What specific type of registration is used for images affected by motion and tumor growth?

Deformable registration is specifically designed to handle images that are affected by motion and changes such as tumor growth. In medical imaging, particularly in modalities like PET, tumor size and shape can change significantly over time due to factors like treatment or disease progression. Deformable registration allows for the adaptation of the image corresponding to these changes by using algorithms that can flexibly align images based on alterations in shape and position.

This technique contrasts with other types of registration, such as linear registration, which typically assumes a rigid transformation (i.e., the images being registered do not change in size or shape). Non-deformable registration also involves similar rigid conditions, while static registration refers to aligning images captured at the same point in time without accounting for any temporal changes, thus rendering it ineffective in dealing with the dynamic nature of tumors.

By utilizing deformable registration, healthcare professionals can achieve a more accurate comparison of images taken at different times, enhancing the assessment of tumor growth or response to treatment. This capability is crucial for planning and evaluating treatment strategies in oncology.