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

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function for each of the considered organs was calculated. The urinary and fecal excretion functions were then calculated multiplying the retention functions in liver and blood by the relative excretion transfer rates, respectively. The calculated function for the percentage daily urinary excretion is: eu(t)=0.8344e −0.693t + 0.06587e −0.03t + +0.003870e −0.0028 t + 0.001254e −0.0000216t For the fecal excretion of Plutonium the calculated function is: 40 equation 2.1.13 equation 2.1.14 It should be stressed that negative coefficients resulted for the fecal excretion function. 2.1.3 OCCUPATIONAL EXPOSURES ef (t)=−0.002811e −0.693t − 0.005870e −0.03t + +0.007936e −0.0028 t + 0.0007450e −0.0000216t Over the years the numerous applications of Plutonium and other transuranium elements in civil and military field has determined an increasing number of workers exposed to the risk of an internal contamination. The monitoring of contaminated workers has enabled to collect several data relating to Plutonium in bioassays after occupational exposures. Most of these data are today available in scientific literature. Even if these cases relate to expositions through not only systemic path, they were recently used also for determining systemic biokinetics of Plutonium, as in the aforementioned study of Khokhryakov and coworkers [114]. Yet it is often difficult to extrapolate information on the systemic behaviour of a radionuclide from such kind of observations. Data sets based on the results from the monitoring of occupational exposed workers are more commonly and easily used for checking models. Yet, even for verification purposes, some minimal characteristics are required: • Complete information on the scenario of the contamination is given, such as working activities carried out by the subjects, protection facilities adopted, commonly manipulated compounds and their chemical form; • Multiple kinds of data are available for the same contamination event as activity in different bioassay samples, direct measurements when feasible, workplace monitoring measurements; • The data set covers a significantly long time period after the contamination event; • An exhaustive information about health impairments occurred in subject’s life are given, with particular care to those illnesses that could significantly influences the radionuclide biokinetics. Information on the scenario of the contamination should firstly enable to make realistic assumptions about the most probable path of intake that, in case of an occupational exposure, will be basically inhalation, ingestion or introduction through wound. The path of intake plays a particular role because of its strong influence on the biokinetics of a
adionuclide. For instance discrepancies in dose assessments of several orders of magnitude are possible between via inhalation or ingestion hypotheses of intake [97]. Accidental events such as damage on radiation protection facilities or errors in the manipulation activities can provide information on the most probable time of intake. When such events can't be determined, a continuous and constant rate of intake can be realistically assumed. Path of intake and time modality can be better established if the information on the scenario of the contamination is integrated with available workplace monitoring measurements. For instance anomalous level of air radioactivity concentration can suggest a probable contamination via inhalation. Furthermore if multiple stage impactors are used to sample the air in the working area, aerosol size distribution can also be determined and condition of exposure can be realistically quantified. Sometimes nose wipe measurements can be a useful way of discriminating a prevalent contaminatiuon via inhalation. Information on chemical form of contaminating compound can also be obtained from air or surface monitoring measurements. Availability of multiple kinds of measurements on contaminated subjects such as direct and undirect measurements is extremely useful because they provide information on model accuracy in describing the numerous physiological processes and on the truthfulness of initial assumptions. Information strictly related to the health status of the subjects are also important because it was already observed that pathologies and illnesses can significantly change the biokinetic of a radionuclide in human body. Examples were already given in Durbin’ and Khokhryakov’s studies [106, 114] where significant enhancement of Plutonium urinary excretion was observed in subjects with different health impairments. Finally data sets must cover a time period comparable with the effective half life of the radionuclide in human body. In fact the shorter is time series of available measurements, the greater the possibility of fitting them with different models or the same model but with different initial assumptions (time or path of intake, chemical and physical characteristics, etc.). In the specific case of Plutonium and other long-lived radionuclides time series from several years up to decades could be necessary. Unfortunately few data sets relating to Plutonium occupational exposures comply all the aforementioned conditions. Among those ones available in scientific literature, two main data sets should be considered: Manhattan Project Workers (MPW) and United States Transuranium and Uranium Registries (USTUR) data sets. The former is composed by the results of the monitoring of twenty-five male subjects who worked with Plutonium at what is now the Los Alamos National Laboratory (Los Alamos, New Mexico, US) in the days of the Manhattan Project during World War II. They were engaged in different activities under extraordinarily cruel working conditions and therefore with high risk of Plutonium exposure, mainly from recovery operations. They have been monitored for a long time and, for some of these subjects, medical follow-up and bioassay measurements are available up to recent years [107, 108, 117, 118, 119, 120]. The second data set relates to workers generally engaged in Plutonium industries [121], even if the societies or laboratories were they carried out their activities are less clearly stated. Some of the subjects included in this data set can also be found in Manhattan Project workers data set under different codes. Among all the contamination cases reported in the these two data sets, a further selection should be carried out in order to facilitate the use of them for verification purposes of Plutonium urinary excretion predicted by a model. Firstly, measurements of urinary excretion should be available because other kind of bioassays (feces or blood) or direct measurements of activity in organs and tissues offer only indirect information on urinary excretion. The measurements should be always higher then 41
Page 1: Forschungszentrum Karlsruhe in der
Page 4 and 5: Für diesen Bericht behalten wir un
Page 7 and 8: i ABSTRACT The biokinetic model pre
Page 9 and 10: ZUSAMMENFASSUNG Das von der Interna
Page 11 and 12: 1 INDEX OF CONTENTS INDEX OF SYMBOL
Page 13 and 14: 3 INDEX OF SYMBOLS Here a short glo
Page 15: Chapter 1 Introduction 5
Page 18 and 19: the duties of the Department for Ra
Page 20 and 21: adionuclide. Therefore only isotope
Page 22 and 23: stabilise the +4 oxidation state [1
Page 24 and 25: techniques adopted in the early pha
Page 26 and 27: present in spent and MOX reactor fu
Page 28 and 29: INTRAVENOUS INJECTION skin WOUND bl
Page 30 and 31: functions, defined as retained and
Page 32 and 33: the contamination event, of such as
Page 34 and 35: Table 1.3.2 Indicative 239 Pu detec
Page 36 and 37: The kinetics of Plutonium in the ki
Page 38 and 39: 1.4.2 COMMENTS ON THE ICRP 67 MODEL
Page 41: Chapter 2 Data and measurements 31
Page 44 and 45: Therefore the radiolysis process, m
Page 46 and 47: Recent technologic developments in
Page 48 and 49: eu(t) = 0.19e −0.272t + 0.023e
Page 52 and 53: 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.
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leave the total clearance from the
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Figure 3.1.4 shows that the use of
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3.1.3 MODIFICATION OF ICRP 67 MODEL
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The structure of Polig’s skeleton
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Percentage daily urinary excretion
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of 0.693d -1 . The values of the F
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the basis of all the reference data
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Table 3.1.10 Transfer rates of the
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3.1.4 VERIFICATION OF THE OPTIMIZED
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Table 3.1.13 Intakes and percentage
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soft tissue ST2 soft tissue ST0 sof
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For the routine application of Mode
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excreted by individuals aged sixty
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Table 3.1.20 Exponents and coeffici
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tract [57] to consider a contaminat
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The sensitivity coefficients for th
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Sensitivity coefficients S i Figure
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transfer rates on the Plutonium uri
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Geometric standard deviations rangi
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3.2 APPLICATION OF THE OPTIMIZED MO
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lymph nodes, as in the LLNL phantom
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Americium in the lungs [Bq] 1000 10
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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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Plutonium Biokinetics in Human Body A. Luciani - Kit-Bibliothek - FZK

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