Non-linear fitting of Gamma variate bolus plus recirculation function with time delay term to plasma and tissue time-activity curves (TACs). Function: | 0 , t < p1 f(t) = | | p2*((t-p1)^p3)*exp(-(t-p1)/p4) , t >= p1 | + p5*(1-exp(-(t-p1)/p4))*exp(-(t-p1)/p6) Usage: fit_gvar [Options] tacfile [fitfile] Options: -recirc=<Y|n> Fit recirculation terms p5 and p6 (y, default), or fit only gamma variate function setting p5=p6=0 (n). -lim[=<filename>] Specify the constraints for function parameters; This file with default values can be created by giving this option as the only command-line argument to this program. -w1 All weights are set to 1.0 (no weighting); by default, weights in data file are used, if available. -wf Weight by sampling interval. -stoptime=<Fit end time> All data with sample time > stoptime is excluded from the fit. -thr=<Threshold%> If sample value after the peak is less than Threshold% of the peak, then that sample and all samples after that are omitted from the fit. Hint: try to set threshold close to 100, e.g. 99%, to get a good estimate of tracer appearance time. -auto Automatically sets the fit range from 0 to peak + at least one sample more, until WSS/(sum of weights) gets worse. -svg=<Filename> Fitted and measured TACs are plotted in specified SVG file. -fit=<Filename> Fitted TACs are written in TAC format. -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. TAC file must contain at least 2 columns, sample times and concentrations. Weights can be specified as usual if data is in DFT format. Program writes the fit start and end times, nr of points, WSS, and parameters (p1, p2, ...) of the fitted function to the fit file. See also: fit2dat, fit_sinf, fit_exp, fit_ratf, fit_hiad Keywords: curve fitting, TAC, simulation

This program comes with ABSOLUTELY NO WARRANTY. This is free software, and you are welcome

to redistribute it under GNU General Public License.

Source codes are available in https://gitlab.utu.fi/vesoik/tpcclib.git.