Gamma-therapy - radiation therapy gamma radiation of radioactive isotopes (With60, Cs -137, Ra226, Ta182, Ir192 and others); used in the treatment of malignant, less - benign tumors. The main task for gamma therapy is the creation of conditions of exposure that attain or immediate destruction of tumor cells, or permanent cessation of reproduction of irradiated cells with mandatory saving regenerative capacity of the surrounding normal tissue.
Depending on the localization, distribution and histological structure of tumor can be applied to contact methods in which radioactive drugs (see) in direct contact with tissues or are from them at a distance of no more than 1-2 cm, and remote sensing methods in which the radiation is delivered from a distance of 6 cm to 1 m
Contact methods. Gamma-therapy application - method in which radioactive drugs, located in a certain order on the applicator, form a radiating surface. The applicator is prepared individually for each patient from plastics or similar material. Plate thickness 1 cm lower in hot water (temperature of about 40 degrees) for 5-10 minutes until softened, after which it is removed, dried with a place to be irradiated area and carefully modelled so that the applicator exactly repeated all the curves of the exposed surface of the body. After manufacturing the applicator hardens and accordingly tumor localization stack and fix radioactive drugs cylindrical or spherical shaped activity 2-10 mg-EQ Ra (see Gram-equivalent radium). In order to protect from radiation, radioactive applicators top cover lead hollow semi-cylinders with wall thickness of 3-4 mm Ready applicator is put on the tumor and firmly fixed on the body of the patient. Irradiation is carried out daily on 3-12 hours. within 7-12 days. Dose field in the application method is characterized by rapid dose fall as the passage of radiation in the tissues. Necessary to ensure the radiation dose is created in the first inch of tissue and underlying tissues are not damaged. Application method is indicated for the treatment of skin cancer, lips, cavernous angiomas and other tumors, infiltrating tissue to a depth of not more than 1 to 1.5, see
Gamma therapy of interstitial - method in which radioactive drugs with a linear density of 0.3-1 MK 1 cm injected into the tumor and adjacent normal tissue. Drugs - rudonosnye needle - are cylindrical in shape; one end of their Ostrovsky, the other has the eye to pull the threads. In addition, With60, Ir192, Ta182 used in the form of segments of a wire in length 3-4 mm to fill in thin nylon tubes used as thread for flashing of the tumor. Drugs are sterilized by boiling. Their introduction is done under local or regional anaesthesia in the operating rules of asepsis. Drugs extract on receipt of the necessary amount. Interstitial method is indicated in the treatment of limited differentiated tumors diameter not exceeding 5 cm for skin cancer, persons century, lips, tongue, anus, the cancer relapses after radiotherapy and surgical treatment. Dose field in interstitial method is characterized by irregularity and the rapid fall of the dose rate at the distance of 1 cm from the drug.
Gamma-therapy intracavitary - method in which radioactive drugs cylindrical or spherical form is injected into the affected cavity in the rubber tubes, cylinders or special applicators. The total activity of drugs varies within 20-60 MK. If the entered drugs controlled rentgenograficheskie. Intracavitary method can be carried out with the help of machines with the source of greater activity that allows you to automatically enter radioactive drugs in pre-fixed applicators. Is used for the treatment of cancer of the esophagus, nose, throat, neck and body of the uterus, bladder and rectum. As an independent method is used when only defeat mucous membrane. In all other cases, combined with remote radiation.
Gamma-therapy remote - method of radiation from a distance of one source of significant activity using gamma-ray apparatus. A method is indicated for the treatment of deep tumors. There are static gamma-therapy, in which the source and the patient during irradiation is fixed in position, and gamma-therapy moving beam in which the radiation fixed in position of the patient is moving in a circle or arc source. Fixation of the patient is carried out with special devices, models, or at least sacks filled with sand. The choice of location and size of radiation based on data from clinical and radiological examination and the so-called cross, or sagittal, "cut", corresponding to the center of the tumor, which calculates daily and total focal dose in the tumor and normal tissues. Field exposure outline on the skin of the patient. The angle of incidence of the Central beam, selected by transverse shear, establish on a goniometer system, iris output window of the device limit the field of radiation. The necessary distance from the surface of the body to the source establish special measuring with a ruler. Dose field in remote gamma-therapy characterized by slow, at a distance of 10 -15 cm, dose fall. Cm. also Gamma-radiation, Radiation therapy.