fit_frtm - tpcclib 0.8.0 © 2023 by Turku PET Centre
NLLSQ estimation of R1 (=K1/K1'), k2, k3, and BPnd (binding potential)
using the (full) reference tissue compartment model, FRTM/RTCM (1,3).
Assumption is that K1/k2 is the same in all brain regions, but 1TCM with
plasma input does not need to fit the tissue curves satisfactorily
as is assumed in SRTM (2), and Cref(t) is not assumed to be the same as
Cfree(t) as is assumed in the ratio methods.
Usage: fit_frtm [Options] ttacfile reference endtime resultfile
TTAC file can be in DFT or PMOD format. Sample times must be in minutes.
If TTAC file contains weights, those are used in the NLLSQ fitting.
Reference region TAC can be given separate TAC file or as the name or number
of the reference region in TTAC file.
Instead of BPnd, program saves the DVR (=BPnd+1) values.
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.
Standard deviations are calculated and saved in results (y), or
not calculated (n).
95% Confidence limits are calculated and saved in results (y), or
not calculated (n).
All weights are set to 1.0 (no weighting); by default, weights in
TTAC file are used, if available.
Weight by sampling interval.
Fitted regional TACs are written in file.
Fitted and measured TACs are plotted in specified SVG file.
Display usage information on standard output and exit.
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.
Suppress displaying normal results on standard output.
Suppress displaying anything except errors.
Values of R1, k2, k3, and BPnd are written in the specified result file.
Fitted curves are written in DFT format, if file name is given.
Example 1: file a789.tac contains regions-of-interest and reference region,
with name 'cereb all'. The whole time range is used in the fit.
fit_frtm a789.tac 'cereb all' 999 a789.res
Example 2: Reference region TAC is in a separate file, a789ref.tac;
standard deviations and confidence limits are also estimated.
fit_frtm -SD=y -CL=y a789.tac a789ref.tac 999 a789.res
1. Cunningham VJ, Hume SP, Price GR, Ahier RG, Cremer JE, Jones AKP.
Compartmental analysis of diprenorphine binding to opiate receptors
in the rat in vivo and its comparison with equilibrium data in vitro.
J Cereb Blood Flow Metab 1991;11:1-9.
2. Lammertsma AA, Hume SP. Simplified reference tissue model for PET
receptor studies. Neuroimage 1996;4:153-158.
3. Oikonen V, Sederholm K. TPCMOD0002: Model equations for reference tissue
compartmental models. http://www.turkupetcentre.net/reports/tpcmod0002.pdf
See also: bfmsrtm, tacweigh, rescoll, logan, fit_srtm, sim_rtcm
Keywords: TAC, modelling, binding potential, RTCM, reference input