During the same time, the OAEP was informed of the three teletherapy units in the car park, and a separate investigating team found one of the units to have had its drawer assembly missing.
12.
Cobalt therapy, teletherapy machines using megavolt gamma rays emitted by cobalt-60, a radioisotope produced by irradiating ordinary cobalt metal in a reactor, revolutionized the field between the 1950s and the early 1980s.
13.
Beginning in the 1950s cobalt-60 was widely used in external beam radiotherapy ( teletherapy ) machines, which produced a beam of gamma rays which was directed into the patient's body to kill tumor tissue.
14.
Cobalt-60 tends to be used in teletherapy units as a higher photon energy alternative to Cs-137, while iridium-192 tends to be used in a different mode of therapy, internal radiotherapy or brachytherapy.
15.
It has been said that such was his renown, especially for bringing in the use of the radiological unit the Harold Elford Johns, inventor of the cobalt-60 teletherapy unit, that Johns was prompted to go into medical physics.
16.
One example is the radiological accident occurring in Goi�nia, Brazil, between September 1987 and March 1988 : Two metal scavengers broke into an abandoned radiotherapy clinic and removed a teletherapy source capsule containing powdered caesium-137 with an activity of 50 TBq.
17.
External beam radiotherapy ( teletherapy ) began around the turn of the 20th century with ordinary diagnostic x-ray tubes, which used voltages below 150 kV . Physicians found that these were adequate for treating superficial tumors, but not tumors inside the body.
18.
Meanwhile, the owners of IGR wrote several letters to the National Nuclear Energy Commission, warning them about the danger of keeping a teletherapy unit at an abandoned site, but they could not remove the equipment by themselves once a court order prevented them from doing so.
19.
He has assisted the World Health Organization as Consultant in several major workshops and meetings such as design modification of teletherapy machines 1992, preparation of managerial guidelines for cancer control 1994 and 2000, preparation of pain and palliative care guidelines 1994, the Cancer Technical Group meeting 2005, and the Cancer Advisory Group meeting 2005.
20.
The original teletherapy capsule was seized by the Brazilian military as soon as it was discovered, and since then the empty capsule has been on display at the " Escola de Instru��o Especializada " ( " School of Specialized Instruction " ) in Rio de Janeiro as a memento to those who participated in the cleanup of the contaminated area.
