fitshape 2.3.0 © 2001-2009 by Turku PET Centre

Estimates the enzyme activity (k3) from regional brain PET studies using the shape analysis method (1,2). This model assumes that: 1) there is no metabolic product in the tissue at time 0 2) metabolite is retained in tissue completely 3) tissue radioactivity consists of parent tracer and metabolite, i.e. Ct(t) = Cs(t) + Cm(t) 4) The increment of Cm during scan frame n can be calculated as: Cm(n)-Cm(n-1) = k3*Cs(n-1)*DT(n) , where DT is the duration of frame. Command-line parameters: 1) Tissue TAC file 2) Fit time (in minutes from injection) 3) Result file (existing file is overwritten) Options: -h or --help Print this message and exit -smooth=<biexp|cexp|cbiexp|no> Tissue TACs will be smoothed by fitting to biexponential function as suggested in (2), or exponential function plus constant (default), or biexponential with constant; or not smoothed, in which case TACs should have been previously smoothed and interpolated to frequent sample times. -wf Weight by sampling interval. -step[size]=<time> Set the interpolated sample time frequency; 0.1 by default. -starttime=<time> Set the exponential fit start time (min); by default 3 min from injection, suitable for biexponential fits (2). For single exponential 20 min or later is recommended unless option -wf is used. -svg=<Filename> Original data and fitted curves are plotted in specified file in Scalable Vector Graphics (SVG) 1.1 format; specification in -fit=<Filename> Fitted regional TACs are written in DFT format. -int=<Filename> Interpolated regional TACs are written in DFT format. --version or --build Print software build information and exit. --silent Program works silently, printing only error and warning messages. --verbose Program prints more information about what it is doing. Format of the TAC data and result files are specified in and Example: fitshape -svg=ua1309shape.svg ua1309.dft 999 ua1309shape.res References: 1. Koeppe RA, Frey KA, Snyder SE, Meyer P, Kilbourn MR, Kuhl DE. Kinetic modeling of N-[11C]methylpiperidin-4-yl propionate: alternatives for analysis of an irreversible positron emission tomography tracer for measurement of acetylcholinesterase activity in human brain. J Cereb Blood Flow Metab. 1999;19:1150-1163. 2. Tanaka N, Fukushi K, Shinotoh H, Nagatsuka S, Namba H, Iyo M, Aotsuka A, Ota T, Tanada S, Irie T. Positron emission tomographic measurement of brain acetylcholinesterase activity using N-[11C]methylpiperidin-4-yl acetate without arterial blood sampling: methodology of shape analysis and its diagnostic power for Alzheimer's disease. J Cereb Blood Flow Metab. 2001;21:295-306. See also: simshape, fitk3, fit_trtm, rescoll Keywords: DFT, modelling, reference input, enzyme activity, shape analysis This program comes with ABSOLUTELY NO WARRANTY. This is free software, and you are welcome to redistribute it under GNU General Public License.

CC-GNU GPL Valid XHTML 1.0! Valid CSS!

Last updated 2010-10-04 17:41:05