumentation).
Remote radiation therapy - radiation with the help of special facilities that generate ionizing radiation and the radiation source have some distance from the patient. Source of radiation may be an x-ray machine - radiotherapy; radioactive cobalt or cesium - telehomecare; betatron or linear accelerator - megavoltage therapy. Depending on what type of radiation betatron used - e (see Electron radiation) or brake, there are megavoltage therapy electronic or bremsstrahlung. Remote radiation therapy is the most common form of radiation therapy. It is only in special treatment rooms, where radiation sources are stationary (see Gamma-ray apparatuses). When using devices "Ray" and "Rocus", characterized by a good protection of the radiation source, the risk exposure for staff very small.


Radiation therapy [synonym: criteria, radioterapia, radiotherapy (obsolete name)] - is a method of treatment of diseases by means of various types of ionizing radiation of different energies.
As a clinical discipline radiation therapy is closely connected with the radiobiology (see), physics of radiation to dosimetry (see), as well as with equipment medical application of radiation sources; its main sections - the technique of medical applications of radiation and radiological clinic.
Radiation therapy combines the therapeutic use of x-ray, gamma, electron, proton, neutron and other ionizing radiation (see alpha therapy, Beta-therapy, Gamma-therapy, Neutron therapy, Proton therapy, Radiotherapy, E-therapy).
Rational organization of radiation therapy involves the concentration of different species within large centralized hospital (clinical) institutions.
Radiation therapy should be comprehensive; it depends on the success of the treatment. L. I. is done with friendly doctors of radiologists and physicists, jointly solving fundamental and private clinical problem of optimal exposure.
Tasks L. T.: 1) the dosimetric characteristics of the exposure assessment of dose fields, created in the lesions and healthy tissues; 2) radiobiological justification of radiation characteristics of radiosensitivity of tissues, a directional change of radiosensitivity; 3) determining reactions of healthy and pathological tissues and whole body irradiation, development of methods and tactics exposures, the fight against the immediate and late complications.