Fitting of full or reduced compartmental model to plasma and tissue time-activity curves (PTAC and TTAC) to estimate the model parameters. ____ ____ ____ ____ | Cp |--K1->| C1 |--k3->| C2 |--k5->| C3 | compartments in series (s) |____|<-k2--|____|<-k4--|____|<-k6--|____| ____ ____ ____ | |--k3->| C2 | compartments in parallel (p) | |--K1->| |<-k4--|____| | Cp | | C1 | ____ |____|<-k2--| |--k5->| C3 | |____|<-k6--|____| Compartmental models are transformed into general linear least squares functions (1, 2, 3, 4), which are solved using Lawson-Hanson linear least-squares algorithms (5). Note that rate constants and macroparameters are represented per volume (as measured by PET) including vascular volume. Usage: lhsol [options] PTAC TTAC fittime results Options: -model=<k1 | k2 | k3 | k4 | k5s | k6s | k5p | k6p> representing the following compartmental model settings: k1 (for assuming k2=k3=k4=k5=k6=0) k2 (for assuming k3=k4=k5=k6=0) k3 (for assuming k4=k5=k6=0) k4 (for assuming k5=k6=0); default k5s (for assuming k6=0 and compartments in series) k6s (compartments in series) k5p (for assuming k6=0 and compartments in parallel) -Vp=<ignored|fitted> Vascular volume is ignored (default) or fitted; note that PTAC is assumed to represent vascular blood curve. -w1 | -wf Sample weights are set to 1 (-w1) or to frame lengths (-wf); by default weights in TTAC file are used, if available. -svg=<Filename> Fitted and measured TACs are plotted in specified SVG file. -fit=<Filename> Fitted regional TTACs are written in specified file. -lp=<Filename> Parameters of linear model are saved in specified 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. References: 1. Blomqvist G. On the construction of functional maps in positron emission tomography. J Cereb Blood Flow Metab 1984;4:629-632. 2. Gjedde A, Wong DF. Modeling neuroreceptor binding of radioligands in vivo. In: Quantitative imaging: neuroreceptors, neurotransmitters, and enzymes. (Eds. Frost JJ, Wagner HM Jr). Raven Press, 1990, 51-79. 3. Oikonen V. Multilinear solution for 4-compartment model: I. Tissue compartments in series. http://www.turkupetcentre.net/reports/tpcmod0023.pdf 4. Oikonen V. Multilinear solution for 4-compartment model: II. Two parallel tissue compartments. http://www.turkupetcentre.net/reports/tpcmod0024.pdf 5. Lawson CL & Hanson RJ. Solving least squares problems. Prentice-Hall, 1974. See also: fitk4, fitk5, patlak, logan, imglhdv, fitdelay, taccbv Keywords: TAC, modelling, compartmental model, LLSQ

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.