Charged Particle Equilibrium of Small Field in Clinical Proton Beams
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- OHTANI HIROKI
- Tokyo Metropolitan University, Faculty of Health Sciences, School of Radiologic Science
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Description
It is expected that proton beam radiotherapy will become an effective treatment for tumors. For an organ for which a correct dose prescription is required, a proton beam has the ability to provide the dose most suitable for the specific purpose. We measured the charged particle equilibrium factor of proton beams in water using a plane parallel ionization chamber. The maximum energy of the proton beam used in this study was 70 MeV, produced from an isochronous cyclotron. We assume that the charged particle equilibrium factor can be separated into longitudinal and lateral components, that is, the factor E(Z, R)is dependent on depth, Z, and field radius, R; such that E(Z, R)=E(Z)E(R). The E(Z)-factor of primary protons was considered in order to investigate the influence of secondary charged particles. From the results, the charged particle equilibrium factor for the longitudinal component does not remain sharp with the decrease of water depth, and the lateral component is not maintained with the decrease of field size. However, the longitudinal components of primary protons at shallow depth were in equilibrium.
Journal
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- Japanese Journal of Radiological Technology
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Japanese Journal of Radiological Technology 61 (12), 1645-1650, 2005
Japanese Society of Radiological Technology
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Details 詳細情報について
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- CRID
- 1390282681366976896
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- NII Article ID
- 110004756034
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- NII Book ID
- AN00197784
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- ISSN
- 18814883
- 03694305
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- NDL BIB ID
- 7777934
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- Text Lang
- en
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- Data Source
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- JaLC
- NDL
- Crossref
- CiNii Articles
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- Abstract License Flag
- Disallowed