imglhk3 - tpcclib 0.8.0 © 2023 by Turku PET Centre

Computation of parametric image of k3 from dynamic PET image in ECAT, NIfTI,
or Analyze format applying irreversible two-tissue compartmental model with
arterial plasma input.
The compartmental models are transformed to general linear least squares
functions (1), which are solved using Lawson-Hanson non-negative least
squares (NNLS) algorithm (2).
 
Dynamic PET image and plasma time-activity curve (PTAC) must be corrected
for decay to the tracer injection time.
 
Usage: imglhk3 [Options] ptacfile imgfile k3file
 
Options:
 -thr=<threshold%>
     Pixels with AUC less than (threshold/100 x PTAC AUC) are set to zero;
     default is 1%.
 -end=<Fit end time (min)>
     Use data from 0 to end time; by default, model is fitted to all frames.
 -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>
     Vb is fitted, and parametric Vb image is saved; without this,
     Vb is assumed to be zero (or precorrected).
 -k2k3=<filename>
     Parametric k2+k3 image is saved.
 -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.
 
The vascular volume is considered in the model setting only if file name for
Vb image is given. Otherwise the contribution of vasculature to the total
radioactivity concentration is assumed to be negligible, or pre-corrected.
Note that this model can correctly estimate Vb only if
1) plasma does not contain any labelled metabolites, and
2) plasma and blood curves are similar in shape.
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.
 
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
 
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, ISBN 0-89871-356-0.
 
See also: imgcbv, imgki, fitk3
 
Keywords: image, modelling, irreversible uptake, Ki, NNLS