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Title: A Three-Isocenter Jagged-Junction IMRT Approach for Craniospinal Irradiation Without Beam Edge Matching for Field Junctions

Abstract

Purpose: Traditionally craniospinal irradiation treats the central nervous system using two or three adjacent field sets. We propose a technique using a three-isocenter intensity-modulated radiotherapy (IMRT) plan (jagged-junction IMRT) which overcomes problems associated with field junctions and beam edge matching and improves planning and treatment setup efficiencies with homogenous target dose distribution. Methods and Materials: Treatments for 3 patients with a prescription of 36 Gy in 20 fractions were retrospectively planned with jagged-junction IMRT and compared to conventional treatment plans. Planning target volume (PTV) included the whole brain and spinal canal to the S3 vertebral level. The plan used three field sets, each with a unique isocenter. One field set with seven fields treated the cranium. Two field sets treated the spine, each set using three fields. Fields from adjacent sets were overlapped, and the optimization process smoothly integrated the dose inside the overlapped junction. Results: For jagged-junction IMRT plans vs. conventional technique, the average homogeneity index equaled 0.08 {+-} 0.01 vs. 0.12 {+-} 0.02, respectively, and conformity number equaled 0.79 {+-} 0.01 vs. 0.47 {+-} 0.12, respectively. The 95% isodose surface covered (99.5 {+-} 0.3)% of the PTV vs. (98.1 {+-} 2.0)%, respectively. Both jagged-junction IMRT plans and themore » conventional plans had good sparing of organs at risk. Conclusions: Jagged-junction IMRT planning provided good dose homogeneity and conformity to the target while maintaining a low dose to organs at risk. Results from jagged-junction IMRT plans were better than or equivalent to those from the conventional technique. Jagged-junction IMRT optimization smoothly distributed dose in the junction between field sets. Because there was no beam matching, this treatment technique is less likely to produce hot or cold spots at the junction, in contrast to conventional techniques. The planning process is also simplified as only one IMRT plan is required for the entire target volume.« less

Authors:
 [1]; ; ;  [1]; ; ;  [2]; ;  [3]; ;  [2]
  1. Department of Medical Physics, Fraser Valley Centre, BC Cancer Agency, Surrey, British Columbia (Canada)
  2. Department of Radiation Oncology, Fraser Valley Centre, BC Cancer Agency, Surrey, British Columbia (Canada)
  3. Department of Radiation Oncology, Vancouver Centre, BC Cancer Agency, Vancouver, British Columbia (Canada)
Publication Date:
OSTI Identifier:
22149563
Resource Type:
Journal Article
Journal Name:
International Journal of Radiation Oncology, Biology and Physics
Additional Journal Information:
Journal Volume: 84; Journal Issue: 3; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0360-3016
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; EFFICIENCY; HEALTH HAZARDS; IRRADIATION; OPTIMIZATION; PATIENTS; PLANNING; RADIATION DOSE DISTRIBUTIONS; RADIATION DOSES; RADIOTHERAPY; VERTEBRAE

Citation Formats

Cao, Fred, E-mail: fcao@bccancer.bc.ca, Ramaseshan, Ramani, Corns, Robert, Harrop, Sheryl, Nuraney, Nimet, Steiner, Peter, Aldridge, Stephanie, Liu, Mitchell, Carolan, Hannah, Agranovich, Alex, and Karvat, Anand. A Three-Isocenter Jagged-Junction IMRT Approach for Craniospinal Irradiation Without Beam Edge Matching for Field Junctions. United States: N. p., 2012. Web. doi:10.1016/J.IJROBP.2012.01.010.
Cao, Fred, E-mail: fcao@bccancer.bc.ca, Ramaseshan, Ramani, Corns, Robert, Harrop, Sheryl, Nuraney, Nimet, Steiner, Peter, Aldridge, Stephanie, Liu, Mitchell, Carolan, Hannah, Agranovich, Alex, & Karvat, Anand. A Three-Isocenter Jagged-Junction IMRT Approach for Craniospinal Irradiation Without Beam Edge Matching for Field Junctions. United States. doi:10.1016/J.IJROBP.2012.01.010.
Cao, Fred, E-mail: fcao@bccancer.bc.ca, Ramaseshan, Ramani, Corns, Robert, Harrop, Sheryl, Nuraney, Nimet, Steiner, Peter, Aldridge, Stephanie, Liu, Mitchell, Carolan, Hannah, Agranovich, Alex, and Karvat, Anand. Thu . "A Three-Isocenter Jagged-Junction IMRT Approach for Craniospinal Irradiation Without Beam Edge Matching for Field Junctions". United States. doi:10.1016/J.IJROBP.2012.01.010.
@article{osti_22149563,
title = {A Three-Isocenter Jagged-Junction IMRT Approach for Craniospinal Irradiation Without Beam Edge Matching for Field Junctions},
author = {Cao, Fred, E-mail: fcao@bccancer.bc.ca and Ramaseshan, Ramani and Corns, Robert and Harrop, Sheryl and Nuraney, Nimet and Steiner, Peter and Aldridge, Stephanie and Liu, Mitchell and Carolan, Hannah and Agranovich, Alex and Karvat, Anand},
abstractNote = {Purpose: Traditionally craniospinal irradiation treats the central nervous system using two or three adjacent field sets. We propose a technique using a three-isocenter intensity-modulated radiotherapy (IMRT) plan (jagged-junction IMRT) which overcomes problems associated with field junctions and beam edge matching and improves planning and treatment setup efficiencies with homogenous target dose distribution. Methods and Materials: Treatments for 3 patients with a prescription of 36 Gy in 20 fractions were retrospectively planned with jagged-junction IMRT and compared to conventional treatment plans. Planning target volume (PTV) included the whole brain and spinal canal to the S3 vertebral level. The plan used three field sets, each with a unique isocenter. One field set with seven fields treated the cranium. Two field sets treated the spine, each set using three fields. Fields from adjacent sets were overlapped, and the optimization process smoothly integrated the dose inside the overlapped junction. Results: For jagged-junction IMRT plans vs. conventional technique, the average homogeneity index equaled 0.08 {+-} 0.01 vs. 0.12 {+-} 0.02, respectively, and conformity number equaled 0.79 {+-} 0.01 vs. 0.47 {+-} 0.12, respectively. The 95% isodose surface covered (99.5 {+-} 0.3)% of the PTV vs. (98.1 {+-} 2.0)%, respectively. Both jagged-junction IMRT plans and the conventional plans had good sparing of organs at risk. Conclusions: Jagged-junction IMRT planning provided good dose homogeneity and conformity to the target while maintaining a low dose to organs at risk. Results from jagged-junction IMRT plans were better than or equivalent to those from the conventional technique. Jagged-junction IMRT optimization smoothly distributed dose in the junction between field sets. Because there was no beam matching, this treatment technique is less likely to produce hot or cold spots at the junction, in contrast to conventional techniques. The planning process is also simplified as only one IMRT plan is required for the entire target volume.},
doi = {10.1016/J.IJROBP.2012.01.010},
journal = {International Journal of Radiation Oncology, Biology and Physics},
issn = {0360-3016},
number = 3,
volume = 84,
place = {United States},
year = {2012},
month = {11}
}