fit_o2bl 1.4  © 2001,2002 by Turku PET Centre

   
  Estimates the whole body production rate of labelled water in dynamic
  [O-15]O2 bolus studies. Model parameters are fitted to the measured
  whole blood curve Cb(t) and whole blood [O-15]H2O curve Cw(t).
   
  The estimated model parameters can then be used to calculate
  the [O-15]O2 and [O-15]H2O blood curves using program o2metab.
   
  The whole blood [O-15]H2O curve must first be calculated from measured
  plasma curve Cp(t) by multiplying it with [O-15]H2O blood-to-plasma ratio
  e.g. using program o2_p2w.
   
  The representation of the compartmental model is:
           k1           k3       
     Co  ----->  Cw  <=====>  Ct 
                        k4       
  , where Co(t) is the arterial [O-15]O2 curve, and Co(t)=Ct(t)-Cw(t).
  The corresponding differential equations are:
     dCw(t)/dt = k1*Cb(t-delay) - (k1+k3)*Cw(t) + k4*Ct(t) 
     dCt(t)/dt = k3*Cw(t) - k4*Ct(t)                       
   
  In the default model it is assumed that k4=0.
  With option -h (Huang model) the full model is fitted.
  With option -i (Iida model) it is assumed that k3=k4=0.
   
  The model is based on the following articles:
  1. Huang S-C et al. Modelling approach for separating blood time-activity
     curves in positron emission tomographic studies.
     Phys Med Biol. 1991;36(6):749-761.
  2. Iida H et al. Modelling approach to eliminate the need to separate
     arterial plasma in oxygen-15 inhalation positron emission tomography.
     J Nucl Med. 1993;34:1333-1340.
   
  Parameters for the program:
    1) Blood TAC file (total)
    2) Blood [O-15]H2O TAC file (calculated from plasma TAC)
    3) Result file; note that existing file is overwritten
    4) Fitted [O-15]H2O file (optional)
    5) Weighted residuals (optional with 4)
   
  TAC files must contain two columns: sample times (sec) and
  decay corrected calibrated radioactivity concentrations.
   
  If default model or Iida's model is used and fitting is successful,
  program prints on screen only the fitted macroparameters k1'=k1,
  k2'=k1+k3, and the delay time.
  The result file will contain all of the possible parameters, k1, k3, k4
  and time delay.