The Dform module allows users to implement the requirements of the AAPM Task Group 132 report on the ‘Image Registration and Fusion Algorithms and Techniques in Radiotherapy’. The user can create deformed changes to virtual or real image structures. Deformations can be local or global and applied to any user defined anatomy or object. Once deformations have been applied, static or 4D image series of CT/MR/PET can be created, and exported to a 3rd party system for testing of for example, image fusion software. Examples could include: CT-CBCT IGRT image matching assessing daily anatomy changes; CT-MR image fusion of pre and post-operative images; image fusion of MR images on curved couches – CT image on flat couch tops.
With the Dform module users also have access to an additional library of 10 original and deformed synthetic head and neck phantoms created where the deformed dataset is based on actual anatomical changes seen during the radiotherapy treatment course. From these a ground truth deformable vector field (DVF) was created for each phantom. This allows the phantoms to be used to assess the accuracy and precision of the DIR algorithm in any available system, with clinically relevant data. This was developed through work with clinical partners.
As well as creating ground truth deformed datasets for testing your clinical system. ImSimQA can also be used to compare the ground truth deformation with the clinical dataset. Comparisons can be made in 4 ways:
1. Direct comparison of CT images visually and quantitatively using Mutual Information and correlation coefficient.
3. Comparison of the ground truth and clinical deformation vector fields (DVFs).
4. Jacobian matrix display (pictured below).