IMBA® Internal Dosimetry Software

The IMBAPlus and IMBAPro versions provide more advanced functionality, to meet the needs of internal dose specialists and researchers, which would previously have required the purchase of individual Add-Ons. IMBAPlus comes pre-packaged with a selection of the most commonly requested Add-Ons, while IMBAPro includes all available add-on functionality to provide a powerful tool for the most demanding of users. A summary of the functionalities are given below.

IMBAPlus IMBAPro
IMBALite functionality + IMBAPlus functionality +
Multiple Intake Regimes Errors on Intake
Multiple Bioassay Types Bayes Implementation
Associated Radionuclides Tritium Tool
Uranium Mixtures Compensation Type Calculations
Uptake from Wounds Ingrowth of Americium
Statistics Package
Candu Models

Further information

Multiple Intake Regimes

An intake regime defines both the mode of intake (inhalation of aerosols or vapours, ingestion, injection, wound etc.) and the time of intake (e.g. an acute intake on a certain date, or a chronic intake between two dates). This option enables the user to deal with up to 10 separate intake regimes simultaneously.

Thus when calculating doses or predicting bioassay quantities, the software automatically includes the contribution from each intake. It is also possible to assign different model parameter values separately to each intake regime if required. This option also works during intake estimation and so up to 10 intakes can be fitted to the measurement data simultaneously.

Multiple Bioassay Types

The Base Unit will deal with 8 different bioassay quantities (whole body, lung, urinary and faecal excretion, blood, thyroid, liver and user defined). However, only one type of data set can be used at any one time.

This option enables the user to fit the intake to different bioassay types simultaneously. It can be used with the Multiple Intake Regimes option to enable multiple intakes to be fitted to multiple bioassay data types simultaneously.

Associated Radionuclides

The Base Unit performs dose calculations on the selected radionuclide (known in IMBA® Professional Plus as the indicator nuclide). In some situations, many different radionuclides are bound together in a particle matrix (e.g. fission products).

This option enables the user to specify up to 30 additional associated radionuclides, defining the amount of each with respect to the indicator radionuclide. Subsequent dose calculations will include the components from all of the associated radionuclides.

In the dose calculations, it is assumed that the absorption rates (and f1 values) of each associated radionuclide are identical to that of the indicator radionuclide.

Uranium Mixtures

This option enables the user to specify a mixture of uranium isotopes (U-234, U-235, U-236 and U-238) for dose and bioassay calculations.

The user can choose default values for enriched, depleted, or natural uranium, or specify the mixtures directly. The specific activity of the resulting mixture is automatically calculated. It also allows the user to specify the intakes in terms of mass (mg).

Uptake from wounds

The base module allows intakes via inhalation (aerosols and vapours), ingestion or direct injection. This option enables the user to deal with intakes from a wound site using the NCRP wound model.

This functionality is integrated automatically with all of the calculations (dosimetry, bioassay and intake fitting).

Errors on intake

In cases where an intake is being estimated from bioassay data, and all of the data are assumed to be normally distributed with a specified standard deviation, then this option will propagate the relevant errors to calculate their contribution to the error in the estimate of intake. The method of error fitting employed in this case is based on the Least Squares method.

Bayes Implementation

The Base Unit uses a fitting method based on the Maximum Likelihood Method to estimate intakes from measurement data. This option enables the user to use a Bayesian approach to estimate an intake.

Thus prior knowledge about the intake (either from other measurements such as air sampling, or from hypothetical judgements) can be used in conjunction with the measurement data to obtain the probability distribution of intake. The user can choose from a variety of 'prior' intake distributions and both graphical and statistical displays are given.

It works in conjunction with the Multiple Intake Regimes option to enable the probability distributions of different intakes (each with their own prior) to be estimated simultaneously.

Tritium Tool

Typical procedures for estimating tritium intakes which have occurred at some unknown time in a monitoring interval involve making assumptions about (a) the time of intake, and (b) the contribution to the current measurement from intakes in previous monitoring intervals.

Because the new International Commission on Radiological Protection (ICRP) tritium model is no longer a single exponential, it is no longer possible to use just the previous measurement to correct the current measurement. This option enables the user to select up to 10 previous tritium measurements, and to fit simultaneously the best 10 intakes. In a sense, the previous 9 intakes are used to correct for the current estimate of intake.

Compensation Type Calculations

This option enables the user to select an organ, and a date on which cancer was diagnosed in the organ. The program then calculates the equivalent dose to the organ in each (of up to 99) calendar years previous to the cancer diagnosis.

A simple wizard for exporting this data to other files or databases is also included. This type of information is required as part of the process of estimating causation probabilities for compensation type calculations.

Ingrowth of Americium

The interpretation of measurements of Am-241 in an individual can be complicated if the individual has also had an intake of Pu-241 because of the continuous ingrowth of Am-241 from Pu-241. This option allows the user to take ingrowth into account automatically when performing calculations.

Statistics Package

This Add-On enables the user to bring up useful statistical information immediately after fitting intakes to measurement data. It calculates the chi-square value for each bioassay type, the total chi- square and the associated P value (probability of obtaining a chi square greater than or equal to the calculated value by random chance).

CANDU models

The Base Unit allows the user to assess intakes from bioassay measurement data, calculate bioassay quantities at different times from a specified intake and calculate equivalent organ doses and effective dose for various chemical forms of hydrogen and carbon.

This option implements chemical forms of hydrogen and carbon that occur in CANDU type reactors using models that are currently recommended by COG (CANDU Owners Group) in Canada. These models are based on International Commission on Radiological Protection (ICRP) models but differ slightly from them.

The chemical forms of hydrogen and carbon supplied in this option are Inorganic hydrogen CANDU model, Metal tritides CANDU model, Tritiated methane CANDU model, Carbon dioxide CANDU model.