Evaluation of special monitoring


For evaluation of the special monitoring data please go to the "Evaluation" window and select "Am-241" as "Single radionuclide". The first "Feces" value is underlaid in red because it has already been evaluated. However, this value should be included into the  evaluation of the special monitoring data and so the previous evaluation of this value should be deleted. For doing so, please go to the "Results" window in the background and push the "Delete last intake" button.


Now please mark all the four measurements which have been collected by 03.07.2000 (first screenshot to the left).


After selection of these date the software asks for the earliest time of intake. in this case the program suggests the begin of monitoring according to the Person data (01.01.2000). If there would be any evidence for another date of the earliest time of intake, you may enter that date in the respective window (next screenshot).


After having confirmed the earliest time of intake the program checks the database for previous intakes of Am-241 (next screenshot).


After having confirmed the information about previous intakes you have to select the "Evaluation procedure". In this case the most important intake parameter is the time of intake. So you should start with the "Special evaluation (Level 2 or 3; fitting time of intake" (next screenshot).


After selection of the "Evaluation procedure" a window opens with the suggested "Evaluation parameters". You may change the reference parameters given here if there should be any evidence for different values. Please make sure that the default absorption type M is selected in the "Materials" window (next row of screenshots).


After having started the evaluation the program first checks the significance of the selected data. In this case all data are significant and so the program gives the qualitative information that there is a new intake (next screenshot).


After confirmation of this qualitative information the program calculates the intake for the best fitting time of intake based on the  intake parameters as selected previously (next screenshot).


It turns out that the intake occurred most probably on the 21.06.2000, i. e. just 10 days before the first routine measurement rather than in the middle of the monitoring interval. So, the resulting intake is much smaller (396 Bq Am-241) and the effective dose is only 3,17 mSv and thus below the limit (next screenshot).


The plots (next screenshot) show a very good agreement of the fecal data with the respective excretion function (lower plot). The urine value, however, is significant smaller than the respective excretion function, whereas the lung value is higher than the lung retention function. These discrepancies indicate that the solubility of the inhaled material is actually smaller than the solubility of type M material as assumed for the evaluation.


So it seems to be reasonable to check the absorption type of the inhalaed material in the next step of evaluation.




















Prof. Dr.-Ing. Hans Richard Doerfel

IDEA System GmbH, Am Burgweg 4, D-76227 Karlsruhe, Germany.

E-Mail: info@idea-system.com