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Microbeam studies of the sensitivity of structures within living cellsDetermining the biological effects of low doses of radiation with high linear energy transfer (LET) is complicated by the stochastic nature of charged-particle interactions. Populations of cells exposed to very low radiation doses contain a few cells which have been hit by a charged particle, while the majority of the cells receive no radiation damage. At somewhat higher doses, a few cells receive two or more events. Because the effects of damage produced by separate events can interact in the cell, we have had to make assumptions about the nature of these interactions in order to interpret the results of the experiments. Many of those assumptions can be tested if we can be sure of the number of charged-particle events which occur in individual cells, and correlate this number with the biological effect. We have developed a special irradiation facility at Pacific Northwest Laboratory (PNL) to control the actual number of charged particle tracks that pass through cell nuclei. The beam from a 2 MeV tandem accelerator is collimated to approximately 5 microns. Cells, grown in special dishes with 1.5 microns thick plastic bottoms, are positioned so that the desired portion of the cell aligns with the collimator. A shutter in the beam line is opened and closed after the desired number of particle tracks has been counted. This approach can be used to investigate the effects of the interaction between irradiated and unirradiated cells in an organized system, as well as to study the effects of spatial and temporal distribution of radiation damage within single cells.(ABSTRACT TRUNCATED AT 250 WORDS).
Document ID
20050000748
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Braby, L. A.
(Pacific Northwest Laboratory Richland, WA 99352)
Date Acquired
August 22, 2013
Publication Date
March 1, 1992
Publication Information
Publication: Scanning microscopy
Volume: 6
Issue: 1
ISSN: 0891-7035
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
Non-NASA Center
Review, Tutorial
NASA Discipline Radiation Health
Review

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