Fig. 2
Vascular permeability in beam path ceases 2 hours after delivery of 10 Gy peak dose at 10 Gy/s. (A) Perfusion in the beam path ceases by 2 h post-irradiation and the capillary plexus in this region is unperfused clearly demarcating the peak (double-headed arrows) and valley regions. (B) Line enhancement filter was applied to one peak region selected from A (A; asterisks) to enhance visualization of vascular structure. Larger supplying vessels bridging the peak area and their attached microvessels remain perfused in the beam path. Complete irradiation of a larger vessel running longitudinally in the beam path appears partially occluded and is observed as an unperfused vascular structure (B’; arrowheads). (C) Ultrastructural changes show grossly enlarged epithelium and capillary structures with a basement membrane denuded of endothelial and peri-endothelial cells (black arrowheads). The vessel is completely congested with erythrocytes (Er) and platelets (P) with the latter accumulating along the exposed basement membrane (i). Scale bar in A and B is equivalent to 500 μm, 250 μm in B’ and 1 μm in Ci.
