Microscopic observation of biological specimen smears is the mainstay of diagnostic pathology, as defined by the Digital Pathology Association. Though automated systems for this are commercially available, their bulky size and high cost renders them unusable for remote areas. The research community is investing much effort towards building equivalent but portable, low-cost systems. An overview of such research is presented here, including a comparative analysis of recent reports. This paper also reviews recently reported systems for automated staining and smear formation, including microfluidic devices; and optical and computational automated microscopy systems including smartphone-based devices. Image pre-processing and analysis methods for automated diagnosis are also briefly discussed. It concludes with a set of foreseeable research directions that could lead to affordable, integrated and accurate whole slide imaging systems.
Diagnosis of some diseases such as cervical cancer is done using a microscope, and this process still relies heavily on human experts. Since the need for such diagnosis is increasing at a rapid pace, it makes a lot of sense to automate the whole process. This requires automatic microscopes, which should be able to take images of a ‘slide’ - a glass slab with colorized human cells at its surface. These images should get analyzed by a software, resulting in a fully automated diagnosis. This article reviews recent research into this field, especially the technical advances on the hardware for automated microscopes (also known as slide imagers). It compares research reports and highlights how there's still more effort needed to build low-cost, yet clinically useful systems. It also highlights some of the emerging technologies that can be integrated into slide imagers to enable new kinds of diagnostics.
Keywords: clinical applications; medical optics instrumentation; microscopy; systems.
© 2021 Royal Microscopical Society.