## sim_3tcm - tpcclib 0.7.8 © 2022 by Turku PET Centre

```Simulation of PET tissue time-radioactivity concentration curves (TACs)
from arterial plasma (Ca) and blood (Cb) TACs, based on three-tissue
compartmental model, where the compartments are in series (default):

____    K1   ____    k3   ____    k5   ____
| Ca | ----> | C1 | ----> | C2 | ----> | C3 |
|____| <---- |____| <---- |____| <---- |____|
k2           k4           k6

dC1(t)/dt = K1*Ca(T) - (k2+k3)*C1(T) + k4*C2(T)
dC2(t)/dt = k3*C1(T) - (k4+k5)*C2(T) + k6*C3(T)
dC3(t)/dt = k5*C2(T) - k6*C3(T)
Ct(T) = C1(T) + C2(T) + C3(T)
Cvb(T) = Cab(T) - dCt(t)/dt / f
Cpet(T)= Vb*fA*Cab(T) + Vb*(1-fA)*Cvb(T) + (1-Vb)*Ct(T)

, or, optionally, three-tissue compartmental model, where the 2nd and 3rd
tissue compartments are parallel, often used to represent specific and
non-specific binding:

____    K1   ____    k3   ____
| Ca | ----> | C1 | ----> | C2 |
|____| <---- |____| <---- |____|
k2           k4
| ^
k5 | | k6
v |
____
| C3 |
|____|

dC1(t)/dt = K1*Ca(T) - (k2+k3+k5)*C1(T) + k4*C2(T) + k6*C3(T)
dC2(t)/dt = k3*C1(T) - k4*C2(T)
dC3(t)/dt = k5*C1(T) - k6*C3(T)
Ct(T) = C1(T) + C2(T) + C3(T)
Cvb(T) = Cab(T) - dCt(t)/dt / f
Cpet(T)= Vb*fA*Cab(T) + Vb*(1-fA)*Cvb(T) + (1-Vb)*Ct(T)

Usage: sim_3tcm [options] parfile [plasmafile bloodfile simfile]

Options:
-paral[lel]
Model with parallel compartments C2 and C3 is applied, overriding
possible model settings in parameter file.
-ser[ies]
Model with compartments C1, C2, and C3 in series is applied, overriding
possible model settings in parameter file.
-vvm=<1|2>
Vascular volume is modelled as (1, default)
Cpet(T)= Vb*fA*Cab(T) + Vb*(1-fA)*Cvb(T) + (1-Vb)*Ct(T)
or as (2)
Cpet(T)= Vb*fA*Cab(T) + Vb*(1-fA)*Cvb(T) + Ct(T).
-sub | -nosub
TACs of sub-compartments (C1, C2 and C3) are written (-sub)
or not written (-nosub, default) into the simfile.
-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.

To create a template parameter file, do not enter names for input and
simulated TACs. Obligatory parameters are:
K1, k2 (or K1/k2), k3, k4 (or k3/k4), k5, k6 (or k5/k6), and Vb.
Additionally, values for perfusion (f), arterial fraction of Vb (fA), and
delay time (dT) can be set; otherwise it is assumed that f>>K1, Cvb=Cab,
fA=1, and dT=0.
If parameter file does not contain units, then per min and per mL units
are assumed, except sec for dT.
For accurate results, plasma TAC should have very short sampling intervals.
To reduce the model, k5 or k3 can be set to 0.
When blood file is not used (Vb=0), 'none' can be entered in its place.