fitk4 3.2.4 © 2000-2013 by Turku PET Centre
Non-linear fitting of two-tissue compartment model to plasma and tissue
time-activity curves (TACs) to estimate K1, k2, k3, k4, and optionally Vb.
______ ___________________
| | K1 | k3 |
| | --> | -------> |
| Ca | <-- | C1 <------- C2 |
| | k2 | k4 |
|______| |___________________|
K1/k2 can be constrained to the value estimated in reference region.
By default 2-compartmental model is fitted to reference region.
Datafile(s) must be in DFT format. If tissue TAC file contains weights,
those are used in the fitting.
Parameters:
1) Plasma file (corrected for labeled metabolites)
2) Blood file
3) Tissue TAC file (*.dft)
4) Fit end time (duration)
5) Result file
Options:
-lim[=<filename>]
Specify the constraints for model parameters;
This file with default values can be created by giving this
option as the only command-line argument to this program.
Without filename the default values are printed on screen.
-SD[=<y|N>]
Standard deviations are calculated and saved in results (y),
or not calculated (N, default).
Program runs a lot faster if SD and CL are not calculated.
-CL[=<y|N>]
95% Confidence limits are calculated and saved in results (y), or
not calculated (N, default).
-r=<Reference region name or filename>
Optional reference region is used to constrain K1/k2.
-rmod=<2|3>
Specify the model (2- or 3-compartments) that is fitted to reference
region data; by default 2-CM (1-tissue compartment model)
-Vb=<Vb(%)>
Enter a fixed Vb; fitted by default.
-fk1k2=<<value> || <result filename>>
K1/k2 is constrained to the given value in all regions; if result
filename is entered, then K1/k2 is constrained to the median of
K1/k2 values in the result file.
-BPnd[=<reference region name>]
BPnd is calculated as BPnd=VtROI/VtREF-1; reference region name
is not needed if the same is specified with option -r.
-fit=<Filename>
Fitted regional TACs are written in DFT format.
-svg=<Filename>
Fitted and measured TACs are plotted in specified SVG file.
-h or --help
Print this message and exit
--version or --build
Print software build information and exit
--silent
Program works silently, printing only error and warning messages
--verbose
Program prints more information about what it is doing.
Example 1: estimate K1, K1/k2, k3 and k3/k4; Vb is estimated;
Fitted curves are plotted with measured data in SVG file
fitk4 -svg=a919fit.svg a919ap.kbq a919ap.kbq a919.dft 90 a919.res
Example 2: estimate K1, k3 and k3/k4; Vb is set to 1.5%%;
K1/k2 is constrained to K1/k2 estimated from region 'cer' with 2-CM
fitk4 -Vb=1.5 -r=occip -rmod=2 ua919ap.kbq ua919ab.kbq ua919.dft 60 ua919.res
Example 3: constrain K1/k2 to the regional median; Vb is set to 4%%;
fitk4 -Vb=4 ua919ap.kbq ua919ab.kbq ua919.dft 60 tmp.res
fitk4 -Vb=4 -fk1k2=tmp.res ua919ap.kbq ua919ab.kbq ua919.dft 60 ua919fk1k2.res
See also:
logan,
fitk2,
fitk3,
p2t_v3c,
dftweigh,
extrapol,
dftcbv,
rescoll
Keywords: TAC, modelling, binding potential, reversible uptake
This program comes with ABSOLUTELY NO WARRANTY. This is free software, and
you are welcome to redistribute it under GNU General Public License.