PMID- 34679247 OWN - NLM STAT- MEDLINE DCOM- 20211214 LR - 20240404 IS - 1526-9914 (Electronic) IS - 1526-9914 (Linking) VI - 22 IP - 12 DP - 2021 Dec TI - SBRT of ventricular tachycardia using 4pi optimized trajectories. PG - 72-86 LID - 10.1002/acm2.13454 [doi] AB - PURPOSE: To investigate the possible advantages of using 4pi-optimized arc trajectories in stereotactic body radiation therapy of ventricular tachycardia (VT-SBRT) to minimize exposure of healthy tissues. METHODS AND MATERIALS: Thorax computed tomography (CT) data for 15 patients were used for contouring organs at risk (OARs) and defining realistic planning target volumes (PTVs). A conventional trajectory plan, defined as two full coplanar arcs was compared to an optimized-trajectory plan provided by a 4pi algorithm that penalizes geometric overlap of PTV and OARs in the beam's-eye-view. A single fraction of 25 Gy was prescribed to the PTV in both plans and a comparison of dose sparing to OARs was performed based on comparisons of maximum, mean, and median dose. RESULTS: A significant average reduction in maximum dose was observed for esophagus (18%), spinal cord (26%), and trachea (22%) when using 4pi-optimized trajectories. Mean doses were also found to decrease for esophagus (19%), spinal cord (33%), skin (18%), liver (59%), lungs (19%), trachea (43%), aorta (11%), inferior vena cava (25%), superior vena cava (33%), and pulmonary trunk (26%). A median dose reduction was observed for esophagus (40%), spinal cord (48%), skin (36%), liver (72%), lungs (41%), stomach (45%), trachea (53%), aorta (45%), superior vena cava (38%), pulmonary veins (32%), and pulmonary trunk (39%). No significant difference was observed for maximum dose (p = 0.650) and homogeneity index (p = 0.156) for the PTV. Average values of conformity number were 0.86 +/- 0.05 and 0.77 +/- 0.09 for the conventional and 4pi optimized plans respectively. CONCLUSIONS: 4pi optimized trajectories provided significant reduction to mean and median doses to cardiac structures close to the target but did not decrease maximum dose. Significant improvement in maximum, mean and median doses for noncardiac OARs makes 4pi optimized trajectories a suitable delivery technique for treating VT. CI - (c) 2021 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, LLC on behalf of The American Association of Physicists in Medicine. FAU - Q M Reis, Cristiano AU - Q M Reis C AUID- ORCID: 0000-0002-4793-3778 AD - Department of Radiation Oncology, Dalhousie University, Halifax, Nova Scotia, Canada. AD - Department of Medical Physics, Scotia Health Authority, Nova, Halifax, Nova Scotia, Canada. AD - Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada. AD - Department of Radiation Oncology, London Regional Cancer Program, London Health Sciences Centre, 790 Commissioners Road East, London, ON, N6A 4L6, Canada. FAU - Little, Brian AU - Little B AD - Department of Radiation Oncology, Dalhousie University, Halifax, Nova Scotia, Canada. AD - Department of Medical Physics, Scotia Health Authority, Nova, Halifax, Nova Scotia, Canada. AD - Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada. AD - Adaptiiv Medical Technologies Inc, 405-1344 Summer Street Halifax, NS B3H 0A8, Canada. FAU - Lee MacDonald, Robert AU - Lee MacDonald R AD - Department of Radiation Oncology, Dalhousie University, Halifax, Nova Scotia, Canada. AD - Department of Medical Physics, Scotia Health Authority, Nova, Halifax, Nova Scotia, Canada. AD - Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada. FAU - Syme, Alasdair AU - Syme A AUID- ORCID: 0000-0003-3173-0949 AD - Department of Radiation Oncology, Dalhousie University, Halifax, Nova Scotia, Canada. AD - Department of Medical Physics, Scotia Health Authority, Nova, Halifax, Nova Scotia, Canada. AD - Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada. AD - Beatrice Hunter Cancer Research Institute, Halifax, Nova Scotia, Canada. FAU - Thomas, Christopher G AU - Thomas CG AD - Department of Radiation Oncology, Dalhousie University, Halifax, Nova Scotia, Canada. AD - Department of Medical Physics, Scotia Health Authority, Nova, Halifax, Nova Scotia, Canada. AD - Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada. AD - Beatrice Hunter Cancer Research Institute, Halifax, Nova Scotia, Canada. AD - Department of Radiology, Dalhousie University, Halifax, Nova Scotia, Canada. FAU - Robar, James L AU - Robar JL AD - Department of Radiation Oncology, Dalhousie University, Halifax, Nova Scotia, Canada. AD - Department of Medical Physics, Scotia Health Authority, Nova, Halifax, Nova Scotia, Canada. AD - Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada. LA - eng PT - Journal Article DEP - 20211022 PL - United States TA - J Appl Clin Med Phys JT - Journal of applied clinical medical physics JID - 101089176 SB - IM MH - Humans MH - Organs at Risk MH - *Radiosurgery MH - Radiotherapy Dosage MH - Radiotherapy Planning, Computer-Assisted MH - *Radiotherapy, Intensity-Modulated MH - *Tachycardia, Ventricular MH - Vena Cava, Superior PMC - PMC8664144 OTO - NOTNLM OT - 4pi trajectories OT - SBRT OT - radiosurgery OT - ventricular tachycardia COIS- R. Lee MacDonald reports grants from Brainlab AG, outside the submitted work; In addition, he has a patent US patent: US 10, 441, 813 B2; with royalties paid to Brainlab AG. Alasdair Syme reports grants from Atlantic Canada Oppurtunities Agency - Atlantic Innovation Fund, outside the submitted work. Christopher G. Thomas reports grants from Atlantic Canada Oppurtunities Agency - Atlantic Innovation Fund, grants from Brainlab AG, outside the submitted work; In addition, he has a patent "Method and System for Cancer Treatment with Radiation" with royalties paid to Brainlab AG. James L. Robar reports grants from Varian Medical Systems, other from Adaptiiv Medical Technologies, outside the submitted work. The other authors declare no conflict of interest. EDAT- 2021/10/23 06:00 MHDA- 2021/12/15 06:00 PMCR- 2021/10/22 CRDT- 2021/10/22 21:11 PHST- 2021/09/05 00:00 [revised] PHST- 2021/04/26 00:00 [received] PHST- 2021/10/03 00:00 [accepted] PHST- 2021/10/23 06:00 [pubmed] PHST- 2021/12/15 06:00 [medline] PHST- 2021/10/22 21:11 [entrez] PHST- 2021/10/22 00:00 [pmc-release] AID - ACM213454 [pii] AID - 10.1002/acm2.13454 [doi] PST - ppublish SO - J Appl Clin Med Phys. 2021 Dec;22(12):72-86. doi: 10.1002/acm2.13454. Epub 2021 Oct 22.