Hello,
 I use a line scanning laser confocal microscope (biorad) to look at bone
(specifically cracks in bones). I have been looking at cuboidal specimens
of bovine and human bone and getting excellent pictures. I am now trying
to look at fish bone. This is a lot more difficult as the cod's head
bones that I am using are very awkward shapes, some are very thin and
flat and concave/convex and some like squashed cylinders. I can polish
parts of it so they are flat(ish) but loose information about the outer
layer of bone if I do this.
The problem that has arisen is that I get vertical bright lines running
across any bright areas of my image. These lines are wavy, are only seen
at a depth just below (say 20 microns) the surface, and have very blured
edges. They are nothing like lines I have seen previously which are
caused by dust on the apeture. And I see them using an air, water and an
oil objective. They look annoyingly similar to the broken fibres in the fish
bone which is what I want to look at but are less distinct. The reason I
think they are not fibres is that if
I rotate my specimen on the stage the lines remain vertical whatever
angle the specimen is at.
What I was wondering is whether anyone else has had a similar problem to
this or if anyone who knows more about light diffraction patterns than I
do can think of an explanation for what I see. The fish bone has a very
irregular surface made of thin longitudinal fibres which seem to be
arranged in cylinders. I think it must be an effect of the interaction of
the light with the structure but am not sure what.
I'll be gratefaull if anyone can help.
Gwen Reilly,
York University biology dept.