Cobalt cannon
Cobalt cannon and cobalt bomb were popular names for radiation therapy devices that contained the radionuclide cobalt-60 as the source of their gamma radiation . Usually neither manufacturers nor oncologists called the devices that. The terms Telegamma- or Telecurie devices or their brand names were common among experts. Teletherapy units with cobalt-60 sources were the main instrument of decades irradiation of cancer tumors .
radiotherapy
In general, radiation therapy for cancerous tumors is based on methods of exposing the tumor tissue to ionizing radiation. Radiation therapy procedures can be divided into teletherapy and brachytherapy . Teletherapy devices generate ionizing radiation either by means of electro-physical methods (X-ray devices, linear accelerators, circular accelerators) or by means of a so-called gamma source (Telegamma devices). The first such device was used in 1951 by the Canadian doctor Harold Johns at Victoria Hospital in Saskatoon , Saskatchewan . Two years later, the first facility in Europe opened at the Borgo Valsugana hospital in Italy.
Radiation sources
The sources contain the radioactive cobalt-60 (alternatively also cesium-137. The radiation from cobalt has a higher penetrating power, a cesium source remains practically usable for longer due to its longer half-life.)
Radiation sources with the necessary high activity , over 1000 Curie = 37,000 GBq , can only be produced in hot cells . The radioactive substance is filled as a pressed powder or shot into approx. 1 cm³ steel vessels and welded airtight. So that such a source can be transported and handled, it must be mounted in a carrier made of shielding material (tungsten) that is suitable for the respective device.
After the end of use, the proper disposal of the still high activity is of the greatest importance. In the past there have been accidents as a result of improper scrapping, for example in 1983 in Ciudad Juárez , in 1987 in the Goiânia accident and in 2000 in the nuclear accident in Samut Prakan .
commitment
Around 1990, around a hundred Cobalt devices were still in use in Germany. The current state of the art in Germany and other industrialized nations is radiotherapy treatment with linear accelerators . Linear accelerators allow much more precise and sophisticated irradiation techniques.
Despite their immunity to interference and low operating costs, Telegamma devices are no longer state of the art in tumor therapy. The Gamma Knife is a device that works with gamma radiation but is completely different in design for the special purpose of radiosurgery in the skull area .
Individual evidence
- ^ H. Bronk: No life without hope: memory of a cancer patient. BoD - Books on Demand, 2005, ISBN 3-8334-1964-4 , p. 39, (online)
- ↑ The Cobalt Cannon. In: Der Spiegel . December 17, 1958. (magazin.spiegel.de)
- ↑ On the history of radiation therapy in Borgo Valsugana. accessed on May 19, 2017. (Italian)
- ↑ Eberhard Scherer, Horst Sack: Telecuriegeräte. In: Radiation Therapy. 4th edition. ISBN 3-13-394404-5 .
- ↑ Article of the Oak Ridge Associated Universities on the accident in Ciudad Juárez, Mexico 1983 (English)