lhtrtm 0.3.3 © 2003-2008 by Turku PET Centre

Estimates the k3 from transport-limited reference tissue model for irreversible tracer uptake [1,2]. ______ K1' ___________ | | --> | | dCt(t)= | | <-- | Cr | +R1*dCr(t) | | k2'|___________| +R1*k3*Cr(t) | | ____________________ -(k2+k3)*Ct(t) | Cp | K1 | k3 | | , where | | --> | Cf -------> Cb | concentration in tissue: | | <-- | <------- | Ct(t)=Cf(t)+Cb(t) | | k2 | | k4=0 | and in reference region Cr(t) |______| |___________|________| k3'>>k2' The model is transformed to general linear least squares functions [2,3], which are solved using Lawson-Hanson non-negative least squares (NNLS) algorithm [4]. The k3 can be estimated from either original model setting [5], or directly without division, but if fitted TACs are saved, those are always calculated from original model setting. Parameters: 1) Regional tissue TAC file (*.dft) 2) Name of reference region in tissue file, or name of file containing reference tissue TAC 3) Fit end time (min from injection) 4) Result file (existing file is overwritten) 5) Fitted regional TAC file (optional) Options: -k3=<original|direct> k3 is estimated either from original model setting (original, default) or from rearranged model without division (direct) -mid[=<y|n>] Middle frame times are used (y, default) or not used (n) even if frame start and end times are available -h or --help Print this message and exit --version or --build Print software build information and exit --silent Program works silently, printing only error and warning messages --verbose Program prints lots of information about what it is doing Weights are used if found in TAC data file. References: 1. Herholz K, Lercher M, Wienhard K, Bauer B, Lenz O, Heiss W-D. PET measurement of cerebral acetylcholine esterase activity without blood sampling. Eur J Nucl Med 2001;28:472-477. 2. Nagatsuka S, Fukushi K, Shinotoh H, Namba H, Iyo M, Tanaka N, Aotsuka A, Ota T, Tanada S, Irie T. Kinetic analysis of [11C]MP4A using a high- radioactivity brain region that represents an integrated input function for measurement of cerebral acetylcholinesterase activity without arterial blood sampling. J Cereb Blood Flow Metab 2001; 21: 1354-1366. 3. Blomqvist G. On the construction of functional maps in positron emission tomography. J Cereb Blood Flow Metab 1984;4:629-632. 4. Lawson CL & Hanson RJ. Solving least squares problems. Prentice-Hall, 1974. 5. Oikonen V. Model equations for reference tissue compartmental models. http://www.turkupetcentre.net/reports/tpcmod0002.pdf See also: fit_trtm, fitk3, dftweigh, r2t_rtcm, tac2svg Keywords: DFT, modelling, irreversible uptake, reference tissue This program comes with ABSOLUTELY NO WARRANTY. This is free software, and you are welcome to redistribute it under GNU General Public License.

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Last updated 2009-04-07 14:52:16