







Fig. 5. These 6 pictures demonstrate histologic material taken from the brain ot 

 rats subjected to 10.000 rad alpha particle radiation delivered through a slit aperture 

 from the 184 in. cyclotron at Berkeley. California. Van Gieson's \ascular stain. (A.) 

 Low power view of cervical spinal cord (level C-1 ) 2 months after radiation. Note 

 the pronounced cyst formed in the dorsal funiculi. X 27. (B and C.) Examples of 

 perivascular infiltration, vascular lumen thickening, and almost complete occlusion of 

 the left (B) and right (C) dorsal descending spinal arteries (surface vessels) taken 

 froin the same level as shown in Fig. 5A. X 310. (D, E, and F.) Three examples of 

 perivascular infiltration, thickening, and hyalinization of deeply situated vessels in 

 the brain. Rat sacrificed 3 months after radiation. These \essels were situated in the 

 nucleus gracilis. (D) X 250: medullary reticular formation, (E) X 480; and central 

 medulla at the level of the pyramids. (F) X 480. 



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