236 Applied Biophysics 



developed on lines which insure, as far as possible, an adequate 

 dose to the malignant regions with no overdose to the normal 

 contiguous structures. This is most successfully done, perhaps, 

 in the treatment of cancer of the uterus and in buccal cancer, but 

 when growths originate in the rectum or esophagus, there are 

 greater difficulties in insuring the necessary conditions. 



In the treatment of uterine cancer, radium is put into the 

 body of the uterus, the cervical canal, and the fornices, by means 

 of special applicators containing radium in platinum thick enough 

 to insure that practically homogeneous gamma rays are being 

 used. Supplementary to this disposition of the radium, every 

 effort is made by the use of packs to keep the normal tissues well 

 away from the zones of most intense irradition. This is also 

 attempted when radium is applied to the rectum in cases of 

 malignancy ; one of the most successful appliances is that devised 

 by Margaret Tod, who arranged the radium inside a pneumatic 

 device which could be expanded in situ ; this helps to push the 

 normal structures awav from the irradiated zones. 



For growths of the esophagus, the device of Souttar allows 

 the introduction of radium into the lumen of the esophagus, 

 but immediate contact is prevented by means of a Souttar's tube, 

 which holds the radium axially. A valuable measure of control 

 and protection is afforded by this device. 



Interstitial Radium 



Dominici was among the first to introduce radium enclosed 

 in platinum into the tissues ; the method was developed so that 

 large volumes of tissue such as occur in mammary cancer were 

 penetrated at many points by radium tubes 6 centimeters or 

 more in length with a diameter of several millimeters. An 

 extensive though not uniform irradiation of the malignant 

 process occurred under these conditions, but the disadvantages 

 of 'the method, with its associated trauma, brought interstitial 

 work into disfavor, and today, it is probably true to say that 

 if radium therapy can be carried out without recourse to inter- 

 stitial methods then it is so done. Nevertheless, there are several 



