Figure 6.

Representative histological images of ears on day 92 upon a 4-fraction course with different doses per fraction: sham (A), 5 Gy (B), 10 Gy (C), 20 Gy (D), 30 Gy (E). Panel A: Sham-irradiated. The central cartilage of the pinna is flanked by a layer of skeletal muscle, a dermal layer of moderate thickness and the epidermis. Hair follicles, nerves, sebaceous glands, and blood vessels are present. Panel B: 4 × 5 Gy. The dermal layer of the ear skin is slightly thickened. Hair follicles are rarely present. Panel C: 4 × 10 Gy. The dermal layer is further increased, and the epidermis is mildly hyperplastic. Hair follicle profiles are almost completely absent. No sebaceous glands are present. Panel D: 4 × 20 Gy. The dermal layer of the skin is markedly thickened and infiltrated by a mixed population of inflammatory cells. No hair follicles and sebaceous glands are detectable. Panel E: 4 × 30 Gy. The ear section displays severe dermal thickening and inflammatory cell infiltration, as well as marked epithelial hyperplasia. No hair follicles and sebaceous gland section profiles are present. Paraffin sections were stained with hematoxylin and eosin. Scale bar: 200 µm.