Microscope reveals changes over time

A three-dimensional microscope that works in a new way is giving unprecedented insight into the internal structure and chemical composition of materials. It can also accurately reveal how they are affected, over time, by changes in temperature, humidity, weight load and other conditions.

The device, developed by a team drawn from six UK universities, could lead to advances in various areas such as healthcare (in furthering, for instance, the understanding of conditions such as osteoporosis), the development of better construction materials, improved oil extraction methods and even the study of fossils.

Similar to some other microscopes, the new instrument harnesses x-rays to provide information about an object's internal structure down to micron scale. What makes it unique is its use of time delivery integration that enables it to generate much better images of larger objects than other devices. This means that microscopic structure can be studied with greater accuracy.

Conventional x-ray microscopes can produce 3D internal pictures of an object by taking a large number of 2D images from different angles - this is known as x-ray microtomography. But the way in which the new microscope combines this technique with time delay integration is new.

It compensates for variations in the sensitivity of the pixels that make up the picture captured by the x-ray sensor that reduce the clarity of the final computer-generated 3D image. With the time delay integration technique the camera incorporating the sensor is moved through the x-ray shadow while collecting the x-ray image.

At the same time, the image being created on the surface of the sensor is electronically shifted in the opposite direction. In this way, any imperfections are 'smoother' by averaging them over all pixels before the 3D image is generated. The final image is thus of much higher quality and enables bigger pictures to be produced than was previously possible. The use of time delay integration also allows larger objects to be examined without loss of image quality. The new microscope is claimed to be the only one in the world that uses time delay integration for microtomography.

Some of the many potential uses for the microscope, developed with funding from the UK's Engineering & Physical Scientists Research Council (EPSRC), include:

• Studying how bone and tooth tissue behave in conditions such as osteoporosis, osteoarthritis and tooth decay.
• Observing how crude oil is held in sandstone pores.
• Investigating the mechanical behaviour of metals at a microscopic level.
• Detailed study of fossils embedded in rocks without having to remove and risk damaging them.

Professor Jim Elliot of Queen Mary, University of London led the project. He said: "As well as developing these microscopes to study subtle variations in internal structure, a main aim of ours is to work with the wider scientific community to identify problems where they could make a real contribution. There's no limit to what it would be useful or interesting to look at:. The microscope looks set to be a valuable research tool that many different organisations in a range of sectors could benefit from using. The team now aims to develop a radical new design that could be even more effective.

The three-and-a-half-year research project involved experts in electronic engineering, physics, biophysics, chemistry, anatomy, materials science, dentistry, veterinary medicine and engineering from Cranfield, Manchester and Southampton universities, Imperial College London and the Royal Veterinary College as well as Queen Mary.