Nano-CT could cut radiation, time, toxicity in histological exams

German researchers have developed a streamlined approach to histological examination using nano-scale computed tomography, according to a report published in the current issue of PNAS.

Since unveiling his team’s Nano-CT system in November 2017, Franz Pfeiffer, PhD, and colleagues at the Technical University of Munich (TUM) have worked to create a staining method that would allow clinicians to use the 100-nanometer resolution system in their histology work. The aim, Pfeiffer and co-authors wrote in PNAS, was to expedite workflow and avoid time-consuming manual exams.

CT hasn’t always been an option in the field of histological analysis. Since the stains needed to render tissue sections readable in the first place can be highly toxic and since conventional CT scanners are too low-res for accurate results, researchers have shied away from computed tomography as an option for histological work and tissue sectioning.

That isn’t the case anymore, though, Pfeiffer et al. said. Using a cross-disciplinary research team from physics, medicine and chemistry departments, the researchers were able to develop a staining method suitable for use in Pfeiffer’s Nano-CT.

Eosin, a specialized dye used routinely in tissue sampling, has long been considered unsafe for use in CT operations, the authors explained. But rather than cutting the chemical completely from the process, they developed a “special pre-treatment” that would allow for eosin use anyways.

“Another important benefit is that there are no problems using established methods to examine the tissue sample following the scan,” co-author Madleen Busse said in a TUM release.

The researchers successfully tested the Nano-CT process in mouse kidneys and were able to generate 3D images that matched the information granularity of tissue sections from the rodent. Next, they said, will be human samples, but for now their novel approach to histology will be constrained to supplementing conventional methods of tissue sampling.

“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,” Pfeiffer said.