Telegamma therapy is a high-energy radiation therapy method that belongs to teletherapy (percutaneous radiation therapy) and uses gamma rays. Gamma rays are ionizing photon radiation emitted by excited atomic nuclei during transition from a state of higher energy to a state of lower energy. Telegamma therapy specifically uses gamma radiation produced by the decay of the radioactive isotope cobalt-60 (60 Co).
Indications (areas of application)
Many indications arise for modern telecobalt devices in radiation oncology today. In principle, no catalog of indications should be fixed for this radiotherapy method, but decisions should be made according to what dose distribution is required in the target volume and whether this results in an adequate indication for telegamma therapy. In principle, deep-seated tumors are more likely to be irradiated because the dose maximum of the radiation is only 0.5 cm in depth and superficial structures (esp. skin) can thus be relieved.
The procedure
In a nuclear reactor, neutron bombardment of the inactive 58 Co artificially produces the radioactive 60 Co. This forms the radiation source in the form of 60 Co beads packed into a cylinder 2-4 cm long and 1-2 cm in diameter, which in turn is contained within a lead shield. By rotating the cylinder from the shutter position to the irradiation position, the unshielded side of the cylinder faces the patient.
Telecobalt devices have the advantage of being uncomplicated and largely trouble-free. A disadvantage, however, is that the activity decreases with time, so that the source must be replaced and disposed of approximately every 3 years.
Possible complications
Not only tumor cells but also healthy body cells are damaged by radiotherapy. Therefore, careful attention must always be paid to radiogenic side effects and these must be prevented, detected in time if necessary, and treated. This requires a good knowledge of radiation biology, radiation technique, dose and dose distribution as well as permanent clinical observation of the patient. The possible complications of radiation therapy are essentially dependent on the localization and size of the target volume. Prophylactic measures must be taken especially if there is a high probability of side effects occurring. Common complications of radiation therapy:
- Radiogenic dermatitis (skin inflammation).
- Mucositides (mucosal damage) of the respiratory and digestive tracts.
- Tooth and gum damage
- Intestinal diseases: Enteritides (intestinal inflammation with nausea, vomiting, etc.), strictures, stenoses, perforations, fistulas.
- Cystitis (urinary bladder infections), dysuria (difficult bladder emptying), pollakiuria (frequent urination).
- Lymphedema
- Radiogenic pneumonitis (collective term for any form of pneumonia (pneumonia), which does not affect the alveoli (alveoli), but the interstitium or intercellular space) or fibrosis.
- Radiogenic nephritis (inflammation of the kidneys) or fibrosis.
- Limitations of the hematopoietic system (blood-forming system), especially leukopenias (decreased number of white blood cells (leukocytes) in the blood compared with the norm) and thrombocytopenias (decreased number of platelets (thrombocytes) in the blood compared with the norm)
- Secondary tumors (second tumors).
