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Dynamic Lung Tumor Tracking for Stereotactic Ablative Body Radiation Therapy
Published on: June 7, 2015
A volumetric-modulated arc therapy using sub-conformal dynamic arc with a monotonic dynamic multileaf collimator
Piotr Zygmanski1, Wolfgang Högele, Robert Cormack
1Department of Radiation Oncology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA. pzygmanski@LROC.havard.edu
Physics in Medicine and Biology
|October 23, 2008
Summary
We introduce sub-conformal dynamic modulated arc (sub-CD-MARC) therapy, a novel radiation delivery method using dynamic multileaf collimator modulation. This technique improves dose conformity while protecting organs at risk.
Area of Science:
- Radiation Oncology
- Medical Physics
- Radiotherapy Techniques
Background:
- Conventional arc therapy requires multiple arcs for uniform dose distribution in 3D.
- Sub-conformal dynamic arc (sub-CD-ARC) therapy uses limited aperture conformity to avoid organs at risk (OARs).
- Dose deposition in sub-CD-ARC varies with target geometry and rotation, necessitating advanced modulation.
Purpose of the Study:
- To present a new dose delivery scheme, sub-conformal dynamic modulated arc (sub-CD-MARC) therapy.
- To compensate for dose variations in 3D using dynamic multileaf collimator (dMLC) modulation.
- To simplify inverse planning by reducing it to a linear equation problem.
Main Methods:
- Utilizing sub-conformal delivery where the MLC aperture conforms to a portion of the target, sparing OARs.
- Implementing quasi-periodic monotonic dMLC modulation to correct for 3D dose deposition variations.
- Analyzing dosimetric properties of sub-CD-ARC and sub-CD-MARC for rotationally symmetric targets and OARs.
- Performing numerical inverse planning optimization for sub-CD-MARC.
Main Results:
- The sub-CD-MARC scheme effectively compensates for dose variations in 3D.
- MLC leaf motion requires only a few control points, simplifying treatment delivery.
- Inverse planning is reduced to a linear equation problem with physically meaningful parameters.
- Dosimetric properties were analyzed for a specific target and OAR geometry.
Conclusions:
- Sub-CD-MARC therapy offers a simplified yet effective approach to radiation dose delivery.
- The technique allows for precise dose conformity and OAR sparing in a single rotation.
- This method holds promise for improving radiotherapy planning and delivery efficiency.
