Fundamental Processes in Radiation Damage to DNA: How Low-Energy Electrons Damage Biomolecules

Illustration showing that secondary electrons have a higher damage probability for thiolated DNA as opposed to unthiolated DNA, due to the former's higher density of LUMO states, which leads to more efficient capture of the low energy electrons.

Download Full-text

Nanocrystal ghosting: Extensive radiation damage in MgO induced by low-energy electrons

Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms ◽

10.1016/j.nimb.2017.01.029 ◽

2017 ◽

Vol 395 ◽

pp. 52-56

Author(s):

Zackery Frankenfield ◽

Kenneth Kane ◽

William H. Sawyer

Keyword(s):

Radiation Damage ◽

Low Energy ◽

Low Energy Electrons

Download Full-text

Transfer optics for high spatial resolution electron spectroscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105394 ◽

1988 ◽

Vol 46 ◽

pp. 666-667

Author(s):

G. G. Hembree ◽

Luo Chuan Hong ◽

P.A. Bennett ◽

J.A. Venables

Keyword(s):

Magnetic Field ◽

Scanning Transmission Electron Microscope ◽

Low Energy ◽

Objective Lens ◽

State University ◽

Arizona State University ◽

Initial Field ◽

Resolution Electron ◽

Scanning Transmission ◽

Low Energy Electrons

A new field emission scanning transmission electron microscope has been constructed for the NSF HREM facility at Arizona State University. The microscope is to be used for studies of surfaces, and incorporates several surface-related features, including provision for analysis of secondary and Auger electrons; these electrons are collected through the objective lens from either side of the sample, using the parallelizing action of the magnetic field. This collimates all the low energy electrons, which spiral in the high magnetic field. Given an initial field Bi∼1T, and a final (parallelizing) field Bf∼0.01T, all electrons emerge into a cone of semi-angle θf≤6°. The main practical problem in the way of using this well collimated beam of low energy (0-2keV) electrons is that it is travelling along the path of the (100keV) probing electron beam. To collect and analyze them, they must be deflected off the beam path with minimal effect on the probe position.

Download Full-text

Preincubation with Sn-complexes causes intensive intracellular retention of 99mTc in thyroid cells in vitro

Nuklearmedizin ◽

10.3413/nukmed-0450-11-12 ◽

2012 ◽

Vol 51 (05) ◽

pp. 179-185 ◽

Cited By ~ 3

Author(s):

M. Wendisch ◽

D. Aurich ◽

R. Runge ◽

R. Freudenberg ◽

J. Kotzerke ◽

...

Keyword(s):

Cell Model ◽

Low Energy ◽

Thyroid Cells ◽

Low Energy Electrons ◽

A Cell ◽

Vitro Model ◽

Uptake Studies ◽

Radiobiological Effects ◽

Radioactivity Retention

SummaryTechnetium radiopharmaceuticals are well established in nuclear medicine. Besides its well-known gamma radiation, 99mTc emits an average of five Auger and internal conversion electrons per decay. The biological toxicity of these low-energy, high-LET (linear energy transfer) emissions is a controversial subject. One aim of this study was to estimate in a cell model how much 99mTc can be present in exposed cells and which radiobiological effects could be estimated in 99mTc-overloaded cells. Methods: Sodium iodine symporter (NIS)- positive thyroid cells were used. 99mTc-uptake studies were performed after preincubation with a non-radioactive (cold) stannous pyro - phosphate kit solution or as a standard 99mTc pyrophosphate kit preparation or with pure pertechnetate solution. Survival curves were analyzed from colony-forming assays. Results: Preincubation with stannous complexes causes irreversible intracellular radioactivity retention of 99mTc and is followed by further pertechnetate influx to an unexpectedly high 99mTc level. The uptake of 99mTc pertechnetate in NIS-positive cells can be modified using stannous pyrophosphate from 3–5% to >80%. The maximum possible cellular uptake of 99mTc was 90 Bq/cell. Compared with nearly pure extracellular irradiation from routine 99mTc complexes, cell survival was reduced by 3–4 orders of magnitude after preincubation with stannous pyrophosphate. Conclusions: Intra cellular 99mTc retention is related to reduced survival, which is most likely mediated by the emission of low-energy electrons. Our findings show that the described experiments constitute a simple and useful in vitro model for radiobiological investigations in a cell model.

Download Full-text