imglhk3 0.8.9 © 2003-2010 by Turku PET Centre
Estimation of rate constant k3 from dynamic PET images in ECAT 6.3 or 7.x
format using linearized three-compartment model with rate constants K1, k2
and k3 (1) and, if required, also vascular volume fraction Vb, applying
Lawson-Hanson non-negative least squares (NNLS) to solve general linear
least squares functions (2).
Parameters:
1) Plasma file (sample times in minutes!)
2) Dynamic image file
3) Parametric k3 image file
Options:
-Thr=<threshold%>
Pixels with AUC less than (threshold/100 x max AUC) are set to zero.
Default is 5 %
-ThrDV=<threshold%>
DV and k3 in pixels with DV less than (threshold/100 x DV) are
set to zero. By default, this threshold is not applied.
-DV=<filename>
Parametric K1/(k2+k3) image is saved
-K1=<filename>
Parametric K1 image is saved
-k2=<filename>
Parametric k2 image is saved
-Ki=<filename>
Parametric Ki image is saved
-Vb=<filename>
Parametric Vb image is saved
-alt
Alternative method to estimate k3; Ki is fixed
-F Remove parametric pixel values that are over 4x higher than
their closest neighbours
-E=<Fit end time (min)>
Use data from 0 to end time; by default, model is fitted to all frames
-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.
Example 1b: Vb is assumed negligible:
imglhk3 ua2917ap.kbq ua2917dy1.v ua2917k3.v
Example 1b: Vb is fitted as one of the model parameters:
imglhk3 -Vb=ua2917vb.v ua2917ap.kbq ua2917dy1.v ua2917k3.v
Example 1c: Vb is pre-corrected:
imgcbv ua2917dy1.v ua2917ab.kbq 0.04 ua2917dy1_cbv.v
imglhk3 ua2917ap.kbq ua2917dy1_cbv.v ua2917k3.v
Example 2: K1, DV, and k3 images are saved:
imglhk3 -K1=ua2917k1.v -DV=ua2917dv.v ua2917ap.kbq ua2917dy1.v ua2917k3.v
Example 3: k3 pixel values are set to zero if DV is less than 10% of DVmax:
imglhk3 -ThrDV=10 ua2917ap.kbq ua2917dy1.v ua2917k3.v
The vascular volume is considered in the model setting only if filename
for Vb image is given. Otherwise the contribution of vasculature to the
total radioactivity concentration is assumed to be negligible.
Note that this model can correctly estimate Vb only if
-plasma does not contain any labelled metabolites
-plasma and blood curves are similar in shape.
Alternatively, vascular volume can be pre-corrected with imgcbv.
The units of pixel values in the parametric images are 1/min for k3,
ml/(min*ml) for K1 and Ki, and ml/ml for DV and Vb.
References:
1. Blomqvist G. On the construction of functional maps in positron
emission tomography. J Cereb Blood Flow Metab 1984;4:629-632.
2. Lawson CL & Hanson RJ. Solving least squares problems.
Prentice-Hall, 1974.
See also:
imgcbv,
imglhki,
imglk3,
imglhlk3,
ecat2tif,
lhsolvk3,
lhsolk3
Keywords: image, modelling, irreversible uptake, enzyme activity
This program comes with ABSOLUTELY NO WARRANTY. This is free software, and
you are welcome to redistribute it under GNU General Public License.
