Ne a P Bone-marrow dose equivalent rate, mrem/y 2.0 18 | 1.67 Newborn 4-month old 9-month old 1.5-y oid 1.4f 18-y old 4-y oid 12-y old 1.2 | 1.0 0.8 0.6 0.4 0.2 | 40 60 Bone-marrow dose equivalent rate, mrem/y 2.0 1.85 1.07 0.87 Newborn 4-month old 9-month old 1.5-y old 4-y old 12-y oid 18-y old 0.4 0.2 10 Years after ingestion 30 Figure 4. The annual bone-marrow dose when intake of ?9Sr begins at different ages; (a) shows lifetime dose equivalentrates and (b) shows an expanded view of(a) for the first 30 y of exposure. JO00T Ty 20