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Proceedings Paper

Radiation damage to chromosomes in the scanning transmission x-ray microscope
Author(s): Shawn P. Williams; Chris J. Jacobsen; Janos Kirz; Xiaodong Zhang; Jack Van't Hof; Susan Lamm
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Paper Abstract

Imaging with soft x rays having energies between the carbon and oxygen K edge (284 - 531 eV) yields large absorption contrast for wet organic specimens, but these soft x rays are known to be very effective in damaging biological specimens. The commonly used criterion of mass loss was employed for assessing radiation damage in the scanning transmission x-ray microscope. Multiple images of freeze-dried V. faba chromosomes show no significant mass loss after 150 Mrad. Experiments performed on fixed hydrated chromosomes revealed them to be radiation sensitive. The greater total mass loss observed in multiple low dose images compared to that incurred during a single high dose image suggests that the effects of radiation damage occur slower than the acquisition time for neighboring pixels. The radiation sensitivity of chromosomes depends critically on the fixative used, with damage minimized in glutaraldehyde fixed samples. Radiation damage to chromosomes is independent of ionic strength above 65 mM, but increases for ionic strengths below 65 mM. Using free radical scavengers in the buffer, and changing the design of the sample cell reduced the amount of damage incurred as a function of dose.

Paper Details

Date Published: 13 January 1993
PDF: 7 pages
Proc. SPIE 1741, Soft X-Ray Microscopy, (13 January 1993); doi: 10.1117/12.138747
Show Author Affiliations
Shawn P. Williams, SUNY/Stony Brook (United States)
Chris J. Jacobsen, SUNY/Stony Brook (United States)
Janos Kirz, SUNY/Stony Brook (United States)
Xiaodong Zhang, SUNY/Stony Brook (United States)
Jack Van't Hof, Brookhaven National Lab. (United States)
Susan Lamm, Brookhaven National Lab. (United States)


Published in SPIE Proceedings Vol. 1741:
Soft X-Ray Microscopy
Chris J. Jacobsen; James E. Trebes, Editor(s)

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