Catheter Ablation -> Ventricular Arrhythmias -> Mapping & Imaging D-PO01 - Featured Poster Session (ID 11) Poster

D-PO01-123 - Tracking The Effects Of Proton Beam Ablation Therapy In Myocardial Infarct Scar With Delayed Contrast-Enhanced Magnetic Resonance Imaging (ID 925)

Abstract

Background: It has been previously shown that proton beam therapy can create lesions in healthy myocardial tissue, suggesting a potential for treatment of VT. To date, the effects of proton beam energy in infarcted myocardial tissue is unknown.
Objective: In the current work, we track proton beam dose maps in a series of delayed contrast-enhanced magnetic resonance (DCE-MR) imaging swine datasets to assess the effects of proton beam ablation on infarcted myocardial tissue.
Methods: In five swine, myocardial infarct scar was created using an infarction-reperfusion protocol; 4-6 weeks after the procedure, baseline imaging (CT/MR) was acquired followed by proton beam ablation targeting a portion of the scar. Swine were survived 12-20 weeks, during which DCE-MR were obtained every 4 weeks. The infarct scar was segmented at baseline and deformed across the time points. Proton beam dose maps were also deformed to assess the relationship between infarct scar and delivered dose.
Results: Baseline infarct scar had a mean (std) volume of 6348 (2372) mm3. After selecting a portion of the scar and compensating for motion and uncertainty, the treatment volume was 8447 (2205) mm3. Results of tracking the infarct scar contour and proton beam dose maps are shown in a sample swine across 6 time points (Figure). Delayed enhancement appears within the deformed infarct scar or the deformed 20-30 Gy dose regions, indicating that the deformed scar contour accurately tracks the in vivo infarct scar and new fibrosis is not created in regions outside the target dose region.
Conclusion: Infarct scar can be accurately targeted using proton beam therapy without creation of new fibrotic regions as measured by in vivo MR imaging.
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