The Development of Volumetric Quantitative Evaluation Software for Assessing Respiratory-Induced Target Motion

Area of Science:

• Medical Imaging
• Radiotherapy Physics
• Computational Anatomy

Background:

• Respiratory motion significantly impacts radiotherapy accuracy.
• Quantitative assessment of organ motion is crucial for effective treatment planning.

Purpose of the Study:

• To develop and evaluate Vector Volume Histogram (VVH) software for volumetric quantitative evaluation of respiratory-induced organ motion.
• To utilize deformable image registration (DIR) for assessing motion using VVH.

Main Methods:

• Developed VVH software as a Python plug-in.
• Employed a B-spline-based DIR algorithm to compute deformation vector fields (DVF).
• Validated VVH using a moving phantom and applied it to 4D CT scans of a lung cancer patient.

Main Results:

• VVH accurately measured phantom target displacements (e.g., 19.9 mm and 19.6 mm for 20 mm shift).
• In a lung cancer patient, VVH quantified motion: 1.9 mm (LR), 1.9 mm (AP), 18.8 mm (CC), and 18.9 mm (3D).
• VVH results were compared to the centroid method, highlighting significant CC and 3D motion (13.5 mm).

Conclusions:

• VVH software offers a volumetric quantitative assessment of respiratory-induced target motion.
• The tool may inform strategic clinical decisions during radiotherapy treatment planning.
• VVH provides a valuable method for evaluating organ motion in 4D CT imaging.