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SU-E-T-645: Radiobiologic Evaluation of Lung Toxicity in Treatment Plan Quality Comparisons for Hypofractionated Stereotactic Body Radiotherapy Using Relative Damaged Volume Modeling
- Source :
- Medical Physics. 38:3638-3638
- Publication Year :
- 2011
- Publisher :
- Wiley, 2011.
-
Abstract
- Purpose: We proposed using relative damaged volume (RDV) models to evaluate lung toxicity in treatment plans for hypofractionated stereotactic body radiotherapy(SBRT) of lungcancer, and performed plan comparisons using RDV with helical tomotherapy (HT), 3‐dimensional conformal radiotherapy (3D‐CRT), and volumetric modulated arc therapy (VMAT) treatment plans for lungcancerSBRTtreatments. Methods: Ten lungcancer patients treated with SBRT were retrospectively selected. Four treatment plans were generated for each patient to deliver 50 Gy in five fractions to the planning target volume (PTV). HT plans were generated using 1.0 cm or 2.5 cm jaw size. 3D‐CRT plans with 6 MV (3D‐6MV) and 10 MV (3D‐10MV) photon energy were generated using 12 non‐coplanar beams. VMAT plans were generated using one single arc field. The dose volume histogram (DVH) for the normal lung was first normalized to the biologic equivalent DVH. The lung RDV was then calculated with both the S‐shaped and logistic function models, respectively. The sensitivity of the RDV to the model parameter of 50% local dose effect level (D_L50) was evaluated. Results: The logistic function model gave higher RDV than the S‐shaped model. With D_L50 increasing from 20 Gy to 30 Gy, the average RDV decreased by 30.1% and 29.4% using the S‐shaped and logistic function models, respectively. The VMAT plans achieved similar average RDV with non‐coplanar 3D‐CRT plans. The HT plans showed the lowest average RDV compared to the other treatment modalities. The average maximum dose to the PTV was 61.3+\−2.2 Gy, 67.0+\−3.7 Gy, 67.1+\−4.4 Gy, and 61.8+\−2.6 Gy in the HT, 3D‐6MV, 3D‐10MV, and VMAT plans, respectively. Conclusions: The lung RDV allowed for efficient lung toxicity evaluation. Based on RDV evaluation, HT treatment plans could provide lower lung toxicity compared to non‐coplanar 3D‐CRT and single‐arc VMAT plans for SBRTtreatment of lungcancer.
Details
- ISSN :
- 00942405
- Volume :
- 38
- Database :
- OpenAIRE
- Journal :
- Medical Physics
- Accession number :
- edsair.doi...........5305ca441b611dfcd69430530f9e2e76
- Full Text :
- https://doi.org/10.1118/1.3612608