Add Gaussian noise to PET images. fvar4img is a program for adding Gaussian noise to dynamic PET images in ECAT 6.3 or 7.x format.
Here is an example for this utility: fvar4img simulated.v 0.5 noisy.v. So, if you were looking for a program to help you work with ECAT files, take fvar4imgfor a spin and check out if its capabilities are enough to satisfy your needs.

Usage:
fvar4img [Options] <image file> <proportionality constant c> <output image>

Options:
-S[eed]=<seed for random number generator>
Computer clock is used by default
-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 more information about what it is doing.

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