| |
Why This Project:
The aim
of this project is to determine the effects of low radiation
doses using a machine that makes it possible to radiate one
cell at a time. Our soft X-ray microprobe can irradiate individual
cells, or locations within cells with defined doses and with
sub-micron precision. We can use low doses approaching that
of a single electron track, which is of relevance to environmental
level exposures. Much of our work is concentrating on irradiating
specified individual cells within cell populations to identify
"bystander responses" where non-radiated cells respond
to signals from nearby radiated cells. Higher energy x-rays
are being generated to extend the studies beyond experiments
involving single cell layers. These higher x-rays have properties
more like those encountered in the environment.
Project
Goals:
- Continue
to evaluate the influence of alpha particles on individual
"hit" cells and on their neighbors Expand the capability
of the X-ray microprobe such that several higher X-ray energies
are available
- X-rays
with higher energy and increased penetration will be used,
which will make it possible to irradiate multi-cellular layers
and tissue samples.
Experimental Approach:
Our microprobe
currently produces X-rays by bombarding a carbon target with
energetic electrons. This generates so-called 'characteristic
X-rays' whose energy depends on the target material. The X-rays
are then focused to a very fine spot (smaller than an individual
cell) using a 'zone-plate', which is a small lens (less than
1mm diameter) of a type developed initially for X-ray microscopy.
To increase the energy is simply a matter of choosing other
target materials, for example, by using aluminium or titanium
instead of carbon. However, using different targets changes
both the power needed to produce higher energy X-rays, and increases
the focal length of the X-ray lenses. Therefore, swapping between
targets is not possible with the source in its current form.
In this proposal, a new source will be developed that can accommodate
a range of targets, greatly increasing the energy of the x-rays
and the versatility of the facility.
Expected Outcomes:
- A new
source that can accommodate a range of targets
- Increased
energy of the x-rays and versatility of the facility
- Use
of x-rays to study cells that are environmentally relevant
in a more normal tissue or organ environment
|
|
|
