fitprfs 0.1  © 2003 by Turku PET Centre

   
  Non-linear fitting of mathematical function to measured aortic activity
  profiles in x and y directions simultaneously.
  Function for x profile P(x) without background activity is [1]:
   
           C        x + R          x - R     
    P(x) = - (Erf(---------)-Erf(---------)) 
           2      Sqrt(2)*s      Sqrt(2)*s   
  , where
    C = true uniform activity (kBq/mL)
    s = FWHM/2.355 (mm)
    R = radius of aorta (mm)
  C and R are estimated in the fit, and FWHM is provided by the user.
  Profiles must be shifted so that the activity peak is in the middle
  i.e. its x and y value is zero. This can be done using program prfpeak.
   
  Usage:  fitprfs <X profile file> <Y profile file> <FWHM (mm)> <Fit file>
   
  Profiles must be in DFT format, and can be produced e.g. using program
  eprofile. Distances in profile file must be given in mm from the peak.
   
  Program writes the estimated function parameters to the fit file.
   
  Options:
  -B   Also background activity is assumed and fitted as one parameter.
       Note that this violates the model!
  -A<arterial TAC file>
       Arterial blood TAC is calculated from profile peak values and
       recovery coefficients based on the equation [1]
                         R^2   
    RCaorta = 1 - Exp(- -----) 
                        2*s^2  
   
  References:
  1. Germano G, Chen BC, Huang S-C, Gambhir SS, Hoffman EJ, Phelps ME.
     Use of abdominal aorta for arterial input function determination
     in hepatic and renal PET studies. J Nucl Med 1992;33:613-620.