[Fifty-year-old history of cobalt radiotherapy in Hungary]. / Otvenéves a telekobalt-terápia Magyarországon.

The first patient in Hungary was treated by cobalt therapy fifty years ago at the National Institute of Oncology with a Gravicert type equipment. On the occasion of this anniversary, the 50-year history of the Hungarian cobalt therapy is reviewed, and its present role is discussed. The first cobalt unit (Gravicert) was designed by László Bozóky seven years after the first cobalt unit installation in the world in Canada. The megavoltage energy of the Co-60 source (average: 1.25 MeV) resulted in more successful treatments of deep-seated tumors compared to the X-ray therapy. In the next two-three decades, until the widespread use of the high-energy linear accelerators, the Co-60 teletherapy meant the modern radiation treatment throughout the world. Improvements of quality in radiation techniques necessitated exact localization of the tumors and developments of treatment planning methods. At the beginning, the localization was performed with X-ray machines, while the treatment planning was done manually. In 1965 a Rotacert type cobalt unit was installed at our institute. This machine was already capable of making irradiation in multiple directions and it worked in rotating mode, too. In Hungary, more cobalt units - first the Gravicert type, then foreign made machines - were gradually installed in other radiotherapy centers too. The quality of treatments was significantly improved by the introduction of the computerized treatment planning, and the foundation of the IAEA-supported National Treatment Planning Network in 1978 was an important step in this process. The next important development was the commencement of the CT image based treatment planning in 1981. With the spread of modern linear accelerators the role of the cobalt units has greatly decreased by now, however, nearly 2,500 cobalt units are still in use worldwide. Their usage could be further increased with technical developments. At present, radiation treatments are performed with cobalt units in eight out of twelve radiotherapy centers in Hungary.

Spread of 60Co contaminated steel and its legal consequences in Taiwan.

Since 1992, over 200 civilian residential and school buildings in Taiwan have been identified to have contained 60Co contaminated steel rebar emitting excessive gamma-radioactivity in living environments. These buildings were mostly constructed in early 1983 and 1984 by employing steels from one steel mill, which had recycled unknown 60Co orphan sources in northern Taiwan. In 1994, a group of residents who once stayed for a protracted period up to 10 y in the contaminated Ming-Sheng Villa filed a civil action against Taiwan's nuclear regulatory office, the Atomic Energy Council, for state tort compensation of 3.4 M U.S. dollars in equivalent. After three years of court processes, the Taipei District Court handed down a decision in partial favor of the exposed residents. Both parties soon appealed against this judgment to the Taiwan Appellate Court. This article analyzes the main legal issues involved, including government's obligations to prevent and eliminate contamination, to take preventive measures, and to take necessary remedial measures; and plaintiffs' assertion on any legal right against governmental offices. Moreover, discussion issues contain the scope of damage and compensation, causation analysis, absence of effective and efficient regulation over radioactive contamination, limit of tort compensation law and compensation amount, weight of medical evidence as well as role of expert witnesses, and related comparative legal studies.