fon is the fraction of the radionuclide entering B which is Vv" transferred to organ n n = bone, Liver, kidney, etc. 05 T, is the half-life of the radionuclide (day), Ty is the biological half-life of radioactive dust deposited in subcompartment k of the respiratory tract (day) FA Ty 4s the biological half life of the radionculide deposited in NP _ 1n(2)/T = h (day 1 } a NPp faD5 organ n (day), In(2)/T, t (b) 1h039] j NASOPHARYNGEAL REGION b -1 A, (day ) in(2)/T| = xP (day) u v8] BLOOD 1B c DgQy (ch 0, 5.1216 x 10> E,/M, {1s the dose conversion factor T ! FgDgQ] pero eee 1 : l G.E. TRACT : TRACHEOBRONCHIAL | REGION (rem/pCi-day) for region or organ n. E_ (d) 18 fh (q) is the energy deposited by radionuclide in region or organ n (MeV/dis). Same as LEF(RBE)n in Table 5 of Refs.[4,5]. (eb M, is the mass of region or organ n (g} Myp = 1.35 g, Mpg = 4008, Mp = 500g [6,7], For other organs 4 see Refs, [3,4,5]. We [Wo \ Pe I 4 Ph T Pt T Py te05Q] ! HOsQ, 1 Ds. 1 NqD5ey | th} t L. ui une LYMPH! 1 j PULMONARY REGION i I t toSO eee ee J FIGURE1. Schematic Diagram of the Task Group Lung Model (8) 692 693