Memory Capture after app launch

I have a program that opens files. The file in memory however is different than the actual Hex/binary stored on the hard drive. I need to capture the file from the RAM once it is opened in my software package.

I have read about memory dump. I would open the app, and then open the file, and attempt to dump the memory and locate my file structure. I was hoping there was a capture utility that snapshots the memory at interval points so compares can be done.