Journal article
Effects of spot size and spot spacing on lateral penumbra reduction when using a dynamic collimation system for spot scanning proton therapy
Physics in medicine & biology, Vol.59(22), pp.N187-N196
10/21/2014
DOI: 10.1088/0031-9155/59/22/N187
PMID: 25330783
Abstract
The purpose of this work was to investigate the reduction in lateral dose penumbra that can be achieved when using a dynamic collimation system (DCS) for spot scanning proton therapy as a function of two beam parameters: spot size and spot spacing. This is an important investigation as both values impact the achievable dose distribution and a wide range of values currently exist depending on delivery hardware. Treatment plans were created both with and without the DCS for in-air spot sizes (σair) of 3, 5, 7, and 9 mm as well as spot spacing intervals of 2, 4, 6 and 8 mm. Compared to un-collimated treatment plans, the plans created with the DCS yielded a reduction in the mean dose to normal tissue surrounding the target of 26.2-40.6% for spot sizes of 3-9 mm, respectively. Increasing the spot spacing resulted in a decrease in the time penalty associated with using the DCS that was approximately proportional to the reduction in the number of rows in the raster delivery pattern. We conclude that dose distributions achievable when using the DCS are comparable to those only attainable with much smaller initial spot sizes, suggesting that the goal of improving high dose conformity may be achieved by either utilizing a DCS or by improving beam line optics.
Details
- Title: Subtitle
- Effects of spot size and spot spacing on lateral penumbra reduction when using a dynamic collimation system for spot scanning proton therapy
- Creators
- Daniel E Hyer - University of Iowa Department of Radiation Oncology, 200 Hawkins Drive, Iowa City, Iowa 52242, USAPatrick M Hill - University of Iowa Department of Radiation Oncology, 200 Hawkins Drive, Iowa City, Iowa 52242, USADongxu Wang - University of Iowa Department of Radiation Oncology, 200 Hawkins Drive, Iowa City, Iowa 52242, USABlake R Smith - University of Iowa Department of Radiation Oncology, 200 Hawkins Drive, Iowa City, Iowa 52242, USARyan T Flynn - University of Iowa Department of Radiation Oncology, 200 Hawkins Drive, Iowa City, Iowa 52242, USA
- Resource Type
- Journal article
- Publication Details
- Physics in medicine & biology, Vol.59(22), pp.N187-N196
- Publisher
- IOP Publishing
- DOI
- 10.1088/0031-9155/59/22/N187
- PMID
- 25330783
- ISSN
- 0031-9155
- eISSN
- 1361-6560
- Number of pages
- 10
- Language
- English
- Date published
- 10/21/2014
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Radiation Oncology
- Record Identifier
- 9984047778602771
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