234 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1953 



determined by using a geiger counter or other radiation detector placed 

 over the neck outside the gland. Comparison with a normal uptake 

 rate indicates whether the gland is overactive or underactive. This 

 particular test is now being used routinely by hundreds of hospitals 

 and physicians all over the world. 



One thing that makes radioisotopes such a useful diagnostic aid is 

 that only extremely small harmless amounts of the radiomaterial are 

 required. This means that we should see a much wider diagnostic 

 use of radioisotopes in the future. 



MEDICAL THERAPY 



Radioisotopes have also been used in medical therapy for treating 

 such things as hyperthyroidism (overactive thyroid), cancer, poly- 

 cythemia vera (overproduction of red cells), leukemia (overproduc- 

 tion of white cells) , and lesions of the eye and skin. 



Some applications are like those of radium and X-rays ; a diseased 

 tissue or organ is exposed to radiation from a source placed either 

 inside or outside the body. Some of you no doubt have read in the 

 papers about the teletherapy cobalt unit at the Los Angeles Tumor 

 Institute. This device contains a large amount of radioactive cobalt — 

 about 1,000 curies — and it gives out a penetrating beam of gamma rays 

 which can be used in treating deep-seated lesions, like cancer of the 

 lung. The beam is as penetrating as that from a 2- to 3-million volt 

 X-ray machine. The radiocobalt unit, besides being cheaper to buy 

 and operate, offers a number of medical advantages. As soon as a 

 sufficient quantity of highly radioactive cobalt has been produced, 

 similar units will be put into operation in a number of other hospitals 

 and clinics throughout the country. 



The same radioactive cobalt in much smaller quantities has been 

 used, again like radium, for treating cancer of easily accessible areas 

 of the body like the cheek and lip. Radium is usually used as 

 "seeds" or "needles," and although it is widely employed it is ex- 

 pensive and cannot be easily adapted to a wide variety of uses. The 

 use of cobalt, on the other hand, can be made very flexible. For ex- 

 ample, radioactive-cobalt wire can be inserted into small-diameter 

 nylon tubing and sewed into the tissue to be treated. 



The more unique type of treatment possible with radioisotopes is 

 based on giving the radiomaterial to the patient by vein or mouth and 

 depending on body processes to locate the radioactivity in the desired 

 tissue or organ. For example, radioactive iodine is used in treating 

 hyperthyroidism in the same way that it is used to diagnose hyper- 

 thyroidism, except that much larger quantities of the radiomaterial 

 are used. Indeed, radioactive iodine is becoming the treatment of 

 choice in an increasing number of medical centers both in the United 



