Cancer Equipment For Hospital

Press, Volume CIV, Issue 30803, 15 July 1965, Page 16

Cancer Equipment For Hospital

The radioactive source for the cobalt unit used for treating cancer at the Christchurch Hospital is due for replacement, at a cost of about £lO,OOO. At the same time, the North Canterbury Hospital Board is calling tenders for the supply of a linear accelerator to do the same kind of work.

Dr. A. J. Campbell, director of radiotherapy at the hospital, said yesterday that the linear accelerator would cost several thousand pounds more than the cobalt unit, which was given to the people of New Zealand by Sir Arthur Sims. It eost £47,000. He said the cobalt source lost half its energy in about five years, and it then took twice as long to treat each patient For that reason the source had to be renewed every three or four years. The unit was installed in 1957, and the source has been renewed once since then.

“We hope for some improvement in results with the linear accelerator,” said Dr. Campbell. He said it could be used

in some cases for which the cobalt unit was not particularly suitable. It did the same job of killing malignant growths, but at a higher dose rate, with better beam definition. It could treat bigger areas than the cobalt unit, and with slightly greater accuracy. Whereas the cobalt unit worked with a radioactive source material, the linear accelerator ran on electricity. It worked on the principle of speeding up a stream of electrons by a series of "bumps" The stream of electrons itself could be used for treatment, or the stream could be stopped by a target to produce rays in the range of 5m to 8m volts. The cobalt unit’s energy was equivalent to 3m volts.