(Updated: 2021-12-19). Comments to: guillermo2046(at)gmail.com).

Here the intake can be estimated using measurements from different bioassay types: Whole body,
Urine excretion, Faecal excretion, Thyroid (only for Iodine) and Lungs (only for uranium by Inhalation).

The ICRP 130, ICRP 134 and ICRP 137 biokinectic models are used.

Different intake pathways can be selected and different kind of intake (acute or chronic).
If chronic intake is chosen then the last day of exposure should be indicated, after this date it is assumed that the intake ceases.

The decay constant is charged choosing the isotope, if not available it can be entered, expresed in days^-1, writing its value (e.g 0.011674 for I 125,
or as an expression e.g: Log[2]/(5.13*10^6/(24*60*60)), if one knows the half-life in seconds).

The absortion factors (fA- ingestion or inhalation-, fr, sr, ss) and the Dose coefficient e(50) can be obtained
using the OIR (ICRP134/137) data viewer.

As example, the data by default represent the following case: the whole body data from a person that he has been exposed to continuous and unknown ingestion of Cs137 ).We wish to evaluate the intake. Sol: Show should be selected: Caesium, Ingestion, Constant, Decay constant= 0.000063133 d^1. Bioassay type: Wholebody. Run the example, and look at the Chi2 value, then go changing the Period of chronic intake to find the Chi2 smallest. It is is arount 550 days that gives as solution about 27 Bq/day. Then the total intake will be 27 Bq/day x 550 days.

Case description:

Select Element:

Decay constant (in days^-1):

In case of ingestion (fA for ingestion):

In case of inhalation select:

Bioassay:

Bioassay data {{t1, m1, s1}, {t2, m2, s2}, ...}, being ti=time, mi=measurement(Bq), si=uncertainty (*)

Scattering factor B:

Dose coefficient e(50) (mSv/Bq):

LimitPlot: {min, max}:

Push EVALUATE, wait a few seconds.

Manual:>

I is the intake (in Bq for an acute intake) or the daily intake (Bq/d for a chronic intake) computed using a the Sd-Method (the sample uncertainties are assumed normal) and the ML(maximum likelihood) method.

Click Crt + Evaluate to open the ouput in a new window. The solution are given as an formated table, you can save it as usual (ej.: pick in the table with your mouse and paste it into a file -ej.: MS EXCEL- for later uses).