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
http://www.w3.org/TR/SVG/
-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
http://www.turkupetcentre.net/analysis/doc/format_dft.html and
http://www.turkupetcentre.net/analysis/doc/format_res.html
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.