Related Experiment Video
Updated: Apr 28, 2026
08:17
Dynamic Lung Tumor Tracking for Stereotactic Ablative Body Radiation Therapy
Published on: June 7, 2015
15.2K
Toward the development of intrafraction tumor deformation tracking using a dynamic multi-leaf collimator
Yuanyuan Ge1, Ricky T O'Brien1, Chun-Chien Shieh1
1Radiation Physics Laboratory, University of Sydney, NSW 2006, Australia.
Medical Physics
|June 1, 2014
Summary
This study developed a dynamic multi-leaf collimator (DMLC) tracking system to adapt radiotherapy beams to intrafraction tumor deformation, significantly improving targeting accuracy for moving tumors.
Area of Science:
- Medical Physics
- Radiation Oncology
- Image-Guided Therapy
Background:
- Intrafraction tumor deformation exceeds 10 mm, challenging current radiotherapy accuracy.
- Existing radiotherapy methods struggle to adapt to significant tumor motion.
- Accurate targeting is crucial for effective radiation delivery and minimizing side effects.
Purpose of the Study:
- To develop and experimentally validate a dynamic multi-leaf collimator (DMLC) tracking system for real-time adaptation to tumor deformation.
- To investigate the system's ability to maintain targeting accuracy during intrafraction motion.
- To assess the feasibility of compensating for both single tumor and system deformation.
Main Methods:
- A DMLC tracking strategy was employed, warping planned beam apertures to conform to real-time tumor shape changes.
- Two deformable phantoms simulating single tumor and tumor system deformation were used for experimental validation.
- In-house deformable image registration software computed tumor deformation for aperture warping, with accuracy evaluated using a geometric target coverage metric.
- A clinical proof-of-principle experiment utilized patient MR images in a simulated MRI-Linac environment.
Main Results:
- The DMLC system reduced geometric target coverage errors by over 56% for single tumor deformation (>2 mm) and over 75% for tumor system deformation.
- Overall target coverage improvement reached 82% for single tumor and 86% for tumor system deformation.
- Deformable image registration was the primary source of tracking error, with finite leaf width offering partial compensation.
- Clinical proof-of-principle experiments confirmed the feasibility of intrafraction deformable tracking in realistic scenarios.
Conclusions:
- The developed experimental system successfully adapted MLC apertures to intrafraction tumor deformation, a first for radiotherapy.
- This technology offers a potentially widely applicable method for managing tumor deformation during treatment.
- This proof-of-principle study represents a significant step towards real-time image-guided radiotherapy for deforming tumors.
