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Updated: Jul 9, 2026

08:54
Treatment of Liver Metastases Using an Internal Target Volume Method for Stereotactic Body Radiotherapy
Published on: May 8, 2018
Inter-subject modelling of liver deformation during radiation therapy
M von Siebenthal1, G Székely, A Lomax
1Computer Vision Laboratory, ETH Zurich, 8092 Zurich, Switzerland. mvonsieb@vision.ee.ethz.ch
Summary
This study models liver deformation during breathing, crucial for accurate radiation therapy. A statistical model using 4D MRI and non-rigid registration accurately predicts liver movement from limited data, improving tumor targeting.
Area of Science:
- Medical Physics
- Radiotherapy
- Medical Imaging
Background:
- Accurate liver tumor targeting in radiation therapy is challenging due to respiratory motion.
- Understanding and modeling non-periodic liver deformation is essential for improving treatment precision.
Purpose of the Study:
- To develop a statistical model for liver deformation beyond respiratory motion.
- To assess the model's accuracy in predicting liver deformation from partial information for improved radiotherapy targeting.
Main Methods:
- Collected 4D MRI data from 12 volunteers over one hour to capture liver deformation.
- Utilized non-rigid registration to establish correspondence between subjects based on liver surface landmarks.
- Performed leave-one-out experiments to evaluate predictive accuracy using limited data, such as ultrasound tracking points.
Main Results:
- A statistical model of liver deformation was successfully created.
- Predictions based on even a single tracked point significantly reduced localization errors.
- The prediction method demonstrated robustness regardless of the specific measurement point chosen.
Conclusions:
- The developed statistical model effectively captures liver deformation during respiration.
- This model is a significant advancement for reliable liver tumor targeting in radiation therapy.
- Predicting liver motion from minimal data, like ultrasound, enhances localization accuracy and treatment efficacy.

