Sec. 29.3] ISOTOPES IN THERAPY AND DIAGNOSIS 539 



29.2. Radiophosphorus. The first artificial radioisotope to be used success- 

 fully in therapy was P 32 . Although applied as early as 1936 it was not until 

 1939 that the first clinical reports [P249] of its application to the treatment of 

 chronic leukemia were published. 



The most important use of P 32 has been in soluble form (in labeled isotonic 

 disodium acid phosphate) given by mouth or vein in the treatment of blood 

 dyscrasias. The determination and calculation of dosage, routes of adminis- 

 tration, and supportive treatment of patients receiving this type of therapy 

 are discussed in works cited in Table 49. Other uses of P 32 have been in 

 topical application [P265] for warts, angiomas, and other skin lesions, and 

 in insoluble colloid anhydrous chromic phosphate for hepatosplenomegaly 

 in leukemia and allied diseases. 



The use of P 32 as a possible diagnostic tool has been suggested by Low- 

 Beer and associates [P266]. They have found in a few cases that, if small 

 doses of labeled sodium phosphate are given fo women with suspected 

 breast carcinoma, the activity of the superficially located malignant lesion 

 (except for slow-growing mucoid carcinomas) is 25 per cent or more above 

 that of the surrounding tissue of the skin. Benign lesions in their series 

 consistently showed less than 25 per cent greater activity. 



The use of P 32 has thus been shown to have considerable therapeutic and 

 possible diagnostic value. Further research may well expand its clinical use- 

 fulness in the form of other inorganic or organic compounds. 



29.3. Radioiodine. The therapeutic use of radioactive iodine was reported 

 for the first time simultaneously in 1942 [129,40] for the treatment of hyper- 

 thyroidism {i.e., thyrotoxicosis, Graves' disease, Basedow's disease, etc.). 

 Comprehensive reports on two series of patients with hyperthyroidism have 

 appeared recently [19,41]. 



For therapeutic purposes carrier-free radioiodine in the form of an aqueous 

 sodium iodide solution is used, being administered by mouth. In the two 

 most recent reports [19,41], the iodine has consisted of a mixture of I 130 and 

 I 131 , of which the former has been the clinically more important component. 

 The determination and calculation of dosage are given in both papers. 



In the last few years workers have also reported a few cases in which treat- 

 ment of iodine-metabolizing thyroid malignancy has met with partial or 

 considerable success when radioiodine has been used [183,105,114]. 



As a diagnostic tool for the determination of the level of the thyroid func- 

 tion, radioiodine appears to offer good clinical possibilities. So far, however, 

 most of the publications dealing with thyroid physiology as studied with 

 radioiodine have been in the nature of fundamental investigations rather 

 than of diagnostic developments. 



In general the use of iodine for the treatment and diagnosis of certain 

 thyroid diseases appears highly promising. 



