The tested digital microscope attempts at substituting a regular optical microscope, while providing also basic digital imaging facilities.
In our tests, the digital microscope behaviour has been very close to the one of a traditional microscope. Start-up time was of course higher than time needed to start a basic optical microscope, but not far from time needed to start a research microscope with robotized movements. Slightly more disturbing is the need for stage calibration at every start-up, but this can be avoided by leaving the system in standby mode.
Most common operations (focusing, stage movements, objective changes) were very similar in activation modality and execution time to the same operations carried out on a traditional microscope. According to pathologists, quality of images as seen on video is good at magnifications greater than 10x, and video refresh is sufficiently quick to see any change in focus and in captured field in real time. However, no quantification has been made to objectively evaluate these subjective assessments.
So, for the sake of pure microscopic examination, the present digital microscope can be considered a good substitute for a traditional microscope.
However, some concern exists regarding all digital imaging applied to microscopes, and compared, the ergonomics of the traditional microscope has two advantages:
• the view field is wider, due to the circular shape that cannot be digitally reproduced with an equivalent area; this may translate in more time needed for examination, like already shown for digital slides ;
• the binocular vision helps in focusing attention on the slide, by making the external world invisible during examination.
While the former concern cannot be really overcome, regarding the latter it is probably matter of habits and attitudes, that will change when the “videogame generation”, more used to computer screens, will be in charge of microscope examinations .
On the other side, the system seemed easy to use, and only a short training period, during which part of discussion time was spent in understanding the device functioning, has been needed before reaching a good knowledge of the tool.
However, for the pathologist that only needs to look at slides alone, with only occasional need for digital images, there is no strict recommendation of leaving a traditional microscope for a digital one like this, because traditional functions are performed more or less in the same way.
The pathologist with need for collaboratively discussing cases (head of Institute, or teacher that routinely shows slides to residents) instead has different needs that can be easily fulfilled with the examined digital microscope. Current approaches to collaborative vision include the multi-headed microscope, which presents two or more eyepieces, or a video camera able to show images on a television-style monitor on the side of the microscope. The former represents the traditional way of teaching, but –except for the double eyepiece version- it is very cumbersome. The latter provides slightly sub-standard images, because resolution is often 600 lines according to television standards.
The digital functions provided by the microscope are to be compared with a traditional microscope enriched by a microscope photo camera. In this comparison, any digital microscope including the studied shows some clear advantages, including:
• integrated environment: no need for an external computer to be activated every time a picture is needed;
• easier focusing: not always aftermarket microscope cameras are installed in a perfect parafocality, so the sample cannot be focused directly at the eyepiece. Microscope cameras almost always allow for real time viewing on a computer or on an external monitor at a resolution much lower than the final one, thus making difficult to focus at the maximum level of detail.
The only microscope feature that was not functioning appropriately, at least in our device, was polarized light. It is an infrequently needed feature that however, when needed, cannot at present be reliably obtained with this microscope.
Whenever a pathologist needs to routinely acquire digital images, a digital microscope may become an efficient way of accomplish the task, in particular when coupled to an institutional server to store images.
Finally, we also preliminarily evaluated the digital microscope behaviour as a remote discussion tool. For this, the system was coupled with a videoconferencing system chosen by the microscope manufacturer and thus well integrated with it. To allow transmission through videoconferencing, image resolution has been reduced to 1024x768 pixels.
However, no specific problems have been recognised regarding image quality. Also ease of use of the combined microscope plus videoconference system has not been an obstacle to communications, so that after the first discussion sessions there has not been necessary to provide technical support.
As with other telepathology techniques , remote observation of cytologic specimens is more difficult due to the need of screening the whole slide (and thus with much interaction between two sites), while histologic and intraoperatory specimens may be observed first at very low magnification, and then only few interesting parts should be explored at high magnification.
The test was carried out in the framework of an international project between Italy and Slovenija, funded by Interreg Interreg initiative of the European Regional Development Fund. This allowed to experiment with a heterogeneous access to the Internet, that always but in one occasion behaved consistently. It should however be noted that implementing the system inside a protected hospital network may be not so easy due to the presence of firewalls and closed ports . A close collaboration is needed with hospital ICT services to adequately configure the network.
Finally, occasional collaboration can be also done with remote users of videoconference systems, because the enclosed system is compliant with H.263 standard. Such systems could even be realised only by software, although the ones we tested were not able to negotiate the maximum resolution provided by the source videoconference system.