Plutonium Biokinetics in Human Body A. Luciani - Kit-Bibliothek - FZK

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to 73 years, and thus does not relate to a specific age. The age dependent bone remodelling rates in the ICRP67-b model were calculated by a linear interpolation between the values suggested by the ICRP 70 for subjects 22, 35 and 60 years old. For ages greater than 60 years constant bone turnover rates were assumed. In Figure 3.1.5 the bone remodelling rates, used in the ICRP67-b model, are presented as a function of the age of an adult subject and compared with the constant remodelling rates of ICRP 67. Table 3.1.5 Age dependent cortical and trabecular remodelling rates for different age classes according to ICRP 70. Bone remodelling rate [%y -1 ] 30 25 20 15 10 5 0 Age Bone remodelling rates [%/year] Cortical Bone Trabecular Bone 0 – 3 months 300 300 1 year 105 105 5 year 56 66 10 year 33 48 15 year 19 35 22 year 9 27 35 year 2 10 60 year 4 20 Average after age 25 years 3 18 Trabecular Bone (ICRP67) Cortical Bone (ICRP67) Trabecular Bone (ICRP67-b) Cortical Bone (ICRP67-b) 20 30 40 50 60 70 Age [y] Figure 3.1.5 Cortical and trabecular remodelling rates as functions of age. 94
Figure 3.1.4 shows that the use of time dependent bone turnover rates does not remedy the underestimation of the ICRP67-a model, because practically no significant lifting of the urinary excretion curve occurs. At around 10.000 days post injection the Plutonium urinary excretion is increased by about 10% relative to the value of ICRP67-a with constant bone rates, but it is still smaller by a factor of three than the experimental value at this time (0.0014 %/d on average). The ICRP 67 model predictions for Plutonium fecal excretion and blood retention were also compared to the reference data set (Figure 3.1.6 and Figure 3.1.7). It can be pointed out that the ICRP 67 model overestimates the fecal excretion up to a factor 2 during the first week after the injection, whereas underestimates up to a factor 5 in the following twenty days. The general trend of model predictions in this time range seems to be in disagreement with experimental outcomes because the reference data shows a more gradually decrease of Plutonium activity in feces. A sufficient agreement with the reference data exists only at longer term: At around 10,000 days post injection model and experimental data differ by less than 15%. For the Plutonium activity in blood the situation is similar with an initial overestimation in the first week post injection, followed by an underestimation in the following twenty days. However in this case the ICRP 67 model underestimates the reference data up to about a factor of 20. The effect of the deletion of the connection between the ST1 soft tissue compartment and urinary bladder on fecal excretion and blood retention was also investigated. Because of such modification the activity in the ST1 compartment is completely transferred to the blood compartment. Therefore an increase of activity in the blood compartment and consequently in the excreted activity in feces is expected. This can be seen in Figure 3.1.6 and Figure 3.1.7 (ICRP67-a curves). For the fecal excretion the effect is significant only at very long times (at 10,000 days post injection the excreted activity increases by about 30%). No effect is observable at shorter times when the model predictions and reference data are in total in disagreement. In case of the blood retention of Plutonium the activity increases at shorter times: Already at around 30 days it is increased by 50%. However the predictions of blood retention are still very far from the reference data. Analogously to the urinary excretion analysis, the effect of age dependent bone remodelling rates according to ICRP 70 is also shown in Figure 3.1.6 and Figure 3.1.7 (ICRP67-b curves). As in the case of urinary excretion, the effect of such modification on fecal excretion and blood retention of Plutonium is quite small and, in any case, doesn’t improve significantly the agreement with the reference data set. On the basis of the previous considerations it can be summarized that: • The Plutonium urinary excretion predicted by ICRP67 shows some disagreements with the reference data set; the fecal excretion and blood retention of Plutonium predicted by this model shows even more severe disagreement; • If a physiologically based modelling is assumed by deleting the transfer of activity from ST1 soft tissue to urinary bladder content compartment, the ICRP 67 predictions for the Plutonium urinary excretion are significantly far from the reference data. This points out that the ICRP 67 assumption of such transfer of activity is not a minor correction of the model but essentially determines the urinary excretion of Plutonium at long times; • Age dependent bone remodelling rates as suggested by ICRP in Publication 70 were also considered but they don’t result in a significant improvement. Therefore a general overhaul of the ICRP 67 model seems to be necessary. 95
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Forschungszentrum Karlsruhe in der
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Für diesen Bericht behalten wir un
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i ABSTRACT The biokinetic model pre
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ZUSAMMENFASSUNG Das von der Interna
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1 INDEX OF CONTENTS INDEX OF SYMBOL
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3 INDEX OF SYMBOLS Here a short glo
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Chapter 1 Introduction 5
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the duties of the Department for Ra
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adionuclide. Therefore only isotope
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stabilise the +4 oxidation state [1
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techniques adopted in the early pha
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present in spent and MOX reactor fu
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INTRAVENOUS INJECTION skin WOUND bl
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functions, defined as retained and
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the contamination event, of such as
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Table 1.3.2 Indicative 239 Pu detec
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The kinetics of Plutonium in the ki
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1.4.2 COMMENTS ON THE ICRP 67 MODEL
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Chapter 2 Data and measurements 31
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Therefore the radiolysis process, m
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Recent technologic developments in
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eu(t) = 0.19e −0.272t + 0.023e
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function for each of the considered
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the minimum detectable activity of
Page 54 and 55: 2.2.2 AVAILABLE MEASUREMENTS Immedi
Page 56 and 57: Table 2.2.4 Daily fecal excretion o
Page 58 and 59: elements the spectral distribution
Page 60 and 61: The phoswich detector is based on t
Page 62 and 63: HPGe crystals are produced in cylin
Page 64 and 65: This quantity is normally expressed
Page 66 and 67: The peak is located in the region B
Page 68 and 69: To introduce the second quantity, t
Page 70 and 71: 117 cm 3 h -1 for the incoming and
Page 72 and 73: Figure 2.3.8 The Lawrence Livermore
Page 74 and 75: three detectors are used. Two detec
Page 76 and 77: Table 2.3.4 Efficiency factors of p
Page 78 and 79: • the necessity of performing mea
Page 80 and 81: Table 2.3.7 Impulses in the measure
Page 82 and 83: 2.4 ACTIVITY MEASUREMENTS IN BIOASS
Page 84 and 85: If more then one radionuclide is ma
Page 86 and 87: L A is the air layer in µgcm -2 ;
Page 88 and 89: The electrodeposition cell used for
Page 90 and 91: Table 2.4.1 238 Pu, 239 Pu and 241
Page 93 and 94: 3.1.1 MATHEMATICAL TOOLS 3.1.1.1 So
Page 95 and 96: calculating the amount of Plutonium
Page 97 and 98: 3.1.2 ANALYSIS OF THE ICRP 67 MODEL
Page 99 and 100: empirical curves given by Langham,
Page 101 and 102: the worst performance of the group.
Page 103: leave the total clearance from the
Page 107 and 108: 3.1.3 MODIFICATION OF ICRP 67 MODEL
Page 109 and 110: The structure of Polig’s skeleton
Page 111 and 112: Percentage daily urinary excretion
Page 113 and 114: of 0.693d -1 . The values of the F
Page 117 and 118: the basis of all the reference data
Page 119 and 120: Table 3.1.10 Transfer rates of the
Page 121 and 122: 3.1.4 VERIFICATION OF THE OPTIMIZED
Page 123 and 124: Table 3.1.13 Intakes and percentage
Page 125 and 126: soft tissue ST2 soft tissue ST0 sof
Page 127 and 128: For the routine application of Mode
Page 129 and 130: excreted by individuals aged sixty
Page 131 and 132: Table 3.1.20 Exponents and coeffici
Page 133 and 134: tract [57] to consider a contaminat
Page 135 and 136: The sensitivity coefficients for th
Page 137 and 138: Sensitivity coefficients S i Figure
Page 139 and 140: transfer rates on the Plutonium uri
Page 141 and 142: Geometric standard deviations rangi
Page 147 and 148: 3.2 APPLICATION OF THE OPTIMIZED MO
Page 149 and 150: lymph nodes, as in the LLNL phantom
Page 151 and 152: Americium in the lungs [Bq] 1000 10
Page 153 and 154: Daily urinary excretion [Bqd -1 ] 1
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long time is not yet described by t
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excretion that is one of the main i
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The comparison of model’s predict
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Americium in the lungs [Bq] 1000 10
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153 CONCLUSIONS The optimized model
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Annex Quantities used in Radiologic
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present. As the radiation weighting
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w R is the radiation weighting fact
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161 BIBLIOGRAPHY 1. Plutonium. W. K
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29. Nenot, J.-C. and Stather, J. W.
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55. International Atomic Energy Age
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81. Crowley, J., Lanz, H., Scott, K
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107. Hempelmann, L.H., Langham,W.H.
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137. Breitestein, B.D., Newton, C.E
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167. Harrison, J.D., Khursheed, A.,
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JOURNALS OWN PUBLICATIONS RELATED T
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177 ACKNOWLEDGEMENTS Special thanks
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Name: Andrea Luciani Date and place
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