UCLA researchers have developed a method to predict future anatomical motion during MRI-guided radiotherapy treatments to overcome system latency and increase the accuracy of radiation delivery.
BACKGROUND:
Anatomical motions (e.g. expansion and compression of the lungs and diaphragm during respiration) reduce the accuracy of radiation delivery to the target and increase exposure to nearby healthy tissues. MRI-guided radiotherapy prevents radiation inaccuracy caused by anatomical motions via reaction beam gating, which is performed by turning off the radiation when the target is outside the beam. However, due to electronic, mechanical and computational constraints, the system experiences a delay before turning off the radiation. This gating latency was measured to be 0.436 seconds using the ViewRay MRIdian system at UCLA.
INNOVATION:
UCLA researchers led by Prof. John S. Ginn developed a method to predict future anatomical motion during MRI-guided radiotherapy treatments to overcome system latency and increase the accuracy of radiation delivery. The method utilizes an initial training set of images and motion observations to build a library for motion predictions. Motion predictions are derived by comparing each newly acquired image set during treatment to those available in the training library. These predictions could be used to turn off the radiation preemptively when the radiotherapy target is expected to leave that radiation beam. Additionally, the technique could be used to predict the future position of the target enabling the system to follow the target by moving the radiation beam through multileaf collimator target tracking.
POTENTIAL APPLICATIONS:
• Anatomical motion prediction in MRI-guided radiotherapy
ADVANTAGES:
• Ensure the radiotherapy target receives the prescribed radiation dose while avoiding healthy tissue
• Initialize the deformable image registration software used to extract motion information from images and track the radiotherapy target.
DEVELOPMENT-TO-DATE:
This invention has been tested in patients.