Monitoring procedure

IDEA System
The expert system for internal dosimetry

2003 - 2023: Twenty years experience

Monitoring procedure

There are two general requirements for routine monitoring:

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

first column: radionuclide to be monitored
second column: type of measurement for monitoring
third column: monitoring interval (days)
fourth column: detectable activity to meet sensitivity criterion for this monitoring interval
last column: indication of fulfilled criteria

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 fulfilled.

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.