MEDICAL USES OF THE CYCLOTRON * 



By F. G. SPEAR, M. A., M. D., D. M. R. E. 



Strangeicays Research Laboratory, Cambridge, England 

 Member Scientific Staff, Medical Research Council 



[With 4 plates] 



The idea of transmutation seems to have arisen among the 

 Alexandrian Greeks in the early centuries of our era, and to have been 

 transmitted to western Europe by the Arabs. The alchemy of the 

 Middle Ages was something more than the pretended art of turning 

 base metals into gold by the philosopher's stone : it was a phase in the 

 development of systematic chemistry. In the sixteenth century 

 Paracelsus gave it a new direction by declaring that its true object was 

 not the making of gold but the preparation of medicines, and this led 

 to increasing attention being paid to the investigation of the proper- 

 ties of substances and of their effects on the human body (l). 2 



It was not, however, until 1896 that the dream of the alchemists was 

 realized with the discovery of the "natural" radioactivity of uranium 

 by Becquerel (2) , when the first genuine transmutation was recognized. 

 Within two years Madame Curie discovered radium, with a radioac- 

 tivity (in the pure state) several million times that of uranium (3). 

 This "gave an impetus to the systematic chemical examination of ura- 

 nium minerals and soon led to the detection of several new radioactive 

 bodies" (4). Almost as soon as they were discovered their effects on 

 the human body were studied, and the consequence to physics, medi- 

 cine, and later to industry of the discovery of radioactivity has been 

 immense, but the distribution of the radioactive material has been 

 much influenced by international conditions during the (nearly) 50 

 years since radium was discovered. Half the world's supply of radium 

 at the time of the last war was taken by industry, and its value rose 

 to 100,000 times that of gold (5). This philosopher's stone, presented 



1 Based on a paper read on April 29, 1944, before the Midland Branch of the Institute 

 of Physics at Birmingham. Reprinted by permission from the Journal of ScientiOc Instru- 

 ments, vol. 22, No. 2, February 1945. 



2 Numbers in parentheses refer to bibliography at end of paper. 



137 



