Development of a novel post-processing treatment planning platform for 4D radiotherapy

Area of Science:

• Medical Physics
• Radiotherapy
• Image Processing

Background:

• Four-dimensional (4D) treatment planning is crucial for accurately targeting tumors affected by respiratory motion.
• Manual post-processing steps in 4D treatment planning are time-consuming and prone to variability.
• Automating these processes can significantly improve efficiency and consistency in radiotherapy.

Purpose of the Study:

• To develop and validate an Automatic Post-processing Tool for 4D treatment planning (APT4D).
• To integrate automated image registration, contour propagation, and dose distribution transformation within a single tool.
• To enhance the efficiency and functionality of the 4D treatment planning workflow.

Main Methods:

• Utilized Demons-based deformable image registration to map respiratory phases to a reference phase.
• Implemented automatic propagation of contours from the reference phase to moving phases.
• Transformed and averaged dose distributions across respiratory phases to create a composite dose.
• Validated APT4D using 4D CT images from lung and abdominal cancer patients.

Main Results:

• Achieved high correlation coefficients (0.977–0.999) for image registration across patient cohorts.
• Demonstrated high accuracy in automatic contour propagation with match indices around 0.92–0.95.
• Observed dosimetric reductions in organs at risk (liver, kidneys) in the high-dose region on the 4D composite dose-volume histogram.

Conclusions:

• APT4D successfully automates key procedures in 4D treatment planning, including image registration and contour propagation.
• The tool enhances efficiency and functionality, integrating the entire 4D treatment planning process.
• Validation results indicate high accuracy and potential for clinical utility in improving radiotherapy precision.