fit_hill 1.8.5 © 1999-2010 Turku PET Centre
Fits the following Hill function to a fraction curve of unchanged
(parent) tracer in plasma, where fractions are between 0 and 1 (1, 2).
B B
f(x) = 1 - (A * x ) / ( x + C ) , where 0<A<=1 , B>0 , C>0
Usage: fit_hill [Options] <Fraction file> [Fit file]
General options:
-ND Some fractions are known to exceed 1, not divided by 100.
-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.
Options to constrain the fit:
-a=<value>
Parameter A is fixed to given (population mean) value.
-b=<value>
Parameter B is fixed to given (population mean) value.
-c=<value>
Parameter C is fixed to given (population mean) value.
Options to refine the fitted function:
-Asc | -Desc
Fit an additional parameter D, so that
f(x) = 1 - (A(1+Dx)x^B)/(x^B+C), where
0<=D<=0.05 (Asc) or -0.05<=D<=0 (Desc).
-Lwr Fit function f(x) = A - (Ax^B)/(x^B+C) with usual constraints.
Options to set weights:
-W1 All weights are set to 1.0; by default, sample times are used to
calculate weights unless weights are not supplied in fraction file.
-WC The last data column contains sample weights.
-WF Multiply sample weights with sample times.
Fraction datafile must contain two columns, sample times and fractions
of parent tracer. Weights can be specified as specified in DFT format,
http://www.turkupetcentre.net/analysis/doc/format_dft.html ;
any additional columns are ignored.
Lines that start with a '#' are not read from the datafile.
Program writes the fit start and end times, nr of points, WSS/n,
and parameters of the fitted function to the result (fit) file,
in format:
http://www.turkupetcentre.net/analysis/doc/format_fit.html
References:
1. Fitting the fractions of parent tracer in plasma.
http://www.turkupetcentre.net/analysis/doc/fraction_fit.html
2. 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,
fit_sigm,
fit_fexp,
fit_ppf,
dft2svg
Keywords: input, 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.
