(Sunday, 7/12/2020) [Eastern Time (GMT-4)]
Room: AAPM ePoster Library
Purpose: phase I/II trial has been initiated at Washington University for delivering ablative dose to patients with recurrent VT. The initial published results have been promising. Our institution treated our first VT SBRT patient, and we compiled our experience from simulation to treatment.
Methods: patient is a 58-year-old with non-ischemic cardiomyopathy s/p ICD and LVAD placement. He has a history of recurrent symptomatic VTs with multiple failed ablations. Cardiology determined that the patient did'n have further ablative options, so the patient was referred for cardiac SBRT, which was prescribed to 25Gy in single fraction. Simulation was performed with compression belt for motion management, and both free-breathing and 4DCT were acquired. Electrophysiological voltage map was used to assist in target delineation. ITV was contoured based on the largest motion on 4DCT and a 5mm-margin was used for PTV. Treatment planning was done in Eclipse (V15.6, Varian) with one coplanar and two non-coplanar arcs. Average scan generated from 4DCT was the reference CT for patient alignment. ICD and LVAD dose were constrained and in-vivo dosimetry was performed for ICD.
Results: ITV, and PTV volumes were 14.95cc, 27.59cc and 73.22cc, respectively. All OAR dose constraints were compliant with the guideline from Washington University. The plan quality measures were as follows – conformity index(CI):0.974, gradient index(GI):2.7, homogeneity index(HI):1.2, gradient measures:2.1cm, mean heart–PTV dose:4.56Gy, and MU ratio:4.53. These parameters showed our plan quality is comparable with the cases investigated in their published results. ICD and LVAD maximum dose estimated in Eclipse were 0.25Gy and 5.26Gy, respectively and the in-vivo ICD dose was measured 0.17cGy.
Conclusion: for VT is a relatively new procedure and has great potential in treating cardiac patients with limited treatment options. Future work will be focused on fusion of simulation scan with the cardiac voltage map and motion management for treatment.
Keywords
Not Applicable / None Entered.
Taxonomy
Not Applicable / None Entered.
Contact Email
