Researchers in Lund have developed a new mathematical method that makes it possible to produce even more detailed X-ray images. In a study of brain tissue, image resolution improved by around threefold. Extremely fine structures, such as synapses and mitochondria in brain cells, became visible.
In an international collaboration, researchers have developed a method that produces significantly higher-quality three-dimensional X-ray images than previously possible. The technique is used for 3D imaging with so-called X-ray nanotomography. The researchers' approach draws on expertise in mathematics and computational science.
"Our work shows that the limitation has not only been in the X-ray optics, but also in the mathematics used to reconstruct the image," says Marcus Carlsson, a mathematics researcher at Lund University.
The new method can distinguish extremely small structures down to 20 nanometres in size. By comparison, a human hair is between 80,000 and 100,000 nanometres thick.
The high image resolution makes it possible to study individual details in the body at the cellular level. In the current study, image resolution improved by around threefold using the new method. Very fine structures, such as synapses, mitochondria and other subcellular structures, became visible in three dimensions.
Marcus Carlsson played a leading role in the mathematical and algorithmic aspects of the research. He developed the optimisation approach underlying the refined imaging method.
When imaging structures at the nanoscale, researchers normally use a completely different technique from X-rays, namely electron microscopy. The drawback is that material to be examined using this technique must be cut into very thin slices for three-dimensional imaging. Electron microscopy provides extremely high levels of detail, but it also causes permanent damage to the material.
Large amounts of data
Using X-ray technology instead makes it possible both to examine much larger samples at the nanoscale and to image them in three dimensions without first having to cut them apart. A key challenge, however, is extracting all the information contained in the enormous amounts of data generated by these examinations, Marcus Carlsson points out. This is where mathematics and computational science can help.
"With better mathematical models and optimisation algorithms, we can extract significantly more information from the same type of measurement data. The new method opens up possibilities both in biological imaging and in other fields where researchers want to study materials three-dimensionally and non-destructively," says Marcus Carlsson.
