Supported models

All model fitting is performed by the kinfitr package. You can configure up to three models simultaneously for comparison.

Models are either nonlinear (compartmental models fitted by nonlinear least squares) or linear (graphical or multilinear methods fitted by linear regression).

Plasma input models

Invasive models requiring an arterial blood input function. Available in the Modelling App with Plasma Input.

Model	Description	Type
1TCM	One tissue compartment model	Nonlinear
2TCM	Two tissue compartment model	Nonlinear
2TCM_irr	Two tissue compartment model, irreversible (k4 = 0)	Nonlinear
Logan	Logan graphical analysis (VT)	Linear
MA1	Multilinear analysis 1 (VT)	Linear
Patlak	Patlak graphical analysis (Ki, irreversible tracers)	Linear

Reference tissue models

Non-invasive models using a reference brain region instead of blood data. Available in the Modelling App with Reference Tissue.

Model	Description	Type
SRTM	Simplified reference tissue model	Nonlinear
SRTM2	Simplified reference tissue model 2 (fixed k2prime)	Nonlinear
refLogan	Reference Logan analysis (BPND)	Linear
MRTM1	Multilinear reference tissue model	Linear
MRTM2	Multilinear reference tissue model 2 (fixed k2prime)	Linear
refPatlak	Reference Patlak analysis (irreversible tracers)	Linear

The constrained models (SRTM2, MRTM2, refLogan) take a fixed k2prime value, which can come from a fixed value, another model in the same analysis (e.g. MRTM1), or an ancillary analysis.