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Title: Poster — Thur Eve — 65: A dosimetric comparison of isocentric and non-isocentric coplanar SBRT VMAT plans for peripheral lung tumours

Abstract

Volumetric modulated arc therapy (VMAT) delivers lung sterotactic body radiotherapy (SBRT) in shorter treatment time and less monitor units with comparable coverage and organ at risk sparing compared to conventional SBRT treatments. Isocentric VMAT treatment of peripheral lung tumours occasionally requires couch shifts that can inhibit 360° gantry rotation, resulting in additional imaging shifts for each treatment session, and increased potential for involuntary in-fraction motion. Here, we investigate whether non-isocentric VMAT plans can achieve comparable plan quality to isocentric plans for peripheral lung tumours. Three patient plans were selected with targets displaced > 8.5 cm (range: 8.8 – 9.9 cm) laterally from patient midline. For each patient, a plan with isocentre placed within the target volume (isocentric plan) was created and optimized. The same optimization parameters were then used to create a plan with the isocentre at patient midline (non-isocentric plan). Plan quality was evaluated and compared based on planning target volume (PTV) coverage, high dose spillage, dose homogeneity, intermediate dose spillage, dose fall-off gradient, and organ at risk contraints. Non-isocentric plans of equivalent plan quality to isocentric plans were achieved for all patients by optimizing collimator rotations. Field isocentres can be placed at patient midline, as opposed to insidemore » the target volume, with no significant degradation in VMAT plan quality for lateral tumour displacements up to 10 cm. Non-isocentric treatment of peripheral lung tumours could result in decreased overall treatment session time and eliminate the need for imaging shifts prior to VMAT treatment.« less

Authors:
 [1];  [2];  [3];  [1]
  1. Department of Medical Physics, Tom Baker Cancer Centre, Calgary, Alberta (Canada)
  2. Central Alberta Cancer Centre, Red Deer, Alberta (Canada)
  3. Department of Oncology, University of Calgary, Calgary, Alberta (Canada)
Publication Date:
OSTI Identifier:
22407688
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 41; Journal Issue: 8; Other Information: (c) 2014 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-2405
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; COLLIMATORS; COMPARATIVE EVALUATIONS; LUNGS; NEOPLASMS; OPTIMIZATION; PATIENTS; PLANNING; RADIATION DOSES; RADIOTHERAPY; ROTATION

Citation Formats

Conroy, L, Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Liu, HW, Department of Oncology, University of Alberta, Edmonton, Alberta, Lau, H, Smith, WL, Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, and Department of Oncology, University of Calgary, Calgary, Alberta. Poster — Thur Eve — 65: A dosimetric comparison of isocentric and non-isocentric coplanar SBRT VMAT plans for peripheral lung tumours. United States: N. p., 2014. Web. doi:10.1118/1.4894925.
Conroy, L, Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Liu, HW, Department of Oncology, University of Alberta, Edmonton, Alberta, Lau, H, Smith, WL, Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, & Department of Oncology, University of Calgary, Calgary, Alberta. Poster — Thur Eve — 65: A dosimetric comparison of isocentric and non-isocentric coplanar SBRT VMAT plans for peripheral lung tumours. United States. https://doi.org/10.1118/1.4894925
Conroy, L, Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Liu, HW, Department of Oncology, University of Alberta, Edmonton, Alberta, Lau, H, Smith, WL, Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, and Department of Oncology, University of Calgary, Calgary, Alberta. 2014. "Poster — Thur Eve — 65: A dosimetric comparison of isocentric and non-isocentric coplanar SBRT VMAT plans for peripheral lung tumours". United States. https://doi.org/10.1118/1.4894925.
@article{osti_22407688,
title = {Poster — Thur Eve — 65: A dosimetric comparison of isocentric and non-isocentric coplanar SBRT VMAT plans for peripheral lung tumours},
author = {Conroy, L and Department of Physics and Astronomy, University of Calgary, Calgary, Alberta and Liu, HW and Department of Oncology, University of Alberta, Edmonton, Alberta and Lau, H and Smith, WL and Department of Physics and Astronomy, University of Calgary, Calgary, Alberta and Department of Oncology, University of Calgary, Calgary, Alberta},
abstractNote = {Volumetric modulated arc therapy (VMAT) delivers lung sterotactic body radiotherapy (SBRT) in shorter treatment time and less monitor units with comparable coverage and organ at risk sparing compared to conventional SBRT treatments. Isocentric VMAT treatment of peripheral lung tumours occasionally requires couch shifts that can inhibit 360° gantry rotation, resulting in additional imaging shifts for each treatment session, and increased potential for involuntary in-fraction motion. Here, we investigate whether non-isocentric VMAT plans can achieve comparable plan quality to isocentric plans for peripheral lung tumours. Three patient plans were selected with targets displaced > 8.5 cm (range: 8.8 – 9.9 cm) laterally from patient midline. For each patient, a plan with isocentre placed within the target volume (isocentric plan) was created and optimized. The same optimization parameters were then used to create a plan with the isocentre at patient midline (non-isocentric plan). Plan quality was evaluated and compared based on planning target volume (PTV) coverage, high dose spillage, dose homogeneity, intermediate dose spillage, dose fall-off gradient, and organ at risk contraints. Non-isocentric plans of equivalent plan quality to isocentric plans were achieved for all patients by optimizing collimator rotations. Field isocentres can be placed at patient midline, as opposed to inside the target volume, with no significant degradation in VMAT plan quality for lateral tumour displacements up to 10 cm. Non-isocentric treatment of peripheral lung tumours could result in decreased overall treatment session time and eliminate the need for imaging shifts prior to VMAT treatment.},
doi = {10.1118/1.4894925},
url = {https://www.osti.gov/biblio/22407688}, journal = {Medical Physics},
issn = {0094-2405},
number = 8,
volume = 41,
place = {United States},
year = {Fri Aug 15 00:00:00 EDT 2014},
month = {Fri Aug 15 00:00:00 EDT 2014}
}