Journal article
Toward improved target conformity for two spot scanning proton therapy delivery systems using dynamic collimation
Medical physics (Lancaster), Vol.43(3), pp.1421-1427
03/2016
DOI: 10.1118/1.4942375
PMCID: PMC5360164
PMID: 26936726
Abstract
Purpose:
To quantify improvement in target conformity in brain and head and neck tumor treatments resulting from the use of a dynamic collimation system (DCS) with two spot scanning proton therapy delivery systems (universal nozzle, UN, and dedicated nozzle, DN) with median spot sizes of 5.2 and 3.2 mm over a range of energies from 100 to 230 MeV.
Methods:
Uncollimated and collimated plans were calculated with both UN and DN beam models implemented within our in-house treatment planning system for five brain and ten head and neck datasets in patients previously treated with spot scanning proton therapy. The prescription dose and beam angles from the clinical plans were used for both the UN and DN plans. The average reduction of the mean dose to the 10-mm ring surrounding the target between the uncollimated and collimated plans was calculated for the UN and the DN. Target conformity was analyzed using the mean dose to 1-mm thickness rings surrounding the target at increasing distances ranging from 1 to 10 mm.
Results:
The average reductions of the 10-mm ring mean dose for the UN and DN plans were 13.7% (95% CI: 11.6%–15.7%; p < 0.0001) and 11.5% (95% CI: 9.5%–13.5%; p < 0.0001) across all brain cases and 7.1% (95% CI: 4.4%–9.8%; p < 0.001) and 6.3% (95% CI: 3.7%–9.0%; p < 0.001), respectively, across all head and neck cases. The collimated UN plans were either more conformal (all brain cases and 60% of the head and neck cases) than or equivalent (40% of the head and neck cases) to the uncollimated DN plans. The collimated DN plans offered the highest conformity.
Conclusions:
The DCS added either to the UN or DN improved the target conformity. The DCS may be of particular interest for sites with UN systems looking for a more economical solution than upgrading the nozzle to improve the target conformity of their spot scanning proton therapy system.
Details
- Title: Subtitle
- Toward improved target conformity for two spot scanning proton therapy delivery systems using dynamic collimation
- Creators
- Alexandra Moignier - Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242Edgar Gelover - Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242Blake R Smith - Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242Dongxu Wang - Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242Ryan T Flynn - Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242Maura L Kirk - Department of Radiation Oncology, University of Pennsylvania, TRC 2 West, 3400 Civic Center Boulevard, Philadelphia, Pennsylvania 19104Liyong Lin - Department of Radiation Oncology, University of Pennsylvania, TRC 2 West, 3400 Civic Center Boulevard, Philadelphia, Pennsylvania 19104Timothy D Solberg - Department of Radiation Oncology, University of Pennsylvania, TRC 2 West, 3400 Civic Center Boulevard, Philadelphia, Pennsylvania 19104Alexander Lin - Department of Radiation Oncology, University of Pennsylvania, TRC 2 West, 3400 Civic Center Boulevard, Philadelphia, Pennsylvania 19104Daniel E Hyer - Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242
- Resource Type
- Journal article
- Publication Details
- Medical physics (Lancaster), Vol.43(3), pp.1421-1427
- DOI
- 10.1118/1.4942375
- PMID
- 26936726
- PMCID
- PMC5360164
- NLM abbreviation
- Med Phys
- ISSN
- 0094-2405
- eISSN
- 2473-4209
- Number of pages
- 7
- Grant note
- IBA company
- Language
- English
- Date published
- 03/2016
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Radiation Oncology
- Record Identifier
- 9984046935002771
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