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.
• The acquisition time intervals may have gaps, but must not overlap.
• The input curve C_P(t) represents the authentic tracer in arterial plasma which is available for exchange with tissue.
• The whole blood curve C_Blood(t) represents the activity concentration of the tracer and all its metabolites in whole blood.
• In compartment models the whole-blood signal contribution can optionally be considered in the operational equation by
  C_Model = vB*C_Blood +(1-vB)*C_Tissue
  where v_B represents the fractional volume of the blood space in the VOI, C_Blood(t) the whole blood concentration, and C_Tissue(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.