Real-time dynamic MLC tracking for inversely optimized arc radiotherapy
(2010) In Radiotherapy and Oncology 94(2). p.218-223- Abstract
Background and purpose: Motion compensation with MLC tracking was tested for inversely optimized arc radiotherapy with special attention to the impact of the size of the target displacements and the angle of the leaf trajectory. Materials and methods: An MLC-tracking algorithm was used to adjust the MLC positions according to the target movements using information from an optical real-time positioning management system. Two plans with collimator angles of 45° and 90°, respectively, were delivered and measured using the Delta4® dosimetric device moving in the superior-inferior direction with peak-to-peak displacements of 5, 10, 15, 20 and 25 mm and a cycle time of 6 s. Results: Gamma index evaluation for plan delivery with MLC... (More)
Background and purpose: Motion compensation with MLC tracking was tested for inversely optimized arc radiotherapy with special attention to the impact of the size of the target displacements and the angle of the leaf trajectory. Materials and methods: An MLC-tracking algorithm was used to adjust the MLC positions according to the target movements using information from an optical real-time positioning management system. Two plans with collimator angles of 45° and 90°, respectively, were delivered and measured using the Delta4® dosimetric device moving in the superior-inferior direction with peak-to-peak displacements of 5, 10, 15, 20 and 25 mm and a cycle time of 6 s. Results: Gamma index evaluation for plan delivery with MLC tracking gave a pass rate higher than 98% for criteria 3% and 3 mm for both plans and for all sizes of the target displacement. With no motion compensation, the average pass rate was 75% for plan 1 and 70% for plan 2 for 25 mm peak-to-peak displacement. Conclusion: MLC tracking improves the accuracy of inversely optimized arc delivery for the cases studied. With MLC tracking, the dosimetric accuracy was independent of the magnitude of the peak-to-peak displacement of the target and not significantly affected by the angle between the leaf trajectory and the target movements.
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- author
- Falk, Marianne ; af Rosenschöld, Per Munck LU ; Keall, Paul ; Cattell, Herbert ; Cho, Byung Chul ; Poulsen, Per ; Povzner, Sergey ; Sawant, Amit ; Zimmerman, Jens and Korreman, Stine
- publishing date
- 2010-02
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- MLC, Motion, RapidArc, Tracking
- in
- Radiotherapy and Oncology
- volume
- 94
- issue
- 2
- pages
- 218 - 223
- publisher
- Elsevier
- external identifiers
-
- scopus:77249161672
- pmid:20089322
- ISSN
- 0167-8140
- DOI
- 10.1016/j.radonc.2009.12.022
- language
- English
- LU publication?
- no
- additional info
- Funding Information: The authors wish to acknowledge Dan Ruan (Stanford) for her involvement in the development of MLC tracking implemented in this study. The authors would also like to thank Michelle Svatos (Varian) and Scott Johnson (Varian) for their help in getting this project started, and for their continuous support of it. Thanks to Thomas Carlslund (Rigshospitalet) and Mikael Olsen (Rigshospitalet) for technical support during the installation of the tracking system at Rigshospitalet. Finally thanks to Gitte Persson for technical assistance and to Anna Fredh for reviewing the manuscript and improving the clarity. Research support from Varian Medical Systems and CIRRO – The Lundbeck Foundation Center for Interventional Research in Radiation Oncology and The Danish Council for Strategic Research are gratefully acknowledged. Varian Medical Systems contributed to the study with detailed information regarding use of the RPM system. The manuscript was reviewed by Varian Medical Systems prior to submission as is.
- id
- 0d756975-9267-4d40-b73e-9b7857f53976
- date added to LUP
- 2023-07-19 17:03:59
- date last changed
- 2024-04-05 21:22:42
@article{0d756975-9267-4d40-b73e-9b7857f53976, abstract = {{<p>Background and purpose: Motion compensation with MLC tracking was tested for inversely optimized arc radiotherapy with special attention to the impact of the size of the target displacements and the angle of the leaf trajectory. Materials and methods: An MLC-tracking algorithm was used to adjust the MLC positions according to the target movements using information from an optical real-time positioning management system. Two plans with collimator angles of 45° and 90°, respectively, were delivered and measured using the Delta<sup>4</sup>® dosimetric device moving in the superior-inferior direction with peak-to-peak displacements of 5, 10, 15, 20 and 25 mm and a cycle time of 6 s. Results: Gamma index evaluation for plan delivery with MLC tracking gave a pass rate higher than 98% for criteria 3% and 3 mm for both plans and for all sizes of the target displacement. With no motion compensation, the average pass rate was 75% for plan 1 and 70% for plan 2 for 25 mm peak-to-peak displacement. Conclusion: MLC tracking improves the accuracy of inversely optimized arc delivery for the cases studied. With MLC tracking, the dosimetric accuracy was independent of the magnitude of the peak-to-peak displacement of the target and not significantly affected by the angle between the leaf trajectory and the target movements.</p>}}, author = {{Falk, Marianne and af Rosenschöld, Per Munck and Keall, Paul and Cattell, Herbert and Cho, Byung Chul and Poulsen, Per and Povzner, Sergey and Sawant, Amit and Zimmerman, Jens and Korreman, Stine}}, issn = {{0167-8140}}, keywords = {{MLC; Motion; RapidArc; Tracking}}, language = {{eng}}, number = {{2}}, pages = {{218--223}}, publisher = {{Elsevier}}, series = {{Radiotherapy and Oncology}}, title = {{Real-time dynamic MLC tracking for inversely optimized arc radiotherapy}}, url = {{http://dx.doi.org/10.1016/j.radonc.2009.12.022}}, doi = {{10.1016/j.radonc.2009.12.022}}, volume = {{94}}, year = {{2010}}, }