imgdecayc.c File Reference

Physical decay and isotopes in IMG. More...

#include "libtpcimgio.h"

Go to the source code of this file.

Functions
int	imgDecayCorrection (IMG *image, int mode)
char *	imgIsotope (IMG *img)
int	imgSetDecayCorrFactors (IMG *image, int mode)
int	imgBranchingCorrection (IMG *image, int mode, int verbose, char *status)

Detailed Description

Physical decay and isotopes in IMG.

Author

Vesa Oikonen

Definition in file imgdecayc.c.

Function Documentation

imgBranchingCorrection()

int imgBranchingCorrection	(	IMG *	image,
		int	mode,
		int	verbose,
		char *	status )

Corrects image data for branching fraction (mode=1) or removes correction (mode=0). Removal is primarily based on branching factor stored in IMG structure, secondarily on isotope; after removal, branching factor is set to 1, and pixel values and calibration factor are multiplied with it. Correction is based on branching fractions in branch.h; pixel values and calibration factor are divided by it, and its value is stored in IMG structure.

Note

This function can not know if branching fraction correction is included in the data (as it usually is) or not.

Returns

Returns 0 if ok.

See also

imgDecayCorrection, imgSetDecayCorrFactors, imgIsotope

Parameters

image	Pointer to IMG data
mode	Branching fraction correction (1) or removal of correction (0)
verbose	Verbose level; if zero, then nothing is printed into stdout or stderr
status	Pointer to allocated string where error message will be written; NULL, if not needed.

Definition at line 132 of file imgdecayc.c.

  {
  int isotope;
  float bf;
  float cf;
 
  if(verbose>0) printf("imgBranchingCorrection(*img, %d, %d, *status)\n",
    mode, verbose);
  /* Check for arguments */
  if(status!=NULL) strcpy(status, "invalid input");
  if(image->status!=IMG_STATUS_OCCUPIED) return(1);
  if(image->isotopeHalflife<=0.0) {
    if(verbose>0) printf("Error: unknown isotope.\n");
    if(status!=NULL) strcpy(status, "unknown isotope");
    return(2);
  }
 
  /* If branching factor not found in IMG, then get it based on half-life */
  bf=image->branchingFraction;
  if(bf<=0.0 || bf>=1.0) {
    isotope=hlIsotopeFromHalflife(image->isotopeHalflife/60.0);
    if(verbose>2) printf("isotope := %d\n", isotope);
    bf=branchingFraction(isotope);
  }
  if(bf<=0.0 || bf>=1.0) {
    if(verbose>0) printf("Error: branching fraction unknown for the isotope.\n");
    if(status!=NULL) strcpy(status, "branching fraction unknown for the isotope");
    return(3);
  }
 
  /* Multiply with BF to remove correction, and divide to correct */ 
  if(mode==0) cf=bf; else cf=1.0/bf;
  /* Process pixel values */
  if(verbose>1) printf("multiplying data by %g\n", cf);
  for(int fi=0; fi<image->dimt; fi++) {
    for(int pi=0; pi<image->dimz; pi++)
      for(int i=0; i<image->dimy; i++)
        for(int j=0; j<image->dimx; j++)
          image->m[pi][i][j][fi]*=cf;
  }
 
  /* Fix header contents, too */
  if(image->calibrationFactor>0.0) image->calibrationFactor*=cf;
  if(mode==0) image->branchingFraction=0.0;
  else image->branchingFraction=bf;
 
  if(status!=NULL) strcpy(status, "ok");
  return(0);
}

imgDecayCorrection()

int imgDecayCorrection	(	IMG *	image,
		int	mode )

Corrects (mode=1) or removes correction (mode=0) for physical decay. Removal is based on existing decay correction factors, when possible.

Returns

0 if ok, 1 image status is not 'occupied', 2 decay already corrected/not corrected, 3 image frame times missing

See also

imgSetDecayCorrFactors, imgBranchingCorrection, imgIsotope

Parameters

image	Pointer to IMG data.
mode	0=Remove decay correction; 1=Correct for decay.

Definition at line 16 of file imgdecayc.c.

  {
  float lambda;
  float cf, dur;
 
  /* Check for arguments */
  if(image->status!=IMG_STATUS_OCCUPIED) return(1);
  if(image->isotopeHalflife<=0.0) return(1);
  /* Existing/nonexisting decay correction is an error */
  if(mode==1 && image->decayCorrection!=IMG_DC_NONCORRECTED) return(2);
  if(mode==0 && image->decayCorrection!=IMG_DC_CORRECTED) return(2);
 
  /* All time frames */
  for(int fi=0; fi<image->dimt; fi++) {
    dur=image->end[fi]-image->start[fi];
    if(image->end[fi]>0.0) {
      if(mode==0 && image->decayCorrFactor[fi]>1.000001) {
        /* if decay correction is to be removed, and factor is known,
           then use it */
        cf=1.0/image->decayCorrFactor[fi];
      } else {
        lambda=hl2lambda(image->isotopeHalflife); if(lambda<0.0) return(1);
        /* remove decay correction by giving negative lambda */
        if(mode==0) lambda=-lambda;
        if(fi==image->dimt-1 && image->end[fi]<=0.0) return(3);
        cf=hlLambda2factor_float(lambda, image->start[fi], dur);
      }
      if(IMG_TEST) printf("applied_dc_factor[%d] := %g\n", fi+1, cf);
      /* Set decay correction factor inside IMG for future */
      if(mode==0) {
        image->decayCorrFactor[fi]=1.0;
      } else {
        image->decayCorrFactor[fi]=cf;
      }
      /* All planes, all matrices */
      for(int pi=0; pi<image->dimz; pi++)
        for(int i=0; i<image->dimy; i++)
          for(int j=0; j<image->dimx; j++)
            image->m[pi][i][j][fi]*=cf;
      if(mode==0) image->decayCorrection=IMG_DC_NONCORRECTED;
      else image->decayCorrection=IMG_DC_CORRECTED;
      /* in some cases left unchanged! */
    }
  } /* next frame */
  return(0);
}

imgIsotope()

char * imgIsotope

(

IMG *

img

)

Returns pointer to string describing the isotope in image data

Parameters

img	image structure

Returns

pointer to string

See also

imgDecayCorrection

Definition at line 76 of file imgdecayc.c.

                           {
  return(hlIsotopeCode(hlIsotopeFromHalflife(img->isotopeHalflife/60.0)));
}

Referenced by ecat63AddImg(), ecat63WriteAllImg(), img2sif(), imgSetEcat63MHeader(), imgSetEcat7MHeader(), and sifAllocateWithIMG().

imgSetDecayCorrFactors()

int imgSetDecayCorrFactors	(	IMG *	image,
		int	mode )

Sets (mode=1) or removes (mode=0) decay correction factors in IMG. IMG pixel data is not changed.

Returns

0 if ok, 1 image status is not 'occupied', 2 invalid exponent value, 3 image frame times are missing.

See also

imgDecayCorrection, imgBranchingCorrection, imgIsotope

Parameters

image	Pointer to IMG data.
mode	Factors are calculated for decay correction (1) or for removing decay correction (0).

Definition at line 87 of file imgdecayc.c.

  {
  float lambda, cf, dur;
 
  /* Check for arguments */
  if(image->status!=IMG_STATUS_OCCUPIED) return(1);
  if(image->isotopeHalflife<=0.0) return(1);
 
  /* Check that image contains frame times */
  if(mode!=0 && image->end[image->dimt-1]<=0.0) return(3);
 
  /* All time frames */
  for(int fi=0; fi<image->dimt; fi++) {
    if(mode==0) {
      image->decayCorrFactor[fi]=1.0;
    } else {
      dur=image->end[fi]-image->start[fi];
      if(image->end[fi]>0.0) {
        lambda=hl2lambda(image->isotopeHalflife); if(lambda<0.0) return(2);
        cf=hlLambda2factor_float(lambda, image->start[fi], dur);
        image->decayCorrFactor[fi]=cf;
      }
    }
  } /* next frame */
  if(mode==0) image->decayCorrection=IMG_DC_NONCORRECTED;
  else image->decayCorrection=IMG_DC_CORRECTED;
  return(0);
}