Program for adding Gaussian noise to dynamic PET image using equations (1, 2): SD(t) = TAC(t) * sqrt(Pc/(TAC(t)*exp(-lambda*t)*deltat) TAC_noisy(t) = TAC(t) + SD(t)*G(0,1) , where Pc is the proportionality constant that determines the level of noise, TAC(t) is the mean activity concentration in the image frame, Deltat is the scan frame length, and G(0,1) is a pseudo random number from a Gaussian distribution with zero mean and SD of one. Image must be in ECAT (6.3 or 7) format, or, Analyze 7.5 or NIfTI-1 format with SIF. Image is assumed to be decay corrected to zero time. Usage: fvar4img [Options] image Pc outputimage Options: -seed=<seed for random number generator> Computer clock is used by default. -i=<O-15|N-13|C-11|F-18|Ge-68|Ga-68|Br-76|Rb-82|Cu-62> Specifies the isotope. -minsd=<SD> Set a minimum SD to add a minimum level of noise also to the image frames with no activity. -efile=<TAC filename> Save image mean TAC and SD that were used in noise simulation. -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. Example: fvar4img -i=C-11 simulated.v 5.0 noisy.v References: 1. Chen K, Huang SC, Yu DC. Phys Med Biol 1991;36:1183-1200. 2. Varga J, Szabo Z. J Cereb Blood Flow Metab 2002;22:240-244. See also: dft2img, flat2img, eframe, imgdecay, fvar4tac, img2tif Keywords: image, simulation, noise

This program comes with ABSOLUTELY NO WARRANTY. This is free software, and you are welcome

to redistribute it under GNU General Public License.

Source codes are available in https://gitlab.utu.fi/vesoik/tpcclib.git.