scndv 1.2  © 2003 by Turku PET Centre
   
  Calculation of distribution volume (DV) or distribution volume ratio (DVR)
  sinograms from dynamic PET sinograms in CTI ECAT 6.3 format applying model
  independent graphical analysis approach of Logan et al [1, 2, 3] for
  reversible tracer uptake or binding.
  Simple non-iterative perpendicular line fitting algorithm [4] is applied
  in determination of the slope of the Logan plot.
  Please note that when using reference region input, the population average
  of k2 for reference region [2] can not be used with sinogram data, and
  this may produce bias in the results. 
   
  Parameters:
    1) Input file (Plasma or Reference region TAC; times in minutes)
    2) Dynamic sinogram file
    3) Linear fit start time (0 for automatic determination)
    4) Parametric sinogram file
  Options:
   -V<filename>
       Y axis intercepts times -1 are written as a sinogram in specified file.
   -N<filename>
       Numbers of selected plot data points are written as an sinogram.
   
  e.g.: scndv  ua3818ap.kbq  ua3818dy1.scn  20  ua3818dv.scn
   
  The unit of pixel values in the parametric DV image after reconstruction
  and calibration is (mL plasma)/(mL tissue), and DVR images are unitless.
  If reference region TAC was determined from noncalibrated image, the
  parametric DVR sinogram or image must not be calibrated either.
   
  Do not subtract 1 from DVR sinograms before reconstruction.
   
  References:
  1. Logan J, Fowler JS, Volkow ND, Wolf AP, Dewey SL, Schlyer DJ,
     MacGregor RR, Hitzemann R, Bendriem B, Gatley SJ, Christman DR.
     Graphical analysis of reversible radioligand binding from time-activity
     measurements applied to [N-11C-methyl]-(-)-cocaine PET studies in human
     subjects. J Cereb Blood Flow Metab 1990; 10: 740-747.
  2. Logan J, Fowler JS, Volkow ND, Wang GJ, Ding YS, Alexoff DL.
     Distribution volume ratios without blood sampling from graphical
     analysis of PET data. J Cereb Blood Flow Metab. 1996; 16: 834-840.
  3. Logan J. Graphical analysis of PET data applied to reversible and
     irreversible tracers. Nucl Med Biol 2000; 27:661-670.
  4. Varga J & Szabo Z. Modified regression model for the Logan plot.
     J Cereb Blood Flow Metab 2002; 22:240-244.