(Sunday, 7/12/2020) [Eastern Time (GMT-4)]
Room: AAPM ePoster Library
Purpose:
Sudden cardiac death caused by ventricular tachycardia (VT) results in >150,000 deaths/year in U.S. Noninvasive Cardiac Radio-Ablation (NCRA) was recently reported as a novel noninvasive alternative treatment to treat VT refractory to the anti-arrhythmogenic drugs and catheter ablation. Under-managed heart and respiratory motions can significantly affect multiple-modal images that are involved in target definition and treatment planning, and jeopardize the precision of image-guided target localization and radiation delivery. A heart motion phantom is needed to provide simultaneous cardiac and respiratory motions to support motion-compensated 4DCT and 4DMR studies, and allows end-to-end radiation dosimetry testing of NCRA.
Methods:
A heart motion phantom with multiple components was constructed. Two double-layered balloons were filled with ~350 ml water to simulate the blood-flow. Each balloon was narrowed in its upper middle by a rubber band to separate upper and lower chambers simulating the dynamics of blood-flow between atrium and ventricle. Two such balloons wrapped by an air bag and packed in a container simulated four chambers of a heart. The air bag, inflated and deflated at 1 Hz by an air pump, squeezed the lower chambers rhythmically to create heart beating and blood-flow between atria and ventricles. The balloon and air bag assembly was placed on the motion platform which provided respiratory motion in superior-inferior at 0.25 Hz. Both the respiratory and cardiac cycle frequencies are adjustable.
Results:
The phantom was imaged with MR, helical CT and CBCT. All three scans showed clear 5D motion (3D + cardiac + respiratory motions). Landmarks placed on the balloon, air bag and motion platform were visible and trackable.
Conclusion:
A 5D motion phantom supporting simultaneous cardiac and respiratory motions was constructed. It will be useful for imaging, motion-management and dosimetry research studies for NCRA.
Keywords
Heart, Motion Artifacts, Phantoms
Taxonomy
IM- Multi-Modality Imaging Systems: CT/MR - human
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