Scanning electron microscopy as a new tool for diagnostics in pathology

Pathologists generally examine micrometer-thin tissue slices by means of brightfield light microscopy (LM) and transmission electron microscopy (TEM) [1] in order to identify cellular changes and diagnose disease. Scanning electron microscopy (SEM) is generally believed to be non-contributory to ultrastructural studies of disease as early SEM studies were mainly used to image sample topography [2] rather than the cell interior. In this paper, we present an alternative to TEM with the new generation high-resolution SEMs (HRSEM) that not only have equivalent performance but exhibit new capabilities and applications that can be usefully employed for diagnostic pathology and cell biology. HRSEM has important and crucial advantages over TEM. It is not limited by sample thickness (~ 100 nm thick) or by beam damage to delicate structures, such as cytoskeletal filaments. HRSEM allows manual and automated re-imaging as many times as needed with different electron signals. Additionally, the cost of HRSEM, its operation and its maintenance are considerably lower than for TEM. Current high-end HRSEMs have automated scan generation systems such as the new integrated system ATLAS 5 from Carl Zeiss, Germany [3] and Maps from ThermoFisher, USA [4]. Lastly, it is now possible to view both cell internal structure in STEM mode and external macromolecular structures in two and three dimensions, thereby enhancing depth information lacking in conventional microscopic studies

Scanning electron microscopy as a new tool for diagnostic pathology and cell biology

Scanning electron microscopy (SEM) use in the biomedical sciences has traditionally been used for characterisation of cell and tissue surface topography. This paper demonstrates the utility of high-resolution scanning electron microscopy (HRSEM) to diagnostic pathology and cell biology ultrastructural examinations. New SEM applications based on the production of transmission electron microscopy-like (TEM-like) images are now possible with the recent introduction of new technologies such as low kV scanning transmission electron microscopy (STEM) detectors, automated scan generators and high-resolution column configurations capable of sub-nanometre resolution. Typical specimen types traditionally imaged by TEM have been examined including renal, lung, prostate and brain tissues. The specimen preparation workflow was unchanged from that routinely used to prepare TEM tissue, apart from replacing copper grids for section mounting with a silicon substrate. These instruments feature a small footprint with little in the way of ancillary equipment, such as water chillers, and are more cost-effective than traditional TEM columns. Also, a new generation of benchtop SEMs have recently become available and have also been assessed for its utility in the tissue pathology and cell biology settings