Sequence of X-Radiation Damage in 

 Mouse Cerebellum 



NORBERT SCHUMMELFEDER 



Institute of Pathology 

 University of Bonn, Germany 



Since the time of Brunner and Schwartz 1918: Brunner, 1920, 1921), 

 who in 1918 were the first to observe that the cerebellar o;ranule cells of 

 young- dogs and cats could be easily injured by x-radiation, little attention 

 was directed to the radioxulnerability of this part of the brain until the past 

 few years. Our work in this field was concerned with the effect of x-rays 

 on the cerebellum of mice ( Schiimmelfeder 1957, 1959a, b; Schiimmel- 

 feder ct al, 1957; Krogh and Bergeder, 1957). We used single x-ray doses 

 and studied the irradiated tissue by morphologic, histochemical, and fluo- 

 rescence techniques. The x-ray dosage ranged from 250 to 60,000 r. Fields 

 of the cerebellum .3 X '^ "ini and 0.5 X 2 mm were irradiated by a half-wave 

 x-ray unit (50 kv, 20 ma. focal distance 6 cm. 0.12 mm Al filter) at 3,000 

 r per min to the surface of the cerebellum. The irradiated animals were 

 sacrificed at interxals up to 6 months. 



Observations 



Morphologically demonstrable radiation effects were seen in the range of 

 2,000 to 60,000 r. T\w latent period between irradiation and the first mor- 

 phologic changes decreased correspondingly. At 2,000 r, damage was first 

 noted at the end of 4 months, while at 60,000 r, changes were observed in 

 30 minutes. Irradiation doses less than 2,000 r induced no morphologic 

 changes in the cerebellum during the observation time ot 6 months. 



A few typical experiments will indicate the nature, se\erity, and sequence 

 of damage after exposure of the cerebellum of mice to different x-ray doses. 



ToT.\L Necrosis of Cerebellar Tissue Following Exposure to X-rav 

 Doses Ranging from 60,000 to 10,000 r 



In the range from 60,000 to 10,000 r. x-irradiation induced total necrosis 

 of cerebellar tissue within a time depending on the dosage. 



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