fit_ppf - tpcclib 0.8.0 © 2023 by 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] fractionfile [fitfile]
 
Options:
 -model=<PF | HILL | GCDF | EP | 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=<OLS|LAD|ODR>
     Sum-of-squares (ordinal least squares, OLS) is minimized by default,
     but optionally, sum of absolute deviations (LAD), or
     sum-of-squares of Akaho distances (orthogonal distances, ODR) 
     can be selected. ODR can be used only with PF and HILL.
 -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).
 -fix0
     Parent fraction at time zero is fixed to zero sample, if available.
 -a=<value>, -b=<value>, -c=<value>, ...
     Specified parameter is fixed to given (population mean) value.
     Option -fix0 overrides other options when possible.
 -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, --help
     Display usage information on standard output and exit.
 -v, --version
     Display version and compile information on standard output and exit.
 -d[n], --debug[=n], --verbose[=n]
     Set the level (n) of debugging messages and listings.
 -q, --quiet
     Suppress displaying normal results on standard output.
 -s, --silent
     Suppress displaying anything except errors.
 
Fraction datafile must contain at least two columns: sample times (min) and
fractions of parent tracer. Fractions of 1-3 metabolites can be given in
additional columns. Weights column can be given 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)
  where C>0<=A<=D, 1<=B, 0<C, 0<D<=1, 0<=E.
GCDF - Inverted Gamma CDF (7)
  f(x) = A{1-B*gcdf(C(x-E),D)}, where 0<A<=1,0<=B<=1,C>0,D>0.
EP - Exponential/Power function based on Mu et al (8)
  f(x) = B*(C*exp(-D*(x-A)^3/(E+(x-A)^2)) + (1-C)*exp(-F*(x-A))), when x>A,
  f(x) = B                                                      , when x<=A ,
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/petanalysis/input_parent_fitting.html
2. http://www.turkupetcentre.net/petanalysis/format_tpc_dft.html
3. http://www.turkupetcentre.net/petanalysis/format_tpc_fit.html
4. Meyer PT, et al. J Cereb Blood Flow Metab. 2004;24(3):323-333.
   https://doi.org/10.1097/01.wcb.0000110531.48786.9d
5. Watabe H, et al. J Cereb Blood Flow Metab 2000;20:899-909.
   https://doi.org/10.1097/00004647-200006000-00002
6. Wu S, et al. J Nucl Med 2007;48:926-931.
   https://doi.org/10.2967/jnumed.106.038075
7. Naganawa M, et al. J Cereb Blood Flow Metab. 2014;34:1818-1825.
   https://doi.org/10.1038/jcbfm.2014.150
8. Mu L et al. EJNMMI Res. 2020;10:114.
   https://doi.org/10.1186/s13550-020-00700-7
 
See also: fit2dat, metabcor, avgfract, fitedit, fit_fexp, fith2met, tac2svg
 
Keywords: input, plasma, modelling, simulation, metabolite correction