Effect of Local Irradiation of the Central 

 Nervous System with High Energy Protons 



Bengt Axderssox. Borje Larsson, Lars Leksell. \Villiam Mair, 

 Bror Rexed. axd Patrick Souraxder 



Gustaf Werner Institute for Nuclear Chemistry and 



the Institute of Anatomy, 



University of Uppsala, Sited en 



Hish ener^ry beams of licht atomic nuclei have physical properties which 

 make them suitable when small volumes of tissue are to be unifomily irradi- 

 ated (Tobias et al., 1952 i. Anderson et al. (1957) made lesions in the hypo- 

 thalamus of the rat usins: 190 Mev deuterons. Malis ct al. (1957). making 

 use of the thin ionization peak at the end of the beam, produced laminar 

 lesions at a depth of 0.8 mm in the cerebral cortex of the cat with 10 Mev 

 protons. Larsson et al. (1958) biiefly described several types of localized 

 lesions in the central nervous system within 2 months after irradiation by a 

 185 Mev proton beam. The histopatholooy of lesions produced by this tech- 

 nicjue in the spinal cord and brain of the rabbit was described in detail by 

 Larsson et al. (1959) and Rexed et al. (1960). Zeman et al. (1959), when 

 investioatino- the effects of primaiy cosmic rays on nervous tissue, irradiated 

 mouse brains with 22.5 Mc\- deuterons and studied the relationship between 

 the size of the impact area and the threshold dose for a radiogenic lesion. 

 Larsson i I960: described blood \essel changes following local irradiation of 

 the rats brain with high energy protons. 



The present report is a summary of the neuropathologic findings in rab- 

 bits and goats after local irradiation with a beam of 185 Mev protons from 

 the 230 cm synchrocyclotron at the Gustaf Werner Institute, Uppsala. Lesions 

 up to about 1 year are considered. The experiments were performed to get 

 fundamental data concerning local effects of hea\y particle beams on the 

 central nervous system. ha\'ing in mind their possible application to stereo- 

 taxic neurosurgery. 



Material and Methods 



L-radiations were performed with a beam of 185 Mev protons from the 

 svnchrocyclotron as described by Larsson et al. (1959). By focusinu' magnets 



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