MEDICAL USES OF THE CYCLOTRON — SPEAR 



147 



tration of the salt in the bone marrow, where red cells are manufac- 

 tured, without disturbing the normal number of white in circulation. 

 The presence of cancer (sarcoma) "screens" both kinds of blood cells 

 so that doses of radio phosphorus which would normally have affected 

 the blood-cell count have no such effect if a tumor is present, as the 

 radio phosphorus becomes concentrated in the tumor cells (pi. 4, 

 fig.l). 



20O 



180- 



160- 



140- 



O '20- 



o * 

 - I00-- 



80- 



M 



60- 



40 



20- 



V 



C K CHRONIC MYELOS LEUK 



RBC 





MMC 29i|f 



* •» «. — — "*— — •** " 



298IMC 

 NOV 28 



29NMC 

 JAN \b 



488IMC 

 JUNE 15 



NOV. I 



Figube 1. — The effect of radio phosphorus in reducing the excessive white-cell 

 count (w, b. c.) in a case of leukemic disease of the blood (22a). The red-cell 

 count (e. b. c.) is practically unaltered. 



Radio phosphorus was first used therapeutically in 1936, when it 

 was found that its beneficial effect on certain blood diseases resembled 

 that following X-radiation. It is still early to judge its usefulness, 

 but it is clear already that artificial radioactivity is at least as good 

 as the X-radiation treatment and far less inconvenient for the patient. 

 Neither is a certain cure, but considerable periods of relief are often 

 obtained before the blood shows abnormality again. It is possible 

 that better results will be obtained by a combination of (external) 

 radiotherapy and (internal) administration of radio salts, but it will 

 take some time to determine what is the best form in which to give 

 the combined treatment. 



MEDICAL AND BIOLOGICAL EFFECT OF NEUTRONS 



The bombardment of beryllium by deuterons in the cyclotron pro- 

 duces a yield of high-energy neutrons which is of sufficient intensity 

 for radiotherapeutic trials. For this purpose the cyclotron (No. 2Z> 

 of table 1) was made more "presentable" from the patient's point of 

 view by being enclosed in a shell of white-enameled woodwork which 

 concealed the entire apparatus and the protecting screens of wax and 



