3D ultrasound-guided motion compensation for intravascular radiation therapy

Purpose: Motion compensation is a well-known practice for radiation therapy. X-ray images are used to track the target area with a low temporal resolution. To increase the temporal resolution surrogate signals such as chest motion for respiration are tracked and correlated to the target motion. Currently effort is taken to use radiation therapy to cure heart diseases like arrhythmia [1]. Because of the high speed of motion of the heart, fluoroscopic tracking of fiducials or anatomical structures as in IGRT would require high frame rates. Correlation of target movement to surrogate signals is difficult, too. Especially for cardiac applications three-dimensional ultrasound has become an indispensable visualization method. But while it is extensively used for diagnoses it is currently not used for target localization in radiation therapy. This work concentrates on using three-dimensional ultrasound for direct target localization and motion compensation.