Use of dMLC for implementation of dynamic respiratory-gated radiation therapy

Pepin, Eric W.; Wu, Huanmei; Shirato, Hiroki

doi:10.1118/1.4820534

Title: Use of dMLC for implementation of dynamic respiratory-gated radiation therapy

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Abstract

Purpose: To simulate and evaluate the use of dynamic multileaf collimators (dMLC) in respiratory gating to compensate for baseline drift.Methods: Tumor motion tracking data from 30 lung tumors over 322 treatment fractions was analyzed with the finite state model. A dynamic respiratory gating window was established in real-time by determining the average positions during the previous two end-of-expiration breathing phases and centering the dMLC aperture on a weighted average of these positions. A simulated dMLC with physical motion constraints was used in dynamic gating treatment simulations. Fluence maps were created to provide a statistical description of radiation delivery for each fraction. Duty cycle was also calculated for each fraction.Results: The average duty cycle was 2.3% greater under dynamic gating conditions. Dynamic gating also showed higher fluences and less tumor obstruction. Additionally, dynamic gating required fewer beam toggles and each delivery period was longer on average than with static gating.Conclusions: The use of dynamic gating showed better performance than static gating and the physical constraints of a dMLC were shown to not be an impediment to dynamic gating.

Authors:

Pepin, Eric W.; Wu, Huanmei ^[1]; Shirato, Hiroki ^[2]

Purdue School of Engineering Technology, IUPUI, Indianapolis, Indiana 46202 (United States)
Hokkaido University School of Medicine, Sapporo 060-8638 (Japan)

Publication Date:: Tue Oct 15 00:00:00 EDT 2013

OSTI Identifier:: 22220407

Resource Type:: Journal Article

Journal Name:: Medical Physics

Additional Journal Information:: Journal Volume: 40; Journal Issue: 10; Other Information: (c) 2013 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:: 62 RADIOLOGY AND NUCLEAR MEDICINE; 61 RADIATION PROTECTION AND DOSIMETRY; APERTURES; COLLIMATORS; LIMITING VALUES; LUNGS; NEOPLASMS; RADIOTHERAPY; RESPIRATION; SIMULATION

Citation Formats


                    Pepin, Eric W., Wu, Huanmei, and Shirato, Hiroki. Use of dMLC for implementation of dynamic respiratory-gated radiation therapy.  United States: N. p., 2013. 
        Web.  doi:10.1118/1.4820534.

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                    Pepin, Eric W., Wu, Huanmei, & Shirato, Hiroki. Use of dMLC for implementation of dynamic respiratory-gated radiation therapy.  United States.  https://doi.org/10.1118/1.4820534

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                    Pepin, Eric W., Wu, Huanmei, and Shirato, Hiroki. 2013.  
        "Use of dMLC for implementation of dynamic respiratory-gated radiation therapy".  United States.  https://doi.org/10.1118/1.4820534.

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@article{osti_22220407,

  title        = {Use of dMLC for implementation of dynamic respiratory-gated radiation therapy},

  author       = {Pepin, Eric W. and Wu, Huanmei and Shirato, Hiroki},

  abstractNote = {Purpose: To simulate and evaluate the use of dynamic multileaf collimators (dMLC) in respiratory gating to compensate for baseline drift.Methods: Tumor motion tracking data from 30 lung tumors over 322 treatment fractions was analyzed with the finite state model. A dynamic respiratory gating window was established in real-time by determining the average positions during the previous two end-of-expiration breathing phases and centering the dMLC aperture on a weighted average of these positions. A simulated dMLC with physical motion constraints was used in dynamic gating treatment simulations. Fluence maps were created to provide a statistical description of radiation delivery for each fraction. Duty cycle was also calculated for each fraction.Results: The average duty cycle was 2.3% greater under dynamic gating conditions. Dynamic gating also showed higher fluences and less tumor obstruction. Additionally, dynamic gating required fewer beam toggles and each delivery period was longer on average than with static gating.Conclusions: The use of dynamic gating showed better performance than static gating and the physical constraints of a dMLC were shown to not be an impediment to dynamic gating.},

  doi          = {10.1118/1.4820534},

  url          = {https://www.osti.gov/biblio/22220407},
  journal      = {Medical Physics},

  issn         = {0094-2405},

  number       = 10,

  volume       = 40,

  place        = {United States},

  year         = {Tue Oct 15 00:00:00 EDT 2013},

  month        = {Tue Oct 15 00:00:00 EDT 2013}

}

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