To view both images simultaneously in physical space - check checkboxes in list widget. It is applicable to only one 3D view "Physical space, intensity projection"
Particular images have different dimensions and don't occupy same physical space.
Create mask image for CT. Masks are optional.
To open registration dialog click at "R" button (left main window panel).
Select working directory. There are several predefined configurations, in particular case one rigid registration. Fast, robust and precise presets are available. It is possible to use own parameter files and arguments.
During registration process "Registration is running" message will appear. It is possible to cancel registration.
After registration moving image, mask, etc. can be closed, they are still available in .mha format in output folder.
Use Fusion (physical space), generate check-board images.
Create custom views (all image settings - window, palette, rectangular selection, transparency etc. are working per image).