HISTOLOGICAL CHANGES AFTER PARENTERAL THORIUM ADMINISTRATION 



for assumed cancer incidence has been drawn ; the optimum is at 16 years 

 and the ordinate is arbitrary as nothing is known about the percentage 

 incidence ; for the uranium mine workers the cancer incidence was about 



OVr- 



Possible cancer incidence 



10 ;^ n m m eo ze 

 Duration of observation 

 Figure 1 



Sf 26 28 30 ^jt 



Unknown 



50 per cent, and for the New Jersey patients the cancer incidence has been 

 about 10 per cent so far in a non-selected material*. It is evident from 

 Figure 1 that we must wait about 10 years before we can answer the cancer 

 question and about 20 years before it can be fully cartographed. 



REFERENCES 



1 Spier,.!., Cluff, L. E. and Urry, W. D. J. Lah. Clin. Med. 1947, 32 147. 



2 Schmidt, W., Schultz, A. and Lapp, H. Strahlentherapie, 1950, 81 93. 



3 MacMahon, H. E., Murphy, A. S. and Bates, M. I. Amer. J. Path. 1947, 23 585. 



* LiJDiN, M. Schweiz. Z- Allg. Path. 1953, 16 987. 



5 HoRTA DA SiLVA, J. Ckirurg. 1953, 218. 



6 Zollinger, H. V. Schweiz. Med. Wsch. 1949, 52 1266. 



* Abrahamson, L., O'Connor, M. H. Irish J. med. Sci. 1950, 6 229. 



* Lima, P. A. Cerebral Angiography, London, 1950. 



» Thomas. Cited Loeb, V., Jr., Seamann. W. B. and Moore, C. V. Blood, 1952, 

 7 915. 



DISCUSSION 

 M. A. Gerebtzoff : Errera has asked me to present a document showing the long 

 persistence of thorium in the human organism. It is an autoradiography of a liver 

 preparation taken from a man who had received an injection of thorotrast some 20 

 years previously. One still sees thorium granules from which escape a-particles. 



* AuB, Evans, Hempelmann and Martland [Medicine 31, Sept. 1952) describe a 

 cancer-incidence of 33 per cent in their selected material of patients with deposits of • 7-7 [ig 

 C Ra± MsTh. 



360 



