Estimate the delay time between blood and PET time-activity curves. fitdelay help you estimate and correct the delay time between blood or plasma and PET time-activity curves (TACs).
The program is based on the methods used by Meyer et al. (1) and van den Hoff et al. (2): The plasma/blood curve is shifted -60 - +60 sec, and a two-tissue compartment model (with parameters K1, k2, k3, k4 and Vb) in multilinear form (3) is fitted to the shifted TAC and each regional tissue TAC, with the nonnegative least squares method (4). For each region, the delay leading to the lowest sum-of-squares is selected; the over-all delay value is calculated as a median of the regional delays. Dispersion is not considered in this application.

Command-line arguments:
1) Blood or plasma TAC filename
2) Tissue TAC filename
3) Fit time (s)
4-5) Upto three additional blood or plasma files (optional)

Options:
-o=<Filename>
-o2=<Filename>
-o3=<Filename>
-o4=<Filename>
Filename(s) for the time delay corrected TAC(s) can be speficied with these options; by default the file names for result files are formed as is told below.
-timeunit=<min|sec>
If datafile(s) do not contain the unit of sample times, it is recommended to specify it with this option. By default, units in data files are trusted.
-format=<none|dft>
Specify the output data format; none means that no title lines are saved.
-fit=<Filename>
Fitted best TACs are written is specified file.
-model=<1|2>
Select whether 1- or 2-tissue (default) compartment model is applied.
-L[og]
Time delay and other log information is written as comments in
the corrected TAC file.
-h or --help
Print this message and exit
--version or --build
Print software build information and exit
--verbose
Program prints more information about what it is doing
--silent
Program works silently, printing only warnings and error messages.

The license of this software is Freeware, you can free download and free use this calculator software.