fit_ppf 2.0.10 © 2010-2013 Turku PET Centre
Fits an empirical function to plasma parent (unchanged) tracer
fraction curve (1), where the fractions are between 0 and 1.
Usage: fit_ppf [Options] <Fraction file> [Fit file]
Options:
-model=<PF | HILL | MPF | MHILL>
Select the function (see descriptions below); default is HILL.
Use MPF or MHILL to fit functions to 2-3 metabolite fraction curves
instead of parent fraction curve.
-min=<SS|ABS>
Sum-of-squares (SS) is minimized by default, but optionally
sum of absolute deviations (ABS) can be selected.
-delaymin=<value>
Set the lower limit for delay parameter.
-mdelay=<separated | joint>
Delay parameter for each metabolite is fitted separately, or
all metabolites are assumed to share common delay time (default).
-a=<value>, -b=<value>, -c=<value>, ...
Specified parameter is fixed to given (population mean) value.
-WC The last data column contains sample weights.
-W1 All weights are set to 1.0 (no weighting)
-WF Less frequent samples are given more weight.
-WP=<weight>, -WM1=<weight>, -WM2=<weight>, -WM3=<weight>
Put additional or less weight to parent and/or metabolite fractions.
-ND Some fractions are known to exceed 1, not divided by 100.
-MRL Error is returned if MRL check is not passed.
-svg=<Filename>
Fitted and measured TACs are plotted in specified SVG file.
-h or --help
Print this message and exit.
--build or --version
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.
Fraction datafile must contain at least two columns: sample times and
fractions of parent tracer. Fractions of 1-3 metabolites can be given in
additional columns. Weights can be specified as specified in DFT format (2)
or with option -wc.
Program writes the fit start and end times, nr of points, WSS,
and parameters of the fitted function to the FIT file (3).
Available functions:
PF - extended power function (1,4,5)
f(x) = {D^(-1/C) + (A*(x-E))^B }^-C , when x>E,
f(x) = D , when x<=E ,
where 0<A<=1, B>1.5, C>0, 0<D<=1, 0<=E.
With option -d=1 this is essentially the same function as proposed in (4)
or with options -b=2 -d=1 -e=0 the same as suggested in (5).
HILL - Extended Hill type function (1,6)
f(x) = D - {(D-A)(x-E)^B}/{C+(x-E)^B} , when x>E,
f(x) = D , when x<=E ,
where 0<=A<=D, 1<=B, 0<C, 0<D<=1, 0<=E.
With options -d=1 -e=0 this is the traditional Hill type function (6)
f(x) = 1 - {(1-A)x^B}/(C+x^B)
MPF - Extended power function is fitted to 1-3 metabolite fractions.
MHILL - Extended Hill type function is fitted to 1-3 metabolite fractions.
References:
1. Fitting the fractions of parent tracer in plasma.
http://www.turkupetcentre.net/analysis/doc/fraction_fit.html
2.
http://www.turkupetcentre.net/analysis/doc/format_dft.html
3.
http://www.turkupetcentre.net/analysis/doc/format_fit.html
4. Meyer PT, Bier D, Holschbach MH, Boy C, Olsson RA, Coenen HH, Zilles K,
Bauer A. Quantification of cerebral A1 adenosine receptors in humans
using [18F]CPFPX and PET. J Cereb Blood Flow Metab. 2004;24(3):323-333.
5. Watabe H, Channing MA, Der MG, Adams HR, Jagoda E, Herscovitch P,
Eckelman WC, Carson RE. Kinetic analysis of the 5-HT2A ligand
([11C]MDL 100,907. J Cereb Blood Flow Metab 2000;20:899-909.
6. Wu S, Ogden RT, Mann JJ, Parsey RV. Optimal metabolite curve fitting for
kinetic modeling of 11C-WAY-100635. J Nucl Med 2007;48:926-931.
See also:
fit2dat,
metabcor,
avgfract,
fitedit,
fit_fexp,
fith2met,
dft2svg
Keywords: input, plasma, modelling, simulation, metabolite correction
This program comes with ABSOLUTELY NO WARRANTY. This is free software, and
you are welcome to redistribute it under GNU General Public License.