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Dose equivalent near the bone-soft tissue interface from nuclear fragments produced by high-energy protonsDuring manned space missions, high-energy nucleons of cosmic and solar origin collide with atomic nuclei of the human body and produce a broad linear energy transfer spectrum of secondary particles, called target fragments. These nuclear fragments are often more biologically harmful than the direct ionization of the incident nucleon. That these secondary particles increase tissue absorbed dose in regions adjacent to the bone-soft tissue interface was demonstrated in a previous publication. To assess radiological risks to tissue near the bone-soft tissue interface, a computer transport model for nuclear fragments produced by high energy nucleons was used in this study to calculate integral linear energy transfer spectra and dose equivalents resulting from nuclear collisions of 1-GeV protons transversing bone and red bone marrow. In terms of dose equivalent averaged over trabecular bone marrow, target fragments emitted from interactions in both tissues are predicted to be at least as important as the direct ionization of the primary protons-twice as important, if recently recommended radiation weighting factors and "worst-case" geometry are used. The use of conventional dosimetry (absorbed dose weighted by aa linear energy transfer-dependent quality factor) as an appropriate framework for predicting risk from low fluences of high-linear energy transfer target fragments is discussed.
Document ID
20040173246
Document Type
Reprint (Version printed in journal)
Authors
Shavers, M. R.
(College Station TX 77843-3133, United States)
Poston, J. W.
Cucinotta, F. A.
Wilson, J. W.
Date Acquired
August 22, 2013
Publication Date
April 1, 1996
Publication Information
Publication: Health physics
Volume: 70
Issue: 4
ISSN: 0017-9078
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Number 45-10
NASA Discipline Radiation Health
NASA Program Radiation Health

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