General Assumptions in PKIN

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General Assumptions in PKIN

The following is generally assumed:

All loaded data has been decay corrected to the same time point. This means that the PET scanner and the blood sampling times must have been synchronized. An exception is the processing of dosimetry data, which is preferably not decay corrected.

The acquisition time intervals may have gaps, but must not overlap.

The whole blood curve CBlood(t) represents the activity concentration of the tracer and all its metabolites in whole blood samples.

Most PET models require the input curve CP(t), namely the authentic tracer in arterial plasma which can exchange with tissue. Depending on how the plasma-related information is prepared and loaded, the input curve needs to be calculated differently.

In compartment models the whole-blood signal contribution can optionally be considered in the operational equation by
CModel = vB*CBlood +(1-vB)*CTissue
where vB represents the fractional volume of the blood space in the VOI, CBlood(t) the whole blood concentration, and CTissue(t) the summed concentrations in all tissue compartments.

The results of non-cardiac flow models are returned per cm3 tissue. To convert to flow per g tissue the values must be divided by the tissue density.

Exceptions to these rules are specified in the description of the individual models.