Photomicrography and Digital Pathology by Smartphone: A Short ReviewPhotomicrography and Digital Pathology by Smartphone: A Short Review

The teaching, learning and practice of pathology depends on good understanding of microscopic morphology. Demonstrating microscopic features and understanding those by conventional method is often frustrating. Practicing pathologists also need affordable hardware and software to capture, share, preserve and print histopathology images. Camera attachment, multi head microscope, digital microscope and virtual microscopy are available but these are expensive, take table space, and only few institutes/ pathologists with limited resources can afford to invest in these.  

Rise of digital cameras have generated a shift toward digital-image capturing methods, including mounted digital cameras and whole slide digital-slide scanning. Digital image capture techniques – whole slide imaging (WSI) have introduced new applications for slide sharing and second-opinion consultations of unusual or difficult cases in pathology. This has created a new branch: digital pathology. Digital pathology is an image-based information environment which is enabled by computer technology that allows for the management of information generated from a digital slide. Digital pathology is enabled in part by virtual microscopy, which is the practice of converting glass slides into digital slides that can be viewed, managed, and analysed on a computer monitor. With the advent of Whole-Slide Imaging, the field of digital pathology has exploded and is currently regarded as one of the most promising avenues of diagnostic medicine in order to achieve even better, faster and cheaper diagnosis, prognosis and prediction of cancer and other important diseases. Updates on digital pathology can be found on Digital Pathology Association website.

With their recent surge in popularity, smart phone cameras have become a widespread cost-effective method for pathology image acquisition. In addition, software/apps/technologies useful for image and video management are freely available from Google app store. Therefore, we thought of exploring the possibility of smartphones and its technologies as an affordable way to get introduced to basic functions/ applications of digital pathology.

Photomicrography by Smartphone

Manual method: While taking photomicrographs by smartphone camera, we need to hold the mobile with steady hands, a little away from the eyepiece, align, focus and click. This technique is described by Annie Morrison et al. This is quite tricky and to start with, requires practice, patience and time.

DIY (do it yourself) devices: A simple and easy solution to keep appropriate distance between eyepiece lens and mobile camera is the adaptor. Adaptor makes focusing easier and helps to steady hands. Though many have used paper roll as DIY device, a better option is PET/plastic bottle. We can simply cut the bottom of a suitable plastic bottle which fits the eyepiece and use it as an adaptor. However, adaptor is only half the solution- we still have to hold the mobile and cannot move slide or alter focus. With further innovation, we can make hands free display system easily. I have shared this innovation on PathoIndia website which was well appreciated and was published as power point article in May 2015.

Commercially available attachments: Few attachments are available for holding smartphones and attaching them to microscopes. These are mostly designed for specific models of microscopes or smartphones. Some models can be used even for telescopes or binoculars. Use of these attachments is discussed by Roy et al in their article in Journal of Pathology Informatics. Recently I have also developed and patented an attachment which can be used on any microscope for any smartphone or tablet.

Uses

Contemporary smartphones have many applications which are already built in: camera – to shoot microscopic images and videos, file manager for renaming images in files/ folders at specific location; Bluetooth for transfer of data without wire and internet. Images can be stored on Google cloud drop box. Screen cast/mirror can be used for viewing images on bigger screens with or without wire. Many free downloadable apps are available for image and video editing and sharing. Video calls can be used for live telepathology. We can record these sessions by screen recorder application. Panorama function can be used for covering larger areas of each section. All these functions can be used in teaching of histomorphology to students. Similarly, images and videos can be shared on social media for fast and easy discussion amongst pathologists.

Advantages of Smartphone Photomicrography Using Attachments:

Quality of images: This depends on the smartphone camera and megapixels. Basic models of top brand devices have good quality camera; images with 5 megapixels camera are fine.  For other devices generally 8-megapixel images are satisfactory.13+ megapixel cameras will give excellent images. For viewing images, display resolution is important. Tablets are more comfortable for viewing images as they have larger screens. Quality of microscope optics improves with quality eyepiece (especially wide field eyepieces) and objective lenses that provide better images. In addition, LED light source gives sharper images without colour abrasion.

Limitations

In spite of the advantages of smartphone photomicrography in teaching and practice of pathology, its limitations in histopathology practice must be understood.  Limited number of images/subjective limited data submitted cannot be compared to whole slide images obtained by high end state-of-the-art slide scanners especially when seeking opinion on difficult cases.

Further Scope

This innovation has unlimited scope for further research and development. Engineers can develop robotic arm/stage which can be manipulated remotely. We can interact with information technology professionals to develop user friendly apps for teaching purposes, for practicing pathologists and for telepathology use in primary healthcare facilities. I should mention that a mobile application for rapid diagnostic surgical pathology consultation has been described by Hartman et al.

Summary

Smartphones and related technologies are quite useful as affordable and simple tools for practicing pathologists and pathology teachers (with limited resources) to a great extent. However, its limitations should be understood. It can serve as small step to get experience of digital pathology. This sub-branch of digital pathology has further scope for research and development.
References available on request.