Four-dimensional computed tomography ventilation imaging-guided radiotherapy planning in different techniques for...

Area of Science:

• Radiation oncology
• Medical imaging
• Computational biology

Background:

• Four-dimensional computed tomography (4DCT) enables functional lung (FL) imaging.
• Integrating FL imaging into radiotherapy (RT) planning can potentially improve treatment outcomes.
• Different RT techniques may yield varying dosimetric results when incorporating functional data.

Purpose of the Study:

• To integrate 4DCT ventilation imaging into functional RT planning.
• To compare dosimetric differences between intensity-modulated radiotherapy (IMRT), hybrid IMRT, and volumetric modulated arc therapy (VMAT) using functional planning.
• To evaluate the impact of functional planning on FL and organs at risk (OARs).

Main Methods:

• 4DCT ventilation images were generated using Jacobian values from deformable image registration.
• Anatomical and functional plans were created for 18 lung cancer patients using IMRT, hybrid IMRT, and VMAT.
• Dosimetric parameters, including FL radiation dose and OAR doses, were systematically compared.

Main Results:

• Functional planning, irrespective of RT technique, reduced FL radiation dose metrics (fV5, fV10, fV20, fV30, fMLD) while maintaining target coverage.
• Increases in OAR radiation dose were not statistically significant.
• f-IMRT and f-VMAT reduced FL and OAR doses compared to f-hybrid IMRT, with f-VMAT showing a lower esophageal Dmean.

Conclusions:

• Functional planning effectively reduces FL radiation dose and meets OAR constraints compared to anatomical planning.
• Among evaluated techniques, functional VMAT (f-VMAT) appears to be the preferred method for functional RT planning.
• This approach optimizes dose delivery for lung cancer patients undergoing radiotherapy.