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Exploring Appropriate Offset Values for Pencil Beam and Monte Carlo Dose Optimization in Lung Stereotactic Body Radiotherapy Encompassing the Effects of Respiration and Tumor Location

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Date Issued:
2014
Abstract/Description:
Purpose: To explore offset values in dose optimization with pencil beam (PB) algorithm to minimize dosimetric differences with plans calculated with Monte Carlo (MC) for lung cancer treatment with Stereotactic Body Radiotherapy (SBRT). Methods: 20 cases of Non-Small Cell Lung Cancer, treated with gated full motion range SBRT were selected. According to the proximity of the Gross Tumor Volume (GTV) to the chest wall, two groups are defined. Treatment plans were created on 4D average intensity projection (AIP) CT set with Brainlab iPlanDose® 4.1.2 planning system. The D97 of PTV was normalized to 50Gy using the fast PB and compared with MC. The optimized plan was then recomputed over each 4D respiratory phase, and compared with MC. Results: The mean difference in the PB and MC D97 of the ITV was 10.5% (±0.8%) of the prescription dose (50Gy). PB algorithm showed 2.3-2.4% less overestimation to the D97 of the ITV, when comparing to MC, in the maximum exhalation phase than in the maximal inhalation phase. Significantly smaller dose difference between PB and MC is also shown in plans for peripheral lesions (7.7 ± 0.7%) versus for central lesions (12.7±0.8%) (p< 0.01). Conclusions: The dosimetric differences between PB and MC can be reasonably predicted depending on the location of lesion in the lung, and may be used as offset value in dose optimization with PB. Caution is suggested when using the maximum inhalation phase for treatment planning.
Title: Exploring Appropriate Offset Values for Pencil Beam and Monte Carlo Dose Optimization in Lung Stereotactic Body Radiotherapy Encompassing the Effects of Respiration and Tumor Location.
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Name(s): Evans, Grant
Shang, Charles
Leventouri, Theodora
Graduate College
Type of Resource: text
Genre: Abstract
Date Created: 2014
Date Issued: 2014
Publisher: Florida Atlantic University
Place of Publication: Boca Raton, Fla.
Physical Form: application/pdf
Extent: 1 p.
Language(s): English
Abstract/Description: Purpose: To explore offset values in dose optimization with pencil beam (PB) algorithm to minimize dosimetric differences with plans calculated with Monte Carlo (MC) for lung cancer treatment with Stereotactic Body Radiotherapy (SBRT). Methods: 20 cases of Non-Small Cell Lung Cancer, treated with gated full motion range SBRT were selected. According to the proximity of the Gross Tumor Volume (GTV) to the chest wall, two groups are defined. Treatment plans were created on 4D average intensity projection (AIP) CT set with Brainlab iPlanDose® 4.1.2 planning system. The D97 of PTV was normalized to 50Gy using the fast PB and compared with MC. The optimized plan was then recomputed over each 4D respiratory phase, and compared with MC. Results: The mean difference in the PB and MC D97 of the ITV was 10.5% (±0.8%) of the prescription dose (50Gy). PB algorithm showed 2.3-2.4% less overestimation to the D97 of the ITV, when comparing to MC, in the maximum exhalation phase than in the maximal inhalation phase. Significantly smaller dose difference between PB and MC is also shown in plans for peripheral lesions (7.7 ± 0.7%) versus for central lesions (12.7±0.8%) (p< 0.01). Conclusions: The dosimetric differences between PB and MC can be reasonably predicted depending on the location of lesion in the lung, and may be used as offset value in dose optimization with PB. Caution is suggested when using the maximum inhalation phase for treatment planning.
Identifier: FA00005813 (IID)
Collection: FAU Student Research Digital Collection
Note(s): The Fifth Annual Graduate Research Day was organized by Florida Atlantic University’s Graduate Student Association. Graduate students from FAU Colleges present abstracts of original research and posters in a competition for monetary prizes, awards, and recognition
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