Radiation From Radium 



65 



28 (19S8) 



Possibilities of increasing the value at depth of radiation from 

 radium externally applied. 



By W1LHELM STENSTROM (by invitation) 



[From the State Institute for the Study of Malignant Diseases, 

 Buffalo, New York] 



The methods that generally are used for external application 

 of radium are rather crude and unsatisfactory. This refers 

 especially to the old "radium pack'" where a number of radium 

 containers are spread out over a big surface, which is placed 

 at a certain distance from the skin (usually 4 to 10 cm. away). 

 The disadvantages are : 



1. It takes a great distance and a long time to get a depth 

 dose comparable to the depth dose from X-rays produced by 200 

 K. V. 



2. The protection is unsatisfactory and the weight is trouble- 

 some for the patient. 



3. The distribution of the radiation is poor and the total 

 amount of radiation absorbed by the whole body is many times 

 (say 10 times) the amount absorbed by a cylinder or parallelo- 

 piped of tissue directly under the pack. 



The attempt to eliminate these bad features has resulted in an 

 apparatus which gives very little radiation outside the cylinder 

 directly under the pack. The amount absorbed inside this cylin- 

 der is at least one half of the total amount absorbed by the 

 whole body. 



The following table gives a comparison between the effectivity 

 of the two packs. The filter is for both 2 mm. of brass and 

 1 mm. of aluminum. 





| Distance 



Depth dose 10 cm. 



Krythema skin 





1 from skin 



under skin 



dose in : 



Old pack 



(3 em. 



17 per cent. 



6 gram hrs. 



Old pack 



20 cm. 



34 per cent. 



60 gram hrs. (approx.) 



Xew pack 



3 cm. 



35 per cent, (approx.) 



15 gram hrs. (approx.) 



The new pack is attached to a modified X-ray stand and consists of three 

 main parts. 



(1) A cylindrical box of aluminum with lead-lined wall. 



(2) A rotating lead-screen with holes of a complicated shape through 

 which the rays are directed. 



(3) A heavy lead cover. 



