It appears that when CTB Locker encrypts a file it first makes a copy of it, encrypts the copy, and then deletes the original. Due to this you can may be able to use a file recovery software such as R-Studio or Photorec to recover some of your original files. It is important to note that the more you use your computer after the files are encrypted the more difficult it will be for file recovery programs to recover the deleted un-encrypted files.