SU-E-J-213: Imaging and Treatment Isocenter Verification of a Gantry Mounted Proton Therapy System
Abstract
Purpose: The Mevion proton therapy machine is the first to feature a gantry mounted sychro-cyclotron. In addition, the system utilizes a 6D motion couch and kV imaging for precise proton therapy. To quantify coincidence between these systems, isocentricity tests were performed based on kV imaging alignment using radiochromic film. Methods: The 100 ton gantry and 6D robotic couch can rotate 190° around isocenter to provide necessary beam angles for treatment. The kV sources and detector panels are deployed as needed to acquire orthogonal portals. Gantry and couch mechanical isocenter were tested using star-shots and radiochromic-film (RCF). Using kV imaging, the star-shot phantom was aligned to an embedded fiducial and the isocenter was marked on RCF with a pinprick. The couch and gantry stars were performed by irradiating films at every 45° and 30°, respectively. A proton beam with a range and modulation-width of 18 cm was used. A Winston-Lutz test was also performed at the same gantry and couch rotations using a custom jig holding RCF and a tungsten ball placed at isocenter. A 2 cm diameter circular aperture was used for the irradiation. Results: The couch star-shot indicated a minimum tangent circle of 0.6 mm, with a 0.9 mmmore »
- Authors:
-
- Washington University, St. Louis, MO (United States)
- Publication Date:
- OSTI Identifier:
- 22334091
- Resource Type:
- Journal Article
- Journal Name:
- Medical Physics
- Additional Journal Information:
- Journal Volume: 41; Journal Issue: 6; Other Information: (c) 2014 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:
- 07 ISOTOPES AND RADIATION SOURCES; APERTURES; CYCLOTRONS; LINEAR ACCELERATORS; OSMIUM 190; PHANTOMS; PROTON BEAMS; RADIOTHERAPY; TUNGSTEN
Citation Formats
Price, S, Goddu, S, Rankine, L, and Klein, E. SU-E-J-213: Imaging and Treatment Isocenter Verification of a Gantry Mounted Proton Therapy System. United States: N. p., 2014.
Web. doi:10.1118/1.4888266.
Price, S, Goddu, S, Rankine, L, & Klein, E. SU-E-J-213: Imaging and Treatment Isocenter Verification of a Gantry Mounted Proton Therapy System. United States. https://doi.org/10.1118/1.4888266
Price, S, Goddu, S, Rankine, L, and Klein, E. 2014.
"SU-E-J-213: Imaging and Treatment Isocenter Verification of a Gantry Mounted Proton Therapy System". United States. https://doi.org/10.1118/1.4888266.
@article{osti_22334091,
title = {SU-E-J-213: Imaging and Treatment Isocenter Verification of a Gantry Mounted Proton Therapy System},
author = {Price, S and Goddu, S and Rankine, L and Klein, E},
abstractNote = {Purpose: The Mevion proton therapy machine is the first to feature a gantry mounted sychro-cyclotron. In addition, the system utilizes a 6D motion couch and kV imaging for precise proton therapy. To quantify coincidence between these systems, isocentricity tests were performed based on kV imaging alignment using radiochromic film. Methods: The 100 ton gantry and 6D robotic couch can rotate 190° around isocenter to provide necessary beam angles for treatment. The kV sources and detector panels are deployed as needed to acquire orthogonal portals. Gantry and couch mechanical isocenter were tested using star-shots and radiochromic-film (RCF). Using kV imaging, the star-shot phantom was aligned to an embedded fiducial and the isocenter was marked on RCF with a pinprick. The couch and gantry stars were performed by irradiating films at every 45° and 30°, respectively. A proton beam with a range and modulation-width of 18 cm was used. A Winston-Lutz test was also performed at the same gantry and couch rotations using a custom jig holding RCF and a tungsten ball placed at isocenter. A 2 cm diameter circular aperture was used for the irradiation. Results: The couch star-shot indicated a minimum tangent circle of 0.6 mm, with a 0.9 mm offset from the manually marked isocenter. The gantry star-shot showed a 0.6 mm minimum tangent circle with a 0.5 mm offset from the pinprick. The Winston Lutz test performed for gantry rotation showed a maximum deviation from center of 0.5 mm. Conclusion: Based on star-shots and Winston-Lutz tests, the proton gantry and 6D couch isocentricity are within 1 mm. In this study, we have shown that the methods commonly utilized for Linac characterization can be applied to proton therapy. This revolutionary proton therapy system possesses excellent agreement between the mechanical and radiation isocenter, providing highly precise treatment.},
doi = {10.1118/1.4888266},
url = {https://www.osti.gov/biblio/22334091},
journal = {Medical Physics},
issn = {0094-2405},
number = 6,
volume = 41,
place = {United States},
year = {Sun Jun 01 00:00:00 EDT 2014},
month = {Sun Jun 01 00:00:00 EDT 2014}
}