3D Rigid Registration

Utility optimized for rigid registration between a CT and a CBCT. CT is referred and is expected to be the Fixed Image. On the opposite side CBCT is expected to be the Moving Image

Usage from command line

ImageRegistration3DClass <MetricNumber> CTName&Path CBCTName&Path <options>

Various options are provided and can be print out using the help command:

ImageRegistration3DClass -h

Suggested options are:

• Fixed cropping, activated with -c --> will crop the fixed image (CT) to the region that overlaps to the moving image (CBCT);
• Isocenter alignment, activated with -rt <RTplanFilename> --> will align the moving image to the first isocenter in the RTPlan file and execute option -c (this is under the assumption that the isocenter is a good initialization for this registration);
• -res, -fres and -mres --> call a resampling routine for one or both images, affecting accuracy and execution time.

Notes

Currently the registration uses a BSpline interpolator for the registration process and also for the optional resamplings. Such choice slows down both processes but guarantee a higher degree of convergence.

At this stage the class is written to output and write and image. This could be optional, while the tranform should be fed to external routines

Current developing

Multistage registration is currently implementable but kept locked as a non activated option. The goal would be to optimize the registration to give an acceptable improvement in short time. Creating a user varying initialization could be a good idea (select coarseness, number of steps and guarantee a continuity).

Feeding the output to a reinitialization routine.