Table I.

Histological Scoring. The results of blinded scoring using a semiquantitative scale. Acute and chronic changes in the vascular compartment and the airways were scored as follows- 0: absence of histological changes; 1: parenchymal alterations in 1 to 25% of the tissue examined; 2: parenchymal alterations in 26 to 50% of the tissue examined; 3: parenchymal alterations in 51 to 75% of the tissue examined; 4: parenchymal alterations in 76% to 100% of the tissue examined. The 1^st and 2^nd columns show the time after irradiation and the specific changes and compartments scored respectively. The figures represent mean scores ± sem for each compartment (n=7–10).

Time PI	Compartment - Characteristic	0 Gy Mean±sem	5 Gy Mean±sem	10 Gy Mean±sem
3 days	Acute Vascular changes - Perivascular edema	0.67±0.17	0.5±0.26	1.3±0.36
2 wks	Acute Vascular changes - Perivascular edema	0.55±0.22	0.3±0.16	1±0.32
4 wks	Acute Vascular changes - Perivascular edema	0.63±0.32	0.88±0.29	1.63±0.41
8 wks	Acute Vascular changes - Perivascular edema	0.4±0.22	1.38±0.32	0.4±0.26
	Chronic vascular changes- Vessel wall hyalinization, perivascular fibrosis	1.1±0.27	1.38±0.32	1.2±0.36
20 wks	Acute Vascular changes - Perivascular edema	0	0	0
	Chronic vascular changes- Vessel wall hyalinization, perivascular fibrosis	0.6±0.22	1±0.43	1.13±0.22
52 wks	Acute Vascular changes - Perivascular edema	0.22±0.14	-	0.88±0.35
	Chronic vascular changes- Vessel wall hyalinization, perivascular fibrosis	±0.33	-	1.25±0.36
	Chronic Airway changes- mononuclear cells	0.78±0.36	-	0.88±0.35