Dose-Escalation Study for Cardiac Radiosurgery in a Porcine Model
- Department of Radiation Oncology, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany)
- Medical Department II, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany)
- Institute of Pathology, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany)
- Department of Radiology and Nuclear Medicine, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany)
- Department of Anaesthesiology and Intensive Care Medicine, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany)
- Institute for Robotics and Cognitive Systems, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany)
- Institute of Medical Biometry and Statistics, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany)
Purpose: To perform a proof-of-principle dose-escalation study to radiosurgically induce scarring in cardiac muscle tissue to block veno-atrial electrical connections at the pulmonary vein antrum, similar to catheter ablation. Methods and Materials: Nine mini-pigs underwent pretreatment magnetic resonance imaging (MRI) evaluation of heart function and electrophysiology assessment by catheter measurements in the right superior pulmonary vein (RSPV). Immediately after examination, radiosurgery with randomized single-fraction doses of 0 and 17.5-35 Gy in 2.5-Gy steps were delivered to the RSPV antrum (target volume 5-8 cm{sup 3}). MRI and electrophysiology were repeated 6 months after therapy, followed by histopathologic examination. Results: Transmural scarring of cardiac muscle tissue was noted with doses ≥32.5 Gy. However, complete circumferential scarring of the RSPV was not achieved. Logistic regressions showed that extent and intensity of fibrosis significantly increased with dose. The 50% effective dose for intense fibrosis was 31.3 Gy (odds ratio 2.47/Gy, P<.01). Heart function was not affected, as verified by MRI and electrocardiogram evaluation. Adjacent critical structures were not damaged, as verified by pathology, demonstrating the short-term safety of small-volume cardiac radiosurgery with doses up to 35 Gy. Conclusions: Radiosurgery with doses >32.5 Gy in the healthy pig heart can induce circumscribed scars at the RSPV antrum noninvasively, mimicking the effect of catheter ablation. In our study we established a significant dose-response relationship for cardiac radiosurgery. The long-term effects and toxicity of such high radiation doses need further investigation in the pursuit of cardiac radiosurgery for noninvasive treatment of atrial fibrillation.
- OSTI ID:
- 22420345
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 89, Issue 3; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
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