esetstrt is a tool to help you process ECAT files, can set the scan_start_time in ECAT 6.3 or 7.x files.
Note that this program does not change frame times or decay correction; use this only if you know what you are doing. Time is written in ECAT file as GMT, but local time should be given on command line.
So, if you need a tool to help you analyze ECAT files, give esetstrt a try and see if its capabilities can satisfy your needs.

Usage:
esetstrt [Options] <ECAT file> <YYYY-MM-DD> <hh:mm:ss>

Options:
-h or --help
Print this message and exit

-v, --version, or --build
Print software build information and exit

--silent
Program works silently, printing only warnings and error messages

--verbose
Program prints more information about what it is doing.

The license of this software is Freeware, you can free download and free use this calculator software.