SU-E-T-410: Evaluation of Treatment Modalities for Stereotactic Lung Radiation Therapy: A Phantom Study
Abstract
Purpose: To evaluate and verify the accuracy of alternative treatment modalities for stereotactic lung therapy with end-to-end testing. We compared three dimensional conformal therapy (3DCRT), dynamic conformal arc therapy (DCAT), intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) treatment using 6 MV, 6 MV flattening filter free (FFF) and 10 MV FFF photons. Methods: A QUASAR respiratory motion phantom was utilized with custom ion chamber and gafchromatic EBT2 film inserts. The phantom contained a low density lung medium with a cylindrical polystyrene tumor (35 cc). Pseudo representative structures for various organs at risk (OAR) were created. All treatment plans were created using Eclipse ver. 11 using the same image and structure sets, and delivered via Varian TrueBeam STx linear accelerator equipped with high definition MLC. Evaluation of plan quality followed ROTG 0813 criterion for conformity index (CI100%), high dose spillage, D2cm, and R50%. Results: All treatment plans met the OAR dose constraints per protocol and could be delivered without any beam hold offs or other interlocks and hence were deemed clinically safe. For equivalent beam energies, target conformity was improved for all modalities when switching to FFF mode. Treatment efficiency increased for VMAT FFF by a factormore »
- Authors:
-
- Roswell Park Cancer Institute, Buffalo, NY (United States)
- Publication Date:
- OSTI Identifier:
- 22548456
- Resource Type:
- Journal Article
- Journal Name:
- Medical Physics
- Additional Journal Information:
- Journal Volume: 42; Journal Issue: 6; Other Information: (c) 2015 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:
- 60 APPLIED LIFE SCIENCES; 61 RADIATION PROTECTION AND DOSIMETRY; 43 PARTICLE ACCELERATORS; ACCURACY; BEAMS; DOSE RATES; IONIZATION CHAMBERS; LIMITING VALUES; LINEAR ACCELERATORS; LUNGS; NEOPLASMS; PHANTOMS; POLYSTYRENE; QUASARS; RADIATION DOSES; RADIOTHERAPY; TESTING
Citation Formats
Mohatt, D, and Malhotra, H. SU-E-T-410: Evaluation of Treatment Modalities for Stereotactic Lung Radiation Therapy: A Phantom Study. United States: N. p., 2015.
Web. doi:10.1118/1.4924771.
Mohatt, D, & Malhotra, H. SU-E-T-410: Evaluation of Treatment Modalities for Stereotactic Lung Radiation Therapy: A Phantom Study. United States. https://doi.org/10.1118/1.4924771
Mohatt, D, and Malhotra, H. 2015.
"SU-E-T-410: Evaluation of Treatment Modalities for Stereotactic Lung Radiation Therapy: A Phantom Study". United States. https://doi.org/10.1118/1.4924771.
@article{osti_22548456,
title = {SU-E-T-410: Evaluation of Treatment Modalities for Stereotactic Lung Radiation Therapy: A Phantom Study},
author = {Mohatt, D and Malhotra, H},
abstractNote = {Purpose: To evaluate and verify the accuracy of alternative treatment modalities for stereotactic lung therapy with end-to-end testing. We compared three dimensional conformal therapy (3DCRT), dynamic conformal arc therapy (DCAT), intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) treatment using 6 MV, 6 MV flattening filter free (FFF) and 10 MV FFF photons. Methods: A QUASAR respiratory motion phantom was utilized with custom ion chamber and gafchromatic EBT2 film inserts. The phantom contained a low density lung medium with a cylindrical polystyrene tumor (35 cc). Pseudo representative structures for various organs at risk (OAR) were created. All treatment plans were created using Eclipse ver. 11 using the same image and structure sets, and delivered via Varian TrueBeam STx linear accelerator equipped with high definition MLC. Evaluation of plan quality followed ROTG 0813 criterion for conformity index (CI100%), high dose spillage, D2cm, and R50%. Results: All treatment plans met the OAR dose constraints per protocol and could be delivered without any beam hold offs or other interlocks and hence were deemed clinically safe. For equivalent beam energies, target conformity was improved for all modalities when switching to FFF mode. Treatment efficiency increased for VMAT FFF by a factor of 3–4 over IMRT, and up to factor of 7 when compared to 3DCRT. Pass rates were > 97% for all treatment using gamma criteria of 3%, 3mm. Absolute dose at iso-center was verified with ion chamber, and found to be within 2% of the treatment planning system. Conclusion: The higher dose rate associated with FFF not only reduces delivery times, but in most cases enhances plan quality. The one modality with succeeding best results for all RTOG criterions was VMAT 6 MV FFF. This end-to-end testing provides necessary confidence in the entire dose delivery chain for lung SBRT patients.},
doi = {10.1118/1.4924771},
url = {https://www.osti.gov/biblio/22548456},
journal = {Medical Physics},
issn = {0094-2405},
number = 6,
volume = 42,
place = {United States},
year = {Mon Jun 15 00:00:00 EDT 2015},
month = {Mon Jun 15 00:00:00 EDT 2015}
}