Abstract
SU-E-J-260: Dose Recomputation Versus Dose Deformation for Stereotactic Body Radiation Therapy in Lung Tumors: A Dosimetric Study
Medical physics (Lancaster), Vol.41(6), pp.217-217
06/01/2014
DOI: 10.1118/1.4888314
Abstract
Purpose: To evaluate the dosimetric accuracy between recomputed dose and deformed dose for stereotactic body radiation therapy in lung tumors. Methods: Two non-small-cell lung cancer patients were analyzed in this study, both of whom underwent 4D-CT and breath-hold CT imaging. Treatment planning was performed using the breath-hold CT images for the dose calculation and the 4D-CT images for determining internal target volumes. 4D-CT images were reconstructed with ten breathing amplitude for each patient. Maximum tumor motion was 13 mm for patient 1, and 7 mm for patient 2. The delivered dose was calculated using the 4D-CT images and using the same planning parameters as for the breath-hold CT. The deformed dose was computed by deforming the planning dose using the deformable image registration between each binned CT and the breath-hold CT. Results: For patient 1, the difference between recomputed dose and deformed mean lung dose (MLD) ranged from 11.3%(0.5 Gy) to 1.1%(0.06 Gy), mean tumor dose (MTD) ranged from 0.4%(0.19 Gy) to −1.3%(−0.6 Gy), lung V20 ranged from +0.74% to −0.33%. The differences in all three dosimetric criteria remain relatively invariant to target motion. For patient 2, V20 ranged from +0.42% to −2.41%, MLD ranged from −0.2%(−0.05 Gy) to −10.4%(−2.12 Gy), and MTD ranged from −0.5%(−0.31 Gy) to −5.3%(−3.24 Gy). The difference between recomputed dose and deformed dose shows strong correlation with tumor motion in all three dosimetric measurements. Conclusion: The correlation between dosimetric criteria and tumor motion is patient-specific, depending on the tumor locations, motion pattern, and deformable image registration accuracy. Deformed dose can be a good approximation for recalculated dose when tumor motion is small. This research is supported by Siemens Medical Solutions USA, Inc and Iowa Center for Research By Undergraduates.
Details
- Title: Subtitle
- SU-E-J-260: Dose Recomputation Versus Dose Deformation for Stereotactic Body Radiation Therapy in Lung Tumors: A Dosimetric Study
- Creators
- M Ma - University of Iowa Hospitals and ClinicsR Flynn - University of IowaJ Xia - University of IowaJ Bayouth - University of Wisconsin–Madison
- Resource Type
- Abstract
- Publication Details
- Medical physics (Lancaster), Vol.41(6), pp.217-217
- DOI
- 10.1118/1.4888314
- ISSN
- 0094-2405
- eISSN
- 2473-4209
- Language
- English
- Date published
- 06/01/2014
- Academic Unit
- Radiation Oncology
- Record Identifier
- 9984314290002771
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