[Application of elastic registration based on Demons algorithm in cone beam CT].

Area of Science:

• Medical Physics
• Radiotherapy Imaging
• Image Registration

Background:

• Accurate tracking of organ changes during radiotherapy is crucial for effective treatment.
• Cone beam CT (CBCT) provides 3D imaging during treatment but requires precise image registration for analysis.
• Elastic registration algorithms are essential for accounting for soft tissue deformation.

Purpose of the Study:

• To develop and evaluate a 3D elastic registration program for CBCT images.
• To provide software support for real-time monitoring of organ changes in radiotherapy.
• To assess the performance of Demons and accelerated Demons algorithms in CBCT image registration.

Main Methods:

• Implementation of a 3D CBCT image elastic registration program using Matlab software.
• Application of the classic Demons and accelerated Demons elastic registration algorithms.
• Validation using 3D CBCT images from two cervical cancer patients.

Main Results:

• The classic Demons algorithm resulted in a 59.7% decrease in minimum mean square error (MSE) and an 11.0% increase in correlation coefficient (CC).
• The accelerated Demons algorithm achieved a 40.1% decrease in MSE and a 7.2% increase in CC.
• Both algorithms demonstrated effectiveness, though precision and registration time require further optimization.

Conclusions:

• The developed Demons-based elastic registration software shows potential for real-time organ change monitoring in radiotherapy.
• Further improvements in accuracy and reduction in registration time are needed for clinical application.
• The study highlights the utility of elastic registration for enhancing radiotherapy precision.