There are two general requirements for routine
The measurement should be sensitive enough to make
sure that any internal exposure of more than 1 mSv/a would be detected for any exposure scenario (sensitivity criterion S).
The monitoring interval should be short enough to
make sure that the underestimation potential for the dose due to unknown time of intake is less than factor 3 (misinterpretation criterion M).
IDEAplus gives guidance for defining the optimum
monitoring procedure taking into account both requirements. For doing so, please go via "Planning" to "Monitoring procedure" (first screen shot to the left).
Next shot: First make sure that the "Monitoring
procedure" window is linked to the correct person (Mary Taylor). Then select via the pull-down menu the radionuclide to be monitored (Am-241).
Next shot: In most countries routine monitoring
for alpha-emitters such as Am-241 is done by room air monitoring. So IDEAplus asks whether room air monitoring should be applied also in this case.
Next shot: After confirmation of room air
monitoring IDEAplus asks whether control measurements should be performed in addition to room air monitoring. Here the answer should be "Yes".
Next shot: Now let us have a look on the yellow
table: Any line of this table represents a monitoring procedure being characterized as follows
For example: If you would apply lung measurements with a monitoring interval of 180
d, you should be able to detect 0.8 Bq Am-241 in the lungs. The best lung counters, however, reach a LLD of 3 - 5 Bq and so the sensitivity criterion S is not
Next shot: When scrolling down the table, you will see at the end four green lines with monitoring procedures fulfilling both the sensitivity criterion S and the misinterpretation
criterion M, Thus, routine measurement of fecal excretion with monitoring intervals of 60 d or more would be optimum for routine incorporation monitoring. It is supposed that Dr. Taylor would
prefer the 180 d monitoring interval and so this interval should be selected.