Researchers at the Technical University of Munich have developed a nano-CT scanning technique. When coupled with a new staining technique, their nano-CT scanner can take extremely high-resolution scans of intact tissue samples, such as tumors. The new method allows clinicians to examine soft tissue samples without the need for sectioning or toxic stains.
At present, examining soft tissue samples frequently involves sectioning them and mounting them on slides. This is time-consuming and laborious and makes it difficult to envisage the intact structure of the tissue. Imaging intact pieces of tissue to generate a 3D reconstruction could save time and help clinicians to analyze such samples.
One option is CT scanning, but current micro- or nano-CT scanners frequently lack the resolution to effectively scan soft tissue samples for clinical applications. In addition, soft tissue is particularly difficult to image using CT, requiring toxic stains which are often time-consuming to apply, and can significantly affect the tissue, making it impossible to analyze it further.
The Munich research team has previously developed a high-resolution nano-CT scanner that can achieve resolutions of 100 nanometers, by using a newly developed x-ray source and a highly focused x-ray beam. Recently, the researchers developed a staining system that allows their nano-CT scanner to effectively scan tissue samples for histological investigations.
By pretreating the tissue samples, the researchers were able to use eosin, a standard histological stain, and achieve high-resolution tissue scans. “Our approach included developing a special pre-treatment so that we can use eosin anyway,” said Madleen Busse, a researcher involved in the study. “Another important benefit is that there are no problems using established methods to examine the tissue sample following the scan.”
The research team was able to scan large tissue segments, such as an intact mouse kidney, and the scans included similar levels of information as tissue sections. However, at present, the team envisages that this type of CT histology will be useful as a supplementary technique, rather than replacing conventional methods. “Alongside diagnostic applications, the non-destructive 3D examination enabled by Nano-CT could deliver new insights into the microscopic origins of widespread diseases such as cancer,” said Franz Pfeiffer, another researcher involved in the study.
Here’s a video demonstrating the imaging resolution achieved using the new nano-CT technique: