Catenation of PET images or sinograms
When PET scanning has been performed in separate sessions, or scan was un-intentionally interrupted, it is advisable to join the scans together into one dynamic image or sinogram before continuing the analysis.
If there is only one scan which was started later than at injection time, then follow the procedure for correcting delayed scans.
Correction procedure
Use program ecatcat.
You need to enter the filenames of the images or sinograms to be catenated and
the name for the catenated file. Program looks the scan start times and frame times
in the file headers, and corrects automatically the frame times and the correction
for physical decay when necessary. Do not apply any extra corrections
before executing this program!
If PET scan was un-intentionally interrupted, it may happen that the
scan that was recorded during the failure contains one or more erroneous matrices
in the end, which either look peculiar or cause an error during execution of
ecatcat. In these cases, try to figure out what the erroneous matrices
are for example by listing them using
lmlist,
and then extract the correct matrices using
esplit.
After the catenation, you can check the frame times in the joined datafile
using for example program
eframe.
Scan Information Files (SIF)
If SIF data are needed in weighting or when
converting data to Analyze format
you need to catenate also the SIF data. Do this using
sifcat.
