Four-dimensional radiotherapeutic dose calculation using biomechanical respiratory motion description

Area of Science:

• Medical Physics
• Radiotherapy
• Computational Biology

Background:

• Patient breathing causes organ motion, complicating hadron therapy for lung tumors.
• Accurate dose distribution requires patient-specific tumor and tissue data.
• Current methods face challenges in precisely estimating dose for moving targets.

Purpose of the Study:

• To develop and test a new 4D dosimetry method for lung tumor hadron therapy.
• To couple biomechanical simulations with dose calculations for improved accuracy.
• To address the challenge of organ motion in radiotherapy.

Main Methods:

• Synthesized anatomical lung and tumor models using CT images and deformable tetrahedral grids.
• Simulated respiratory motion using biomechanical nonlinear finite element analysis.
• Accumulated dose distribution over biomechanically deformed tetrahedral meshes.

Main Results:

• The new method demonstrated mass preservation with 1.6-3.6% error.
• Significant differences were observed compared to existing dose calculation methods.
• The novel approach showed superior performance in dosimetry for moving targets.

Conclusions:

• A unified model for 4D radiotherapy respiratory effects was developed.
• Coupling biomechanical simulations with dose calculations shows promise.
• This approach has significant potential for treating moving tumors with hadron therapy.